How can wild strains of microorganisms be improved?

by mutagenesis or recombinant DNA technology

What can increase the rate of mutations?

exposure to UV light and other forms of radiation or mutagenic chemicals

putting it in sterile conditions

growing it with other microorganisms

What can be used as vectors for recombinant DNA technology?

recombinant plasmids and artificial chromosomes

artificial chromosomes and carbohydrates

recombinant plasmids and carbohydrates

a method for transferring a DNA molecule/carry foreign genetic information into another cell

a method for transferring fatty acids into another cell

a method for transferring carbohydrates into another cell

When is it preferable to use artificial chromosomes rather than plasmids as vectors?

when larger fragments of foreign DNA are required to be inserted

when smaller fragments of foreign DNA are required to be inserted

when larger fragments of foreign fatty acids are required

What is the role of restriction endonucleases in recombinant DNA technology?

they cut open plasmids and to cut specific genes out of chromosomes leaving sticky ends

they cut open the nucleus and leave sticky ends

they cut open the cell and leave sticky ends

How are complementary stick ends produced?

when the same restriction endonuclease is used to cut open the plasmid and the gene from the chromosome

What is the enzyme ligase used for in recombinant DNA technology?

to seal the gene in the plasmid

to seal in the fatty acid in the plasmid

to remove the gene from the plasmid

What sites are on recombinant plasmids and artificial chromosomes?

restriction sites, regulatory sequences, an origin of replication and selectable markers

restriction sites, protein sequences, an origin of replication and selectable markers

restriction sites, regulatory sequences, an origin of protein and selectable markers

What does the restriction site contain?

target sequences of DNA where specific restriction endonucleases cut

site to control gene expression

What is the origin of replication?

allows self-replication of the plasmid/artificial chromosome

What are selectable markers?

genes present in the vector to ensure that only micro-organisms that take up the vector grow in the presence of the selective agent eg. antibiotic resistance genes

genes present in the nucleus to ensure that only micro-organisms that take up the vector grow in the presence of the selective agent eg. antibiotic resistance

genes present in the vector to ensure that all micro-organisms grow in the presence of the selective agent eg. antibiotic resistance genes

How can the prevention of recombinant microorganisms spreading in the environment occur?

genes are often introduced as a safety mechanisms to prevent the survival of microorganisms in an external environment

genes are often introduced as a safety mechanisms to prevent the survival of humans in an external environment

proteins are often introduced as a safety mechanisms to prevent the survival of microorganisms in an external environment

When would recombinant yeast cells be used?

to produce active forms of the protein which are inactive in bacteria

to produce inactive forms of the protein which are inactive in bacteria

to produce active forms of the carbohydrate which are inactive in bacteria

Higher 2.6 Biology

Cells of different organisms and even cells within the same organism are very diverse in terms of shape, size, and internal organization. One theme that occurs again and again throughout biology is that form follows function. In other words, a cell’s function influences its physical features. Cell Shape The diversity in cell shapes reflects the different functions of cells. Compare the cell shapes shown in Figure 4-4. The long extensions that reach out in various directions from the nerve cell shown in Figure 4-4a allow the cell to send and receive nerve impulses. The flat, platelike shape of skin cells in Figure 4-4b suits their function of covering and protecting the surface of the body. As shown below, a cell’s shape can be simple or complex depending on the function of the cell. Each cell has a shape that has evolved to allow the cell to perform its function effectively. SECTION 2 OBJECTIVES ● Explain the relationship between cell shape and cell function. ● Identify the factor that limits cell size. ● Describe the three basic parts of a cell. ● Compare prokaryotic cells and eukaryotic cells. ● Analyze the relationship among cells, tissues, organs, organ systems, and organisms. VOCABULARY plasma membrane cytoplasm cytosol nucleus prokaryote eukaryote organelle tissue organ organ system Cells have various shapes. (a) Nerve cells have long extensions. (b) Skin cells are flat and platelike. (c) Egg cells are spherical. (d) Some bacteria are rod shaped. (e) Some plant cells are rectangular. FIGURE 4-4 (a) Nerve cell (b) Skin cells (c) Egg cell (d) Bacterial cells (e) Plant cells Copyright © by Holt, Rinehart and Winston. All rights reserved. 1. All cubes have volume and surface area. The total surface area is equal to the sum of the areas of each of the six sides (area = length X width). 2. If you split the first cube into eight smaller cubes, you get 48 sides. The volume remains constant, but the total surface area doubles. 3. If you split each of the eight cubes into eight smaller cubes, you have 64 cubes that together contain the same volume as the first cube. The total surface area, however, has doubled again. CELL STRUCTURE AND FUNCTION 73 Cell Size Cells differ not only in their shape but also in their size. A few types of cells are large enough to be seen by the unaided human eye. For example, the nerve cells that extend from a giraffe’s spinal cord to its foot can be 2 m (about 6 1/2 ft) long. A human egg cell is about the size of the period at the end of this sentence. Most cells, how- ever, are only 10 to 50 μm in diameter, or about 1/500 the size of the period at the end of this sentence. The size of a cell is limited by the relationship of the cell’s outer surface area to its volume, or its surface area–to-volume ratio. As a cell grows, its volume increases much faster than its surface area does, as shown in Figure 4-5. This trend is important because the materials needed by a cell (such as nutrients and oxygen) and the wastes produced by a cell (such as carbon dioxide) must pass into and out of the cell through its surface. If a cell were to become very large, the volume would increase much more than the surface area. Therefore, the surface area would not allow materials to enter or leave the cell quickly enough to meet the cell’s needs. As a result, most cells are microscopic in size. Comparing Surface Cells Materials microscope, prepared slides of plant (dicot) stem and ani- mal (human) skin, pencil, paper Procedure Examine slides by using medium magnification (100). Observe and draw the sur- face cells of the plant stem and the animal skin. Analysis How do the surface cells of each organism differ from the cells beneath the surface cells? What is the function of the surface cells? Explain how surface cells are suited to their function based on their shape. Quick Lab Small cells can exchange substances more readily than large cells because small objects have a higher surface area–to-volume ratio. FIGURE 4-5 mb06se_csfs02.qxd 5/18/07 10:54 AM Page 73 74 CHAPTER 4 BASIC PARTS OF A CELL Despite the diversity among cells, three basic features are common to all cell types. All cells have an outer boundary, an interior sub- stance, and a control region. Plasma Membrane The cell’s outer boundary, called the plasma membrane (or the cell membrane), covers a cell’s surface and acts as a barrier between the inside and the outside of a cell. All materials enter or exit through the plasma membrane. The surface of a plasma mem- brane is shown in Figure 4-6a. Cytoplasm The region of the cell that is within the plasma membrane and that includes the fluid, the cytoskeleton, and all of the organelles except the nucleus is called the cytoplasm. The part of the cytoplasm that includes molecules and small particles, such as ribosomes, but not membrane-bound organelles is the cytosol. About 20 percent of the cytosol is made up of protein. Control Center Cells carry coded information in the form of DNA for regulating their functions and reproducing themselves. The DNA in some types of cells floats freely inside the cell. Other cells have a mem- brane-bound organelle that contains a cell’s DNA. This membrane- bound structure is called the nucleus. Most of the functions of a eukaryotic cell are controlled by the cell’s nucleus. The nucleus is often the most prominent structure within a eukaryotic cell. It maintains its shape with the help of a protein skeleton called the nuclear matrix. The nucleus of a typical animal cell is shown in

Can you make a multiple choice of test questions regarding this information given which is Curriculum from Different Points of View There are many definitions of curriculum. Because of this, the concept of curriculum is sometimes characterized as fragmentary, elusive and confusing. However, the numerous definitions indicate dynamism that connotes diverse interpretations of what curriculum is all about. The definitions are influenced by models of thought, pedagogies, political as well as cultural experiences. Let us study some of these definitions. 1. Traditional Points of View of Curriculum In early years of the 20th century, the traditional concepts held of the “curriculum is that it is a body of subjects or subject matter prepaid by the teachers for the student’s to learn”. It was synonymous to the “course of study” and “syllabus” Robert M. Hutchins views curriculum as “permanent studies” where the rules of grammar, reading, rhetoric and logic and mathematics for basic education are emphasized. Basic education should emphasize the 3 Rs and college education should be grounded on liberal education. On the other, Arthur Bestor as an essentialist, believes that the mission of the school should be intellectual training, hence curriculum should focus on the fundamental intellectual disciplines of grammar, literature and writing. It should also include mathematics, science, history and foreign language. The definition leads us to the view of Joseph Schwab that discipline is the sole source of curriculum. Thus in our education system, curriculum is divided into chunks of knowledge we call subject areas in basic education such as English, Mathematics, Science, Social Studies and others. In college, discipline may include humanities, sciences, language and many more. To Phoenix, curriculum should consist entirely of knowledge which comes from various disciplines. Academic discipline became the view of what curriculum is after the cold war and the race to space. Joseph Schwab, a leading curriculum theorist coined the term discipline as a ruling doctrine for curriculum development. Curriculum should consist only of knowledge which comes from disciplines which is the sole source. Thus curriculum can be viewed as a field of study. It is made up of its foundations (philosophical, historical, psychological and social foundations); domains of knowledge as well as its research theories and principles. Curriculum is taken as scholarly and theoretical. It is concerned with broad historical, philosophical and social issues and academics. Most of the traditional ideas view curriculum as written documents or a plan of action in accomplishing goals. 2. Progressive Points of View of Curriculum On the other hand, to a progressivist, a listing of school subjects, syllabi, course of study, and a list of courses or specific discipline do not make a curriculum. These can only be called curriculum if the written materials are actualized by the learner. Broadly speaking, curriculum is defined as the total learning experiences of the individual. This definition is anchored on John Dewey’s definition of experience and education. He believed that reflective thinking is a means that unifies curricular elements. Thought is not derived from action but tested by application. Caswell and Campbell viewed curriculum as “all experiences children have under the guidance of teachers”. This definition is shared by Smith, Stanley and Shores when they defined “curriculum as a sequence of potential experiences set up in the schools for the purpose of disciplining children and youth in group ways of thinking and acting”. Marsh and Willis on the other hand view curriculum as all the “experiences in the classroom which are planned and enacted by the teacher, and also learned by the students”. Points of View on Curriculum Development From the various definitions and concepts presented, it is clear that curriculum is a dynamic process. Development connotes changes which are systematic. A change for the better means any alteration, modification or improvement of existing condition. To produce positive changes, development should be purposeful, planned and progressive. This is how curriculum evolves. Let us look at the two models of curriculum development and concepts of Ralph Tyler and Hilda Taba. Ralph Tyler Model: Four Basic Principles. This is also popularly known as Tyler’s Rationale. He posited four fundamental questions or principles in examining any curriculum in schools. These four fundamental principles are as follows: 1. What educational purposes should the school seek to attain? 2. What educational experiences can be provided that are likely to attain these purposes? 3. How can these educational experiences be effectively organized? 4. How can we determine whether these purposes are being attained or not? In summary, Tyler’s Model show that in curriculum development, the following considerations should be made: (1) Purpose of the school, (2) Educational experiences related to the purposes, (3) Organization of the experiences, and (4) Evaluation of the experiences. On the other hand, Hilda Taba improved on Tyler’s Rationale by making a linear model. She believed that teachers who teach or implement the curriculum should participate in developing it. Her advocacy was commonly called the grassroots approach. She presented seven major steps to her model where teachers could have a major input. These steps are as follows: 1. Diagnosis of learner’s needs and expectations of the larger society. 2. Formulation of learning objectives. 3. Selection of learning content. 4. Organization of learning content. 5. Selection of learning experiences. 6. Organization of learning activities. 7. Determination of what to evaluate and the means of doing it. Thus as you look into curriculum models, the three interacting processes in curriculum development are planning, implementing and evaluating. Types of Curriculum Operating in Schools From the various concepts given, Allan Glatthorn(2000) describes seven types of curriculum operating in the schools. These are (1) Recommended curriculum- proposed by scholars and professional organizations. (2) Written Curriculum- appears in school, district, division or country documents. (3) Taught Curriculum- what teacher’s implement or deliver in the classrooms and schools. (4) Supported Curriculum- resources-textbooks, computers, audio- visual materials which support and help in the implementation of the curriculum. (5) Assessed Curriculum- that which is tested and evaluated. (6) Learned Curriculum- which the students actually learn and what is measured and (7) Hidden Curriculum- the unintended curriculum. 1. Recommended Curriculum- Most of the school curricula are recommended. The curriculum may come from a national agency like the Department of Education, Commission on Higher Education (CHED), Department of Science and Technology (DOST) or any professional organization who has stake in education. For example the Philippine Association for Teacher Education (PAFTE) or the Biology Teacher Association (BIOTA) may recommend a curriculum to be implemented in the elementary or secondary education. 2. Written Curriculum- This includes documents, course of study or syllabi handed down to the schools, districts, division, departments or colleges for implementation. Most of the written curricula are made by curriculum experts with participation of teachers. These were pilot-tested or tried out in sample schools or population. Example of this is the Basic Education Curriculum (BEC). Another example is the written lesson plan of each classroom teacher made up of objectives and planned activities of the teacher. 3. Taught Curriculum- The different planned activities which are put into action in the classroom compose the taught curriculum. These are varied activities that are implemented in order to arrive at the objectives or purposes of the written curriculum. These are used by the learners with the guidance of teachers. Taught curriculum varies according to the learning styles of students and the teaching styles of teachers. 4. Supported Curriculum- In order to have a successful teaching, other than the teacher, there must be materials which should support or help in the implementation of a written curriculum. These refer to the support curriculum that includes material resources such as textbooks, computers, audio-visual materials, laboratory equipment, playgrounds, zoos and other facilities. Support curriculum should enable each learner to achieve real and lifelong learning. 5. Assessed Curriculum- This refers to a tested or evaluated curriculum. At the duration and end of the teaching episodes, series of evaluations are being done by the teachers to determine the extent of teaching or to tell if the students are progressing. This refers to the assessed curriculum. Assessment tools like pencil-and-paper tests, authentic instruments like portfolio are being utilized. 6. Learned Curriculum- This refers the learning outcomes achieved by the students. Learning outcomes are indicated by the results of the tests and changes in behavior which can either be cognitive, affective or psychomotor. 7. Hidden Curriculum- This is the unintended curriculum which is not deliberately planned but may modify behavior or influenced learning outcomes. There are lots of hidden curricula that transpire in the schools. Peer influence, school environment, physical condition, teacher-learner interaction, mood of the teachers and many other factors made up the hidden curriculum.

Lide 1: Introduction to Bioreactor A bioreactor is a vessel used for growing microorganisms, plant or animal cells Provides controlled conditions for biological reactions Maintains optimum pH, temperature, oxygen, and nutrients Widely used in fermentation, enzyme, vaccine, and antibiotic production Ensures sterile and aseptic environment Scale ranges from laboratory to industrial production Slide 2: Basic Design Requirements of a Bioreactor Must be constructed with non-toxic, corrosion-resistant materials Should allow effective mixing and mass transfer Provision for sterilization (in situ sterilization) Must maintain uniform temperature and pH Easy sampling without contamination Should support scalability and automation Slide 3: Materials Used in Bioreactor Construction Stainless steel (SS-316) for industrial bioreactors Glass for laboratory-scale bioreactors Plastic (polycarbonate) for disposable bioreactors Materials must withstand heat and pressure Should be smooth to prevent microbial attachment Resistant to chemicals and cleaning agents Slide 4: Main Parts of a Bioreactor Vessel: holds the culture medium and microorganisms Agitator (impeller): provides mixing Sparger: supplies sterile air Baffles: prevent vortex formation Sensors: monitor pH, temperature, dissolved oxygen Ports: used for inoculation, sampling, and feeding Slide 5: Agitation System Ensures uniform mixing of nutrients and cells Improves oxygen transfer rate Common impellers: Rushton turbine, marine propeller Speed controlled by motor Prevents settling of cells Affects shear stress on cells Slide 6: Aeration System Supplies oxygen for aerobic fermentation Air introduced through sparger Types of spargers: ring, nozzle, sintered Maintains dissolved oxygen concentration Air is filtered for sterility Essential for high cell density cultures Slide 7: Temperature and pH Control Temperature controlled by heating/cooling jackets pH maintained using acid or alkali addition Sensors continuously monitor parameters Automated control systems used Ensures optimal microbial growth Prevents enzyme denaturation Slide 8: Foam Control System Foam formed due to protein and agitation Excess foam reduces oxygen transfer Mechanical foam breakers used Chemical antifoam agents added Foam sensor detects foam formation Maintains efficient fermentation Slide 9: Types of Bioreactors – Based on Mode of Operation Batch bioreactor Fed-batch bioreactor Continuous bioreactor Choice depends on product type Widely used in industrial fermentation Controls productivity and yield Slide 10: Batch Bioreactor All nutrients added at the beginning No addition or removal during process Simple and easy to operate Low risk of contamination Used for antibiotics and enzymes Limited control over nutrient depletion Slide 11: Fed-Batch Bioreactor Nutrients added during fermentation Prevents substrate inhibition High product yield Widely used in industrial fermentation Allows better control of growth rate Used in insulin and enzyme production Slide 12: Continuous Bioreactor Fresh medium continuously added Culture removed at same rate Maintains steady-state conditions High productivity Risk of contamination is high Used in wastewater treatment and SCP production Slide 13: Types of Bioreactors – Based on Design Stirred tank bioreactor Airlift bioreactor Bubble column bioreactor Packed bed bioreactor Fluidized bed bioreactor Photobioreactor Slide 14: Stirred Tank Bioreactor (STR) Most commonly used bioreactor Mechanical agitation using impellers Suitable for aerobic fermentation Excellent mixing and oxygen transfer Used for bacteria and fungi Easy scale-up Slide 15: Airlift Bioreactor Mixing achieved by air circulation No mechanical agitator Low shear stress Energy efficient Suitable for shear-sensitive cells Used in wastewater treatment Slide 16: Bubble Column Bioreactor Air bubbles provide mixing Simple design and low cost No moving parts Limited mixing efficiency Used for microbial fermentation Suitable for large-scale operations Slide 17: Packed Bed Bioreactor Contains immobilized cells or enzymes Substrate flows through packed matrix High cell density Used in continuous processes Limited oxygen transfer Used in enzyme and wastewater treatment Slide 18: Fluidized Bed Bioreactor Immobilized particles kept in suspension Better mass transfer than packed bed Reduced clogging Suitable for continuous operation Used in biotransformations Higher operational complexity Slide 19: Photobioreactor Designed for photosynthetic organisms Provides light source Used for algae and cyanobacteria Controls light, CO₂, and temperature Used in biofuel and pigment production Can be tubular or flat-plate design Slide 20: Applications of Bioreactors Production of antibiotics and vaccines Enzyme and organic acid production Single cell protein production Wastewater treatment Biofertilizer and biopesticide production Biopharmaceutical manufacturing

20. Ang unang yugto sa pagbuo ng Community-Based Disaster Risk Reduction Management (CBDRRM) Plan ay tinatawag na ________. A. pagtugon sa sakuna B. paghahanda sa pagtugon C. pagsasaayos at pagbangon D. pagtataya ng panganib at paghahanda ANSWER: D 21. Ang gawaing ito ay isinasagawa upang maging handa ang komunidad at maiwasan ang malawakang pinsala nito sa pamamagitan ng aktibong pakikibahagi ng mamamayan. Ito ay nakapaloob sa _______. A. Philippine Disaster Risk Management B. Philippine Disaster Risk Reduction Management Council C. Community Preparedness and Risk Management Approach D. Community-Based Disaster Risk Reduction Management Approach ANSWER: D 22. Bahagi ng rehabilitasyon at pagbawi mula sa kalamidad ang mga hakbang at gawain na nakatuon sa pagsasaayos ng mga nasirang pasilidad at estruktura. Ano ang pangunahing gampanin ng yugtong ito? A. Mabigyan ng sapat na proteksiyon ang mga nasalanta ng kalamidad. B. Manumbalik sa dating kaayusan at normal na pamumuhay ang mga nasalantang komunidad. C. Makapagbigay ng mga inaasahang serbisyong panlipunan at paglilingkod sa pamahalaan. D. Maipagkaloob sa mga nasalantang komunidad ang mga pangunahing pangangailangan at gamot. ANSWER: B 23. Alin sa sumusunod na mga sitwasyon ang nagpapakita ng Top-Down Approach sa pagbuo ng Disaster Risk Reduction and Management (DRRM) Plan? A. Pinamunuan ni Kerwin, isang lider ng Non-Government Organization (NGO) ang pagtukoy sa mga kalamidad na maaaring maranasan sa kanilang komunidad. B. Ipinatawag ni Kapitan Capin ang kaniyang mga kagawad upang bumuo ng plano kung paano magiging ligtas ang kaniyang nasasakupan mula sa panganib ng paparating na bagyo. C. Hinikayat ni Albert ang kaniyang mga kapitbahay na maglinis ng estero upang maiwasan ang pagbara nito na maaaring magdulot ng malalim at matagalang pagbaha sa darating na tag-ulan. D. Nakipag-usap si Kelly sa mga may-ari ng malalaking negosyo sa kanilang komunidad upang makalikom ng pondo sa pagbili ng mga first aid kit at iba pang proyekto bilang paghahanda sa iba’t ibang kalamidad. ANSWER: B 24. Bakit mahalaga ang pagkakaroon ng community engagement o kolaborasyon sa pamayanan at iba pang katuwang na sektor? A. Makatutulong ito upang makalikom ng mas maraming pondo. B. Magiging makabuluhan ang plano kung ang gagawa nito ay ang mamamayan. C. Malaki ang posibilidad na maging matagumpay ang proyekto kapag pinagplanuhan. D. Mas magiging komprehensibo at matagumpay ang plano kung binubuo ito ng iba’t ibang sektor. ANSWER: D 25. Sa pagbuo ng CBDRRM Plan, ano ang PINAKAMABISA mong nararapat gawin bilang mamamayan ng isang lugar upang maging handa sa pagdating ng iba’t ibang panganib at kalamidad? A. Maging aktibong kabahagi sa pagbubuo ng plano para sa buong pamayanan. B. Makibahagi sa gawaing panrehabilitasyon at tulungan ang mga naapektuhan. C. Magsagawa ng personal plan para matugunan ang pangangailangan ng lipunan. D. Magkaroon ng planong pampinansiyal upang matustusan ang pangangailangan ng mga tao. ANSWER: A 26. Ang pinuno ng mga bansang kasapi ng organisasyon ay nagpupulong-pulong upang magtulungan para sa kapakanan ng kanilang pangangailangan. Anong anyo ng globalisasyon ang tinutukoy nito? A. ekonomiko B. kultural C. politikal D. teknolohikal ANSWER: C 27. Alin sa sumusunod ang buhay na manipestasyon ng globalisasyon? A. ekonomiko B. OFWs C. sosyo-kultural D. teknolohikal ANSWER: B 28. Ang brain drain ay tumutukoy sa mga propesyonal na manggagawa, samantalang ang brawn drain ay tumutukoy sa ___________. A. construction workers B. domestic workers C. overseas workers D. skilled workers ANSWER: A 29. Alin sa sumusunod ang negatibong epekto ng paglitaw ng maraming multinational companies at transnational companies? A. pagkakaloob ng hanapbuhay B. pagbaba ng presyo ng produkto C. pagdami ng produkto at serbisyo D. pagkalugi ng multinational companies at transnational companies ANSWER: D 30. “Ang globalisasyon ay laganap na noon pa man at naging mas malawak sa kasalukuyang panahon.” Ang mahihinuha natin sa pahayag na ito ay _______. A. ugnayan ng mga bansa sa daigdig na walang pagitan o hadlang B. suliraning panlipunan na pumipigil sa kaunlaran ng mga bansa sa daigdig C. bagong anyo ng malayang kalakalan, pagpapalitan ng produkto, impormasyon at tao, dahil sa pag-unlad ng teknolohiya sa komunikasyon at transportasyon D. isyung panlipunan na tumatalakay sa pamahalaan, ekonomiya, relihiyon, teknolohiya, kapaligiran, komunikasyon at kultura ng mga bansa sa daigdig ANSWER: C 31. Alin sa dalawang pahayag ang nagsasaad ng PINAKAANGKOP na konsepto ng globalisasyon? I. Ang globalisasyon ay proseso ng mabilisang pagdaloy o paggalaw ng tao, bagay, impormasyon at produkto sa iba’t ibang direksiyon na nararanasan sa iba’t ibang panig ng daigdig. II. Ang globalisasyon ay may iba’t ibang pagkakakilanlan tulad ng ekonomiko, teknolohikal, sosyo-kultural at politikal. A. Mali ang nilalaman ng una at ikalawang pahayag. B. Tama ang nilalaman ng una at ikalawang pahayag. C. Tama ang nilalaman ng una at mali ang ikalawang pahayag. D. Mali ang nilalaman ng una at tama ang ikalawang pahayag. ANSWER: B 32. Alin sa sumusunod na mga pahayag ang nagsasaad ng dahilan sa pag-usbong ng globalisasyon? A. pagbuti ng mga lokal na kompanya sa presyo at kalidad ng serbisyo at produkto upang maging kompetitibo laban sa mga banyagang kompanya B. pagpapalitan ng impormasyon at teknolohiya at paggalaw ng mga tao dulot ng migrasyon C. pagbaba ng sahod ng mga manggagawa at pagdami ng mga taong walang trabaho dahil nalulugi ang maliliit na negosyo D. paglaganap ng biological weapons dulot ng mabilis na pagkalat ng impormasyon sa iba’t ibang panig ng mundo at pagdami ng pamilihan ng materyales na ginagamit dito ANSWER: B 33. Alin sa mga sektor ng manggagawa ang madalas nakararanas ng pang-aabuso at hindi pantay na oportunidad sa pagtratrabaho? A. agrikultura B. industriya C. pamahalaan D. serbisyo ANSWER: A 34. Ano ang tawag sa anyo ng subcontracting kung saan ang mga subcontractor ay may sapat na puhunan para maisagawa ang trabaho ng mga manggagawang ipinasok nila? A. iskemang subcontractor B. job mismatch C. job contracting D. labor-only contracting ANSWER: C 35. Bakit hindi maitaas ang pasahod, maipagkaloob ang kasiguraduhan sa trabaho, at madagdagan ang benepisyo ng mga manggagawa sa bansa? Ito ay dahil_____ A. sa sistema ng kontraktuwalisasyon. B. puro regular na ang mga manggagawa. C. mataas na ang pasahod sa ating manggagawa. D. marami ang benepisyong natatanggap ng ating manggagawa. ANSWER: A 36. Bilang tugon sa suliraning nararanasan ng mga manggagawa, mayroon silang karapatang hindi dapat malabag upang masabi na sila ay may disente at marangal na hanapbuhay. Alin sa sumusunod ang HINDI kabilang sa mga karapatan ng manggagawa? A. Karapatan sa pantay na suweldo para sa parehong trabaho. B. Karapatang sumali sa marahas at mapanganib na uri ng unyon. C. Karapatang maging ligtas at malayo sa panganib ang kalagayan ng pagtatrabaho. D. Karapatan na makatanggap ng sapat at karapat-dapat na suweldo para sa makataong pamumuhay. ANSWER: B 37. Halos mapudpod na ang sapatos ni Justin sa paghahanap ng trabaho ngunit hindi pa rin siya natatanggap. Maraming job fairs na rin ang kaniyang pinuntahan ngunit bigo siyang makakuha ng trabaho. Bakit kaya ito nangyayari kay Justin? A. Kulang pa ang kaniyang lakas ng loob. B. Kulang siya sa aspekto ng personal relations kaya hindi siya nagugustuhan. C. Hindi kaaya-aya ang kaniyang pisikal na kaanyuan kaya hindi siya natatanggap sa trabaho. D. Biktima si Justin ng job mismatch kung saan hindi tugma ang kaniyang kakayahan at kasanayan na hinahanap ng mga kompanya. ANSWER: D 38. Ayon sa tala ng Department of Labor and Employment (DOLE), maraming job fairs noong 2010 ngunit kakaunti lamang ang mga natanggap na kalipikadong aplikante mula sa maraming bilang ng mga nag-apply. Alin ang HINDI angkop na dahilan nito? A. Ang mga aplikante ay hindi interesado sa mga trabaho sa bansa. B. Kapansin-pansin ang patuloy na paglaki ng bilang ng job skills mismatch ng mga aplikante sa bansa. C. May patuloy na mismatch sa kasanayan at kakayahan mula sa tinapos na kurso at sa hinihinging kalipikasyon ng mga employer. D. Maraming kurso sa higher education institutions sa bansa ang hindi na tumutugon sa pangangailangan ng mga pribadong kompanya na nagtatakda ng mga pamantayan sa pagpili ng mga manggagawa. ANSWER: A 39. Alin ang angkop na salita na tumutukoy sa sitwasyon kung saan inaako na ng lalaki ang mga gawain sa tahanan dulot ng migrasyon? A. helper B. house boy C. house father D. house husband ANSWER: D 40. Ang sumusunod ay mga ahensiya ng pamahalaan na nangangalaga sa kapakanan ng migrante MALIBAN sa __________________. A. Commission of Filipino Overseas B. Philippine Overseas Labor Offices C. Department of Labor and Employment D. Department of Science and Technology ANSWER: D 41. Isang epekto ng migrasyon ay ang pagtanggap o pagpapadala ng mga lakas-paggawa sa ibang bansa. Alin sa sumusunod ang HINDI nagpapakita ng magandang benepisyo ng brain gain? A. Malaki ang posibilidad ng promotion ng manggagawa. B. Gastusin ng kompanya ang pagpapadala ng manggagawa sa ibang bansa. C. Maaaring magtrabaho sa ibang bansa ang empleadong ipinadala upang matuto. D. Magiging asset ang migranteng manggagawa sa nagpapadala at tumatanggap na bansa kahit saan man sa mundo. ANSWER: B 42. Matagal na naghanapbuhay si Ginoong Pascual sa Australia, kaya sa kaniyang pag-uwi sa pamilya ay hindi siya pinansin ng kaniyang mga anak at nagtago ang mga ito sa kuwarto. Ano ang iyong mahihinuha rito? A. Malaki ang takot ng mga anak sa kanilang ama. B. Walang pasalubong si Ginoong Pascual sa mga anak. C. Hindi kilala si Ginoong Pascual ng kaniyang mga anak. D. Nagkakahiyaan ang mag-aama sa kanilang pagkikita. ANSWER: C 43. Paano nakaaapekto ang pangingibang-bansa sa estado ng ekonomiya ng bansa? A. Madaragdagan ang populasyon ng bansa. B. Mapananatiling matatag ang palitan ng piso at dolyar. C. Mahihirapan ang mga Pilipino na makisama sa mga dayuhan. D. Mas maraming papasok sa bansa na mga imported na produkto. ANSWER: B 44. Marami sa mga OFW na nasa Middle East ang napag-alamang nakararanas ng mga pang-aabuso mula sa kanilang mga amo tulad sa Saudi Arabia. Kung ikaw ang ambassador ng Pilipinas sa Saudi, alin ang pinakamabisa mong gagawin upang matulungan at maprotektahan sila? A. Pababayaan sila hanggang matapos ang kanilang kontrata. B. Maglulunsad ng rally sa embahada ng Saudi Arabia sa Pilipinas. C. Hihingi ng tulong pinansiyal at pauuwiin ang mga manggagawa sa Saudi. D. Maglilikom ng mga ebidensiya ng mga pang-aabuso at isusuplong ang mga amo sa kinauukulan. ANSWER: D 45. Alin sa sumusunod ang konseptong tumutukoy sa slavery? A. pang-aalipin B. sitwasyong payapa C. sapilitang pagtatrabaho D. pagpupuslit ng mga tao ANSWER: A 46. Kung ikaw ay opisyal ng pamahalaan na nangangalaga sa kapakanan ng mga OFW, alin sa sumusunod ang dapat mong gawin sa mga kaso ng pang-aabuso sa mga Pilipino? A. Pauuwiin ang lahat ng OFW at bibigyan na lamang ng trabaho sa Pilipinas. B. Pababayaan na lamang ang mga OFW dahil isolated cases lang naman ang mga ito. C. Ipauubaya na lamang ang mga gagawing aksiyon sa pamahalaan ng bansa kung saan nagtatrabaho ang mga OFW. D. Magtatatag ng mga mekanismo upang ma-monitor ang kalagayan ng mga OFW at gagawa ng kaukulang hakbang kung may pang-aabuso. ANSWER: D 47. Bilang isang mag-aaral sa kasalukuyan, alin sa sumusunod ang maaari mong magawa upang masigurong makaaangkop ka sa pangangailangan ng ating bansa na umunlad sa kabila ng globalisasyon? A. Magpalipas ng panahon at umasa na lamang sa pamilya. B. Tumigil sa pag-aaral at magtrabaho na upang kumita ng pera. C. Magsumikap sa pag-aaral upang makatapos at magkatrabaho. D. Maging layunin ang makapagtrabaho sa ibang bansa upang yumaman. ANSWER: C 48. Alin sa sumusunod na mga pangungusap ang tumutukoy sa konsepto ng fair trade? A. Itinatakda ng mga bansa ang pamantayan ukol sa mga kakayahan ng mga manggagawa. B. Ang mayayamang bansa ay nagbibigay ng tulong sa pinakamahihirap na tao sa mundo lalo na sa Aprika at Asya. C. Sinisiguro ng mga bansa ang patas o pantay na kalakalan gaya ng pagbabantay sa tamang presyo ng mga produkto. D. Ang pamahalaan ay nakikialam sa kalakalang panlabas na may layong protektahan ang mga lokal na namumuhunan. ANSWER: C 49. Marami sa mga pamilya ng OFWs ay nakararanas ng pangungulila sa kanilang kaanak na humahantong sa pagkawasak nito. Paano kaya sila matutulungan? A. Makisimpatiya sa kanila. B. Bigyan sila ng sulat isa-isa. C. Bigyan sila ng load pantawag sa kanilang kaanak. D. Magtayo ng isang samahan ng mga pamilya ng OFW upang gumabay sa kanila. ANSWER: D 50. Sa Pilipinas ay marami ang nangangarap na mangibang-bansa dulot ng kahirapan sa buhay. Nangangamba naman ang mga ekonomista dahil naaapektuhan ng brain drain at brawn drain ang ekonomiya. Bilang ekonomista, ano ang maaari mong gawin upang masolusyunan ang isyung ito? A. Pigilan ang mga nais mangibang-bansa. B. Hayaang umalis ang mga nais na magtrabaho sa ibang bansa. C. Bigyan ng suportang pinansiyal ang mamamayan na walang trabaho. D. Gumawa ng isang development plan na tutugon sa mga isyu ng migrasyon. ANSWER: D

Cell Size Cells differ not only in their shape but also in their size. A few types of cells are large enough to be seen by the unaided human eye. For example, the nerve cells that extend from a giraffe’s spinal cord to its foot can be 2 m (about 6 1/2 ft) long. A human egg cell is about the size of the period at the end of this sentence. Most cells, how- ever, are only 10 to 50 μm in diameter, or about 1/500 the size of the period at the end of this sentence. The size of a cell is limited by the relationship of the cell’s outer surface area to its volume, or its surface area–to-volume ratio. As a cell grows, its volume increases much faster than its surface area does, as shown in Figure 4-5. This trend is important because the materials needed by a cell (such as nutrients and oxygen) and the wastes produced by a cell (such as carbon dioxide) must pass into and out of the cell through its surface. If a cell were to become very large, the volume would increase much more than the surface area. Therefore, the surface area would not allow materials to enter or leave the cell quickly enough to meet the cell’s needs. As a result, most cells are microscopic in size. Comparing Surface Cells Materials microscope, prepared slides of plant (dicot) stem and ani- mal (human) skin, pencil, paper Procedure Examine slides by using medium magnification (100). Observe and draw the sur- face cells of the plant stem and the animal skin. Analysis How do the surface cells of each organism differ from the cells beneath the surface cells? What is the function of the surface cells? Explain how surface cells are suited to their function based on their shape. Quick Lab Small cells can exchange substances more readily than large cells because small objects have a higher surface area–to-volume ratio. FIGURE 4-5 mb06se_csfs02.qxd 5/18/07 10:54 AM Page 73 74 CHAPTER 4 BASIC PARTS OF A CELL Despite the diversity among cells, three basic features are common to all cell types. All cells have an outer boundary, an interior sub- stance, and a control region. Plasma Membrane The cell’s outer boundary, called the plasma membrane (or the cell membrane), covers a cell’s surface and acts as a barrier between the inside and the outside of a cell. All materials enter or exit through the plasma membrane. The surface of a plasma mem- brane is shown in Figure 4-6a. Cytoplasm The region of the cell that is within the plasma membrane and that includes the fluid, the cytoskeleton, and all of the organelles except the nucleus is called the cytoplasm. The part of the cytoplasm that includes molecules and small particles, such as ribosomes, but not membrane-bound organelles is the cytosol. About 20 percent of the cytosol is made up of protein. Control Center Cells carry coded information in the form of DNA for regulating their functions and reproducing themselves. The DNA in some types of cells floats freely inside the cell. Other cells have a mem- brane-bound organelle that contains a cell’s DNA. This membrane- bound structure is called the nucleus. Most of the functions of a eukaryotic cell are controlled by the cell’s nucleus. The nucleus is often the most prominent structure within a eukaryotic cell. It maintains its shape with the help of a protein skeleton called the nuclear matrix. The nucleus of a typical animal cell is shown in Figure 4-6b. Most animal cells have a cell membrane, a nucleus, and a variety of other organelles embedded in a watery substance. The surface of the cell membrane can be seen in (a). The organelles inside the cell are labeled in the diagram (b). FIGURE 4-6 (a) (b) Mitochondrion Microfilaments Lysosome Golgi apparatus Smooth ER Ribosomes Cell membrane Microtubules Rough ER Nuclear pore Nuclear envelope Nucleolus Nucleus Copyright © by Holt, Rinehart and Winston. All rights reserved. Cell wall Ribosome Cell membrane Peptidoglycan Pili Flagellum DNA CELL STRUCTURE AND FUNCTION 75 A prokaryotic cell lacks a membrane- bound nucleus and membrane-bound organelles. Most prokaryotic cells are much smaller than eukaryotic cells are. FIGURE 4-7 A white blood cell (eukaryotic) changes shape as it attacks purple- stained bacterial cells that are much smaller (prokaryotic). FIGURE 4-8 TWO BASIC TYPES OF CELLS Fossil evidence suggests that the earliest cells on Earth were simple cells similar to some present-day bacteria. As cells evolved, they differentiated into two major types: prokaryotes and eukaryotes. Prokaryotes Prokaryotes (proh-KAR-ee-OHTS) are organisms that lack a membrane- bound nucleus and membrane-bound organelles. Although prokaryotic cells lack a nucleus, their genetic information—in the form of DNA—is often concentrated in a part of the cell called the nucleoid. Figure 4-7 shows a typical prokaryotic cell. Prokaryotes are divided into two domains: Bacteria and Archaea (ahr-KEE-uh). The domain Bacteria includes organisms that are similar to the first cellular life-forms. The domain Archaea includes organisms that are thought to be more closely related to eukaryotic cells found in all other kingdoms of life. Eukaryotes Organisms made up of one or more cells that have a nucleus and membrane-bound organelles are called eukaryotes (yoo-KAR-ee-OHTS). Eukaryotic cells also have a variety of subcellular structures called organelles, well-defined, intracellular bodies that perform specific functions for the cell. Many organelles are surrounded by a mem- brane. The organelles carry out cellular processes just as a person’s pancreas, heart, and other organs carry out a person’s life processes. Eukaryotic cells are generally much larger than prokary- otic cells, as seen in Figure 4-8, which shows a white blood cell (eukaryote) destroying tiny bacterial cells (prokaryotes).

LESSON 4. Cellular Respiration • Define cellular respiration • Identify the stages of clan respiration You have just learned how the energy from the sun is captured, processed, and stored in the form of glucose. Cellular respiration, another important life process, is the means by which cells release the stored energy in glucose to make adenosine triphosphate (ATP). The primary goal of this life process is to convert stored energy into usable form, such as ATP, for the cells to carry out their functions. Cellular respiration involves several chemical reactions. The reactions can be summed up in the following equation: C6 H12 O6 + 602 ----- 6 CO₂ +6H₂O + ATP Glucose oxygen carbon dioxide water energy Aerobic respiration reactions, or cellular respiration that takes place in the presence of oxygen, can be grouped into three stages glycolysis, Krebs cycle, and electron transport chain (ETC). Stage 1: Glycolysis Glycolysis is the process that breaks down one molecule of 6-C glucose into 3-C pyruvates or pyruvic acids. It also releases four molecules of ATP. This process occurs in the cytoplasm of the cell. The following is the step-by-step process of glycolysis. Take note that several enzymes are involved in this process. 1. The first step of glycolysis requires energy. It can only proceed when the two ATP molecules donate energy to the glucose by transferring a phosphate group with the help of an enzyme, producing glucose 6-phosphate 2. Then, a specific enzyme promotes the rearrangement of the atoms, producing the fructose 6-phosphate. 3. The action of the enzyme in step 2 promotes the transfer of a phosphate group from another ATP molecule, forming fructose 1,6-bisphosphate. 4. The resulting fructose 1,6-bisphosphate molecules, with the help of another enzyme, splits into two molecules, each with three carbon backbones. These two sugars are dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. 5. Another important enzyme then rapidly interconverts the molecules of dihydro-xyacetone phosphate and glyceraldehyde 3-phosphate. This produces two molecules of glyceraldehyde 3-phosphate or 3-phosphoglyceraldehyde (PGAL) 6. The succeeding step involves another enzyme-mediated action. The hydrogen (H) from PGAL is transferred to the oxidizing agent, nicotinamide adenine dinucleotide (NAD), which forms NADH. A phosphate (P) is also added from the cytosol of the cell to oxidize the two molecules of PGAL, forming two 1.3-bisphosphoglycerate. 7. A phosphate (P) from 1,3-biphosphoglycerate is transferred to ADP to form ATP. This happens for each of the two 1,3-bisphosphoglycerate. resulting to a yield of two ATP and two 3-phosphoglycerate molecules. 8. A phosphate is transferred from 3-phosphoglycerate molecules from the third carbon to the second carbon, forming 2-phosphoglycerate molecules A hydrogen atom and a hydroxyl ((OH) group is released, which then combines to form water (H2O). The removal of H2O from 2-phosphoglycerate results in the formation of 2- phosphoglycerate molecules. 9. A hydrogen atom and a hydroxyl ((OH) group is released, which then combines to form water (H2O). The removal of H2O from 2-phosphoglycerate results in the formation of two phosphoenolpyruvic acid (PEP) 10. Phosphate (P) from PEP is transferred to ADP (and forms ATP) and the final product, pyruvic acid. This reaction yields two molecules of pyruvic acid and two ATP molecules In summary, a single glucose molecule that undergoes the process of glycolysis produces two molecules of pyruvic acid, four molecules of ATP, two molecules of NADEL and two molecules of H.O. However, only two molecules of ATP are counted as net products since two molecules of ATP are spent throughout the process. Stage II: Krebs Cycle The Krebs cycle, named after its proponent Sir Hans Adolf Krebs, is a cyclical series of enzyme-controlled reactions. This stage of cellular respiration occurs in the matrix of the mitochondria. It is sometimes. called the citric acid cycle (CAC) since it produces citric acid. Citric acid contains three carboxyl (COOH) groups; hence, it is also called the tricarboxylic acid cycle (TCA). This requires the pyruvic acids produced during glycolysis. The main function of this cycle is to produce high-energy-yielding molecules, namely, NADH and flavin adenine dinucleotide (FADH) that will later on be used in the electron transport chain reaction. Figure 6-7. Summary of glycolysis and corresponding products in each reaction presented (See Appendix F on page 285 for an enlarged and complete version of the image.) An initial process is needed for the Krebs cycle to begin. As a pyruvate molecule from glycolysis enters the mitochondrion, it undergoes an important preliminary ate to form acetyl-CoA reaction. Coenzyme-A (COA) combines with pyruvate help of an enzymatic complex. This conversion also produces CO, and NADH. The Krebs cycle is summarized as follows. Take note that several enzymes are involved in this process. 1. The Krebs cycle technically begins when the acetyl-CoA combines with oxaloacetic acid (OAA), a 4-C molecule, to produce citric acid, a 6-C molecule. 2. With the aid of an enzyme, the citric acid now goes through a series of reactions that releases energy. Water molecule is removed from the citric acid and is returned in a different location. The-OH group is repositioned, forming the molecule isocitrate. 3. Isocitrate is then oxidized, forming the a-ketoglutarate, a 5-C molecule. The byproducts of this reaction are NADH and CO, 4 The a-ketoglutarate loses its CO, and a coenzyme-A is added in its place. The decarboxylation occurs with the help of NAD, which then becomes NADH. The resulting molecule is called succinyl-CoA. 5. Succinyl-CoA is converted into succinate. Also in this reaction, a molecule of guanosine triphosphate (GTP) is synthesized. The GTP molecule has similar structure and energy properties to that of ATP and is used by cells the same way. The free phosphate group attacks the succinyl-CoA molecule, which detaches the COA. Then, phosphate is attached to GDP to come up with GTP, similar to the process that occur in ATP synthesis (from ADP to ATP). 6. Two hydrogens are removed from succinate, A molecule of flavin adenine dinucleotide (FAD), a coenzyme similar to NAD, is reduced to FADH, as it takes the hydrogens from the succinate. This reaction produces the fumarate. 7. Fumarate is then converted into malate as the addition of a water molecule is catalyzed. The final reaction is the regeneration of oxaloacetate. The resulting byproduct of this regeneration is NADH Recall that two pyruvate molecules were produced during glycolysis, causing the Krebs cycle to turn twice. Each tuts produces three molecules of NADH, single ATH one FADIH, and the by-product CO, which is exhaled. Stage III: Electron Transport Chain The electron transport chain (ETC) is a series of photon pumps on the inner membrane of the mitochondrion. Electron transport is the last stage of the cellular respiration. In this stage, the energy from NADH and FADH, from the Krebs cycle is transferred to ADP to produce ATP. This process is generally known as oxidative phosphorylation. This energy coupling mechanism in the cell was revealed by the work of Peter stored energy in the form of proton (1) gradient to phosphorylate (add phosphate) ADP and produce ATP. The pumping of hydrogen sons across the inner membrane creates higher concentration ions in the inner membrane than on the outside of the membrane. This chemiosmotic gradient causes the ions to flow back across the membrane where the concentration of ions is lower. ATP synthase lined in the matrix serve as a channel protein, helping the ions to move across the membrane. The chemiosmotic gradient powers the phosphorylation of ADP to ATP, which also occurs in the ATP synthase. After passing through the ETC, the oxygen, being the final hydrogen acceptor, combines with two electrons and two protons, forming a water molecule. Water is a by-product of cellular respiration and is excreted. MINI TEST 6-3 1. Which energy-releasing pathway yields the most ATF in each glucose molecule? 2. Briefly describe the two stages of aerobic respiration that follow glycolysis: (a) Krebs cycle (b) Electron transport chain Anaerobic Respiration Most cells carry out arrobic respiration when oxygen is present. Aerobic respiration is an efficient process that yields a lot of ATP. However, many organisms thrive in mud, marshes, animal gut, canned goods, sewage treatment pond, and deep oceans where oxygen is scarce. Organisms that can live without oxygen are called anaerobes. Cellular respiration that proceeds without the presence of oxygen is called anaerobic respiration. In the event that the oxygen supply becomes low, aerobic cells also perform fermentation and lactic acid fermentation anaerobic pathways. There are two common anaerobic pathways in these cells, alcoholic fermentation and lactic acid fermentation. In alcoholic fermentation, ethyl alcohol and carbon dioxide are produced by some cells using the pyruvate from glycolysis. Each pyruvate molecule is rearranged into acetaldehyde and carbon dioxide, which is eventually released. NADII gives up electrons to acetaldehyde to form ethanol Fermentation is widely used in the industry. Yeast, a fungus used in making bread. can undergo anaerobic respiration. Bakers aux sugar, flour, water, and yeast to form the bread dough. The dough rises due to the carbon dioxide and alcohol released by the yeast cells trapped in air bubbles. Beer and wine manufacturers, we yeast to ferment the sugars in wheat and grape juice, forming alcoholic beverages such as beer and wine. In some cells, glycolysis produces two pyruvates, two NADH molecules, and two ATP molecules. Pyruvate itself becomes the final acceptor of the electrons from the NADH that produces the final product: lactate. Oftentimes, this product is called lactic acid. Human skeletal muscles can carry out fermentation when the blood cannot supply the cells with adequate oxygen during strenuous activities. When lactic acid builds up in the muscles, fatigue, burning sensation, and cramps result. Lactic acid will continue to build up until there is adequate supply of oxygen. Lactic acid is then converted back into pyruvate in the liver. Muscles also restore normal functions. Have you ever wondered why milk or cream turns sour after some time? Bacterial cells that undergo fermentation are responsible in producing lactate that turns the milk sour. These bacteria are used in manufacturing yogurt and sour milk products. Fermentation pathways do not breakdown and utilize the glucose completely. ATP is no longer produced beyond the process of glycolysis. Thus, energy produced is just enough for some single-celled organisms, or the energy can only be used by multicellular organisms for a short period.

1. SA node sends an impulse causing the atria to contract 2. Blood moves from the right atrium into the right ventricle past the tricuspid valve 3. Blood moves from the left atrium into the left ventricle past the mitral or bicuspid valve 4. Impulse pauses at AV node to allow for maximum blood to be squeezed into the ventricles 5. Impulse travels to the AV bundle (or bundle of His) and down the bundle branches 6. Impulse travels out Purkinje fibers causing the apex to contract 7. The apex contraction increases the blood pressure in the ventricles causing the Mitral and Tricuspid (AV) valves to close. 8. Atria repolarize and begin to fill 9. Purkinje fibers cause the ventricle walls and papillary muscles to depolarize (contract) 10. Papillary muscles hold the AV valves shut (keep them from prolapsing) through the chordae tendineae connection 11. The aortic and pulmonary semilunar valves open when the pressure is higher in the ventricles than in the major arteries 12. Blood moves from right ventricle to pulmonary trunk/arteries past the pulmonary semilunar valve 13. Blood moves from left ventricle to aorta past the aortic semilunar valve 14. Blood pathway is arteries to arterioles, to capillaries (or capillary bed), to venules, veins and vena cava back to the right atrium 15. The ventricles start to repolarize (relax) which decreases the pressure in the ventricles 16. When the pressure is lower in the ventricles than in the major arteries, blood moves back toward heart shutting semilunar valves 17. When the aortic valve closes, the openings to the coronary arteries are exposed 18. Back pressure in the aorta pushes blood out the left and right coronary arteries supplying the heart with oxygenated blood 19. The AV valves open and blood moves from the atria into the ventricles when the ventricular pressure falls below atrial pressure. 20. The process starts again when the SA node fires causing the atria to contract.

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