Body Tissues and Epidermis

Pre-Assessment: Body Tissues and Organ Systems

Nutrition Notes Nutrition- study of how your body uses food Process by which body uses nutrients How you look and feel Resist diseases and illness How you perform physically and mentally Nutrients: substances in food your body needs to grow, repair and supply energy to your body cells 6 Classes of Nutrients 1.Carbohydrates: 1 gram= 4 calories 2. Protein: 1 gram- 4 calories 3. Fats: 1 gram= 9 calories 4.Water 5. Vitamins 6. Minerals Calorie: measurement of energy in food Metabolism: Rate at which body burns energy(calories) Hunger: physical drive to eat Appetite: pshycological desire for food What influences your food choices: Foods you like Health Reasons Family and Culture Time & Money Advertising Emotions Friends Social Media: Modeling Nutrients Carbohydrates: your body’s main source of energy sugars/starches in food 45%-65% of diet #1 source of energy Simple: sugars converted to glucose= energy (fruits, dairy, honey, some manufactured foods) Complex: sugars linked together (starches) (grains, bread, pasta, beans, vegetables) Fiber: tough, indigestible carbohydrates Cleans our digestive system Prevents some types of cancer Prevents heart disease (fruits, vegetables, whole grains,nuts) 2. Protein: growth and repair of body tissues Made up of chemicals called “amino acids” Basic building material of all body cells (muscles, bones, skin, internal organs) Secondary source of energy protein(hemoglobin) attaches to oxygen in blood Functions as hormones regulating body functions 10-15% of diet *Body uses 20 Amino Acids found in food ( body produces 11 and 9 must come from diet) Essential amino acids: 9 amino acids body doesn't produce Complete Amino Acids: foods that contain all 9 essential amino acids ( animal products) Incomplete Amino Acids: food products that do not contain all 9 essential amino acids. Fats 15-25% of diet Secondary source of energy Blood clotting Controlling inflammation Maintains healthy skin/hair absorb /transport fat soluble vitamins Regulates body temperature Types of Fat Unsaturated: “good” fat Liquid at room temperature Can help fight heart disease (veg oil, nuts) Saturated: “bad” fat Solid at room temp Clogs arteries Causes strokes, heart attack, diabetes (animal products, meat, dairy) Cholesterol: waxy like fat substance found in meat products HDL: good type of cholesterol Body creates(liver) Creates cell wall, hormones, and vit D LDL: bad cholesterol- found in foods (clogs arteries) 4. Trans Fat: “one of the worst type of fats” Formed by a process called “hydrogenation”: adding Hydrogen molecules to unsaturated fats to make it more solid and resistant to chemical change. Vitamins A vitamin is a chemical compound that is needed in small amounts for the human body to work correctly. Vitamins are classified as either fat soluble (vitamins A, D, E and K) or water soluble (vitamins B and C). This difference between the two groups is very important. It determines how each vitamin acts within the body. The fat soluble vitamins are soluble in lipids (fats). Fat soluble vitamins can be stored in our body Water soluble vitamins must be taken every day Human body produces some amounts of Vitamin D & K

LESSON 3 Characteristics of Living Things Learning Objectives • Describe each characteristic of life • Relate each characteristic of life with how first forms of life evolved What sets living things apart from nonliving things? Organisms are equipped with different characteristics that allow them to grow, adapt, survive, and perpetuate. These include the ability to metabolize, respond to stimuli, interact, and reproduce, among others What are the characteristics of life? Try to look at your surroundings and identify the living things that you see. You have probably identified a lot. Many scientists believe that there are more than 10 million kinds of living things that exist on Earth today. But the question is, how can something be considered living? There are certain characteristics that all living things exhibit: the characteristics of life. Living things are made up of cells. They metabolize, grow and develop, respond to stimulus, adapt to their environment, and reproduce. Living Things Are Made up of Cells All living things are made up of cells. Cells are the basic building blocks of all living things. Each cell contains materials that carry out basic life processes such as respiration. In the 1600s, an argument against the theory of spontaneous generation was made. Italian physician and biologist Francesco Redi disproved the theory that all living things come from nonliving things. Cells have different properties and characteristics. The cell theory describes the properties of all cells. There are three tenets of the cell theory: 1. The cell is the basic unit of life. 2. All living things are composed of one or more cells. 3. All cells arise from preexisting cells. The discovery of the cell is largely attributed to Robert Hooke. Upon examining a piece of cork using a microscope that he built, Hooke observed tiny compartments that he called "cells" (from the Latin word cella, meaning "little room"). Matthias Schleiden suggested that all structural parts of plants are made up of cells. In 1839, Theodore Schwann stated that along with plants, all animals were composed of cells. From these conclusions about plants and animals, advancement on the study of animal parts and functions began. In 1855, Rudolf Virchow included the idea that all cells came from preexisting cells. Some living things are made up of only single cells. Single-celled or unicellular organisms include bacteria, some protists, and some fungi. Even though composed of single cells, these organisms carry out all the functions necessary for life. Most living things such as animals and plants, are multicellular organisms. They are composed of many cells, which are grouped together and perform specific tasks in the body. In different organisms, cells also vary in sizes, shapes, parts, and functions. There are two kinds of organisms according to their cell structure, the prokaryotes and eukaryotes (figure 5-3). Prokaryotes are single-celled organisms that lack a membrane-bound nucleus, mitochondria, and all other organelles. Its name comes from the Greek words pro, which means "before," and karyon, which means "nut or kernel." Eukaryotes are organisms with cells that contain membrane-bound nucleus and other membrane-bound organelles. The nucleus of a eukaryotic cell contains the genetic material (DNA), enclosed by a nuclear envelope. Other membrane-bound organelles are mitochondria, Golgi apparatus, and chloroplast found in photosynthetic organisms such as algae and plants. There are also unicellular eukaryotes known as protozoa. All other eukaryotes are multicellular organisms, such as plants, animals, and fungi. Living Things Metabolize Essential chemical reactions in life can be best described as building up (anabolism) and breaking down (catabolism) processes. In anabolism, the substances needed by organisms to grow, store energy, and repair tissues are synthesized. In contrast in catabolism, some complex substances are broken down, releasing the energy stored in their molecules. This happens in food digestion. This chemical building up and breaking down processes are collectively called metabolism. Metabolism, from the Greek word metabole meaning "change," is the sum total of all the life-sustaining chemical reactions in living things. It allows living things to grow, maintain their structures and functions, and respond to stimuli. Living Things Grow and Develop Growth and development are not new concepts to many. In all living things, growth involves the increase in one's size or height. However, growth is not just an increase in physical structure. It also involves complex changes in an organism. Growth and development occur rapidly from younger stages of life to maturity. In humans, animals, and plants, distinct changes brought by growth and development can be dearly identified. Microorganisms such as bacteria also undergo growth and development until they reach their maximum size and maturity. A life span is the average length of time a aving thing can live. Living things have different life spans. Humans have average life spectancy of 60 to 70 years, while some plants, such as the narra trees, can live for more than 100. Living Things Respond to Stimuli All living things respond to stimuli the environment. This responsiveness Increases survivability. Stimulus (plural: uli) is any signal or change in he environment of an organism that produces a response or reaction from that organism. Responses to stimuli depend on an organism's need. Responding to stimuli also maintains homeostasis in living things. Homeostasis is the internal balance of a body system. This balance is needed for the proper function and regulation of the living thing's body. For example, when a person is in a warmer environment, the body sweats, keeping the body maintain a temperature suited for the normal function of the body. Living Things Interact No living thing can live alone. Interaction among organisms is simultaneously happening on Earth. From the smallest microorganisms to the biggest organism, and from the North Pole to the South Pole of Earth, all are connected in one living system. An ecosystem is formed when a community of organisms interacts with another community and with their environment. Many processes and interactions, such as in a feeding relationship, life cycle, and the exchange of gases between plants and animals, occur in the ecosystem. These are some of the important processes needed to maintain life on Earth. Living Things Reproduce The ability of living things to produce offspring of their kind is called reproduction. Reproduction is not an individual organism's need, rather, it is for the species' perpetuation. In some cases, animals become extinct because of their inability to reproduce their kind. Higher forms of plants and animals reproduce through sexual reproduction. Sexual reproduction involves the union of sex cells or gametes-the egg cell from a female organism and the sperm cell from a male organism. This union gives rise to a new individual with characteristics or traits from both parents. Other simple organisms, such as bacteria and plants, can reproduce asexually. These organisms give rise to a new individual from their body. A bacterial cell divided in two through asexual reproduction gives rise to new bacteria, as shown in figure 5-5. A yeast can form buds that later on become separate individual. Plants grow new plants using their stem, leaf, and roots. Both sexual and asexual reproductions have important functions. In both cases, the genetic material (DNA) is passed on from one generation to the next, ensuring the survival of the species on Earth. 1. Bacteria copy their DNA by starting at any point on the circular chromosomes. 2. The two copies of DNA attach to the inside wall of the bacterial cell. 3. The cell starts to divide, forming a new membrane and cell wall. 4. The bacterial cell splits into two separate cells, each with their own DNA. Living Things Adapt and Evolve All living things can adapt to their environment. This adaptation is necessary for rvival. Adaptation depends on the need of an individual. A polar bear, for example, would not be able to survive in an extremely cold environment without its capacity adapt. Adaptation is any response or reaction toward a stimulus that helps in the survival of an organism. A seed-eating bird will eventually eat a worm when there are seeds to be found. This change in food choice is therefore its adapting mechanism. Prolonged adaptation to certain environments may lead to the gradual evolution of the succeeding generations. Evolution is the gradual change in organisms over a long period in response to changing environment. Living Things Are Organized Life on Earth exhibits organization. The atom is the smallest unit of matter, lowed by molecules, which are combinations of atoms. When these molecules are grouped together, they form a cell. The cell is the basic unit of life. In multicellular organisms, such as plants and animals, cells are grouped as tissues to perform specific Functions. Different tissues can be grouped further and form organs. Organs in animals include the heart, brain, and lungs, among others. The organs form organ systems that makes the function of the body more complex and efficient. Organ systems form the whole organism. All living things exhibit organization, whether they are unicellular or multicellular organisms..

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

Nutrition refers to the science that deals with the various factors of which food is composed and the way in which proper nourishment is brought about. Home Economics and Livelihood Education 7 Seibo College 152 Human nutrition involves properly feeding the people. It is therefore important to learn more about nutrition, taking into consideration the three (3) important factors: a. the food we eat b. the way it is digested, absorbed and used in the tissues of the body c. the kind of people for whom the food is intended Good health or “wellness” is not a matter of chance. Good health is a product of good nutrition which is the result of an adequate supply of essential nutrients in your body. Lack of these nutrients lead to illness or a condition known as “malnutrition”. Malnutrition occurs if there is an imbalance intake of nutrients or an inadequacy of one or any of the nutrients. Malnutrition are manifested in the following cases: 1. obesity due to overeating- Obesity occurs when a person eats more than what the body requires under normal condition. This results in an excess supply of calories that leads to obesity or overnutrition. 2. stunted growth of children due to lack of protein- If there is no sufficient supply of carbohydrates or fats protein is used by the body as an alternative source of energy. 3. under weight due to lack of carbohydrates- If the total amount of nutrients provided by the diet is insufficient , it results to undernutrition. What is good nutrition? Home Economics and Livelihood Education 7 Seibo College 153 What are the causes of malnutrition? 1. ignorance or lack of knowledge about proper food intake 2. low standard of living 3. limited food supply 4. emergence of calamities or social unrest 5. increased family size 6. poor eating habits What are food habits? Food habits mean one’s attitude towards food. If the body is fed by junk foods and became over/under supplied with particular vitamins, protein or other nutrients then the body will suffer from malnutrition. Let us identify the factors affecting food habits.  Education – knowledge about nutrition will help one to make wise decision about food.  Foods available - The kinds of food available to you usually are the foods you eat. Some foods can grow only in certain types of geographic locations and this determines the foods available in such locations  Religion - What foods people can eat or cannot eat have been dictated by their religious beliefs. For example, Moslems do not eat pork because Islam forbids them to eat it. Home Economics and Livelihood Education 7 Seibo College 154  Ethnicity – members of cultural groups formed their own living patterns which include food customs. It includes what food can or cannot be eaten.  Income/economic status – the type of food you choose depends on how money you have. Income dictates what food you can eat and how you eat them.  Convenience -. Meal management practices affect food habits because you can only prepare and eat foods you can easily cook with the facilities and the knowledge you have. Food habit refers to the way in which different people select , cook, serve and eat food that are available to them. Home Economics and Livelihood Education 7 Seibo College 155 Look at the diagram below for a better understanding. FACTORS THAT AFFECT FOOD HABITS FOOD HABITS Education Foods available Religion Convenience Economic status Ethnicit

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