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FINAL COACHING GEN ED - 7

MOCK TEST IN GEN ED 7-30-2023

PRE-BOARD IN GEN ED SCIENCE 7/7/2023

MARCH 2025 SD GEN ED FINAL COACHING - 7

Question 1 Category: Current Events Question: What was the primary demand of the Kenyan Gen Z protesters featured in the BBC documentary Unmasked: The Truth Behind the Gen Z Protests? Options: A) Free education B) Repeal of the Finance Bill 2024 C) Climate change action D) New elections Correct Answer: B) Repeal of the Finance Bill 2024 Explanation: The BBC documentary highlights that Kenyan youth protested to demand the repeal of the Finance Bill 2024, which proposed tax hikes raising $2.7 billion. Question 2 Category: Science Question: Which gas, discovered on the sun before Earth, is the second most abundant element in the universe? Options: A) Hydrogen B) Oxygen C) Helium D) Nitrogen Correct Answer: C) Helium Explanation: Helium was first detected in the sun’s spectrum in 1868 and is the second most abundant element after hydrogen in the universe. Question 3 Category: Current Events Question: Which Kenyan city was the epicenter of the Gen Z protests covered in the BBC documentary Unmasked: The Truth Behind the Gen Z Protests? Options: A) Mombasa B) Nairobi C) Kisumu D) Eldoret Correct Answer: B) Nairobi Explanation: Nairobi, Kenya’s capital, was the main hub for the #OccupyParliament protests, with significant events like the Parliament breach occurring there, as shown in the documentary. Question 4 Category: History Question: Which empire, known for its vast trade networks, was centered in modern-day Turkey and lasted until the early 20th century? Options: A) Roman Empire B) Ottoman Empire C) Mongol Empire D) Byzantine Empire Correct Answer: B) Ottoman Empire Explanation: The Ottoman Empire, spanning over 600 years until 1922, was a major trade and cultural power centered in modern-day Turkey. Question 5 Category: Current Events Question: According to the BBC documentary, what technology helped document evidence of police brutality during the Kenyan Gen Z protests? Options: A) Drones B) Smartphone videos C) Facial recognition software D) Satellite tracking Correct Answer: B) Smartphone videos Explanation: The documentary used smartphone videos from protesters and bystanders, analyzed via open-source data, to document police brutality during the 2024 protests. Question 6 Category: Geography Question: What is the smallest country in the world by land area? Options: A) Monaco B) Vatican City C) San Marino D) Liechtenstein Correct Answer: B) Vatican City Explanation: Vatican City, with an area of about 44 hectares, is the smallest sovereign state in the world by land area. Question 7 Category: Current Events Question: What hashtag became synonymous with the Kenyan Gen Z protests, as featured in the BBC documentary Unmasked: The Truth Behind the Gen Z Protests? Options: A) #KenyaRising B) #OccupyParliament C) #TaxRevolt D) #GenZFight Correct Answer: B) #OccupyParliament Explanation: The #OccupyParliament hashtag was widely used by protesters to rally against the Finance Bill 2024, as documented by the BBC. Question 8 Category: Entertainment Question: Which actor starred as the lead in the 2023 film Barbie and also played a role in La La Land? Options: A) Emma Stone B) Margot Robbie C) Zendaya D) Saoirse Ronan Correct Answer: B) Margot Robbie Explanation: Margot Robbie starred as Barbie in the 2023 film and played a supporting role in La La Land (2016). Question 9 Category: Sports Question: Which sport is played at the Wimbledon Championships? Options: A) Cricket B) Rugby C) Tennis D) Golf Correct Answer: C) Tennis Explanation: Wimbledon, held annually in London, is the oldest and one of the most prestigious tennis tournaments in the world. Question 10 Category: Technology Question: In web development, what does the acronym “CSS” stand for? Options: A) Computer Style System B) Cascading Style Sheets C) Creative Script Syntax D) Centralized Style Standard Correct Answer: B) Cascading Style Sheets Explanation: CSS (Cascading Style Sheets) is used to style and format the appearance of web pages written in HTML.

CARBOHYDRATES Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen in a ratio of about one carbon atom to two hydrogen atoms to one oxygen atom. The number of carbon atoms in a carbohydrate varies. Some carbohydrates serve as a source of energy. Other carbohydrates are used as structural materials. Carbohydrates can exist as monosaccharides, disaccharides, or polysaccharides. Monosaccharides A monomer of a carbohydrate is called a monosaccharide (MAHN-oh-SAK-uh-RIED). A monosaccharide—or simple sugar— contains carbon, hydrogen, and oxygen in a ratio of 1:2:1. The gen- eral formula for a monosaccharide is written as (CH2O)n, where n is any whole number from 3 to 8. For example, a six-carbon mono- saccharide, (CH2O)6, would have the formula C6H12O6. The most common monosaccharides are glucose, fructose, and galactose, as shown in Figure 3-6. Glucose is a main source of energy for cells. Fructose is found in fruits and is the sweetest of the monosaccharides. Galactose is found in milk. Notice in Figure 3-6 that glucose, fructose, and galactose have the same molecular formula, C6H12O6, but differing structures. The different structures determine the slightly different properties of the three compounds. Compounds like these sugars, with a single chemical formula but different structural forms, are called isomers (IE-soh-muhrz). SECTION 2 OBJECTIVES ● Distinguish between monosaccharides, disaccharides, and polysaccharides. ● Explain the relationship between amino acids and protein structure. ● Describe the induced fit model of enzyme action. ● Compare the structure and function of each of the different types of lipids. ● Compare the nucleic acids DNA and RNA. VOCABULARY carbohydrate monosaccharide disaccharide polysaccharide protein amino acid peptide bond polypeptide enzyme substrate active site lipid fatty acid phospholipid wax steroid nucleic acid deoxyribonucleic acid (DNA) ribonucleic acid (RNA) nucleotide C HO H C H OH C OH H C CH2OH H C H OH O Glucose C OH C O H OH C OH H CH2OH C H CH2OH Fructose C H HO C OH H C OH H C CH2OH H C H OH O Galactose Glucose, fructose, and galactose have the same chemical formula, but their structural differences result in different properties among the three compounds. FIGURE 3-6 Copyright © by Holt, Rinehart and Winston. All rights reserved. 56 CHAPTER 3 Disaccharides and Polysaccharides In living things, two monosaccharides can combine in a condensa- tion reaction to form a double sugar, or disaccharide (die-SAK-e-RIED). For example in Figure 3-4, the monosaccharides fructose and glu- cose can combine to form the disaccharide sucrose. A polysaccharide is a complex molecule composed of three or more monosaccharides. Animals store glucose in the form of the polysaccharide glycogen. Glycogen consists of hundreds of glucose molecules strung together in a highly branched chain. Much of the glucose that comes from food is ultimately stored in your liver and muscles as glycogen and is ready to be used for quick energy. Plants store glucose molecules in the form of the polysaccha- ride starch. Starch molecules have two basic forms—highly branched chains that are similar to glycogen and long, coiled, unbranched chains. Plants also make a large polysaccharide called cellulose. Cellulose, which gives strength and rigidity to plant cells, makes up about 50 percent of wood. In a single cellu- lose molecule, thousands of glucose monomers are linked in long, straight chains. These chains tend to form hydrogen bonds with each other. The resulting structure is strong and can be broken down by hydrolysis only under certain conditions. PROTEINS Proteins are organic compounds composed mainly of carbon, hydrogen, oxygen, and nitrogen. Like most of the other biological macromolecules, proteins are formed from the linkage of monomers called amino acids. Hair and horns, as shown in Figure 3-7a, are made mostly of proteins, as are skin, muscles and many biological catalysts (enzymes). Amino Acids There are 20 different amino acids, and all share a basic structure. As Figure 3-7b shows, each amino acid contains a central carbon atom covalently bonded to four other atoms or functional groups. A single hydrogen atom, highlighted in blue in the illustration, bonds at one site. A carboxyl group, —COOH, highlighted in green, bonds at a second site. An amino group, —NH2, highlighted in yel- low, bonds at a third site. A side chain called the R group, high- lighted in red, bonds at the fourth site. The main difference among the different amino acids is in their R groups. The R group can be complex or it can be simple, such as the CH3 group shown in the amino acid alanine in Figure 3-7b. The differences among the amino acid R groups gives different proteins very different shapes. The different shapes allow pro- teins to carry out many different activities in living things. Amino acids are commonly shown in a simplified way such as balls, as shown in Figure 3-7c. (a) Many structures, such as hair and horns are made of proteins. (b) Proteins are made up of amino acids. Amino acids differ only in the type of R group (shown in red) they carry. Polar R groups can dissolve in water, but nonpolar R groups cannot. (c) Amino acids have complex structures, so, in this and other textbooks, they are often simplified into balls. FIGURE 3-7 (b) Alanine (an amino acid) (c) Simplified version of amino acid CH3 H N OH C C H O H (a) Copyright © by Holt, Rinehart and Winston. All rights reserved. BIOCHEMISTRY 57 H H N C C OH H O H CH3 H2O Glycine Alanine H N OH C C H O H H H N C C H O H CH3 N OH C C H O H (a) (b) (a) The peptide bond (shaded blue) that binds amino acids together to form a polypeptide results from a condensation reaction that produces water. (b) Poly- peptides are commonly shown as a string of balls in this textbook and elsewhere. Each ball represents an amino acid. FIGURE 3-8 Substrate Products Enzyme 1 2 3 In the induced fit model of enzyme action, the enzyme can attach only to a substrate (reactant) with a specific shape. The enzyme then changes and reduces the activation energy of the reaction so reactants can become products. The enzyme is unchanged and is available to be used again. 3 2 1 FIGURE 3-9 Dipeptides and Polypeptides Figure 3-8a shows how two amino acids bond to form a dipeptide (die-PEP-TIED). In this condensation reaction, the two amino acids form a covalent bond, called a peptide bond (shaded in blue in Figure 3-8a) and release a water molecule. Amino acids often form very long chains called polypeptides (PAHL-i-PEP-TIEDZ). Proteins are composed of one or more polypep- tides. Some proteins are very large molecules, containing hun- dreds of amino acids. Often, these long proteins are bent and folded upon themselves as a result of interactions—such as hydrogen bonding—between individual amino acids. Protein shape can also be influenced by conditions such as temperature and the type of solvent in which a protein is dissolved. For exam- ple, cooking an egg changes the shape of proteins in the egg white. The firm, opaque result is very different from the initial clear, runny material. Enzymes Enzymes—RNA or protein molecules that act as biological catalysts—are essential for the functioning of any cell. Many enzymes are proteins. Figure 3-9 shows an induced fit model of enzyme action. Enzyme reactions depend on a physical fit between the enzyme molecule and its specific substrate, the reactant being catalyzed. Notice that the enzyme has folds, or an active site, with a shape that allows the substrate to fit into the active site. An enzyme acts only on a specific substrate because only that substrate fits into its active site. The linkage of the enzyme and substrate causes a slight change in the enzyme’s shape. The change in the enzyme’s shape weakens some chemical bonds in the substrate, which is one way that enzymes reduce activation energy, the energy needed to start the reaction. After the reaction, the enzyme releases the products. Like any catalyst, the enzyme itself is unchanged, so it can be used many times. An enzyme may not work if its environment is changed. For example, change in temperature or pH can cause a change in the shape of the enzyme or the substrate. If such a change happens, the reaction that the enzyme would have catalyzed cannot occur.

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