BIol 105 Homework 2 2024 Fall PDF

**[BIOL 105 (2024 Fall): Homework 2 (total 50 pts)]** Due date: 10/30 (Wed) before the class Name: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ [(submit it as printout)] **[Questions (Q1-26) (1.4 pt each)]** 1. Which organelle in eukaryotic cells plays a role in degrading (and r...

**[BIOL 105 (2024 Fall): Homework 2 (total 50 pts)]** Due date: 10/30 (Wed) before the class Name: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ [(submit it as printout)] **[Questions (Q1-26) (1.4 pt each)]** 1. Which organelle in eukaryotic cells plays a role in degrading (and recycling) unnecessary macromolecules into building blocks (glucose, nucleotides, fatty acids, and amino acids)? a\) RER b\) SER c\) mitochondria d\) nucleus e\) lysosome 2. Homologous chromosomes move toward opposite poles of a dividing cell during? a\) mitosis b\) fertilization e\) binary fission d\) meiosis I e\) meiosis II 3. Nuclear DNA exists as a complex of proteins called \_\_\_\_\_\_\_\_ that condenses into \_\_\_\_\_\_\_\_ during cell division. a\) chromosomes; chromatin b\) chromatin; chromosomes c\) chromophores; chromatin d\) chromatids; chromosomes e\) chromophores; chromosomes 4. Active transport differs from passive transport in that active transport a\) moves molecules with a concentration gradient. b\) never requires direct input of ATP. c\) doesn't need proteins for transport. d\) requires ATP hydrolysis energy. e\) Both a and c 5. ATP hydrolysis releases energy to fuel various cellular functions. ATP hydrolysis is \_\_\_\_\_\_\_\_\_ (choose multiple correct answers) a\) endergonic. b\) exergonic. c\) endosymbiotic d\) spontaneous e\) nonspontaneous 6\. Enzymes are biological catalysts and function by a\) increasing free energy in a system. b\) lowering activation energy of a reaction. c\) lowering entropy in a system. d\) increasing temperature near a reaction. e\) lowing forward rate of a reaction. 6. One difference between cancer cells and normal cells is that cancer cells a\) are unable to synthesize DNA. b\) are arrested at the G1 phase of the cell cycle. c\) continue to divide even when they are tightly packed together. d\) cannot metabolize glucose. 7. Which of the following describes the role of [the mitochondrial inner membrane]? respiration. b\) The membrane allows for the establishment of a proton-motive force. c\) The membrane acts as a barrier for oxygen gas. d\) Both a and b e\) The membrane allows for the establishment of an electron motive force. 8. Pancreatic cells are active in secreting insulin hormone into blood stream for regulating a blood glucose level. Which organelles play active role in this secretive pathway of pancreatic cells? ([choose two best answers]) a\) lysosome b\) ER c\) centriole d\) mitochondria e\) Golgi complex 9. In mitochondrial inner membrane, exergonic redox reactions a\) are the source of energy driving prokaryotic NADPH synthesis. b\) provide the free energy that establishes the proton gradient. c\) reduce carbon atoms to carbon dioxide. d\) are coupled via phosphorylated intermediates to endergonic processes. 10. Which statement about channels/transporters is not true? a\) They form pores in the membrane. b\) Their transports are facilitated diffusion. c\) Each ion passes through the specific type of ion channel. d\) Movement through them is from regions of high concentration to regions of low concentration. e\) They are the example of simple diffusion. 11. The role of oxygen gas in mitochondria of our (human) cells is to a\) catalyze reactions in glycolysis. b\) produce CO~2~. c\) form ATP. d\) accept electrons from the electron transport chain. e\) react with protein to split water. 12. Glycolysis a\) takes place in the mitochondrion. b\) produces no ATP. c\) is part of the respiratory chain. d\) is the same thing as fermentation. e\) reduces two molecules of NAD^+^ for every glucose molecule processed. 13. Single-celled animals like amoebas engulf entire cells for food. Which of the following represents the manner in which amoebas \"eat\"? a. Exocytosis b. Phagocytosis c. Facilitative diffusion d. Active transport e. Simple diffusion 14. Which of the following processes includes all the others? a\) osmosis b\) diffusion of a solute across a membrane c\) passive transport d\) transport of an ion down its electrochemical gradient e\) movement of water across a membrane 15. Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as \_\_\_\_\_\_\_\_\_\_\_\_ is to \_\_\_\_\_\_\_\_\_\_\_\_. ([Select two answers]) a\) exergonic; spontaneous b\) exergonic; endergonic c\) free energy; enthalpy d\) endergonic; exergonic e\) oxidative; reductive f\) reductive; oxidative 16. Which is not a component of the receptor-mediated endocytosis process? a\) a specific receptor protein of signaling molecule b\) clathrin proteins c\) coated pitt d\) an RNA molecule e\) coated vesicle 17. Ion channel proteins allow ions that would not normally pass through the cell membrane to pass through via the channel. What properties of the proteins are responsible for this? a\) The channels are often composed of polar amino acid groups, that acting as a pore. b\) The channels are often composed of hydrophobic amino acid group, that acting as a pore. c\) Cholesterol molecules in the channel protein act as pore. d\) Modified sugars act as a pore. 18. Ascorbic acid (Vitamin C), found in citrus fruits, acts as an inhibitor to catecholase, the enzyme responsible for the browning reaction in fruits such as apples, peaches, and pears. One possibility for its function could be that ascorbic acid is very similar in size and shape to catechol, [the substrate] of the catecholase-catalyzed browning reaction. If this is true, then this inhibition is most likely an example of inhibition. a\) noncompetitive b\) uncompetitive c\) indirect d\) competitive 19. Which of the following does not occur in the mitochondria of eukaryotic cells? a\) Citric acid cycle b\) Oxidative phosphorylation c\) Fermentation d\) Electron transport (respiration) chain e\) Pyruvate oxidation to acetyl-CoA 20. Which of the following statements best describes the relationship between photosynthesis and respiration? a\) Respiration is the exact reversal of the biochemical pathways of photosynthesis. b\) Photosynthesis stores energy in complex organic molecules, while respiration releases it. c\) Photosynthesis occurs only in plants and respiration occurs only in animals. d\) ATP molecules are produced in photosynthesis and used up in respiration. e\) Respiration is anabolic and photosynthesis is catabolic. 21. Plants give off 0~2~ because a\) 0~2~ results from the incorporation of CO~2~ into sugars. b\) mitochondria respire. c\) water is the initial electron and proton donor, leaving 0~2~ as a light reaction by-product. d\) 0~2~ is produced due to the oxidation of NADPH. 22. An artificial "cell" consisting of an aqueous solution enclosed in a selectively permeable membrane is immersed in a beaker containing a different solution, the "environment," as shown in the accompanying diagram. The membrane is permeable to water and to the monosaccharide sugars, glucose and fructose but impermeable to the disaccharide sucrose. a. Is the solution outside the cell isotonic, hypotonic, or hypertonic? b. Draw a dashed arrow to show the net osmosis, if any. c. Will the artificial cell become more flaccid, more turgid, or stay the same? 23. Which statement about the cell cycle is not true? a\) It consists of interphase, mitosis, and cytokinesis. b\) The cell's DNA replicates during S phase of interphase. c\) A cell can remain in dormant G0 for weeks or much longer. d\) Chromosomes are separated during the metaphase in mitosis. e\) Cells enter the cell cycle as a result of internal or external signals. 24. In meiosis, a\) meiosis II reduces the chromosome number from diploid to haploid. b\) DNA replicates between meiosis I and meiosis II. c\) the chromatids that make up a chromosome in meiosis II are identical. d\) each chromosome in prophase I consists of four chromatids. e\) homologous chromosomes separate from one another in anaphase I. 25. What is reduced in the following reaction? Pyruvate + NADH + H^+^ Lactate + NAD^+^ a\) oxygen b\) NADH c\) lactate d\) pyruvate 26. The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the 27. Plot free energy versus the time course (chemical reaction profile) of an endergonic reaction, and the same for an exergonic reaction. Include the activation energy (E~a~) on both plots and label clearly E~a~ and ΔG on both graphs. (2 pts) 28. Explain the difference between "facilitated diffusion" and "active transport". (2 pts) 29. Enzyme activity is controlled by many ways. Explain [3 major mechanisms] how enzyme activity is controlled. (2 pts) 30. Explain the difference between autotroph and heterotroph. (2 pts) 31\. What are the two major products of [the light reaction] of photosynthesis and what is the major product of [the Calvin cycle] in plants? (2 pts) 32\. Explain briefly how specific cyclin regulates the progression of a cell division cycle (mitosis). (1.6 pts) 33\. Explain the difference between cellular respiration and fermentation. (2 pts)