Photosynthesis and Cellular Respiration, Exams of Biology

Download Photosynthesis and Cellular Respiration and more Exams Biology in PDF only on Docsity! UA BSC 108 Exam 2 Questions & Answers-2024 Update. What is a photosynthetic autotroph? - Correct Answer An organism that makes its own food from inorganic ingredients. What is the fluid inside chloroplasts called? - Correct Answer Stroma What are the membranes inside chloroplasts called? - Correct Answer inner and outer membranes Write the overall equation for photosynthesis. - Correct Answer 6CO2+6H2O→C6H12O6+6O2 What is the primary function of pigments in photosynthesis? Name the primary pigment used in photosynthesis. - Correct Answer Pigments absorb certain wavelengths. They are the means by which the energy of sunlight is captured for photosynthesis. The primary pigment used in photosynthesis is Chlorophylla-a. Why are leaves green? - Correct Answer Their green color is from chlorophyll, a pigment (light- absorbing molecule) in the chloroplasts that plays a central role in converting solar energy to chemical energy. How and where does water enter a plant? - Correct Answer Water enters root hair cells by osmosis. How and where does carbon dioxide enter a plant? - Correct Answer Carbon Dioxide diffuses through small holes in the underside of leaves, called the stomata. The light reactions take place in three stages. Name the stages and summarize the events of each stage. 1. Photons excite electrons in the chlorophyll of the first photosystem. These photons are then trapped by the primary electron acceptor. This photosystem then replaces the lost electrons by extracting new ones from water. This is the step that releases O2 during photosynthesis. 2. Energized electrons from the first photosystem pass down an electron transport chain to the second photosystem. The chloroplast uses the energy released by this electron "fall" to make ATP. 3. The second photosystem transfers its light-excited electrons to NADP+, reducing it to NADPH. List all products of the light reactions. carbon dioxide, water. Glucose, oxygen The Calvin cycle has three main stages. Name the stages and summarize the events of each stage. - Correct Answer "1) Carbon Fixation- The enzyme rubisco combines CO2 with 5-carbon sugar rubulose biphosphate (RuBP). The unstable product formed splits into 2 molecules of 3-carbon 3-phosphoglyceric acid (3-PGA). 2) Reduction- Energy from 6 molecules of ATP is used to oxidize NADPH to NADP+. Six molecules of 3-PGA are reduced, producing six molecules of energy-rich 3-carbon sugar G3P. 3) Release of one molecule of G3P- Five of the previously created G3Ps remain in the cycle, but one molecule is released. 4) Regeneration of RuBP - series of chemical reactions uses energy from ATP to rearrange the atoms of the 5 G3P molecules, (15 total carbons), which forms 3 RuBP molecules (15 total carbons). These will start another turn of the cycle. " List all products in the Calvin cycle. - Correct Answer "6 Turns of the Calvin Cycle→ 1 C₆H₁₂O₆ 6CO₂ → 1 C₆H₁₂O₆ 18 ATP + 12 NADPH → 1 C₆H₁₂O₆ Left over ATP is used elsewhere by the cell. " Give two examples of plants that use C4 photosynthesis. - Correct Answer "1) Corn 2) Sugarcane" What environmental factor is C4 photosynthesis an adaptation for? - Correct Answer High levels of CO2 and drought environments Contrast carbon fixation in C4 and CAM plants. C4 plants initially attach CO2toPEP to form the four-carbon compound OAA using the enzyme PEP carboxylase. This takes place in the loosely packed cells called mesophyll cells. OAA is then pumped to another set of cells, the bundle sheath cells, which surround the leaf vein. There, it releases the CO2for use by Rubisco. By concentrating CO2in the bundle sheath cells, C4plants promote the efficient operation of the Calvin-Benson cycle and minimize photorespiration. CAM plants also initially attach CO2to PEP and form OAA. However, instead of fixing carbon during the day and pumping the OAA to other cells, CAM plants fix carbon at night and store the OAA in large vacuoles within the cell. This allows them to have their stomates open in the cool of the evening, avoiding water loss, and to use the CO2 for the Calvin-Benson cycle during the day, when it can be driven by the sun's energy. 1. How does asexual reproduction differ from sexual reproduction? - Correct Answer Asexual Reproduction involves one parent and produces offspring that are genetically identical to each other and to the parent. Sexual Reproduction involves two parents and produces offspring that are genetically unique. 2. What are the two main phases of the eukaryotic cell cycle? - Correct Answer "a. Interphase b. Mitotic phase" 3. During which phase of the cell cycle does DNA duplicate? - Correct Answer interphase- chromosome duplication 4. What is the function of mitosis? - Correct Answer in mitosis the nucleus and its contents, most importantly, the divided chromosomes, divide and are evenly distributed, forming two daughter, nuclei 9. List the inputs and outputs of the citric acid cycle. - Correct Answer "Inputs- 2 acetyl CoA, 2 oxaloacetate, 2ADP + P, 6 NAD+, 2 FAD Outputs- 4 CO2, 2 ATP, 6 NADH + H+, 2 FADH2" 10. The third stage of cellular respiration is electron transport. Where in the cell does electron transport take place? - Correct Answer inner membrane 11. List the inputs and outputs of electron transport. - Correct Answer "Input- 10 NADH + H+, 2 FADH2 Output- 10 NAD+, 2FAD, H2O, 34 ATP" 12. Is oxygen required for electron transport? - Correct Answer yes 13. Which stage of cellular respiration generates the most ATP? - Correct Answer Electron Transport Chain 14. Describe fermentation in human muscle cells. - Correct Answer Under strenuous conditions, muscles spend ATP faster than the bloodstream can deliver O2, when this happen the muscles begin to work anaerobically. After around 15 second muscle cells begin to generate ATP by the fermentation process Describe fermentation in microorganisms. - Correct Answer microorganisms utilize energy stored in glucose in the absence of oxygen 1. What are alleles? - Correct Answer one of two alternate forms of gene that can have the same locus on homologous chromosomes and are responsible for alternative traits 2. Define homozygous and heterozygous. - Correct Answer "1) Homozygous- having identical alleles at corresponding chromosomal loci 2) Heterozygous- having two different alleles for a trait" 3. State the law of segregation. - Correct Answer members of a pair of homologous chromosomes separate during the formation of gametes and are distributed to different gametes so that every gamete receives only one member of the pair 4. Contrast genotype and phenotype. - Correct Answer genotype is the genetic makeup of an organism. Phenotype is what an organism looks like as a consequence of its genotype 5. State the law of independent assortment. - Correct Answer the law states that genes separate independently of one another in meiosis 6. What is a testcross? - Correct Answer a cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait, so the unknown genotype can be determined from that of the offspring 7. In dogs black hair color (B) is dominant to brown hair color (b). A black dog of unknown genotype mates with a brown dog (bb). Half of the puppies are black and half of the puppies are brown. What is the genotype of the black dog? - Correct Answer Bb Bb - Correct Answer 8. Describe an example of incomplete dominance. - Correct Answer A brown fur coat on a rabbit because of one rabbit's red allele and one rabbits white allele not dominating 9. How is your blood type determined? - Correct Answer each biological parent donates one of two ABO genes to their child. The A and B genes are dominant, and the O gene is recessive 10. Can a woman and a man both with Type A blood have a baby with Type O blood? Explain your answer. - Correct Answer A person with the blood type A can have one of two genotypes: AA, or AO. If the person has genotype AA it would be impossible for them to have a child with blood type O. If the person has genotype AO there would be a 50% chance of passing on the O allele. The father would also have to pass on an O allele for the child to have blood type O 11. What is pleiotropy? - Correct Answer when one gene influences two or more seemingly unrelated phenotypic traits. What is polygenic inheritance? - Correct Answer inheritance pattern of a trait controlled by two or more genes, genes may be the same of different chromosomes