Bio 93 Final Exam Questions And Answers With Complete Solutions 100% Correct 2024, Exams of Advanced Education

Download Bio 93 Final Exam Questions And Answers With Complete Solutions 100% Correct 2024 and more Exams Advanced Education in PDF only on Docsity! Bio 93 Final Exam Questions And Answers With Complete Solutions 100% Correct 2024 What is true regarding Chargaff's Rule? - Correct Answer-[A] = [T] and [G] = [C] Which bond is harder to break; A-T or G-C? - Correct Answer- The bond between G-C (Guanine and Cytosine) is harder to break, because there are three H-bonds between G and C. On the other hand, there are only two H-bonds between A and T (Adenine and Thymine) What did the results of the Griffith Experiment indicate? - Correct Answer-Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form. Which element is found in proteins but not in DNA? - Correct Answer-Sulfur pg. 1 professoraxe l Which element is found in DNA but not in proteins? - Correct Answer-Phosphorus Based on the experimental results of the Hershey and Chase experiment, what is the "genetic material"? - Correct Answer- DNA, because ³²P was found in the pellet. Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? - Correct Answer- 8% thymine. This is because A+T+C+G = 100%. Since C base pairs with G, if there is 42% C, that means there is approximately 42% G. 42% C + 42% G = 84% of the total bases. Then we take 100% - 84% = 16%. Splitting 16% by the two remaining bases (A and T) gives 8% each. Explain what bacterial transformation is and how it was used in the Griffith experiment. - Correct Answer-Bacterial transformation is a change in genotype and phenotype due to assimilation of external DNA by a cell. The Griffith experiment showed that there was transfer of genetic material from heat- killed pathogenic cells and living nonpathogenic cells. Injection of the mouse with this combination led to death, even though the pathogenic cells were dead, indicating that the genetic material must have been transferred to the living pg. 2 professoraxe l Why do we need Okazaki fragments? - Correct Answer-DNA synthesis can occur only in the 5'→3' direction, and DNA strands must be antiparallel How does DNA replication account for mistakes? - Correct Answer-DNA polymerases proofread and replace anything incorrect Mismatch repair: repair enzymes correct errors in base pairing Nucleotide excision repair: nuclease cuts/pastes damaged DNA In prokaryotes, can translation occur while transcription is still finishing? - Correct Answer-Prokaryotic transcription occurs in the cytoplasm alongside translation. Prokaryotic transcription and translation can occur simultaneously. This is impossible in eukaryotes, where transcription occurs in a membrane-bound nucleus while translation occurs outside the nucleus in the cytoplasm. pg. 5 professoraxe l What is the transcript sequence for the following DNA template: 5'-AGG CGA TGC ACT-3' - Correct Answer-3'-UCC GCU ACG UGA-5' ** "U" instead of "T" What are the three steps of translation? - Correct Answer-1) Initiation: The ribosome assembles around the target mRNA. The first tRNA is attached at the start codon. 2) Elongation: The tRNA transfers an amino acid to the tRNA corresponding to the next codon. The ribosome then moves (translocates) to the next mRNA codon to continue the process, creating an amino acid chain. 3) Termination: When a stop codon is reached, the ribosome releases the polypeptide. How much of the human genome is translated into protein? - Correct Answer-<2% pg. 6 professoraxe l What is the polypeptide sequence for the following RNA transcript: 3'-UCC GCU ACG UGA-5' - Correct Answer-Ser-Ala- Ser-Pro **Flip the RNA transcript first so it reads 5'-3' Will the RNA transcript above produce a functional polypeptide? - Correct Answer-No; there is no start/stop codon What is a silent mutation? - Correct Answer-No observable effect on the phenotype; substitution codes for the same amino acid What is a missense mutation? - Correct Answer-Substitution that changes one amino acid to another type. Generally has little effect on protein What is a nonsense mutation? - Correct Answer-Occurs when a point mutation changes a codon for an amino acid into a stop codon. Causes translation to be terminated prematurely and leads to a nonfunctional protein. pg. 7 professoraxe l G2: More growth and double checking everything M: Cell division and cytokinesis Describe the different cell cycle checkpoints - Correct Answer- G1 checkpoint: Does the cell need to divide? G2 checkpoint: Is the cell prepared to divide? M checkpoint: How is division working out? What happens when regulation of the cell cycle fails? - Correct Answer-Cancer, which is the result of too much cell division What is the most important checkpoint in the cell cycle and why? - Correct Answer-The G1 checkpoint is the most important because if the cell passes this checkpoint, it will begin the cell cycle and expend a large amount of energy preparing for division before it is checked again at the beginning of mitosis. pg. 10 professoraxe l Contrast proto-oncogenes and tumor suppressor genes and the mutations that affect each and describe why mutations can cause cancer. - Correct Answer-Proto-oncogenes promote the cell cycle and become pathological through gain of function mutations whereas tumor suppressor genes inhibit the cell cycle and become pathological through loss of function mutations. Mutations in either of these genes has the potential to dysregulate the cell cycle by increasing the rate of cell division which, if left unchecked, can lead to cancer. What are being separated during anaphase I vs anaphase II? At which stage would a nondisjunction event be more detrimental and why? - Correct Answer-Anaphase I - homologous chromosomes Anaphase II - Sister chromatids Nondisjunction during anaphase I is particularly detrimental because all 4 gametes will have inappropriate chromosome numbers compared to only two affected gametes if the nondisjunction occurs during anaphase II. Lecture #9 - Correct Answer---- pg. 11 professoraxe l What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants? - Correct Answer- Traits are inherited in discrete units and are not the results of "blending." Probability rule: "AND" - Correct Answer-Multiplication rule: if looking at the probability of having 2+ independent events happening together For example, "What is the probability of a seed being brownAND long?" (probability of brown) X (probability of long) Probability rule: "OR" - Correct Answer-Addition rule: if looking at the probability of 2+ mutually exclusive events happening together For example, "What is the probability of getting a long seed OR a short seed?" (probability of long) + (probability of short) How to read a pedigree tree: - Correct Answer-Circle: Female Square: Male pg. 12 professoraxe l Consider the cross of GgHhTT x GgHHTt - what is the probability of getting offspring that are GGHhTT OR ggHhTt? - Correct Answer-1/8 Map out the correct chromosome map for four genes given the following information: X-Z = 18% X-G = 35% Z-Y = 27% Z-G = 53% X-Y = 45% - Correct Answer-Y-Z-X-G or G-X-Z-Y Lecture #10 - Correct Answer---- In a developing frog embryo, most of the yolk is _____. - Correct Answer-located near the vegetal pole Cells move to new positions as an embryo establishes its three germ-tissue layers during _____. - Correct Answer-gastrulation A researcher is interested in developing a new drug for depression that supposedly balances serotonin levels in the brain. The researcher specifically wants to target the _________ because this is where neuron-to-neuron communication occurs. - Correct Answer-synapse pg. 15 professoraxe l Myelin sheaths are present mostly in: - Correct Answer-white matter Which of the following is true regarding aphasias? - Correct Answer-Wernicke's Aphasia results from specific damage to an area of the brain mostly associated with reading The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, what would happen at the posterior end? - Correct Answer-Anterior structures would form in the posterior end of the embryo. For a neuron with an initial membrane potential at -70mV, experimentally increasing potassium efflux would depolarize/repolarize/hyperpolarize (choose one) the cell. Explain your answer. - Correct Answer-Hyperpolarize because positively-charged ions are moving out of the cell. Pretend you are a physician and you attempt to trigger the knee-jerk reflex in your patient and there is no response. Can you conclude that the patient has brain damage? Why or why not? In your explanation, use the terms "sensory neurons", "motor neurons", and "interneurons". - Correct Answer-No, pg. 16 professoraxe l because the reflex involves only sensory neurons in the muscle and motor neurons and interneurons from the spinal cord. pg. 17 professoraxe l