Q: Which of the following best describes the overall chemical equation for photosynthesis in chloroplasts?

$$6CO_2 + 6H_2O + \text{energy} \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 1

Which of the following best describes the overall chemical equation for photosynthesis in chloroplasts?

Accepted Answer

$$6CO_2 + 6H_2O + 	ext{energy} ightarrow C_6H_{12}O_6$ + 6O_2$$

Question 2

A scientist discovers an alien organism whose electron transport chain ends with fluorine gas ($$F_2) $$being reduced instead of oxygen ($$O_2). $$Based on the relative electronegativities, what is the most likely effect on ATP yield per glucose?

Accepted Answer

More ATP will be produced because $$F_2 is $$more electronegative than $$O_2.$$

Question 3

Which of the following is a consequence of a nonsense mutation in a protein-coding gene?

Accepted Answer

A premature stop codon is introduced, often resulting in a truncated and nonfunctional protein.

Question 4

Which of the following best explains why frameshift mutations are often more severe than point mutations?

Accepted Answer

Frameshift mutations alter the reading frame, changing every amino acid downstream of the mutation.

Question 5

A cell is exposed to ultraviolet (UV) light, resulting in the formation of thymine dimers. What is the most likely consequence if these dimers are not repaired?

Accepted Answer

DNA replication and transcription will be blocked, potentially leading to cell death.

Question 6

Which of the following is the correct sequence of events in cellular respiration in mitochondria?

Accepted Answer

Glycolysis → Krebs cycle → Electron transport chain

Question 7

A base-pair substitution results in a codon that codes for the same amino acid as the original. What type of mutation is this?

Accepted Answer

Silent mutation

Question 8

Which of the following best describes the role of oxygen in the mitochondrial electron transport chain?

Accepted Answer

Oxygen acts as the final electron acceptor, forming water.

Question 9

Reactive oxygen species (ROS) can cause oxidative DNA damage. Which of the following is a common result of such damage?

Accepted Answer

Formation of 8-oxoguanine, which can mispair with adenine during replication.

Question 10

Which DNA repair mechanism is most likely to be used to fix a double-strand break by copying sequence from the homologous chromosome?

Accepted Answer

Homologous recombination

Question 11

A mutation changes a codon from $$UAC ($$tyrosine) to $$UAA ($$stop). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 12

Which of the following is a likely outcome if DNA damage is not repaired and mutations accumulate in a cell?

Accepted Answer

The cell may develop cancer due to uncontrolled growth.

Question 13

Which of the following best describes a missense mutation?

Accepted Answer

A single nucleotide change results in a different amino acid in the protein.

Question 14

Which of the following is a real-world example of a chemical that can cause bulky DNA adducts and distort the DNA helix?

Accepted Answer

Benzo[a]pyrene from cigarette smoke

Question 15

Which of the following best explains why calorie restriction can increase lifespan in laboratory animals?

Accepted Answer

Calorie restriction reduces metabolic rate and oxidative stress, slowing aging.

Question 16

Which of the following is a direct result of a base-pair insertion in a protein-coding gene?

Accepted Answer

A frameshift mutation that alters the reading frame of the gene.

Question 17

Which of the following is a function of the p53 protein in response to DNA damage?

Accepted Answer

p53 can induce cell cycle arrest, allowing time for DNA repair.

Question 18

Which of the following best describes the difference between benzene and cyclohexane?

Accepted Answer

Benzene is aromatic and flat, while cyclohexane is non-aromatic and adopts a chair conformation.

Question 19

Which of the following is a likely effect of telomere shortening in human cells?

Accepted Answer

Cellular senescence, where cells stop dividing.

DNA Damage, Mutation, and Repair Mechanisms in Cellular Metabolism

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