Question 1

Which phase of mitosis is characterized by the alignment of chromosomes along the center of the cell, and what is the significance of this arrangement?

Accepted Answer

Metaphase; it allows spindle fibers to attach to centromeres for equal segregation.

Question 2

During meiosis, crossing-over occurs in which stage, and what is its genetic consequence?

Accepted Answer

Prophase I; it increases genetic variation by exchanging DNA between homologous chromosomes.

Question 3

Which of the following best describes the difference between DNA replication and transcription?

Accepted Answer

DNA replication produces two identical DNA molecules, while transcription produces an RNA molecule from a DNA template.

Question 4

A mutation that changes a codon from $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} ($$stop) is best described as:

Accepted Answer

Nonsense mutation

Question 5

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 6

If a cell fails to pass the G1 checkpoint, what is the most likely outcome?

Accepted Answer

The cell will enter G0 phase and stop dividing.

Question 7

Which of the following best explains the role of tRNA during translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches its anticodon to the mRNA codon.

Question 8

A cell with a diploid number of 8 undergoes meiosis. How many chromosomes will each gamete contain?

Accepted Answer

4

Question 9

Which process ensures that each daughter cell receives an identical set of chromosomes during cell division?

Accepted Answer

Mitosis

Question 10

Which of the following is a function of the enzyme DNA ligase during DNA replication?

Accepted Answer

Joins Okazaki fragments on the lagging strand

Question 11

A patient is diagnosed with a genetic disorder caused by a frameshift mutation. Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation that inserts or deletes a base, altering the reading frame of the gene.

Question 12

Which of the following best describes the semi-conservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one old strand and one new strand.

Question 13

Which of the following is NOT a function of RNA polymerase?

Accepted Answer

Synthesizing DNA from an RNA template

Question 14

Which of the following best explains why complementary base pairing is essential for DNA replication?

Accepted Answer

It allows for the accurate copying of genetic information.

Question 15

A scientist observes that a cell is synthesizing proteins but not dividing. Which phase of the cell cycle is the cell most likely in?

Accepted Answer

G1 phase

Question 16

Which of the following is the correct sequence of events in gene expression?

Accepted Answer

Replication → Transcription → Translation

Question 17

Which of the following best describes the role of a promoter in transcription?

Accepted Answer

It is the region of DNA where RNA polymerase binds to initiate transcription.

Question 18

Which of the following mutations would most likely have the least effect on the resulting protein?

Accepted Answer

Silent mutation

Question 19

A cell is exposed to a mutagen that causes thymine dimers to form. Which repair mechanism is most likely to fix this damage?

Accepted Answer

Nucleotide excision repair

Question 20

Which of the following best explains the difference between the leading and lagging strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized in short fragments called Okazaki fragments.

Cellular Reproduction, Gene Expression, and Regulation – Study Notes

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