Question 1

Which of the following best describes the structure of a DNA molecule?

Accepted Answer

A double helix with a backbone of alternating phosphate and deoxyribose, and paired nitrogenous bases connecting the two strands

Question 2

Which of the following is a pyrimidine base found in DNA?

Accepted Answer

Cytosine

Question 3

If a segment of DNA has the sequence $$5'	ext{-}ATCGGTA-3'$$, what would be the complementary sequence on the opposite strand?

Accepted Answer

$$3'	ext{-}TAGCCAT-5'$$

Question 4

Which of the following statements about the genetic code is correct?

Accepted Answer

There are 64 possible codons, but only 20 amino acids

Question 5

During DNA replication, which enzyme is primarily responsible for adding new nucleotides to the growing DNA strand?

Accepted Answer

DNA polymerase

Question 6

A mutation changes a DNA triplet from $$	ext{TAC} to$$ $$	ext{TAG}. $$What effect will this have on the resulting protein?

Accepted Answer

It may introduce a stop codon, potentially truncating the protein

Question 7

Which of the following best explains why DNA replication is described as 'semiconservative'?

Accepted Answer

Each new DNA molecule consists of one old (parental) strand and one newly synthesized strand

Question 8

Which of the following is NOT a function of noncoding DNA?

Accepted Answer

Coding for the amino acid sequence of proteins

Question 9

A patient is diagnosed with a genetic disorder caused by a mutation in a gene found on the X chromosome. Which of the following statements is most accurate regarding inheritance of this disorder?

Accepted Answer

Males are more likely to express the disorder because they have only one X chromosome

Question 10

Which of the following best describes the role of transfer RNA (tRNA) during translation?

Accepted Answer

tRNA delivers specific amino acids to the ribosome based on the codon sequence of mRNA

Question 11

A scientist is studying a cell in which the nuclear envelope is breaking down, chromosomes are condensing, and spindle fibers are forming. Which phase of mitosis is being observed?

Accepted Answer

Prophase

Question 12

Which of the following is a correct sequence of events in the cell cycle?

Accepted Answer

G1 phase → S phase → G2 phase → M phase

Question 13

A cell is observed to have 46 chromosomes, each consisting of two sister chromatids. Which stage of the cell cycle is this cell most likely in?

Accepted Answer

G2 phase

Question 14

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

Accepted Answer

It ensures that each new DNA strand is an exact copy of the original

Question 15

Which of the following is true regarding the difference between DNA and RNA?

Accepted Answer

RNA contains ribose sugar, while DNA contains deoxyribose

Question 16

A researcher finds a cell with a mutation that prevents the formation of spindle fibers. Which process will be directly affected?

Accepted Answer

Mitosis

Question 17

Which of the following best describes the function of histones in the cell nucleus?

Accepted Answer

They help package and organize DNA into nucleosomes

Question 18

If a cell fails to complete cytokinesis after mitosis, what will be the result?

Accepted Answer

A single cell with two nuclei

Question 19

Which of the following is a real-world example of the importance of accurate DNA replication?

Accepted Answer

A mutation in a gene coding for hemoglobin can result in sickle cell anemia

Genetics and Cellular Function: DNA Structure and Function

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