Question 1

Which of the following best describes the structure of DNA?

Accepted Answer

A double helix composed of nucleotides with a deoxyribose sugar and phosphate backbone

Question 2

During DNA replication, which of the following statements is correct regarding the semi-conservative model?

Accepted Answer

Each new DNA molecule consists of one parent strand and one newly synthesized strand

Question 3

Which base pairing is correct in RNA, and how does it differ from DNA?

Accepted Answer

Adenine pairs with Uracil in RNA, while in DNA it pairs with Thymine

Question 4

A scientist discovers a mutation in a homeotic gene in a fruit fly. Which of the following is the most likely result?

Accepted Answer

The fly may develop extra or missing body parts, such as legs in the wrong place

Question 5

Which process occurs in the nucleus and results in the formation of mRNA?

Accepted Answer

Transcription

Question 6

A codon is best described as:

Accepted Answer

A three-base sequence on mRNA that codes for a specific amino acid

Question 7

Which of the following best explains why all cells in the human body can have the same DNA but perform different functions?

Accepted Answer

Gene expression varies between cells, allowing for specialized functions

Question 8

A patient is diagnosed with a malignant tumor. Which of the following best describes this condition?

Accepted Answer

The tumor has spread to other parts of the body and is harmful

Question 9

Which of the following substances is considered a mutagen and increases the risk of cancer?

Accepted Answer

Tobacco smoke

Question 10

During translation, what is the role of tRNA?

Accepted Answer

tRNA brings specific amino acids to the ribosome by matching its anti-codon to the mRNA codon

Question 11

A proto-oncogene mutates and becomes an oncogene. What is the most likely consequence?

Accepted Answer

The cell may begin to divide uncontrollably, potentially leading to cancer

Question 12

Which of the following is a recommended way to reduce the risk of developing cancer?

Accepted Answer

Avoid tobacco and radiation, and maintain a healthy diet and exercise routine

Question 13

If a mutation occurs in the DNA sequence coding for a protein, which of the following outcomes is most likely?

Accepted Answer

The protein may be abnormal or not produced at all

Question 14

Which of the following equations correctly represents the central dogma of molecular biology?

Accepted Answer

$$DNA ightarrow RNA ightarrow 	ext{Protein}$$

Question 15

A researcher exposes cells to a chemical that causes frequent errors during DNA replication. What is the most likely classification of this chemical?

Accepted Answer

Mutagen

Question 16

Which of the following best describes the difference between benign and malignant tumors?

Accepted Answer

Benign tumors are isolated and non-spreading, while malignant tumors invade other tissues

Question 17

Which of the following is NOT a component of a DNA nucleotide?

Accepted Answer

A ribose sugar

Question 18

A mutation in a gene results in the loss of a stop codon in mRNA. What is the most likely effect on the resulting protein?

Accepted Answer

The protein will be longer than normal, possibly with abnormal function

Question 19

Which of the following best explains why exposure to UV radiation increases cancer risk?

Accepted Answer

UV radiation acts as a mutagen, causing changes in DNA that can lead to uncontrolled cell growth

Question 20

A cell is observed to have uncontrolled growth and division. Which of the following genetic changes is most likely responsible?

Accepted Answer

A mutation that converts a proto-oncogene into an oncogene, leading to unchecked cell division

Chapter 6: DNA—The Molecule of Life (Study Guide)

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