Question 1

Match the nucleotide to its correct description.
-This nucleotide is a double-ringed molecule.
A)guanine
B)cytosine
C)pyrimidine
D)thymine

Accepted Answer

Guanine is a purine nucleotide, which means it has a double ring structure consisting of a six-membered ring fused to a five-membered ring.

Question 2

The term "DNA sequence" refers to the ____.
A)order of nucleotides in a strand of DNA
B)number of nucleotides in a strand of DNA
C)number of chromosomes in a nucleus
D)number of hydrogen bonds in a strand of DNA
E)identity of genes in a strand of DNA

Accepted Answer

The term "DNA sequence" refers specifically to the order of nucleotides (adenine, guanine, cytosine, and thymine) in a strand of DNA.

Question 3

​The two strands of a DNA molecule are ____ to each other and run in ____.
A)​parallel; opposite directions
B)​parallel; the same direction
C)​perpendicular; opposite directions
D)​perpendicular; the same direction
E)​parallel; either the same or opposite directions

Accepted Answer

The two strands of a DNA molecule are parallel to each other but run in opposite directions.

Question 4

Which statement best describes a DNA mutation?
A)DNA polymerase adds an incorrect base during replication.
B)DNA is damaged by UV irradiation.
C)A mistake in the DNA sequence is repaired during replication.
D)A permanent change occurs in the nucleotide sequence of DNA.
E)Proofreading during replication replaces a mismatched nucleotide.

Accepted Answer

A DNA mutation is a permanent change in the nucleotide sequence of DNA. This can occur from errors during replication, exposure to mutagenic agents, or spontaneous errors in DNA synthesis. The result is a change in the genetic code, which can lead to altered protein function and potentially harmful effects on an organism.

Question 5

​Which bases are purines?
A)​cytosine and thymine
B)​guanine and thymine
C)​guanine and cytosine
D)​adenine and guanine
E)​adenine and thymine

Accepted Answer

Purines are nitrogenous bases that have a two-ring structure. Adenine and guanine are the two purine bases found in DNA.

Question 6

Match the nucleotide to its correct description.
-Three hydrogen bonds connect guanine to this in a DNA molecule.
 
A)guanine
B)cytosine
C)pyrimidine
D)thymine

Accepted Answer

The answer of Match the nucleotide to its correct description.
-Three...

Question 7

Which enzyme assembles new strands of DNA during replication?
A)DNA ligase
B)DNA synthase
C)primers
D)DNA polymerase
E)hybridization

Accepted Answer

DNA polymerase is the enzyme responsible for assembling new strands of DNA during replication. It does this by reading the template strand and adding complementary nucleotides to the growing daughter strand. The other options listed (A, B, C, and E) are involved in the replication process but do not actually assemble the new DNA strands.

Question 8

Which DNA damaging agent can transfer methyl groups (-CH3) to the nucleotide bases in DNA?
A)UV light
B)chemicals in tobacco smoke
C)ionizing radiation
D)x-rays
E)free radicals

Accepted Answer

Chemicals in tobacco smoke, such as benzo[a]pyrene, are known to transfer methyl groups (-CH3) to the nucleotide bases in DNA, causing DNA damage. This can result in mutations and potentially lead to cancer. UV light, ionizing radiation, x-rays, and free radicals can also damage DNA, but they do not directly transfer methyl groups to the nucleotide bases.

Question 9

DNA replication produces ____.
A)one single-stranded RNA molecule
B)one double-stranded DNA molecule
C)two double-stranded DNA molecules
D)one single-stranded DNA molecule
E)new proteins

Accepted Answer

During DNA replication, the double-stranded DNA molecule is unwound and each strand serves as a template for the synthesis of a complementary strand. This results in the production of two identical double-stranded DNA molecules.

Question 10

Match the term with the most appropriate description.
-a protein that organizes DNA
A)nucleosome
B)sister chromatids
C)centromere
D)histone
E)chromosome

Accepted Answer

Histones are proteins that organize DNA by wrapping DNA around them to form nucleosomes.

Question 11

Match the term with the most appropriate description.
-a length of DNA wound twice around histone proteins
A)nucleosome
B)sister chromatids
C)centromere
D)histone
E)chromosome

Accepted Answer

A nucleosome is a length of DNA wound twice around histone proteins.

Question 12

An example of a somatic cell is a(n) ____.
A)nucleus
B)kidney cell
C)sperm
D)egg
E)centromere

Accepted Answer

A somatic cell refers to any cell in an organism that is not part of the reproductive cells. Kidney cells are an example of somatic cells, while sperm and eggs are reproductive cells. A nucleus and centromere are parts of a cell, but not cells themselves.

Question 13

Match the term with the most appropriate description.
-two identical halves of a duplicated eukaryotic chromosome
A)nucleosome
B)sister chromatids
C)centromere
D)histone
E)chromosome

Accepted Answer

Sister chromatids are two identical copies of a duplicated chromosome that are joined at the centromere.

Question 14

Match the term with the most appropriate description.
-a structure that consists of DNA and associated proteins; carries part or all of a cell's genetic information
A)nucleosome
B)sister chromatids
C)centromere
D)histone
E)chromosome

Accepted Answer

A chromosome is a structure that consists of DNA and associated proteins and carries part or all of a cell's genetic information.

Question 15

​Complementary base pairs in a DNA molecule are held together by ____ bonds.
A)​nitrogen
B)​hydrogen
C)​covalent
D)​pyrimidine
E)​purine

Accepted Answer

Complementary base pairs in DNA (A with T, and C with G) are held together by hydrogen bonds. These weak chemical bonds allow the strands to separate for DNA replication and transcription.

Question 16

​In a DNA molecule, cytosine binds to ____ by ____ hydrogen bonds.
A)​thymine; two
B)​adenine; two
C)​adenine; three
D)​guanine; two
E)​guanine; three

Accepted Answer

Cytosine binds to guanine by three hydrogen bonds in a DNA molecule, which helps to stabilize the DNA structure.

Question 17

Match the nucleotide to its correct description.
-Early data indicated that within any DNA molecule, the amount of this was always equal to the amount of adenine.
A)guanine
B)cytosine
C)pyrimidine
D)thymine

Accepted Answer

This statement is referring to Chargaff's rule, which states that the amount of thymine is always equal to the amount of adenine in a DNA molecule. Therefore, the correct choice is D (thymine).

Question 18

Match the term with the most appropriate description.
-constricted region where duplicated chromosomes are attached to each other
A)nucleosome
B)sister chromatids
C)centromere
D)histone
E)chromosome

Accepted Answer

The constricted region where duplicated chromosomes are attached to each other is called a centromere.

Question 19

Match the nucleotide to its correct description.
-If one strand of a DNA molecule has a purine at a given position, this will be its complement on the other strand.
A)guanine
B)cytosine
C)pyrimidine
D)thymine

Accepted Answer

In DNA, purines (adenine and guanine) pair with pyrimidines (cytosine and thymine). If one strand has a purine, its complement will be a pyrimidine.

Question 20

When a cell has two complete sets of chromosomes, it is ____.
A)haploid
B)duplicated
C)diploid
D)triploid
E)complete

Accepted Answer

A cell with two complete sets of chromosomes is called diploid. This means it has both paternal and maternal copies of each chromosome, for a total of 46 chromosomes in humans. This is in contrast to haploid cells, which have only one set of chromosomes, and triploid cells, which have three sets of chromosomes. "Duplicated" and "complete" are not accurate descriptions of a cell with two complete sets of chromosomes.

Quiz 8: DNA Structure and Function

Match the nucleotide to its correct description. -This nucleotide is a double-ringed molecule.

The term "DNA sequence" refers to the ____.

The two strands of a DNA molecule are to each other and run in .

Which statement best describes a DNA mutation?

Which bases are purines?

Match the nucleotide to its correct description. -Three hydrogen bonds connect guanine to this in a DNA molecule.

Which enzyme assembles new strands of DNA during replication?

Which DNA damaging agent can transfer methyl groups (-CH3) to the nucleotide bases in DNA?

DNA replication produces ____.

Match the term with the most appropriate description. -a protein that organizes DNA

Match the term with the most appropriate description. -a length of DNA wound twice around histone proteins

An example of a somatic cell is a(n) ____.

Match the term with the most appropriate description. -two identical halves of a duplicated eukaryotic chromosome

Match the term with the most appropriate description. -a structure that consists of DNA and associated proteins; carries part or all of a cell's genetic information

Complementary base pairs in a DNA molecule are held together by ____ bonds.

In a DNA molecule, cytosine binds to by hydrogen bonds.

Match the nucleotide to its correct description. -Early data indicated that within any DNA molecule, the amount of this was always equal to the amount of adenine.

Match the term with the most appropriate description. -constricted region where duplicated chromosomes are attached to each other

Match the nucleotide to its correct description. -If one strand of a DNA molecule has a purine at a given position, this will be its complement on the other strand.

When a cell has two complete sets of chromosomes, it is ____.