Ch. 10 - The Structure and Function of DNA

Question 1

Adenine (A)

Answer 1

A double-ring nitrogenous base found in DNA and RNA.

Question 2

AIDS

Answer 2

Acquired immunodeficiency syndrome; the late stages of HIV infection, characterized by a reduced number of T cells; usually results in death caused by opportunistic infections.

Question 3

anticodon

Answer 3

On a tRNA molecule, a specific sequence of three nucleotides that is complementary to a codon triplet on mRNA.

Question 4

Bacteriophage

Answer 4

A virus that infects bacteria; also called a phage.

Question 5

cap

Answer 5

Extra nucleotides added to the beginning of an RNA transcript in the nucleus of a eukaryotic cell.

Question 6

Codon

Answer 6

A three-nucleotide sequence in mRNA that specifies a particular amino acid or polypeptide termination signal; the basic unit of the genetic code.

Question 7

cytosine (C)

Answer 7

A single-ring nitrogenous base found in DNA and RNA.

Question 8

DNA

Answer 8

The genetic material that organisms inherit from their parents; a double-stranded helical macromolecule consisting of nucleotide monomers with deoxyribose sugar, a phosphate group, and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T). See also gene.

Question 9

DNA polymerase

Answer 9

An enzyme that assembles DNA nucleotides into polynucleotides using a preexisting strand of DNA as a template.

Question 10

double helix

Answer 10

The form assumed by DNA in living cells, referring to its two adjacent polynucleotide strands wound into a spiral shape.

Question 11

emerging virus

Answer 11

A virus that has appeared suddenly or has recently come to the attention of medical scientists.

Question 12

Exon

Answer 12

In eukaryotes, a coding portion of a gene. See also intron.

Question 13

genetic code

Answer 13

The set of rules giving the correspondence between nucleotide triplets (codons) in mRNA and amino acids in protein.

Question 14

guanine (G)

Answer 14

A double-ring nitrogenous base found in DNA and RNA.

Question 15

HIV

Answer 15

Human immunodeficiency virus; the retrovirus that attacks the human immune system and causes AIDS.

Question 16

Intron

Answer 16

In eukaryotes, a nonexpressed (noncoding) portion of a gene that is excised from the RNA transcript. See also exon.

Question 17

lysogenic cycle

Answer 17

A bacteriophage reproductive cycle in which the viral genome is incorporated into the bacterial host chromosome as a prophage. New phages are not produced, and the host cell is not killed or lysed unless the viral genome leaves the host chromosome.

Question 18

lytic cycle

Answer 18

A viral reproductive cycle resulting in the release of new viruses by lysis (breaking open) of the host cell.

Question 19

messenger RNA (mRNA)

Answer 19

The type of ribonucleic acid that encodes genetic information from DNA and conveys it to ribosomes, where the information is translated into amino acid sequences.

Question 20

molecular biology

Answer 20

The study of the molecular basis of heredity; molecular genetics.

Question 21

Mutagen

Answer 21

A chemical or physical agent that interacts with DNA and causes a mutation.