Chapter 10: Molecular Biology of the Gene

Question 1

BACTERIOPHAGES

Answer 1

A VIRUS THAT INFECTS BACTERIA; ALSO CALLED A PHAGE

Question 2

NUCLEOTIDES

Answer 2

A building block of nucleic acids, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and one or more phosphate groups.

Question 3

POLYNUCLEOTIDE

Answer 3

A polymer made up of many nucleotide monomers covalently bonded together.

Question 4

SUGAR-PHOSPHATE BACKBONE

Answer 4

In a polynucleotide (DNA or RNA strand), the alternating chain of sugar and phosphate to which nitrogenous bases are attached.

Question 5

DNA / DEOXYRIBONUCLEIC ACID

Answer 5

A double-stranded helical nucleic acid molecule consisting of nucleotide monomers with deoxyribose sugar and the nitrogenous bases A, C, G, T. Capable of replicating, XXX is an organism’s genetic material.

Question 6

THYMINE (T)

Answer 6

A single-ring nitrogenous base found in DNA.

Question 7

CYTOSINE (C)

Answer 7

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

Question 8

ADENINE (A)

Answer 8

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

Question 9

GUANINE (G)

Answer 9

A double-ring nitrogenous base found in DNA and RNA

Question 10

URACIL (U)

Answer 10

A single-ring nitrogenous base found in RNA.

Question 11

DOUBLE HELIX

Answer 11

The form of native DNA, referring to its two adjacent polynucleotide strands interwound into a spiral shape.

Question 12

SEMICONSERVATIVE MODEL

Answer 12

Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand.

Question 13

DNA POLYMERASES

Answer 13

A large molecular complex that assembles DNA nucleotides into polynucleotides using a preexisting strand of DNA as a template.

Question 14

DNA LIGASE

Answer 14

An enzyme, essential for DNA replication, that catalyzes that covalent bonding of adjacent DNA polynucleotide strands. XXXX is used in genetic engineering to paste a specific piece of DNA containing a gene of interest into a bacterial plasmid or other vector.

Question 15

TRANSCRIPTION

Answer 15

The synthesis of RNA on a DNA template.

Question 16

TRANSLATION

Answer 16

The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of “language” from nucleotides to amino acids.

Question 17

TRIPLET CODE

Answer 17

A set of three-nucleotide-long “words” that specify the amino acids for polypeptide chains.

Question 18

CODONS

Answer 18

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

Question 19

GENETIC CODE

Answer 19

The set of rules that dictates the amino acid translations of each mRNA nucleotide triplet.

Question 20

RNA POLYMERASE

Answer 20

A large molecular complex that links together the growing chain of RNA nucleotides during transcription, using a DNA strand as a template.

Question 21

PROMOTER

Answer 21

A specific nucleotide sequence in DNA located near the start of a gene that is the binding site for RNA polymerase and the place where transcription begins.

Question 22

TERMINATOR

Answer 22

A special sequence of nucleotides in DNA that marks the end of a gene. It signals RNA polymerase to release the newly made RNA molecule and then to depart from the gene.

Question 23

TRANSCRIPTION OF A GENE

Answer 23

INITATION
ELONGATION
TERMINATION

Question 24

MESSENGER RNA (MRNA)

Answer 24

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 25

INTRONS

Answer 25

An internal, noncoding region of a gene that does not become part of the final messenger RNA molecule and is therefore not expressed.

Question 26

EXONS

Answer 26

The part of a gene that becomes part of the final messenger RNA and is therefore expressed.

Question 27

RNA SPLICING

Answer 27

The removal of introns and joining of exons in eukaryotic RNA, forming an mRNA molecule with a continuous coding sequence; occurs before mRNA leaves the nucleus.

Question 28

TRANSFER RNA

Answer 28

A type of ribonucleic acid that functions as an interpreter in translation. Each tRNA molecule has a specific anticodon, picks up a specific amino acid, and conveys the amino acid to the appropriate codon on mRNA.

Question 29

ANTICODON

Answer 29

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

Question 30

RIBOSOMES

Answer 30

A cell structure consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in the cytoplasm. In eukaryotic cells, the ribosomal subunits are constructed in the nucleolus.

Question 31

RIBOSOMAL RNA (RRNA)

Answer 31

The type of ribonucleic acid that, together with proteins, make up ribosomes; the most abundant type of RNA in most cells.

Question 32

START CODON

Answer 32

On mRNA, the specific three-nucleotide sequence (AUG) to which an initiator tRNA molecule binds, starting translation of genetic information.

Question 33

P SITE

Answer 33

One of a ribosome’s binding sites for tRNA during translation. The XXX hold the tRNA carrying the growing polypeptide chain.

Question 34

A SITE

Answer 34

One of a ribosome’s binding sites for tRNA during translation. The A site holds the tRNA that carries the next amino acid in the polypeptide chain. (A strands for aminoacyl tRNA)

Question 35

CAPSID

Answer 35

The protein shell that encloses a viral genome.

Question 36

AIDS (acquired immunodeficiency syndrome)

Answer 36

The late stages of HIV infection, characterized by a reduced number of T cells and the appearance of characteristic opportunistic infections.

Question 37

CONJUGATION

Answer 37

The union (mating) of two bacterial cells or protist cells and the transfer of DNA between the two cells.

Question 38

STOP CODON

Answer 38

In mRNA, one of three triplets (UAG, UAA, UGA) that signal gene translation to stop.