Unit 6: Gene Expression and Regulation

Question 1

DNA replication

Answer 1

The process of making an identical copy of a DNA molecule before cell division

Question 2

Helicasem

Answer 2

An enzyme that unwinds and separates the two strands of the DNA double helix

Question 3

DNA polymerase

Answer 3

The enzyme that adds complementary nucleotides to a growing DNA strand during replication

Question 4

Leading strand

Answer 4

The new DNA strand synthesized continuously toward the replication fork

Question 5

Lagging strandl

Answer 5

The new DNA strand synthesized discontinuously away from the replication fork in short segments

Question 6

Okazaki fragments

Answer 6

Short, newly synthesized DNA fragments on the lagging strand

Question 7

RNA

Answer 7

Ribonucleic acid; a nucleic acid involved in protein synthesis and gene regulation

Question 8

Transcription

Answer 8

The process of copying a gene’s DNA sequence into an RNA molecule

Question 9

RNA polymerase

Answer 9

The enzyme that synthesizes RNA from a DNA template during transcription

Question 10

Promoter

Answer 10

A DNA sequence where RNA polymerase binds to begin transcription

Question 11

Terminator

Answer 11

A DNA sequence that signals the end of transcription

Question 12

mRNA (messenger RNA)

Answer 12

The RNA transcript that carries genetic information from DNA to the ribosome

Question 13

tRNA (transfer RNA)

Answer 13

RNA that brings amino acids to the ribosome during translation

Question 14

rRNA (ribosomal RNA)

Answer 14

RNA that, together with proteins, makes up the ribosome

Question 15

Translation

Answer 15

The process of synthesizing a polypeptide (protein) from an mRNA template

Question 16

Codon

Answer 16

A three-nucleotide sequence on mRNA that specifies an amino acid

Question 17

Anticodon

Answer 17

A three-nucleotide sequence on tRNA complementary to an mRNA codon

Question 18

Start codon

Answer 18

The mRNA codon (AUG) that signals the start of translation and codes for methionine

Question 19

Stop codon

Answer 19

Any of three mRNA codons (UAA, UAG, UGA) that terminate translation

Question 20

Genetic code

Answer 20

The set of rules by which information encoded in mRNA codons is translated into amino acids

Question 21

Mutation

Answer 21

A change in the DNA sequence

Question 22

Point mutation

Answer 22

A mutation affecting only one or a few nucleotides

Question 23

Frameshift mutation

Answer 23

A mutation caused by insertion or deletion of nucleotides that shifts the reading frame

Question 24

Operon

Answer 24

A cluster of genes under the control of a single promoter and operator (e.g., lac operon)

Question 25

Promoter (in operon)

Answer 25

The site where RNA polymerase binds to initiate transcription of the operon

Question 26

Operator

Answer 26

A DNA segment that acts as an on/off switch for transcription when bound by a repressor

Question 27

Repressor

Answer 27

A protein that binds the operator to block transcription

Question 28

Inducer

Answer 28

A molecule that binds and inactivates a repressor, allowing transcription

Question 29

Enhancer

Answer 29

A distal DNA regulatory element that increases transcription of associated genes

Question 30

Silencer

Answer 30

A DNA regulatory element that represses transcription when bound by regulatory proteins

Question 31

Transcription factor

Answer 31

A protein that helps regulate transcription by binding to DNA regulatory sequences

Question 32

Epigenetics

Answer 32

Heritable changes in gene expression without changes to the DNA sequence (e.g., DNA methylation, histone modification)

Question 33

PCR (Polymerase Chain Reaction)

Answer 33

technique used to amplify small amounts of DNA into millions of copies using a DNA polymerase enzyme, primers, and thermal cycling.

Question 34

Gel Electrophoresis

Answer 34

A method used to separate DNA fragments by size using an electric field through a gel matrix; smaller fragments move farther.

Question 35

DNA sequencing

Answer 35

The process of determining the exact order of nucleotides (A, T, C, G) in a DNA molecule.

Question 36

Bacterial Transformation

Answer 36

The process of inserting foreign DNA (often a gene of interest) into a bacterial plasmid so the bacteria express the gene.