Unit 4 DNA

Question 1

operon (3)

Answer 1

• found in bacteria and phages
• consisting of a promoter
• an operator

Question 2

Operator

Answer 2

A sequence of nucleotides to which an active repressor can attach

Question 3

What does the binding of a repressor prevent

Answer 3

Prevents RNA polymerase from attaching to the promoter and transcribing the genes of the operon

Question 4

Promoter

Answer 4

binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place

Question 5

Repressor

Answer 5

A protein that inhibits gene transcription happens in both prokaryotes and eukaryotes

Question 6

RNA Polymerase

Answer 6

an enzyme responsible for copying a DNA sequence into an RNA sequence, duyring the process of transcription.

Question 7

Lagging strand

Answer 7

• a discontinuously synthesize DNA strand
• elongates by means of okazaki fragments
• synthesized in a 5’to 3’ direction away from the replication fork

Question 8

Leading strand

Answer 8

• The new complementary DNA strand synthesize continuously
• along the template strand toward the replication fork
• in the mandatory five prime to three prime direction

Question 9

Transformation

Answer 9

• a change in genotype and phenotype due to the assimilation is external DNA
• horizontal gene transfer

Question 10

helicase

Answer 10

An enzyme that untwists the double helix of DNA at replication forks separating the two strands and making them available as template strands

Question 11

miRNA

Answer 11

Single-stranded RNA molecule that can degrade or prevent translation of an mRNA with a complementary sequence

Question 12

splicesomes

Answer 12

splice mRNA by interacting with the ends of an RNA intron

Question 13

why does tRNA have the shape it has?

Answer 13

hydrogen bonds hold it together

Question 14

feedback inhibition

Answer 14

a matabolic pathway acts as an inhibitor of an enzyme within that pathway

Question 15

transduction

Answer 15

• a process in which phages (viruses) carry bacterial DNA from one bacterial cell to another.

Question 16

reverse transcriptase

Answer 16

an enzyme coded by certain viruses (retroviruses) that use RNA as a template for DNA synthesis

Question 17

framshift mutation

Answer 17

it occurs when nucleotides are inserted/ deleted from a gene AND THEN the number inserted/deleted is not a MULTIPLE OF 3. results in improper coding

Question 18

exons

Answer 18

• the real gene

- expressed/ coding DNA

Question 19

what region can exons refer to?

Answer 19

the region of DNA from which the sequence was transcribed

Question 20

intron

Answer 20

• the junk

- in between sequence

Question 21

coordinately regulated cluster of genes who’s products function in a common pathway

Answer 21

operon

Question 22

RNA primer

Answer 22

• builds by primase

- serves as a starter sequence for DNA polymerase III

Question 23

plasmid (4)

Answer 23

• small ring or DNA that carries few genes
• replicates separately from bacterial chromosomes
• can carry antibiotic resistance
• used in cloning

Question 24

point mutation

Answer 24

• single base change

- base pair substitution

Question 25

transcription

Answer 25

Transcription is the first step of gene expression, in which a particular segment of DNA is copied into RNA by the enzyme RNA polymerase

Question 26

translation

Answer 26

plate where the code in the mRNA is converted into an amino acid sequence in a protein

Question 27

acetylation of histone proteins

Answer 27

DNA binding proteins to interact with exposed sites to activate gene transcription and downstream cellular functions

Question 28

methylation of DNA

Answer 28

• when methyl groups are added to the DNA molecule

Question 29

corepressor

Answer 29

substance that inhibits the expression of genes

Question 30

trp operon

Answer 30

codes for the components for production of tryptophan

Question 31

DNA polymerase 1

Answer 31

essential for removing of the RNA primers from the fragments and replacing it with the required nucleotides

Question 32

DNA polymerase 3

Answer 32

essential for the replication of the leading and the lagging strands

Question 33

mRNA

Answer 33

molecule carries a portion of the DNA code to other parts of the cell for processing

Question 34

tRNA

Answer 34

molecules that carry amino acids to the ribosome for polymerization into a polypeptide

Question 35

rRNA

Answer 35

• makes polypeptides

- (assemblies of amino acids) that go to make up proteins.