Ch.9 Molecular Biology

Question 1

alternative RNA splicing

Answer 1

a post-transcriptional gene regulation mechanism in eukaryotes in which multiple protein products are produced by a single gene through alternative splicing combinations of the RNA transcript

Question 2

codon

Answer 2

the consecutive nucleotides in mRNA that specify the addition of a specific amino acid or the release of a polypeptide chain during translation

Question 3

deoxyribose

Answer 3

a five-carbon sugar molecule with.a hydrogen atom rather than a hydroxyl group in the 2’ position; the sugar component of DNA nucleotides

Question 4

DNA ligase

Answer 4

the enzyme that catalyzes the joining of DNA fragments together

Question 5

DNA polymerase

Answer 5

an enzyme that synthesizes a new strand of DNA complementary to a template strand

Question 6

double helix

Answer 6

the molecular shape of DNA in which twi strand of nucleotides win around each other in a spiral shape

Question 7

epigenetic

Answer 7

describing non-genetic regulatory factors, such as changes in modifications to histone proteins and DNA that control accessibility to genes in chromosomes

Question 8

exon

Answer 8

a sequence present in protein-codoning mRNA after completion of pre-mRNA splicing

Question 9

gene expression

Answer 9

processes that control whether a gene is expressed

Question 10

genetic code

Answer 10

the amino acids that correspond to three-nucleotide codons of mRNA

Question 11

helicase

Answer 11

an enzyme that helps ton open up the DNA helix during DNA replication by breaking the hydrogen bonds

Question 12

intron

Answer 12

non-protein condoning intervening sequences that are spliced fro mRNA during processing

Question 13

lagging strand

Answer 13

during replication of the 3’ and 5’ strand, the strand that is replicated in short fragments and away form the replication fork

Question 14

mismatch repair

Answer 14

a form of DNA repair in which non-complentary nucleotides are recognized,excised, and replaced with correct nucleotides

Question 15

mRNA

Answer 15

messenger RNA; a form of RNA that carries the nucleotides sequence code for a protein sequence that is translated into a polypeptide sequence

Question 16

mutation

Answer 16

a permanent variation in the nucleotides sequence of a genome

Question 17

nitrogenous base

Answer 17

a nitrogen containing molécule that acts as a base; often referring to one of the purine of pyrimidine components of nucleic acid

Question 18

nontemplate strand

Answer 18

the strand of DNA that is not used to transcribe mRN; this strand is identical to the mRNA except that T nucleotides in the DNA are replaced by U nucleotides in the mRNA

Question 19

nucleotide excision repair

Answer 19

a form of DNA repair in which the DNA molecule is unwound and separated in the region of the nucleotide dance, the damage nucleotides are removed and replaced with new nucleotides using the complementary strand, and the DNA is resealed and allowed to rejoin its complement

Question 20

Okarzaki fragments

Answer 20

the DNA fragments that are synthesized in short stretches on the lagging strand

Question 21

phosphate group

Answer 21

a molecular group consisting of a central phosphorus atom bound to four oxygen atoms

Question 22

post-transcriptional

Answer 22

control of gene expression after the RNA molecule has been created but before it is translated into protein

Question 23

post-translation

Answer 23

control of gene expression after a protein has been created

Question 24

primer

Answer 24

a short stretch of RNA nucleotides that is required to initiate replication and allow DNA polymerase to bind and begin replication

Question 25

promoter

Answer 25

a sequence on DNA to which RNA polymerase and associated factors bing and initiate transcription

Question 26

replication fork

Answer 26

the Y- shaped structure formed during the initiation of replication

Question 27

RNA polymerase

Answer 27

an enzyme that synthesizes an RNA strand from a DNA template strand

Question 28

rRNA

Answer 28

ribosomal RNA; molecules of RNA that combine storage form part of ribosome

Question 29

semiconservative replication

Answer 29

the method used to replicate DNA I which the double stranded molecule is separated and each strand acts as a template for a new strand to the synthesized, so the resulting DNA molecule are composed of one new strand of nucleotides and one old strand of nucleotides

Question 30

splicing

Answer 30

the process of removing introns and reconnecting eons in a pre-mRNA

Question 31

start codon

Answer 31

the AUG(or rarely GUG) on a mRNA from which translation beings; always specifies methionine

Question 32

stop codon

Answer 32

one of the three mRNA codons the specifics termination of translation

Question 33

telomerase

Answer 33

an enzyme that contains a catalytic part and an inbuilt

RNA template; it functions to maintain telomeres at chromosome ends

Question 34

template strand

Answer 34

the strand of DNA that specifies the complementary mRNA molecule

Question 35

transcription bubble

Answer 35

the region of locally unwound DNA that allows for transcription of mRNA

Question 36

tRNA

Answer 36

transfer RNA; an RNA molecule that contains a specific three- nucleotide anticodon sequenced to pair with the mRNA condon and also binds to a septic amino acid

Question 37

telomere

Answer 37

the DNA at the end of linear chromosomes