Molecular Genetics

Question 1

basic unit of a nucleic acid

made of sugar, nitrogenous base, and a phosphate

Answer 1

nucleotide

Question 2

nucleotide without the phosphate ground (i.e. nitrogenous base + sugar)

Answer 2

nucleoside

Question 3

sugar present in DNA

Answer 3

deoxyribose (OH removed from 2’)

Question 4

sugar present in RNA

Answer 4

ribose (OH on 2’ and 3’)

Question 5

purine bases

double-ringed

Answer 5

adenine

guanine

Question 6

pyrimidine bases

single ringed

Answer 6

thymine
cytosine
uracil

Question 7

antiparallel strands joined by base pairs (A = T) (C = G)

Answer 7

DNA double helix

Question 8

usually single-stranded

A pairs w/ U instead of T

Answer 8

RNA

Question 9

DNA used to form RNA in prokaryotes

process regulated by the operon

Answer 9

transcription

Question 10

genes that have DNA that codes for protein

regulated by operon during transcription in prokaryotes

Answer 10

structural genes

Question 11

regulated by operon during transcription in prokaryotes

repressor binding site

Answer 11

operator gene

Question 12

regulated by operon during transcription in prokaryotes

RNA polymerase’s 1st binding site

Answer 12

promoter gene

Question 13

regulated by operon during transcription in prokaryotes

Inducible systems need an ______ for transcription to occur.

Answer 13

inducer

Question 14

Repressible systems need a _________ to inhibit transcription in prokaryotes.

Answer 14

corepressor

Question 15

mutation in which one nucleotide is substituted by another

mutation is silent if the sequence doesn’t change

Answer 15

point mutation

Question 16

mutation in which insertions or deletions shift reading frame
proteins doesn’t form or is nonfunctional

Answer 16

frameshift mutation

Question 17

genetic information of the cell

Answer 17

DNA

Question 18

basic unit of DNA

Answer 18

nucleotide

Question 19

occurs during the S phase of the cell cycle
semiconservative
occurs in the 5’ —> 3’ direction

Answer 19

DNA replication

Question 20

enzyme that unwinds DNA double helix

forms a replication fork

Answer 20

helicase

Question 21

enzyme that synthesizes new DNA strand

Answer 21

DNA polymerase

Question 22

RNA is formed from the genetic code in DNA

occurs in the nucleus

Answer 22

transcription

Question 23

double stranded
carries genetic code
deoxyribose sugar
thymine pairs w/ adenine

Answer 23

DNA

Question 24

single stranded
ribose sugar
has uracil instead of thymine; uracil pairs w/ adenine
3 different types

Answer 24

RNA

Question 25

3 types of RNA

Answer 25

mRNA tRNA rRNA

Question 26

type of RNA carries genetic code out of the nucleus and to the ribosomes where translation will take place contains series of 3 bases called codons which code for a particular amino acid

Answer 26

mRNA (messenger RNA)

Question 27

type of RNA brings amino acids to ribosomes grabs amino acids and brings them to the ribosome to form proteins each is specific for one amino acid has two ends: one end w/ a combo of three nitrogenous bases (anticodon) which are complementary to the codon (series of 3 amino acids on the mRNA) other end carries the amino acid that corresponds to the codon on the mRNA

Answer 27

tRNA (transfer RNA)

Question 28

combination of three nitrogenous bases that are complementary to the codon on mRNA

Answer 28

anticodon

Question 29

series of three nitrogenous bases on mRNA | corresponds to 3 nitrogenous bases at one end of the tRNA

Answer 29

codon

Question 30

type of RNA component of ribosome 2 subunits: large and small

Answer 30

rRNA (ribosomal RNA)

Question 31

process by which RNA is formed from DNA 1. DNA unzipped by helicase to expose nucleotides (bases) 2. mRNA is assembled using RNA polymerase from individual ribonucleotide units that line up according to base pairing rules along the template (antisense / non-coding strand) 3. mRNA is complementary to the DNA sense strand (non-template, coding strand)

Answer 31

transcription

Question 32

DNA strand used to form mRNA through complementary base pairing

Answer 32

DNA template strand (non-coding, antisense strand)

Question 33

mRNA is complementary to the DNA ________ strand.

Answer 33

DNA antisense strand (template, non-coding)

Question 34

mRNA is identical to the DNA _______ strand but with U instead of T

Answer 34

DNA sense strand (non-template, coding)

Question 35

part of RNA processing | intron/exon splicing and addition of cap and poly-A tail

Answer 35

post-transcriptional RNA processing

Question 36

what enzyme adds ribonucleotides to growing RNA strand?

Answer 36

RNA polymerase

Question 37

noncoding sequences of RNA | cut out of RNA during post-transcriptional RNA processing

Answer 37

introns

Question 38

coding sequences of RNA | spliced together during post-transcriptional RNA processing

Answer 38

exons

Question 39

signal sequences added to mRNA during post-transcriptional RNA processing

Answer 39

poly-A tail and 5' cap

Question 40

protein synthesis from mRNA | takes place at the ribosome in the cytoplasm

Answer 40

translation

Question 41

3 stages of translation (protein synthesis)

Answer 41

initiation elongation termination

Question 42

process of translation mRNA attaches itself to the ribosome first codon in the mRNA is always AUG (start sequence) tRNA brings in the first amino acid and places it in its proper place

Answer 42

initiation

Question 43

initiation codon / start sequence | codes for Methionine

Answer 43

AUG

Question 44

always the first amino acid in initiation sequence of translation brought in by tRNA coded for by AUG

Answer 44

methionine

Question 45

second state in translation | subsequent amino acids (after methionine) are brought to the ribosome and bonded together w/ a peptide bond

Answer 45

elongation

Question 46

final stage in translation | three stop codons tell the signal to stop protein synthesis and release the protein from the ribosome

Answer 46

termination

Question 47

three stop codons

Answer 47

UAA UAG UGA

Question 48

structure of a protein unique sequence of amino acids "beads on a string"

Answer 48

primary protein structure

Question 49

structure of a protein alpha helix and beta-pleated sheet twisting or folding of the polypeptide backbone H-bonds b/w peptide bonds of the backbone stabilize this structure

Answer 49

secondary protein structure

Question 50

three types of weak bonding in protein secondary structure that hold the protein in a specific conformation

Answer 50

H-bonding ionic bonds hydrophobic interactions

Question 51

stronger bonds in protein secondary structure | covalent bonds b/w the side chains of cysteine pairs

Answer 51

disulfide bridges

Question 52

structure of a protein interactions between various kinda of side chains of amino acids H-bonds, ionic bonds, and hydrophobic interactions are weak bonds between side chains that collectively hold the protein in a specific conformation stronger bonds are the disulfide bridges

Answer 52

protein tertiary structure

Question 53

protein structure interaction of two or more polypeptides Ex: collagen and hemoglobin

Answer 53

quaternary structure

Question 54

changes in DNA that can be caused by mutagens (i.e. UV light, radiation, or chemicals) may result in the production of nonfunctional proteins or proteins that don't work properly some may not cause any problem

Answer 54

mutation

Question 55

mutation in which a single nucleotide base is substituted by another nucleotide base

Answer 55

point mutation

Question 56

if a point mutation occurs in a noncoding region (intron) or if the substitution is transcribed into a codon that codes for the same amino acid no change in the amino acid sequence

Answer 56

silent mutation

Question 57

a substitution mutation that changes the amino acid | protein may or may not be functional, depending on the location of the mutation

Answer 57

missense mutation

Question 58

substitution mutation produces a premature termination codon | protein may be prematurely terminated and will be nonfunctional

Answer 58

non-sense mutation

Question 59

mutation that involved insertion or deletion of multiple nucleotides which results in a shift in the reading frame usually have serious effects on the protein coded for, since nucleotides are read as part of triplets addition or loss of nucleotides (except in multiples of 3) will change the reading frame of the mRNA proteins are usually nonfunctional

Answer 59

frame shift mutation