BIO 280 Final Exam

MU

Helicase

enzyme that unwinds DNA by breaking hydrogen bonds

DNA Polymerase 3

synthesizes DNA in the 5’ to 3’ direction

DNA Polymerase 1

removes RNA primers and replaces with DNA

Ligase

seals phosphodiester bonds between fragments

Promoter

DNA sequence where transcription begins (Not transcribed)

Sigma Factor

prokaryotic transcription factor recognizing promoter

TATA-binding protein

eukaryotic transcription factor

Introns

transcribed regions removed before translation

exons

coding sequences retained in mRNA

UTR

transcribed but untranslated region

A Site

ribosome site where tRNA enters

P site

ribosome site where peptide bonds form

E site

ribosome site where tRNA exits

Translocation

movement of ribosome using GTp

Missense Mutation

nucleotide change causing amino acid substitution

Nonsense mutation

nucleotide change creating a stop codon

Transition

substitution with same base type

pyrimidine to pyrimidine or vice versa

Transversion

substitution between base types

Pyrimidine to purine

Mismatch repair

corrects replication errors using methylation patterns

Nucleotide excision repair

removes bulky DNA damage (UV dimers)

Base excision repair

removes damaged bases using AP endonuclease

Homologous recombination

repairs double strand breaks using template

Translesion synthesis

bypasses damage with low-fidelity polymerase

Testcross

cross with homozygous recessive to determine genotype

recombination frequency

percentage of recombinant offspring

Chi-square test

statistical test comparing observed vs expected

Hardy-Weinberg Equilibrium

condition where allele frequencies remain constant

Lac operon

inducible gene system regulated by lactose and glucose

Euchromatin

loosely packed DNA, transcriptionally active

Heterochromatin

tightly packed DNA, transcriptionally inactive

miRNA

small RNA that inhibits translation

siRNA

small RNA that degrades mRNA

Dicer

enzyme that processes dsRNA into miRNA/siRNA

Template strand

DNA strand read by RNA polymerase in the 3’ to 5’ direction to synthesize RNA

coding strand

DNA strand identical to RNA sequence except T replaces U

Polyadenylation

addition of poly-a tail to the 3’ end of mRNA in eukaryotes

5’ cap

modified guanine nucleotides added to the 5’ end of eukaryotic mRNA

spliceosome

complex that removes introns from pre-mRNA

self-splicing intron

intron that can remove itself without spliceosome involvement

Aminoacyl-tRNA synthetase

enzyme that attaches the correct amino acid to its tRNA

Charged tRNA

bound to its corresponding amino acid

uncharged tRNA

tRNA without an amino acid

codon

three-nucleotide sequence on mRNA specifying an amino acid

anticodon

three-nucleotide sequence on tRNA complementary to a codon

polypeptide

chain of amino acids formed during translation

N-terminus (Amino end)

beginning of a polypeptide chain

C-terminus (Carboxyl end)

end of a polypeptide chain

initiation

assembly of ribosomes at start codon with initiator tRNA

Elongation

adding of amino acids to growing polypeptide

Termination

release of poylpeptide at stop codon

elongation factors

proteins that assist ribosome movement using GTP

Translocation

movement of ribosome one codon along mRNA

AP site

location where a base has been removed from DNA

AP endonuclease

enzyme that cuts DNA at an AP site during base excision repair

Thymine dimer

covalent linkage between adjacent thymine bases caused by UV light

direct reversal

repair of thymine dimers (prokaryotes)

Double-strand break

break in both strands of DNA

point mutation

change in a single nucleotide

Frameshift mutation

insertion or deletion altering reading frame

silent mutation

mutation that does not change amino acid sequence

Gain of function mutation

enhances protein activity

loss of function mutation

reduces or eliminates protein function

independent assortment

genes on different chromosomes assort independently

linked genes

genes located close together on same chromosome

parental types

most frequent offspring phenotypes

recombinant types

offspring with new allele combinations

Double cross over (DCO)

2 crossover events between genes

Map unit (centimorgan)

unit of genetic distance equal to 1% recombination

directional selection

favoring one extreme phenotype

genetic drift

random change in allele frequencies

natural selection

differential survival and reproduction of individuals

operon

cluster of genes under control of a single promoter

operator

DNA region where repressor binds

repressor

protein that inhibits transcription

inducer

molecule that activates transcription

positive regulation

activator increases transcription

negative regulation

repressor decreases transcription

Histone acetyltransferase

enzyme that adds acetyl groups, increasing transcription

Histone deacetylase

enzyme that removes acetyl groups, decreasing transcription

epigenetics

heritable changes in gene expression without DNA sequence change

PCR

amplifies specific DNA sequences

primer

short DNA sequence that initiates DNA synthesis

restriction enzyme

enzyme that cuts DNA at specific sequences

sticky ends

overhanging DNA end after restriction digest

blunt ends

straight cuts with no overhangs

gel electrophoresis

separates DNA fragments by size

DNA ladder

reference for fragment sizes

Sanger sequencing

DNA sequencing method using chain-terminating nucleotides

NGS

high-throughput DNA sequencing method

CRISPR

genome editing system using guide RNA and Cas9 enzyme

guide RNA

RNA sequence that directs Cas9 to target DNA

Cas9

enzyme that cuts DNA at specific location

replica plating

method showing mutations occur before selection

complementation

test to determine if mutations are in same gene

Merozygote

partially diploid cell used in complementation tests