Exam 1

bacterial transformation

bacteria cell takes up foreign DNA from environment and incorporates into own genome

Griffith

who’s experiment determined that bacteria can transform using foreign biomolecules?

Avery

who’s experiment determined that bacterial transformation is caused by DNA?

Hershey-Chase

who’s experiment determined that DNA is the genetic material?

nucleotides

monomer of DNA; made up of a 5-C sugar, a nitrogenous base, and a phosphate group

x-ray crystallography

method for determining 3D structure of DNA

Franklin

who revealed the helical structure of DNA?

Watson and Crick

who built a definitive model of DNA, showing its helix shape and base pairing?

base pairing w/ hydrogen bonds and van der Waals forces

what holds DNA together?

phosphate group

what is located at the 5’ end of DNA?

hydroxyl group

what is bound to the 3’ end of DNA?

semiconservativey

how does DNA replicate?

semiconservative replication

method where DNA produces two copies of DNA, each containing one parental strand and one new strand

Meselson-Stahl

who proved the semiconservative replication model?

pre-replication complex

a group of several proteins, including DNA polymerase, that assembles at DNA replication origins during G1

ori

site where helicases starts to unwind DNA and replication begins

helicase

unwind double-stranded DNA or RNA at the ori into single strands by breaking H-bonds

single-stranded binding proteins

keep strands of DNA separated during replication

3’

on what end does replication begin?

RNA primer

a short starter strand of RNA that DNA polymerase binds to to begin replication

initiation

at what step does DNA helicase begin to unwind DNA?

DNA polymerase

adds nucleotides to the DNA template during replication starting at the 3’ end

dNTPs

substrates that provide energy and nucleotide components for DNA replication; type of nucleotide

replication fork

site where DNA unwinds into two strands

Okazaki fragments

short segments of DNA that make up the lagging strand in DNA replication

5’ to 3’

in what direction is DNA synthesized?

3’ to 5’

in what direction is DNA read?

phosphodiester bond

what bond holds nucleotides to daughter strands and holds Okazaki fragments together?

DNA ligase

connects Okazaki fragments by forming phosphodiester bonds

50-200

how many base pairs do eukaryotic chromosomes lose with each DNA replication?

telomeres

repetitive DNA sequences at the ends of linear chromosomes that prevent degradation during replication

telomerase

enzyme that maintains chromosome length by adding DNA repeats to the 3’ ends of chromosomes

circular

what shape are prokaryotic chromosomes?

mutation

permanent changes in the nucleotide sequence of DNA; occurs when DNA polymerase makes mistakes

proofreading

corrects base pair mismatches as DNA polymerase makes mistakes

mismatch repair

scans the new DNA strand immediately after replication and corrects mistakes

excision repair

removes damaged base pairs throughout the cell cycle and replaces them w/ functional bases

PCR (polymerase chain reaction)

technique for rapidly producing millions of copies of a short DNA sequence

denaturation

step in PCR when high heat breaks H-bonds holding DNA together

annealing

step in PCR when temp is lowered and primers can attach to target areas on DNA template

elongation

step in PCR when DNA polymerase adds nucleotides to primers and new, complimentary DNA strand is built

Beadle and Tatum

who discovered that the mutation one gene caused a change in one specific enzyme → one gene change can change an entire polypeptide

Srb and Horowitz

expanded on Beadle and Tatum’s work by proving that single genes control single steps in metabolic pathways

the central dogma

DNA → RNA → protein

mRNA

carries genetic instructions from DNA in the nucleus to the cytoplasm, directing ribosomes to synthesize specific proteins

tRNA

translates genetic info in mRNA into protein sequences (acts as an adapter); ensures the correct amino acid is inserted into the polypeptide chain

rRNA

forms the core structure of ribosomes; creates peptide bonds between amino acid

transcription

the process of copying a DNA gene sequence into mRNA by the enzyme RNA polymerase

no

does RNA polymerase require helicase to unwind DNA?

no

does RNA polymerase require a primer to initiate transcription?

promoter

DNA sequence that RNA polymerase can recognize and bind to to begin transcription

template strand

strand used by RNA polymerase to create complimentary RNA strand

coding strand

strand not used by RNA polymerase to create RNA; similar sequence as result RNA

sigma factors

aid in RNA recognizing and binding to promoter sequence on DNA in prokaryotes

transcription factors

aid in RNA recognizing and binding to promoter sequence on DNA in eukaryotes

termination site

specific DNA sequence that signals the end of transcription

nucleic acid hybridization

single-stranded nucleic acid binds to complimentary sequence, resulting in double-stranded hybrid nucleic acid

intron

transcribed portion of a gene that is removed during mRNA processing prior to translation; non-coding

exon

portion of transcribed gene that encodes polypeptide sequence

snRNP (small nuclear ribonucleoprotein)

recognize and splice out introns from pre-mRNA

consensus sequence

sequence identified by snRNP as the beginning/end of an intron

5’ cap

methylated guanine nucleotide; protects mRNA from degradation and initiates translation

poly-A tail

long sequence of adenine nucleotides; stabilizes the transcript and exports mRNA from the nucleus into the cytoplasm

5’ cap and poly-A tail

what is added to pre-mRNA before translation?

Nirenberg-Matthaei

who discovered that mRNA is read in a non-overlapping, triplet code?

codon

three nucleotides in mRNA that direct placement of a particular amino acid in a polypeptide chain

64

how many total codons are there?

5’ to 3’

what direction does rRNA read mRNA in?

3’

what end of a tRNA does an amino acid bind?

anticodon

binds to complimentary mRNA codon

wobble base pairing

interaction of bases in the third position of codon is not that specific

aminoacyl-tRNA synthetase

ensure accurate protein synthesis by attaching the correct amino acid to its corresponding tRNA molecule

initiation complex

charged tRNA and small ribosomal subunit bound to mRNA form what?

A site

the entry point for new tRNA molecules during translation; binds incoming aminoacyl tRNA that matches current mRNA codon

P site

holds the tRNA linked to the growing polypeptide chain during translation; binds the initiator tRNA and mediates the peptide bond formation, passing the growing protein to the A-site tRNA before shifting the deacylated tRNA to the E-site

E site

specific binding location for deacylated (uncharged) tRNA after it has donated its amino acid to the growing polypeptide chain during translation

translation ends

what happens when a stop codon enters the A site?

polysomes

increase the rate of protein synthesis by translating multiple of the same mRNA simultaneously

signal sequences

short stretches of amino acids that direct proteins to their cellular destination

receptor proteins

how are signal sequences recognized?

proteolysis

occurs when proteases cut polypeptides (signal sequence is removed), altering protein function

glycosylation

occurs when sugars are added to polypeptides form glycoproteins

phosphorylation

occurs when phosphate groups are added to polypeptides, altering the function of the protein

snRNA

key component of the spliceosome → help splice out introns

spliceosome

snRNP complex that removes noncoding introns from pre-mRNA

sliding DNA clamp

increases the effectivity of DNA polymerase, preventing the enzyme from dissociating from the DNA template

reverse transcription

synthesizes complimentary DNA from an RNA template

covalent

what kind of bonds form the backbone of DNA?

hydrogen

what kind of bonds hold complimentary bases together?

RNase

destroys RNA

DNase

destroys DNA

protease

destroys protein