Biology 2 Exam 4 Part 1

eukatyotic transcription

-transcription and RNA processing in cell -translation outside of cell -mRNA must be process before translation can occur

missense mutation

A base-pair substitution that results in a codon that codes for a different amino acid.

spliceosome

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons.

nonsense mutation

A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.

TATA box

A promoter DNA sequence crucial in forming the transcription initiation complex.

transcription factors

A regulatory protein that binds to DNA and affects transcription of specific genes.

signal peptide

A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell.

tRNA binding sites

A: attach, P: peptide bond; E: exit

nucleic acid hybridization

Base pairing between a gene and a complementary sequence on another nucleic acid molecule.

artificial selection

Breeding organisms with specific traits in order to produce offspring with identical traits.

exons

Coding segments of eukaryotic DNA.

What is not directly involved in translation?

DNA

what correctly define the most correct and complete description of a gene

DNA sequence that is expressed to form a functional product (RNA or protein)

DNA to Proteins

DNA-transcription-RNA-translation-protein

DNA polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

directional selection

Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

poly-A tail

Modified end of the 3' end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides.

stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes

Introns

Noncoding segments of nucleic acid that lie between coding sequences.

RNA splicing

Process by which the introns are removed from RNA transcripts and the remaining exons are joined together.

genetic engineering

Process of making changes in the DNA code of living organisms

Ribozymes

RNA molecules that function as enzymes

RNAP

RNA polymerase

transcription initiation

RNA polymerase identifies where to begin transcription

transcription Elongation

RNA polymerase moves along DNA and untwists the double helix as RNA nucleotides are added to the chain

transcription termination

RNA polymerase stops transcription when it encounters terminator in the DNA sequence

sticky ends

Single stranded ends of DNA left after cutting with enzymes

transcription initiation complex

The completed assembly of transcription factors and RNA polymerase bound to a promoter.

gene cloning

The production of multiple copies of a gene.

a triplet of bases in the coding sequence of DNA is AAA. The anti codon on the tRNA that binds the mRNA codon is

UUU

which types of mutation, resulting in an error in the mRNA just after the 5' AUG start codon will have the biggest effect

a deletion of 2 nucleotide

Frame shift

a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read

silent mutation

a mutation that is neither harmful nor beneficial (found on the end of codon at the 3rd base point or in non coding region)

variation

all new alleles are the result of nucleotide variability

polymerase chain reaction (PCR)

allows the amplification of a small DNA fragment using primers that flank the region

point mutations

alter a single base

Hardy-Weinberg equation

an assessment of evolution at a particular locus

restriction endonucleases

an enzyme that cuts DNA at specific sites, producing small fragments

P site

binds the tRNA attached to the growing peptide chain

A site

binds the tRNA carrying the next amino acid

signal recognition particle (SRP)

binds to signal peptide and escorts the signal peptide and its ribosome to the receptor in the ER membrane

accuracy in the the translation of mRNA into the sequence of amino acids depends on the specific in which of the following

bonding of the anticodon to the codon and the attachment of amino acids to the chain

evolution of a gene

can happen whenever any of the conditions for HWE are not met for that gene

Mutations

changes in the genetic material of a cell

recombinant DNA

combined plasmid and DNA from a different source "foreign DNA"

the anticodon of a particular tRNA molecule is

complementary to the corresponding mRNA codon

pre-mRNA

contains introns, exons. 5' cap and 3' poly-A tail

DNA ligase

enzyme that chemically links DNA fragments together

disruptive selection

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

peptide transferase

forms peptide bonds carried out by ribosomal RNA (rRNA)

Single base insertion or deletion

frameshift

genetic drift

in evolution which driving factor most consistently requires a small population as a precondition for its occurrence

result of adaptive evolution

increase in frequency of alleles that provide reproductive advantage

population biology

individual of the same species that live in the same species and can interbreed

Transcription steps

initiation, elongation, termination

Translation steps

initiation, elongation, termination

Indels

insertions or deletions of a few base pairs

what correctly describes the function of a signal peptide

it assists in the translation of polypeptides across the ER membrane

which is the function of the release factor in translation

it binds to the stop codon in the A site in place of a tRNA

function of release factor in translation

it binds to the stop codon in the A site of tRNA

what is the effect of a nucleotide pair substitution that results in a nonsense mutation in a gene

it introduces a premature stop codon into the mRNA

what happens to the cut out intro after alternative RNA splicing

it is rapidly degraded

best summarizes evolution as it is view today

it is the differential survival and reproduction of the most-fit phenotypes

in what way could a point mutation in DNA make a difference in the function of a protein

it might substitute a different amino acid, which could change its function

translation initiation

mRNA, tRNA, and the ribosomal subunits form a complex

mRNA

messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome

genetic varitation

must be present in a pop before natural selection can act upon the pop

natural selection

mutations occur at random and can preserve and distribute beneficial mutations

coding stand

non template stand

beadle and Tatum

one gene one enzyme

gene flow

over time the movement of people of earth had increase. this alter the course of human evolution

cloning vector

plasmids that carry the cloned DNA

RNA polymerase

pries the DNA strands apart and joins together the complementary RNA nucleotides. assembles polynucleotides in the 5' to 3' direction. Can start without primer unlike DNA polymerase

ribosomes

protein building machines and are composed of many proteins and RNA

sickle cell anemia

result of a single missense mutation

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

translation termination

ribosome encounter a stop a codon and releases polypeptide

There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that

rules for base pairing between the 3rd base of a codon and tRNA are flexible

what must happed to a newly made polypeptide before it can be secreted from a cell

signal sequence must target it to the ER after which it goes to the Golgi app

start codon (AUG)

signifies the start of the protein-encoding sequence in mRNA

Plasmids

small circular DNA molecules that replicate separately from the bacterial chromosome

most likely to produce an African butterfly species in the wild whose members have one pattern

stabilizing selection

Transcription

synthesis of an RNA molecule from a DNA template

translation elongation

tRNAs bring amino acids to the ribosome for incorporation into the polypeptide

Pribnow box

the TATAAT sequence that is often found at the -10 region of bacterial promoters

E site

the exit site, where discharged tRNAs leave the ribosome

gene expression

the process by which DNA directs protein synthesis, includes two stages: transcription and translation

Tranlation

the synthesis of a polypeptide using the genetic information encoded in an mRNA molecule

Prokaryotic Transcription

transcription and translation occur in all in the cell at the same time

tRNA

transfer RNA; type of RNA that carries amino acids to the ribosome