Kinkle Bio Exam (4)

information is passed in one direction from the gene(DNA) to an RNA copy of the gene and the RNA copy directs the sequential assembly of a chain of amino acids into a protein

central dogma

1. Initiation

code genetic information and can be shuffled to make new protiens

exons

creates the shape of tRNA

base pairing within the molecule

a heritable change in genetic material

mutation

an agent that induces mutation

mutagen

an alteration of one nucleotide in a chromosomal DNA molecule

point mutation

due to a degeneracy in genetic code, usually involves third position of a codon

silent mutation

changes amino acid encoded from argenine to histidine

missenese mutation

T/A to A/T produces UAA stop codon in mRNA

nonsense mutation

target a single kind of DNA lesion and repairs only that damage

specific DNA repair

Use a single mechanism to repair multiple kinds of lesions in DNA

Nonspecific DNA repair

removes incorrect bases replacing by copying template strand by DNA methylation

missmatch repair

DNA is exposed to UV light

photorepair

Damaged region is removed and replaced by DNA synthesis

excision repair

a portion of a chromosome is lost

deletion

portion of chromosome is duplicated

duplication

reversal in order of a segment of a chromosome

inversion

a piece of one chromosome is broken off and joined to another chromosome ; like crossing-over

translocation

replaces purine with purine (AtoG)

transition

replaces purine with pyrimidine (GtoC)

transversion

recognized by termination factors

stop codons

gene expression is the conversion of...

genotype to phenotype

act by modulating the ability of RNA polymerase to bind to the promotor

regulatory proteins

consists of two alpha-helices linked by a nonhelical segment

helix-turn-helix motif

cause one body part to be replaced by another

homeodomain motif

incorporates zinc atoms in its structure

zinc finger motif

two different protein sub-units associate to form a single DNA-binding site

leucine zipper motif

multiple genes that are a part of a single transcription unit having a single promoter

operons

anabolic; occurs when bacteria capable of making biosynthetic enzymes do not produce them; prevents transcription

repression

catabolic; occurs when enzymes for a certain pathway are produced in response to substrate

induction

level of DNA transcription initiation in which frequency of initiation is increased

positive control

consists of genes that encode functions necessary to utilize lactose

lac operon

prevents or decreases DNA transcription with repressor genes

negative gene regulation

increases the frequency of the initiation of transcription

positive gene regulation

a genome of RNA or DNA surrounded by a protien shell called a caspid; can not replicate outside of host

basic structure of virus

virus attaches to cell wall; the viral DNA directs the production of new viral particles by the host cell

lytic bacteriophage

inserts the bacteria into the host cell and allows virus to be replicated along with host cell

lysogenic bacterophage

receive and allow entrance into the membrane

glycoprotiens

confer shape and rigidity upon the cell and prevent cell lysis due to high osmotic pressures

cell wall in bacterial cells

protein all viruses contain; form around a single bacteria

capsule

have a twist; are rigid; rotate to drive cell movement

flagella in bacterial cells

bifunctional molecule that must be able to interact with mRNA and with amino acids

tRNA

3' end; portion that amino acids become attached to during tRNA charging reduction

acceptor end

3-nucleotide sequence and the end of tRNA molecule that is complementary to and base-pairs with an amino acid specifying codon in mRNA

anticodon loop

reaction by which aminoacyl-tRNA synthetase attaches a specific amino acid to the correct tRNA using energy from ATP

charging reaction

binds to tRNA carrying the next amino acid to be added to a polypeptide chain

A site

binds to tRNA attached to growing polypeptide chain

P site

exit site that binds to tRNA that carried previous amino acids added to polypeptide chain

E site

consists of promotor, operator, and 3 genes that encode proteins

lac operon

initiation of transcription of the lac operon is controlled by this; binds to operator

lac repressor

can stimulate transcription from multiple catabolic operons; an allosteric protein with cAMP as an effector

catabolic activator protein (CAP)

if the glucose in a lac operon is low...

inducer is present and promotor is activated

if the glucose in a lac operon is high...

the inducer is absent and promotor is not activated

consists of a series of genes that encode enzymes involved in the same biochemical pathway

trp operon

expressed in absence of tryptophan, not expressed in presence of tryptophan

trp operon

form the binding sites for general transcription factors

promotors

regulatory proteins that bind to DNA at distant sites called enhancers; DNA folds so enhancer is brought into proximity with initiation complex and interact to increase rate of transcription

activators

transcription factors that stabilize the transcription complex by bridging activator proteins with the complex

co-activators

transcription factors that position RNA polymerase at the start of a protein-coding sequence and then release the polymerase to initiate transcription

general factors

has no effect on base pairing but can be recognized by proteins

DNA methylation

appear to be involved in control of gene transcription and that play a role in protecting cells from viral attack

siRNAs

type of gene silencing in which the mRNA transcript is prevented from being translated

RNA interference

can produce multiple proteins from one gene

alternative splicing

enzyme that degrades proteins by breaking peptide bonds

protease

76- amino acid protein that virtually all eukaryotic cells attach as a marker to proteins that are to be degraded

ubiquitin

can give rise to any tissue in an organism

totipotent

can give rise to all of the cell's in the organism's body

pluripotent

can give rise to a limited number of cell types (ex:blood cells)

multipotent

can give rise to only a single cell type

unipotent

2. Elongation

3. Termination

What are the three steps of transcription?