Idl 580 Exam 3

Front 1

Characteristics of transcription factors (4)

Back 1

involved in transcription but are not part of RNA polymerase.
TFs activate transcription by promoting the assemby of large multisubunit complexes at a promoter sequence. DNA loops out and allows for such large gap between TF and promoter region.
TF can act as activator or repressor depending on ligands bound and state of modification

Front 2

TF structural motifs

Back 2

helix turn helix, zinc finger,leucine zipper, helix loop helix

Front 3

helix turn helix characteristics:

Back 3

prokaryotic regulatory protein. one of the helices is the recognition helix, the other is for stabilization. 7 to 9 residues long separated by a beta turn. highly conserved glycine in the turn with hydrophobic residues. does not act alone!

Front 4

zinc finger characteristics

Back 4

consist of antiparallel beta sheets, and alpha helix. zinc does not bind to DNA but stabilizes molec. Mult. zinc fingers to enchance binding. common in euk reg proteins. 30 A.A., 4 CYS OR 2 HIS 2 CYS BIND W/ ZINC

Front 5

Leucine zipper characteristics

Back 5

Leu residue occupy every seventh position along a line of 30 to 40 hydrophobic residues. AMPHIPATHIC ALPHA HELIX. separate dna binding domain of lys and arg residues (+, basic) that interact with neg. charged dna phosphate backbone. acts as homo or hetero dimer

Front 6

many TFs are dimers that recognize _____ sequences? In what motifs are dimers found? explain the difference between homo and hetero dimer:

Back 6

palindromic. Leucine zipper, and Helix loop Helix. homo is when dimers formed between two molecules of the same protein. Heterodimer are dimers formed between different members of a family or different proteins.

Front 7

Explain the characteristics of a helix loop helix

Back 7

share a concerved sequence of about 60 a.a. needed for protein-protein interactions and DNa binding. @ amphipathic alphahelices connected by loop of variable length. basic amino acid region is where binding occurs. Dimerization is possible.

Front 8

Reverse transcriptase works by using what type of mechanism

Back 8

Reverse transcriptions, using RNA to copy a DNA strand, then RNAse removes the RNA template, and a second DNA strand is synthesized.

Front 9

RNApol I synthesizes:
RNApol II synthesizes;
RNApolIII synthesizes:

Back 9

rRNA genes (5.8s, 18s, 28S).
All protein coding genes, plus some RNAs (sno, mi, si, sn
tRNA genes, rRNA genes, some snRNA genes and genes for other small RNAs

Front 10

important features of euk transcriptions:

Back 10

Transcription takes place in the nucleus, translation takes place in the cytoplasm. A MRNA precursr is seen in EUK transcription, which are covalently modified, then transported to cytoplasm for translation.

Front 11

function of the polyA tail in mRNA procesing

Back 11

3' end, makes the mRNA more stable, gives it a longer half life in the cytoplasm.=more protein. PABP binds to the tail, and interacts with the 5' cap, forming a circular molecule, stabilizing complex and increasing efficiency of translation initiation.

Front 12

function of the 5' cap in mRNA processing

Back 12

the cap "blocks and protects the 5'end from degradation. =more protein. essential for translation b/c it recruits eFs to form the translation initiation complex. essential for ribosome binding. therefore, it enhances stability and is essential for translation

Front 13

cap-independent translation initiation

Back 13

viral genome acts as the mRNA, Ribosome is recruited by a covalently attached protein (VPG)

Front 14

EF-Tu functions during translation to ensure accuracy. explain how.

Back 14

EFTu acts as checking step. if A.A. does not modify protein correctly, it won't fit correctly and will not be added to chain, and is removed.

Front 15

quality control during translation includes:

Back 15

nonsense-mediated decay, rescue of broken mRNA

Front 16

quality control pre and post translation include:

Back 16

pre: codon selection, hydrolytic editing.
post: chaperone mediated folding

Front 17

catabolism

Back 17

Catabolism breaks down organic matter,

Front 18

anabolism

Back 18

Anabolism uses energy to construct components of cells such as proteins and nucleic acids.

Front 19

symport v. antiport

Back 19

symport is cotransport where two molecules move in to cell; antiport is when two molecules more in opposite directions (in/out)

Front 20

post pandrial state

Back 20

During and the four hours after a meal has been eaten, GI tract is full.

Front 21

post absortive state

Back 21

The postabsorptive state is the period when energy comes from the breakdown of our body’s reserves. The importance of the postabsorptive state is to maintain blood glucose levels.

Front 22

enzymes used to break down carbs

Back 22

isomaltase, lactase, maltase, sucrase, trehalase

Front 23

enzymes that break proteins into oligo-peptides

Back 23

trypsin, chemotrypsin, elastase, carboxy-peptidase

Front 24

enzymes that break down polypeptides into amino acids

Back 24

amino-, d-, tri- peptidases

Front 25

alpha amylase found where?

Back 25

in pancreas and saliva

Front 26

what does alpha amylase break down?

Back 26

carbs, sugars