ch 9

Question 1

what is gene expression?

Answer 1

-the process where DNA directs protein synthesis
-So differential gene expression leads to cell specialization (every single cell in your body will have different functions despite having the same genetic material

Question 2

How is the process of DNA and amount of RNA different in eukaryotes versus prokaryotes? why?

Answer 2

-e: have DNA processed before it is matured, Transcription and translation happen at different steps - since they are nuclear membranes
-Multiple RNA polymerases with different functions

P:no membrane bound organelles so they can happen at the same time
-1 RNA pol

Question 3

How does RNA pol work with DNA? and what does it not need?

Answer 3

RNA polymerase builds the strands by prying the DNA strands open and hooking RNA nucleotides since it does not need an 3’ OH group like DNA polymerase would

Question 4

what is the base pair change in RNA?

Answer 4

RNA is complementary to the DNA template but T->U chance

Question 5

what is initiation? what are needed?

Answer 5

-binds to the promoter : starts unwinding the DNA and an RNA transcript will run along
- a promoter, transcription factors and transcription initiation complex all need to bind for this process to start

Question 6

promoter

Answer 6

signal for transcriptional start point and extends upstream and is where the RNA polymerase will attach to (specific region of bases)

Question 7

what is the promoter in Eukaryotes and prokaryotes?

Answer 7

E: TATA box
P: there is no designated area but at -35 to -10 elements (upstream) the RNA will recognize this and bind

Question 8

transcription factors

Answer 8

-mediate the binding of RNA polymerase and the initiation of transcription
-(basically just proteins that also bind to the promoter region that help guid RNA pol to the right spot)
-They bind to control elements and modulate gene expression (activating or deactivating gene expression)

Question 9

what affect do enhancers have on DNA ?

Answer 9

Some bind to enhancers (DNA regions that are far away from the coding regions) which can bend DNAs orientation where they come in contact with the promoter protein

Question 10

Transcription initiation complex:

Answer 10

complex of transcription factors and RNA polymerase needed to start transcription in eukaryotes

Question 11

Elongation in transcription
what is it? energy source?

Answer 11

physically builds the RNA transcript by going downstream
Nucleotides are added to the 3’ end using nucleotide triphoshates as energy sources

Question 12

what is transcription?

Answer 12

DNA into RNA

Question 13

What is translation?

Answer 13

RNA into proteins

Question 14

how were they able to tell amino acids from in vitro ?

Answer 14

• They created a synthetic mRNA using only U and fed it to in vitro and told what amino acid came out of it they were able to figure out the proteins that came out of the letters for single letter repeats and ditri..
  -For mRNA with three nucleotides they used synthetic mRNA that had tRNA attached to amino acids (1 ot of 20 were radio active) if the tRNA was able to fall through the filter then the tRNA connected to the RNA and ribsomes could get stuck - telling which amino acid belonged to which

Question 15

which is genetic code redundant?

Answer 15

Most AA can match to multiple codons because of the wobble effect - third nucleotide is loose because of tRNA shape so it can fall off

Question 16

what must tRNA have?

Answer 16

have the correct amino acid attached and the anticodon must match the mRNA codon

Question 17

what is the purpose of aminoacyl-tRNA?

Answer 17

synthases catalyze the attachment of the amino acid to its matching tRNA molcules by hydrolysis of ATP and tRNA will egt released and will be recycled

Question 18

what are ribosomes and what happens there?

Answer 18

• complex of proteins and rRNA that has two sub-unites (large and small)
  -A site: tRNA comes in and matches the codon
  -P site : tunnel where the growing chain snakes out of
  -E site: exist

Question 19

polyribosomes

Answer 19

lets the cell make a bunch of polypeptide chains very quickly (in both E and P) using the large subunit

Question 20

protein domains

Answer 20

They have different codons coding for different domains in a protein

Question 21

what is RNA processing ?

Answer 21

• enzymes in the eukaryotic nucleus modify the pre-mRNA before sending it to the cytoplasm for translation
  -Both ends are altered and the introns are spliced and removed
  -Only eukaryotes

Question 22

what happens to the ends of the RNA during RNA processing? what benefits do they have?

Answer 22

-The ends are modifies to receive a 5’ cap and a 3’ poly-a tail
-help: appearing to facilitate the export of mRNA to the cytoplasm,
= protect mRNA from hydrolytic enzymes
=help attach ribosomes to the 5’ end

Question 23

Spliceosome

Answer 23

consist of a variety of proteins and several small snRNPs that recognize splice sites and will remove the introns using two cuts at the splice acceptor and donor creating a lariat (loop) that causes the cut sites to join together

Question 24

riboenzymes

Answer 24

Catalytic RNA molecules that function as enzymes and can splice RNA

Question 25

what is the point of Alternative splicing?

Answer 25

allows multiple proteins to be made from 1 coding region

Question 26

what are the mutations of the genetic level?

Answer 26

insertions, deltions and subsitutions

Question 27

what are the types of protein level mutations?

Answer 27

silent, misense, nonsense, and frameshift

Question 28

Silent mutations

Answer 28

have no effect on the amino acid produced by the codon because of the wobble effect - codes for the exact same amino acid

Question 29

Misense mutations (define)

Answer 29

• change one amino acid into another (any kind of effect)

Question 30

what are the types of misense mutations?

Answer 30

-Conservative substitutions: the new amino aicds has similar properties to the old amino acid (polar to polar, charged to uncharged)
-Nonconservative: the new amino acid has different properties from the old amino acid
Nonpolar to polar

Question 31

nonsense mutations

Answer 31

changes an amino acid codon into a stop codon nearby always leading to a nonfunctional protein
Making a truncated protein

Question 32

frame shifts define and what are the two types?

Answer 32

-altering the reading frame
-Immediate nonsense: insertion or deletion creates a stop codon
-Extensive missense: insertion or deletion causes every codon to shift 1 or 2

Question 33

what are the types of mutations that happen on the phenotypic level?

Answer 33

loss of function
gain of function
antimorphic

Question 34

what are the the kinds of loss of function mutations in recessive and dominant?

Answer 34

-Recessive mutations that cause no gene activity = null or some gene activity = hypomorph
-Dominant mutation are haplooinsufficent - 1 gene dosage is not enough for the protein to function

Question 35

gain of function types?

Answer 35

Usually dominant and can be
Hypermorph with increased protein activity -
Neomorph new activity

Question 36

antimorphic

Answer 36

(dominant-negative) prevent the normal protein from functioning properly