Ch.17 Gene to Protein

Question 1

what is the form of DNA content?

Answer 1

specific sequences of nucleotides

Question 2

link between genotype and phenotype?

Answer 2

proteins

Question 3

gene expresssion

Answer 3

process by which DNA directs protein synthesis, including transcription and translation

Question 4

central dogma

Answer 4

DNA—>RNA—->Protein

Question 5

template strand

Answer 5

template for ordering the sequence of nucleotides in an RNA transcript

Question 6

codons

Answer 6

mRNA base triplets, read in 5’ to 3’ direction

Question 7

what does each codon specify

Answer 7

an amino acid to be placed along a polypeptide

Question 8

how many codons are there

Answer 8

64

Question 9

how many triplets are “stop” signals?

Answer 9

three

Question 10

genes can be transcribed or translated even after

Answer 10

being transplanted from one species to another

Question 11

what does RNA polymerase attach to?

Answer 11

the promoter

Question 12

promoter?

Answer 12

region of DNA, upstream, where relevant proteins bind to initiate transcription of that gene

Question 13

transcription unit

Answer 13

DNA that is transcribed

Question 14

three stages of transcription

Answer 14

initiation, elongation, termination

Question 15

transcription initiation complex

Answer 15

transcription factors, RNA polymerase II, promoter

Question 16

TATA box

Answer 16

promoter crucial in forming initiation complex in eukaryotes

Question 17

how effective is RNA polymerase (#?)

Answer 17

untwists 10-20 bases at a time, 40/sec in eukaryotes

Question 18

when does polymerase stop in bacteria?

Answer 18

end of the terminator

Question 19

when does polymerase stop in eukaryotes?

Answer 19

polymerase continues transcription after pre-mRNA is cleaved from growing RNA chain; eventually falls off

Question 20

what does 5’ end recieve

Answer 20

modified nucleotide 5’ cap

Question 21

what does 3’ end recieve

Answer 21

poly-A tail

Question 22

functions of modifications:

Answer 22

1) facilitate the export of mRNA
2) protect mRNA from hydrolytic enzymes
3) help ribosomes attach to 5’end

Question 23

introns

Answer 23

stretched of nucleotides that lie between coding regions

Question 24

codons

Answer 24

exons

Question 25

RNA splicing

Answer 25

removes introns and joins exons, creating an mRNA molecule with a continuous coding sequence

Question 26

spliceosomes

Answer 26

proteins and small ribonucleoproteins (snRNPs) that recognize the splice sites

Question 28

why is the number of different proteins an organism can produce much greater than its number of genes?

Answer 28

alternative splicing

Question 29

alternative splicing?

Answer 29

a cellular process in which exons from the same gene are joined in different combinations, leading to different, but related, mRNA transcript

Question 30

ribozymes

Answer 30

catalytic RNA molecules that function as enzymes and can splice RNA