Chapter 17

Question 1

what is gene expression?

Answer 1

gene expression is the process by which DNA directs protein synthesis: stages are transcription and translation

Question 2

what is a metabolic pathway?

Answer 2

the way cells synthesize and degrade molecules in a series of steps

Question 3

what is transcription?

Answer 3

transcription is the synthesis of RNA using information in DNA

Question 4

what does transcription produce?

Answer 4

transcription produces mRNA (messenger RNA)

Question 5

what is translation?

Answer 5

translation is the synthesis of a polypeptide using information in the RNA

Question 6

what are the sites of translation?

Answer 6

ribosomes are the sites of translation

Question 7

what is replication?

Answer 7

copying all of the DNA and all of the chromosomes to prepare for cell division

Question 8

transcription turns - into -

Answer 8

transcription turns DNA to mRNA; it is the recipe for the protein

Question 9

translation turns - into -

Answer 9

translation turns mRNA to proteins; it is the actual making of the protein

Question 10

in eukaryotes, transcription is in? vs prokaryotes

Answer 10

in the nucleus because DNA is in the nucleus
- in prokaryotes, translation can begin before transcription

Question 11

how many amino acids and how many nucleotide bases?

Answer 11

20 amino acids and 4 nucleotide bases

Question 12

what are codons?

Answer 12

triplets of nucleotides; non-overlapping three-nucleotide words that are translated into a chain of amino acids to form a polypeptide; flow of information from gene to a protein is based on triplet code

Question 13

where are codons located?

Answer 13

all are in the messenger RNA, mRNA

Question 14

where are anticodons located?

Answer 14

all are in the tRNA

Question 15

bases in dna vs rna

Answer 15

rna uses A&U G&C, dna uses A&T G&C

Question 16

where does polypeptide synthesis start?

Answer 16

polypeptide synthesis always begins in cytosol at a free ribosome & can be moved to rough ER but never starts in rough ER

Question 17

RNA polymerase does not need?

Answer 17

RNA polymerase does not need a primer

Question 18

What is RNA synthesis?

Answer 18

RNA synthesis is catalyzed by RNA Polymerase, which pries DNA apart and joins together the RNA nucleotides, follows same base pairing rules but uses uracil

Question 19

what is a promoter?

Answer 19

DNA sequence where RNA polymerase attaches

Question 20

what is a terminator?

Answer 20

in bacteria, the sequence signaling the end of transcription is the terminator

Question 21

what are the three stages of transcription?

Answer 21

initiation, elongation, termination

Question 22

what are introns?

Answer 22

introns are intervening sequences that are noncoding and need to be cut out

Question 23

what are exons?

Answer 23

exons are regions that are expressed and usually translated into amino acid sequences

Question 24

what is RNA splicing?

Answer 24

removing introns and joining exons that creates an mRNA molecule with a continuous coding sequence

Question 25

what are ribozymes?

Answer 25

ribozymes are catalytic RNA molecules that function as enzymes and can splice RNA

Question 26

what is mRNA

Answer 26

mRNA has codons (triplets that code for amino acids); it is the recipe

Question 27

what is tRNA

Answer 27

transfer RNA brings amino acids to ribosomes, have an anticodon that is complementary to mRNA

Question 28

what is rRNA

Answer 28

is the platform for where you create the protein; couple tRNA anticodons with mRNA codons

Question 29

what is an anticodon?

Answer 29

an anticodon is a trinucleotide sequence located at one end of a tRNA that is complementary to an mRNA

Question 30

P site

Answer 30

holds the tRNA that carries the growing polypeptide chain

Question 31

A site

Answer 31

holds the tRNA that carries the next amino acid to be added to the chain

Question 32

E site

Answer 32

is the exit site, where discharged tRNAs leave the ribosome to make room for me