Chapter 17 : Gene Expression -From Gene To Protein

Question 1

Transfer of information from DNA to mRNA

Answer 1

Transcription

Question 2

Transfers information from mRNA to a polypeptide (changing from language of nucleotides to amino acids)

Answer 2

Translation

Question 3

Sites of translation (sites of the synthesis of a polypeptide)

Answer 3

Ribosomes

Question 4

In prokaryotes, which lack a nucleus, transcription and translation can occur:

Answer 4

Simultaneously

Question 5

I’m eukaryotes, the mRNA is processed before it exits the _______ and enters the _______, where translation occurs.

Answer 5

Nucleus; cytoplasm

Question 6

Initial RNA transcript of any gene

Answer 6

Primary transcript

Question 7

In what 3 ways does RNA differ from DNA

Answer 7

1. The sugar component is ribose, rather than deoxyribose
2. Uracil (U) replaces thymine (T) as a nitrogenous base
3. RNA is usually single stranded

Question 8

Central dogma

Answer 8

DNA —> RNA —> protein

Question 9

A sequence of 3 nucleotides provides how many possible unique sequences of nucleotides

Answer 9

4^3 or 64

Question 10

The mRNA is _______ to the DNA template

Answer 10

Complimentary

Question 11

What replaces thymine in mRNA?

Answer 11

Uracil

Question 12

The nontemplate strand can also be known as the

Answer 12

Coding strand

Question 13

Is sequence of codons read 3’ to 5’ or 5’ to 3’?

Answer 13

5’ to 3’

Question 14

M. Nirenberg added artificial “poly U” mRNA to a test tube and obtained a polypeptide containing a _____ ____.

Answer 14

Amino acid

Question 15

Stat codon

Answer 15

AUG

Question 16

How many stop codons are there?

Answer 16

3

Question 17

DNA sequence where RNA polymerase attaches and initiates transcription.

Answer 17

Promoter

Question 18

Terminator

Answer 18

Sequence that signals the end of transcription

Question 19

Bacteria have _____ type of RNA polymerase, but eukaryotes have _____.

Answer 19

1 ; 3

Question 20

What RNA polymerase in eukaryotes synthesizes mRNA

Answer 20

RNA polymerase II

Question 21

First step of transcription in Eukaryotes

Answer 21

Initiation : Transcription factors bind to the promoter and facilitate the binding of RNA polymerase II, forming a transcription initiation complex; RNA polymerase II separates DNA strands and transcription begins at the start point

Question 22

Second key step of transcription in Eukaryotes

Answer 22

Elongation : RNA polymerase II moved along DNA strand, connecting RNA nucleotides that have paired to the DNA template to the 3’ end of the growing RNA strand

Question 23

Third key step in transcription in Eukaryotes

Answer 23

Termination : After polymerase transcribes past a polyadenylation signal sequence, the pre-mRNA is cut and released

Question 24

The promoter includes the transcription start point and recognition sequences, such as the ____ box

Answer 24

TATA

Question 25

Transcription factors first have to recognize and bind to the promoter before RNA polymerase II can attach, at which point the assembly is called the

Answer 25

Transcription initiation complex

Question 26

In prokaryotes, transcription ends after mRNA polymerase transcribes the ____ sequence.

Answer 26

Terminator

Question 27

A string of adenine nucleotides

Answer 27

Poly-A tail

Question 28

What end is the poly-A tail added to?

Answer 28

3'

Question 29

What end is the cap added to?

Answer 29

5'

Question 30

Long segments of non-coding nucleotide sequences

Answer 30

Introns

Question 31

The coding regions (opposite of introns)

Answer 31

Exons

Question 32

After a primary transcript is made of a gene, what is removed and what is joined together before the mRNA leaves the nucleus

Answer 32

Introns leave ; exons join together

Question 33

The process of introns being removed and exons joining together

Answer 33

RNA splicing

Question 34

Small RNA's within a large protein complex

Answer 34

Spliceosome

Question 35

What do spliceosomes do?

Answer 35

Snip an introns out of the transcript and connect the adjoining exons

Question 36

RNA molecules that act as enzymes

Answer 36

Ribozymes

Question 37

What 3 properties of RNA relate to its ability to function as an enzyme?

Answer 37

1. RNA is single stranded and can base pair with itself forming a 3 D structure 2. Some of its bases contain functional groups that can participate in catalysis 3. It can hydrogen bond with other nucleic acid molecules, allowing it to precisely locate splicing regions

Question 38

Alternative RNA splicing allows

Answer 38

Different polypeptides to be produced from a single gene

Question 39

How does the mRNA that leaves the nucleus differ from pre-mRNA?

Answer 39

A 5' cap with a modified guanine nucleotide is added to the 5' UTR. A poly-A tail with up to 260 adenine nucleotides is attached to the 3' UTR. Spliceosomes have cut out the introns and spliced the exons together

Question 40

Transfer RNA (tRNA) molecules carry amino acids to

Answer 40

Ribosomes

Question 41

Each tRNA has an anticodon that base pairs with a _____ codon on mRNA

Answer 41

Complimentary

Question 42

Where is tRNA transcribed

Answer 42

The nucleus of a Eukaryote, then it moves into the cytoplasm

Question 43

Each amino acid has a specific aminoacyl-tRNA synthetase that attaches it to its appropriate ____ molecules to create an aminoacyl tRNA

Answer 43

tRNA

Question 44

Ribosomes consist of large and small subunits that are constructed in the

Answer 44

Nucleolus in Eukaryotes

Question 45

What are the 3 tRNA binding sites

Answer 45

1. P site : peptidyl; holds the tRNA carrying the growing polypeptide 2. A site : aminoacyl; holds the tRNA carrying the amino acid to be added next 3. E site : exit site; discharged tRNA's leave the ribosome

Question 46

What kind of RNA is primarily responsible for both the structure and function of a ribosome

Answer 46

tRNA

Question 47

Initiation and elongation require energy from what

Answer 47

Hydrolysis of GTP

Question 48

Name the 3 stop codons

Answer 48

UAA, UAG, UGA

Question 49

Polypeptide synthesis begins in the

Answer 49

Cytoplasm

Question 50

Mutations that are small scale

Answer 50

Point mutations

Question 51

Types of small-scale mutations

Answer 51

1. Nucleotide pair substitution : one nucleotide and its complementary partner is replaced with another pair of nucleotides. 2. Silent mutations : a substitution that doesn't change the amino acid translation 3. Missense mutation : results in the imsertion of a different amino acid 4. Nonsense mutation : occurs when a point mutation changes an amino acid codon into a stop codons 5. Nucleotide pair insertions or deletions (frameshift mutations)