Protein Synthesis

Question 1

Protein is made outside of the nucleus at the ________.

Answer 1

ribosome

Question 2

Define transcription

Answer 2

making of mRNA from DNA

Question 3

messenger RNA is a copy of ___ that can leave the ________.

Answer 3

DNA; nucleus

Question 4

RNA’s base pairs are read in sets of 3 called ______.

Answer 4

codons

Question 5

The three stages of transcription are:

Answer 5

1. Initiation
2. Elongation
3. Termination

Question 6

Give an overview of the initiation stage

Answer 6

starts transcription

Question 7

Give an overview of the elongation stage

Answer 7

lays down the mRNA nucleotides

Question 8

Give an overview of the termination

Answer 8

finalizes the mRNA

Question 9

Describe the promoter

Answer 9

the beginning of the DNA sequence to be copied

Question 10

What enzyme attaches to the promoter?

Answer 10

RNA polymerase II

Question 11

Describe the TATA Box

Answer 11

the promoter begins with a sequence of DNA that includes the base pairs T and A

Question 12

What are transcription factors?

Answer 12

proteins that allow the RNA Polymerase II to bind to the promoter.

Question 13

What is the transcription initiation complex

Answer 13

the promoter, RNA Polymerase II, and Transcription factors all combined and ready to start transcription

Question 14

Describe RNA Polymerase

Answer 14

an enzyme that unwinds DNA and lays down RNA nucleotides

Question 15

A _________ ____ caused the mRNA to be cut free from the DNA.

Answer 15

termination code

Question 16

When the mRNA is cut from DNA, it is called ___-___ and it needs a few modifications

Answer 16

pre-mRNA

Question 17

How is the 5’ end of pre-RNA altered

Answer 17

it receives a modified 5′ cap

Question 18

How is the 3’ end of pre-RNA altered

Answer 18

it a gets a poly-A tail

Question 19

Describe the 5’ cap

Answer 19

a modified guanine nucleotide with 3 phosphate groups

Question 20

Describe the poly-A tail

Answer 20

several adenine nucleotides in a row (50+)

Question 21

What is the purpose of modifying pre-RNA?

Answer 21

• allows mRNA to leave the nucleus
• protects mRNA from hydrolytic enzymes
• helps ribosomes attach to the 5′ end

Question 22

Describe introns

Answer 22

sections that are cut out of the pre-mRNA

Question 23

Describe exons

Answer 23

sections that are left in the finalized mRNA

Question 24

What do spliceosomes do?

Answer 24

carry out RNA splicing

Question 25

Spliceosomes are made out of what?

Answer 25

ribonucleoproteins (snRNPs)

Question 26

What do snRNPs do?

Answer 26

recognize the splice sites

Question 27

Describe ribozymes

Answer 27

catalytic RNA molecules that function as enzymes and can splice RNA

Question 28

Ribozymes are present in _______.

Answer 28

snRNP’s

Question 29

What is alternative RNA splicing?

Answer 29

choosing different regions of introns or exons from the same pre-mRNA sequence

Question 30

What is the purpose of alternative RNA splicing?

Answer 30

So one gene can code for more than one protein

Question 31

What is t-RNA

Answer 31

Transfer RNA

Question 32

Each tRNA has an ___-____ that matches up with a codon on the messenger RNA

Answer 32

anti-codon

Question 33

Each tRNA also has a particular ______ ___ attached to it.

Answer 33

amino acid

Question 34

aminoacyl-tRNA synthetase

Answer 34

enzyme that attaches amino acids to tRNA

Question 35

What do ribosomes do in protein synthesis?

Answer 35

Ribosomes match the tRNA anticodons with mRN

Question 36

The two ribosomal subunits are made of what?

Answer 36

proteins and ribosomal RNA (rRNA)

Question 37

small subunit holds ____

Answer 37

mRNA

Question 38

large subunit holds ____

Answer 38

tRNA

Question 39

A ribosome has three _______ ___ for tRNA

Answer 39

binding sites

Question 40

What is the A-Site for?

Answer 40

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

Question 41

What is the P-Site for?

Answer 41

holds the tRNA that carries the growing polypeptide chain

Question 42

What is the E-Site for?

Answer 42

the exit site, where discharged tRNAs leave the ribosome

Question 43

What is polyribosome (or polysome)

Answer 43

several ribosomes translate a single mRNA simultaneously, allowing a cell to make many copies of a protein very quickly

Question 44

What is a signal peptide

Answer 44

a short peptide added to the finished protein

Question 45

What does a signal-recognition particle (SRP) do?

Answer 45

attaches to the signal peptide that that it may enter the ER