Transcription and Translation

Question 1

What is the order from gene to protein?

Answer 1

DNA–>RNA–>Protein

Question 2

Where does transcription occur in eukaryotes?

Answer 2

The nucleus

Question 3

What does transcription do?

Answer 3

It creates a single stranded copy of mRNA that can leave the nucleus

Question 4

What are the 3 steps of transcription?

Answer 4

Initiation, elongation, and termination

Question 5

What happens during initiation in transcription?

Answer 5

Transcription factors and RNA polymerase bind to the promoter of the gene

Question 6

What happens during elongation in transcription?

Answer 6

DNA is unwound and RNA polymerase creates a strand of mRNA which is complementary to the template strand of DNA (the RNA polymerase synthesizes the mRNA in the 5’ to 3’ direction)

Question 7

What happens during termination in transcription?

Answer 7

Transcription proceeds until the polymerase reaches the terminator sequence which then causes the enzyme to disassociate from the DNA

Question 8

What direction is the mRNA synthesized during the elongation step of transcription?

Answer 8

5’ to 3’

Question 9

What must happen to RNA before it can be transported to the cytoplasm and then what is the next step once the RNA reaches the cytoplasm?

Answer 9

The RNA must be modified in the nucleus and then once it reaches the cytoplasm, translation can occur

Question 10

What are 3 important functions of RNA processing?

Answer 10

Facilitates export from nucleus, Protects from degradation in the cytoplasm, and helps ribosomes attach to the 5’ end for translation

Question 11

What is the term used for noncoding DNA segments?

Answer 11

Introns

Question 12

What is the term used for coding DNA segments?

Answer 12

Exons

Question 13

What is the function of a spliceosome?

Answer 13

To cut out introns and join the exons together

Question 14

Why do we have introns?

Answer 14

They contain sequences which play a role in regulating gene expression and they also allow a single gene to code for more than one polypeptide.

Question 15

What does alternative RNA splicing do?

Answer 15

It can leave some exons out of the final transcript which allows humans to make a wider variety of proteins.

Question 16

Where does translation occur?

Answer 16

In the cytoplasm

Question 17

How many bases are read at a time in mRNA to build a polypeptide? What is the term for it?

Answer 17

3;codon

Question 18

What are the 2 key players in translation?

Answer 18

tRNAs and Ribosomes

Question 19

What does tRNA do?

Answer 19

Translates message from nucleic acids to amino acids

Question 20

What does tRNA contain?

Answer 20

An anticodon which is a triplet that is complementary to codon on the mRNA

Question 21

True/False: tRNAs can carry any protein. It does not have to be specific.

Answer 21

False

Question 22

What are aminoacyl-tRNA synthetases?

Answer 22

Enzymes that attach the amino acid to the tRNA

Question 23

tRNA with an amino acid attached is “___”

Answer 23

Charged

Question 24

What consists of a small and large subunit composed of protein and ribosomal RNA (rRNA)?

Answer 24

Ribosomes

Question 25

In terms of medicine, how are eukaryotic and prokaryotic ribosomes different?

Answer 25

Some antibiotics inactivate the bacterial ribosomes without harming our own

Question 26

What catalyzes the formation of peptide bonds, the rRNA or the protein?

Answer 26

rRNA

Question 27

What are the 3 steps of Translation?

Answer 27

Initiation, elongation, and termination

Question 28

What happens during initiation in translation?

Answer 28

A small unit of the ribosome, with the initiator tRNA, binds to leader sequence of mRNA and scans for AUG

Question 29

What happens during elongation in translation?

Answer 29

Ribosome moves along mRNA adding amino acids to the growing polypeptide chain

Question 30

What happens during termination in translation?

Answer 30

Ribosome hits a stop codon and the subunits separate and the polypeptide is released

Question 31

What is required for elongation in translation?

Answer 31

protein (elongation factors) and energy

Question 32

What are the 3 sites of the ribosome during elongation?

Answer 32

E site, P site, and A site

Question 33

What is the E site?

Answer 33

It's where empty tRNA exits

Question 34

What is the P site?

Answer 34

It's where the tRNA is with the growing polypeptide

Question 35

What is the A site?

Answer 35

It's where the incoming/active tRNA is

Question 36

What is the role of a release factor during termination in translation?

Answer 36

It binds to the stop codon in the A site and causes the polypeptide to be released. Once this is done the translation assembly breaks apart.

Question 37

What happens to the polypeptide after completing translation?

Answer 37

It must undergo correct secondary and tertiary folding