DNA transcription/translation

Question 1

What is transcription catalyzed by?

Answer 1

RNA polymerase

Question 2

Where does transcription occur?

Answer 2

mostly in the nucleus

Question 3

What are the 3 types of RNA?

Answer 3

messenger, transfer, ribosomal

Question 4

What does messenger RNA do?

Answer 4

template for translation (PROTEIN SYNTHESIS)

Question 5

What does transfer rNA do?

Answer 5

reads genetic code in mRNA and transfers appropriate amino acid to a growing polypeptide chain during translation

Question 6

What does ribosomal RNA do?

Answer 6

component of ribosome (cell machinery for translation)

Question 7

What direction does transcription happen?

Answer 7

• read 5’ to 3’ direction (like DNA polymerase)

Question 8

T/F: RNA poly requires a primer

Answer 8

• RNA polymerases do NOT require a primer (unlike DNA polymerase)

False

Question 9

Adenine binds with ____ in RNA

Answer 9

• Uracil binds with adenine (instead of Thymine in DNA)

Question 10

Transcription Begins at a ______

Answer 10

• Begins at a promoter

Question 11

Name 2 inhibitors of transcription

Answer 11

• Actinomycin D, • Rifampin:

Question 12

What does actinomycin D do?

Answer 12

inserts into double helical DNA and prevents movement of polymerase along template DNA; inhibits both prokaryotic and eukaryotic; used for chemo

Question 13

What does rifampin do?

Answer 13

inhibits prokaryotic transcription by binding to prokaryotic RNA polymerase; used to treat TB

Question 14

What do most eukaryotic DNA’s have on the 5’ end? 3’ end?

Answer 14

5’–>cap, 3’–>poly A tail

Question 15

What does the 5” cap do?

Answer 15

protects mRNA from degradation by ribonucleases

Question 16

What does the poly A tail do?

Answer 16

enhances translation process

Question 17

sequences removed by splicing are

Answer 17

introns

Question 18

sequences retained after splicing

Answer 18

exons

Question 19

• Addition of 5’ cap, splicing, and poly(A) tail occur in the ____

Answer 19

nucleus

Question 20

What does reverse transcriptase do?

Answer 20

produces DNA from RNA

Question 21

cDNA synthesis commonly used to ____

Answer 21

clone cellular genes

Question 22

Codons are

Answer 22

a set of 3 nucleotides

Question 23

• Set of 3 nucleotides codes for a ____

Answer 23

amino acid

Question 24

What is the start codon?

Answer 24

AUG (school starts in AUGust)

Question 25

What are the stop codons?

Answer 25

UAA, UAG, UGA

Question 26

codons read by tRNAs using _____, which are complementary to codons

Answer 26

anticodons

Question 27

What does it mean for the genetic code to be degenerate? how is this helpful?

Answer 27

the same amino acid can be encoded by more than 1 codon. minimizes deleterious effects of mutations!!!

Question 28

codes for the SAME amino acid: ____

Answer 28

silent mutation

Question 29

codes for a DIFFERENT amino acid: _____

Answer 29

missense mutation

Question 30

codes for a STOP codon and results in premature termination: _____

Answer 30

nonsense mutation

Question 31

nucleotide insertion or deletion changes the reading frame: _____

Answer 31

frameshift mutation

Question 32

T/F: Genetic code is universal

Answer 32

True

Question 33

Where does translation occur?

Answer 33

• Occurs on RIBOSOMES, consists of proteins and rRNAs

Question 34

• Starts from ___ encoding methionine and terminates at ___ codon

Answer 34

AUG, stop

Question 35

What inhibits translation?

Answer 35

antibiotics, toxins

Question 36

Prokaryotic ribosome consist of which subunits?

Answer 36

• Prokaryotic: 30s + 50s = 70s

Question 37

Eukaryotic ribosome consist of which subunits?

Answer 37

• Eukaryotic: 40s + 60s = 80s

Question 38

Where are ribosomes synthesized in eukaryotes?

Answer 38

i. Ribosomes synthesized in nucleolus and transported to cytoplasm

Question 39

Where does translation occur?

Answer 39

• Ribosomes and mRNAs meet in cytoplasm and this is where translation occurs!

Question 40

• __________ attach correct amino acids to their tRNAs

Answer 40

• Aminoacyl tRNA synthetases attach correct amino acids to their tRNAs

Question 41

T/F: ii. Each synthetase is specific to one amino acid and its corresponding tRNAs

Answer 41

True

Question 42

T/F: • Multiple ribosomes can bind a single mRNA at different points and perform translation

Answer 42

True

Question 43

What is a polysome?

Answer 43

• Polysome: complex of mRNA and multiple ribosomes (allows efficient use for protein synthesis)

Question 44

What are the antibiotics that inhibit prokaryotic ribosome?

Answer 44

* Streptomycin * Tetracycline * Chloramphenicol * Erythromycin

Question 45

What does diphtheria toxin do?

Answer 45

inhibits eukaryotic protein synthesis by inactivating translation factor (eEF2); toxin gene encoded by LYSOGENIC bacteriophage