Definitions

Question 1

Antagonists

Answer 1

• bind hormone receptors
• block receptor activity –> repress gene expression
  ex: tamoxifen (binds estrogen receptor as competitive inhibitor - used to treat breast and other cancers)

Question 2

Agonists

Answer 2

• bind hormone receptors; are often transcriptional activators
• stimulate receptor activity –> gene expression
• ex: anabolic steroids

Question 3

5’ cap

Answer 3

7methylguanosine cap

specialized nucleotide required for binding of initiation factors to mammalian mRNA

Question 4

5’ UTR

Answer 4

Untranslated Region

sequence between 5’ and the initiation codon in translation of mammalian mRNA

Question 5

Start Codon

Answer 5

AUG (methionine)

where translation begins

Question 6

Coding Region

Answer 6

the sequence that gets translated into protein

Question 7

Stop Codon

Answer 7

either UGA, UAA, or UAG

stops translation

Question 8

3’ UTR

Answer 8

sequence between stop codon and poly(A) tail and the site of key regulatory sequences
Untranslated Region

Question 9

Poly(A) Tail

Answer 9

untemplated polyadenylate sequence averaging ~200 nucleotides
protects mRNA from degradation and increases translational efficiency

Question 10

eIF4E

Answer 10

factor that binds the 5’ cap in mammalian translation

Question 11

eIF2

Answer 11

binds and delivers initiator Met-tRNA in mammalian translation (requires GTP)

• recognizes ribosome independently of all other RNAs
• binds directly to subunit with help of elongation factor EIF2 (dont confused with EF2)

Question 12

eIF4G

Answer 12

scaffold protein that binds eIF4E required for assembly of pre-initiation complex in mammalian translation
- provides bridge btwn 5’ end of RNA and 3’ polyA tail - this shape is very efficiently recognized by the small subunit of the ribosome - forms pre-initiation complex