Chapter 10- Transcription and Translation

Question 1

Genetic Code Characteristics

Answer 1

Degenerate
Unambiguous
Non-overlapping, non-punctuated
Nearly Universal

Question 2

Gene

Answer 2

Sequence of DNA that makes a functional product (Protein or RNA)

Question 3

Common Promoter Element

Answer 3

TATA Box- Helps DNA polymerase bind

Question 4

What percent of DNA encodes transcription factors?

Answer 4

8%

Question 5

Cis Regulatory Elements

Answer 5

Enhancers
Insulators
Silencers

Question 6

Enhancers

Answer 6

Facilitate RNA polymerase binding

Question 7

Insulator

Answer 7

Sequence between enhancer and promoter that limits non-target gene transcription

Question 8

Silencers

Answer 8

Repress gene expression by limiting RNA polymerase binding

Question 9

Activators

Answer 9

Bind to enhancers

Question 10

Repressors

Answer 10

Bind to silencers

Question 11

Elongation

Answer 11

RNA polymerase reads template and adds bases in 5’ to 3’ direction

Question 12

Termination

Answer 12

DNA sequence prompts RNA polymerase unbinding

Question 13

Post-Transcription Processing Mechanisms

Answer 13

Spicling
5’ Capping
Poly-A Tail

Question 14

Splicing

Answer 14

Exons connected while introns spliced out
Completed by spliceosome
Directed by consensus-RNA motif
Many mRNA can be made by single gene with alternative splicing

Question 15

5’ capping

Answer 15

Methylated guanine added to 5’ end of mRNA to facilitate splicing and ribosome binding

Question 16

Poly-A tail

Answer 16

100-250 adenines added to 3’ end of mRNA to increase stability

Question 17

Genetic Basis of Prostate Cancer

Answer 17

Chromosome 8, region 8q24 mutation
MYC gene- proto-oncogene
Mutations in PVT1 (normal enhanced product) make enhancer interact with MYC gene to cause tumor growth

Question 18

tRNA

Answer 18

75-80 bases that contain anticodon and amino acid binding region

Question 19

Aminoacyl tRNA Synthetase

Answer 19

Catalyzed addition of amino acid to tRNA
One enzyme per amino acid

Question 20

Translation initiation

Answer 20

Leader mRNA binds to small ribosome to line up start codon (AUG- methionine) to initiation complex

Question 21

Translation Elongation

Answer 21

Large ribosome binds
tRNA binds to mRNA codons
rRNA ribozyme catalyzes peptide bond

Question 22

Translation Termination

Answer 22

When ribosome reads stop codon, polypeptide is released and ribosome dissociates

Question 23

Wobble Effect

Answer 23

3rd position of mRNA codon and 1st position of tRNA anticodon are non-specific

Question 24

Charcot-Marie-Tooth Disease (CMT)

Answer 24

Defects in glycyl tRNA synthetase (GARS)
Glycine is unable to be added during translation
Dominant mutation
Progressive degeneration of distal neurons
Muscle weakness, atrophy, decreased motor skills

Question 25

Post-translational modifications

Answer 25

Cleavage
Formation of quaternary structures
Signal sequences removed
Addition of chemical groups

Question 26

Ubiquitin

Answer 26

Tag for misfolded or excess proteins to mark for degradation by proteasome

Question 27

Prions

Answer 27

PrPc is normal brain protein
PrPsc is scrapie version, misfolded that accumulates and resists degradation
PrPsc contact with PrPc causes propagation of misfolding
Causes death of neuron and eventually organism

Question 28

Prion diseases

Answer 28

Transmissible spongiform encephalopathies (TSEs)
Humans- Kuru
Muscle weakness, atrophy, loss of smooth muscle function, and death