Final Study Deck

Question 1

Alpha Amanitin

Answer 1

Homologous to nucleotides, disrupts RNA polymerase II, leading to the halt of protein synthesis.

Question 2

Diphtheria toxin

Answer 2

Cause ADP-ribosylation which disrupts ribosomes during the translation process, inhibiting protein synthesis.

Question 3

Chloramphenicol

Answer 3

Binds to the 50S ribosomal subunit, inhibiting peptidyl transferase, preventing peptide bond formation.

Question 4

Ciprofloxacin

Answer 4

Inhibits DNA gyrase (bacteria)

Question 5

Why is gene
expression regulated?

Answer 5

To conserve energy, would be impossible to express all genes all the time.

Question 6

What is positive vs negative control?

Answer 6

Positive control are elements like activators, and negative control is anything that represses a gene

Question 7

Cis and Trans Acting

Answer 7

Cis acting are sequences that flank genes that are being coded for, where trans are the actual molecules that bind to the elements

Question 8

Give examples of expression regulation including methylation, chromatin remodeling, and gene rearrangement.

Answer 8

Histone acetyltransferase upregulates access to DNA, histone deacetylase downregulates, methylation downregulates (binds histone tails together).

Question 9

What is the role of dATP in the function of ribonucleotide reductase?

Answer 9

dATP is is an allosteric inhibitor if bound to ribonucleotide reductase. Ribonucleotide reductase is responsible for reducing ribose into deoxyribose.

Question 10

Prokaryotic RNA Polymerases

Answer 10

RNA Polymerase

Question 11

Eukaryotic RNA Polymerases

Answer 11

RNA Pol I (rRNA)
RNA Pol II (mRNA)
Rna Pol III (tRNA)

Question 12

Prokaryotic DNA Polymerases

Answer 12

DNA Pol I (Repair)
DNA Pol II (DNA synthesis)
DNA Pol III (Repair)

Question 13

Eukaryotic DNA Polymerases

Answer 13

Polymerase alpha (Initiates DNA synthesis)
Polymerase beta (Repair)
Polymerase gamma (Mitochondrial DNA replication)
Polymerase Delta (Okazaki Fragment Elongation)
Polymerase Epsilon (Leading Strand Elongation)

Question 14

How is the RNA polymerase enzyme composed?

Answer 14

(α2ββ’)

Question 15

Compare and contrast function of σ70 and σ32

Answer 15

σ-subunits are factors that help recruit the RNA polymerase to the promoter region. σ70 is standard in E. coli , while σ32 helps recognize heat shock promoters.

Question 16

Point Mutation

Answer 16

Base change in codon

Question 17

Silent Mutation

Answer 17

Base change but still codes for the same amino acid

Question 18

Missense Mutation

Answer 18

Base change and codes for a different amino acid

Question 19

Nonsense Mutation

Answer 19

Premature termination

Question 20

Insertion Mutation

Answer 20

Adding of a base

Question 21

Deletion Mutation

Answer 21

Removal of a base

Question 22

Aminoacyl tRNA

Answer 22

Aminoacyl synthetase is the highly specific enzyme that attaches the right amino acid to the tRNA. This process is often called the second genetic code because the specificity of the process.

Question 23

Wobble hypothesis

Answer 23

Says that base pairing does not always follow the Watson and Crick rules. Meaning that multiple codons can code for the same amino acid.

Question 24

Nonsense suppression

Answer 24

tRNA that are mutated to read stop codons and keep going. Usually a tryptophan is involved.

Question 25

Processes of elongation

Answer 25

1. Amino-acyl tRNA binding
2. Peptidyl Transfer
3. Translocation

Question 26

Melanomas

Answer 26

Develop from exposure from the sun, causes pyrimidine dimers to form in the DNA (Thymine Dimers). Mutations may result from non- repair of dimers.

Question 27

Benzo[a]pyrene

Answer 27

A carcinogen, binds to the P53 gene segment of DNA leading to lung cancer. Upon oxidation, it covalently binds to guanine residues in DNA, interrupting G-C pairs and producing distortions

Question 28

Nucleotide Excision Repair (NER)

Answer 28

Identifies pyrimidine dimer or an adduct, specific endonucleases nick both sides of the damaged strand, and the gap is filled with polymerase and ligated.

Question 29

Base Excision Repair (BER)

Answer 29

Removes abnormal bases by using specific glycosylases that cleave the faulty base from the backbone. AP endonuclease recognizes the site of the missing base and nicking the 5’ side of the backbone. Deoxyribose phosphate lyase finishes the job by removing the nicked backbone, allowing for DNA polymerase and ligase to repair.

Question 30

Mismatch Repair

Answer 30

Used when base pairs are mismatched. Mut proteins are used to identify the parent strand via methylation. The daughter strand is then nicked by an endonuclease, and repaired by DNA polymerase and ligase

Question 31

Homologous Recombination

Answer 31

Used when there is a double stranded break. Holliday junction

Question 32

Non-Homologous Recombination

Answer 32

Ku protein is used to ligate the two broken ends together, loss of DNA can lead to mutations.

Question 33

Transcription-Coupled Repair

Answer 33

This pathway is used when RNA polymerase discovers an error in the DNA. The same repair system as NER is used.

Question 34

Xeroderma pigmentosum

Answer 34

A deficiency in the NER pathway, leading to extreme consequences when an individual is exposed to UV radiation. Cannot be exposed.

Question 35

Cockayne Syndrome

Answer 35

An autosomal recessive disorder that is linked to defects in NER and TCR. Results in the inability to repair mutated DNA which can lead to symptoms like premature aging, impaired development of the nervous system, and sensitivity to UV irradiation.

Question 36

Burkitt’s Lymphoma

Answer 36

A lymphoma cancer that is characterized by the translocation and deregulation of the c-myc on chromosome 8. Ultimately leads to deregulation of cell cycle control. One of the fastest growing malignancies in humans.