Function And Dysfucntion Supplement (1)

Question 1

What are the three parts of the central dogma of Genetics

Answer 1

1. Replication
2. Transcription - genetic info carried by DNA is transcribed into RNA
3. Translation - the information carried in mRNA is translated into proteins

Question 2

DNA is what and what?

Answer 2

Double stranded and anti-parallel

Question 3

Why are mitotic chromosomes condensed?

Answer 3

To prevent physical damage to the DNA as chromosomes are passed on to daughter cells

Question 4

What four pairs of proteins make up the Histone-Octamer?

Answer 4

H2A
H2B
H3
H4

Question 5

Heterochromatin stains what color throughout cell cycle?

Answer 5

Very dark

Question 6

When did Watson and Crick describe the structure of DNA?

When did K, K, and H determine the genetic code?

Answer 6

1953

1966

Question 7

What is an intron?

Answer 7

Position where the gene expresses a protein

Question 8

Where does acetylation attach an acetyl group on genes?

Answer 8

On the free lysine residue

Question 9

What is post-translational modification?

Answer 9

Altering of Histone proteins with their DNA

Usually occurs at H3 and H4 on the tails

Question 10

Describe DNA Methylation

Answer 10

Methyl groups added to the DNA molecule (cytosine and adenine) by methyl transferase enzymes

This changes the activity of the DNA segment without changing the sequence

Represses gene transcription when at gene promoter region

Question 11

What key processes is DNA Methyl involved in

Answer 11

Genomic imprinting
X-chromosome inactivation 
Repression of transposable elements
Aging
Carcinogenesis

Question 12

Describe hypomethylation

Answer 12

Chromosome instability
Loss of imprinting

Seen in promoter CpG Islands

Question 13

Describe hypermethylation

Answer 13

Associated with gene promoters
Can arise secondary to gene silencing
Can be a target for epigenetic therapy

Seen in Gene promoter CpG islands

Question 14

Describe DNA Helicase

Answer 14

Unwinds DNA
Comprised of 6 identical subunits

Uses ATP to undergo a conformational change to split DNA apart

Question 15

What do Topoisomerase inhibitors do as anti-cancer agents

Answer 15

Block the cell cycle
Generate single and double stranded breaks
Harms integrity of the genome
Leads to apoptosis

Question 16

What is the purpose of germ cells

Answer 16

Low mutation rates that maintain the species

Question 17

What is the purpose of somatic cells

Answer 17

Low mutation rates avoid uncontrolled cancer

Question 18

What protein spell checks the new DNA

Answer 18

DNA polymerase

Question 19

How can UV damage hurt DNA

Answer 19

Can cause a covalent linkage between two adjacent pyrimidine dimers (T-T) or (C-T)

Question 20

Describe depurination

Answer 20

A or G cut from DNA spontaneously via hydrolysis of the N-glycosidic bond between the base and deoxyribose group

Question 21

Describe deamination

Answer 21

The amino group of purine or pyrimidine bas is hydrolyzed such that:
Adenine to hypoxanthine
Guanine to xanthine
Cytosine to uracil

Question 22

Methylation of CpG causes what

Answer 22

Silence of genes responsible for cancer repair

Question 23

What agents cause cross-links within DNA

Answer 23

Nitrogen mustard
Cisplatin
Mitomycin C
Carmustine

Question 24

What agents cause alkylation of DNA

Answer 24

Dimethyl sulfate

Methyl methansulfonate

Question 25

What specific agent causes intercalation of DNA

Answer 25

Thalidomide

Question 26

Describe mismatch excision repair

Answer 26

Proofreading by DNA dependent DNA polymerase

Question 27

MutS and MutL do what respectively

Answer 27

Muts binds to DNa while MutL scans for nicks and triggers degradation of the nicked strands

Question 28

What are the three causes of double strand breaks

Answer 28

Ionizing radiation
Replication errors
Oxidizing agents

Question 29

Describe cockayne’s syndrome

Answer 29

Defect in transcription-coupled repair

Causes growth retardation, skeletal abnormalities, and sensitivity to sunlight

Question 30

What are the side effects of rifampicin

Answer 30

Upregulation of hepatic cytochrome enzymes, which causes an upregulation of other drugs (warfin and contraceptive hormones)

Makes patient haver red urine, sweat, and tears for a brief time

Question 31

What PTM’s work on lysine

Answer 31

Sumoylation
Ubiquitination
acetylation
Methylation

Question 32

What PTM works on serine and threonine

Answer 32

Phosphorylation

Question 33

Epigentetics are affected by what factors

Answer 33

Development
Enviropnement
Drugs
Aging 
Diet

Question 34

ATG begins what

Answer 34

Start of translation which is initiated by methionine

Question 35

Where does DNA methylation occur in humans

Answer 35

5 position on the pyrimidine ring of cytosine residues

Forms 5-methylcytosines which promotes silenced genes