nucleic acids: the central dogma

Question 1

The complementary nature of DNA is the basis of what?

Answer 1

LIFE

Question 2

The central dogma goes like?

Answer 2

DNA—>RNA—->Protein

Question 3

What is DNA?

Answer 3

two strands of nucleotide polymer
base sugar and phosphodiester linkage
runs antiparallel
has polarity and is directional

Question 4

what pairing has a stronger interaction? C&G or A&T

Answer 4

C&G

Question 5

what charge is the exterior of DNA?

Is the interior hydrophilic?

Answer 5

negative due to the phosphate groups causing it to be polar

NO! hydrophobic

Question 6

What stabilizes DNA?

Answer 6

hydrogen bonds, Mg2+ bound to phosphate backbone, and the hydrophobic effect

Question 7

what happens if DNA is cooled quickly?

Answer 7

the base pairs will pair incorrectly

Question 8

Is denaturation permanent?

Answer 8

No, renaturation can occur with slow cooling.

Question 9

What happens if there is a single base pair mismatch?

Answer 9

the DNA cannot become double stranded again. under the correct conditions oligonucleotides can be synthesized

Question 10

What is the basic structural unit of chromatin?

Answer 10

nucleosome

Question 11

What is condensation due to?

Answer 11

basic histone proteins interacting with acidic DNA backbone

Question 12

what charge do histones normally have?

Answer 12

positive

Question 13

What regulates packing and gene expression?

Answer 13

histone modifications

Question 14

What is a gene?

Answer 14

A basic unit of heredity

Question 15

What percent of DNA is exons?

Answer 15

less than 2%

Question 16

how many proteins coding genes are in the genome?

Answer 16

21,000

Question 17

What is necessary for DNA replication?

Answer 17

DNA polymerase
template strand
4 dNTPs
primer

Question 18

what is released when each nucleotide is added to the growing strand?

Answer 18

a pyrophosphate group

Question 19

What replicates telomeres?

Answer 19

telomerase

if put in cells can create cancer cells

Question 20

Why do we have a finite life span?

Answer 20

finite number of times replication can occur

Question 21

What differentiates RNA and DNA?

Answer 21

RNA contains ribose sugar, 2’ hydroxyl group, uracil, tends to form complex secondary structures; single stranded can hybridize with itself or with DNA, some have catalytic activity

Question 22

what is mRNA?

Answer 22

messenger RNA, codes for proteins (only 5% of total cellular RNA)

Question 23

what is rRNA?

Answer 23

assist protein synthesis on ribosomes

Question 24

what is siRNA?

Answer 24

synthetic small interfering RNAs regulate expression by blocking mRNA translation or stability (therapeutic potential)

Question 25

what is miRNA?

Answer 25

micro interfering RNA, regulate gene expression by blocking mRNA translation or stability

Question 26

What is special about RNA polymerase?

Answer 26

no primer required. | initiates transcription at the 5' end in the promotor region

Question 27

what is the template strand referred to in transcription?

Answer 27

the antisense strand

Question 28

The mRNA product from transcription gives what sequence?

Answer 28

the protein sequence--codons

Question 29

what are the three phases of transcription?

Answer 29

initiation, elongation, termination

Question 30

what is the difference between the mRNA transcript in eukaryotes and prokaryotes?

Answer 30

in prokaryotes the transcript usually encodes several co-regulated genes with no introns, in euks it is only one gene.

Question 31

What modifications must be made after transcription in eukaryotes?

Answer 31

1. additon of 5' cap 2. poly-A tail 3. splicing

Question 32

What does translation accomplish and how?

Answer 32

Makes a protein from the mRNA. uses ribosomes tRNA carries the anticodons--Aminoacyl tRNA synthetase makes sure the correct tRNA binds to correct codon amino acids dictated by the genetic code

Question 33

what is the genetic code?

Answer 33

``` 20 amino acids specified by 3 base codons it is degenerate AUG = start codon universal unambiguous non-overlapping "comma-less"--no interruption ```

Question 34

What does differential gene expression in eukaryotes allow for?

Answer 34

it allows cells and tissues to adapt to the environment

Question 35

What two types of genes are there?

Answer 35

constitutive: "house keeping" regulated: have to be turned on and off

Question 36

what is dominant control point for gene regulation?

Answer 36

initiation

Question 37

what often coordinates gene regulation with other cellular events?

Answer 37

signalling pathways