Lecture 1

Question 1

Why Is Translation E Expensive When Peptide Bond Formation Is Only 21kj/mol?

Answer 1

Specific location bond: 125kj/mol

Question 2

Gene Definition

Answer 2

Code for polypeptide chains or RNA

Question 3

Plasmid definition

Answer 3

Cytosol dna molecule.
-fewer than 1000 bps
-can yield daughter plasmids
-yeast/fungi/bacteria
-circular

Question 4

How many chromosomes do humans have

Answer 4

46

Question 5

Exons

Answer 5

Coding segments of DNA
1.5% humans dna is exons

Question 6

Introns

Answer 6

Non gene coding dna
-transposing
-molecular parasites
-rna genes
-SSR (simple sequence repeats)
-centromere

Question 7

Centromere

Answer 7

Attachment point for proteins that link chromosome to mitotic spindle (a-t rich)

Question 8

Telomeres

Answer 8

End of chromosome for stabilization
Cannot be routinely replicated
Added to end via enzyme telomerase

Question 9

Is dns mostly exons or introns?

Answer 9

Introns / SSRs

Question 10

Why is supercoiling important?

Answer 10

-compacts DNA to fit within cell
-keeps DNA under wound for easier accessibility (strand separation)
-intrinsic to tertiary structure of dna
-helps strand separation with out breaking h bonds = more E efficient

Question 11

B form DNA Base pairs per turn

Answer 11

10.5 Bp / turn

Question 12

Can supercoiling occur if one strand is nicked?

Answer 12

NO

Question 13

Lk Definition

Answer 13

Linking number
-number of times DNA strands overlap

If right handed super coiling = positive

If left handed = negative

B dna = right handed

Question 14

If dna strand is broken, what is Lk?

Answer 14

Undefined

Question 15

Superhelical density

Answer 15

Sigma lower case
Change in Lk/ Lko

If answer -0.01. 1% of turns initially present were removed

Question 16

Molecular weight of base pair

Answer 16

650g/mol Bp

Question 17

What percent about of dna is exons?

Answer 17

40% (unsure what species)

Question 18

Does nucleosome formation change Lk?

Answer 18

No but need more if I

Question 19

How does DNA gyrase affect linking number?

Answer 19

Decreases by 2. But needs ATP present !

Question 20

How does denaturing dna change Lk

Answer 20

No change
No break in backbone