Week 1 Lecture 1

Question 1

what is DNA

Answer 1

deoxyribonucleic acid, macromolecule, nucleic acid

Question 2

what are the small units of DNA

Answer 2

nucleotide

Question 3

what is nucleotide made of

Answer 3

phosphate, pentose sugar, nitrogenous base

Question 4

what is a nucleoside made of

Answer 4

pentose sugar, nitrogenous base

Question 5

what are the 4 nitrogenous bases

Answer 5

adenine, thymine, guanine, cytosine

Question 6

what are the two purines

Answer 6

adenine and guanine

Question 7

what are the two pyrimidines

Answer 7

thymine and cytosine

Question 8

what is the bond between phosphate and pentose sugar

Answer 8

phosphodiester

Question 9

what is the bond between pentose and base

Answer 9

N-glycosidic bond

Question 10

which bond is weaker, hydrogen or covalent

Answer 10

hydrogen

Question 11

what is a condensation reaction

Answer 11

joins molecules together by eliminating water

Question 12

what is a hydrolysis reaction

Answer 12

breaks molecules by adding water

Question 13

what happens in the major groove

Answer 13

allows binding of regulatory proteins and enzymes for processes like DNA replication, transcription and DNA repair

Question 14

what happens in the minor groove

Answer 14

some proteins recognize and bind to minor groove

Question 15

asexual reproduction in prokaryotes

Answer 15

1. entire genome is one circular chromosome
2. replicates to produce 2 identical chromosomes
3. 2 identical chromosomes move towards opposite ends of the cell
4. cytokinesis

Question 16

asexual reproduction in eukaryotes

Answer 16

M- mitosis
S- DNA replication
G1 and G2- transcription (gene expression)

Question 17

DNA Replication initiation steps

Answer 17

1. helicase breaks hydrogen bonds
2. single stranded binding (SBBP) proteins keep the untangled strands apart
3. primase adds ribonucleoside triphosphate to synthesize RNA primer

Question 18

DNA Replication elongation step

Answer 18

1. DNA Polymerase puts complimentary bases in 5’ to 3’ direction (4 dNTPs)

[* must have a template and a primer]

[*can proof read]

Question 19

DNA Replication termination steps

Answer 19

1. exonuclease removes nucleosides from the end of the DNA strand. also removes primer by recognizing ribose sugar. can repair damaged DNA
2. gaps due to primer being removed filled in by DNA Polymerase II
3. ligase joins the DNA strands by making new phosphate bonds

Question 20

what enzymes finish the job of DNA Replication

Answer 20

1. gyrase (a topoisomerase) relaxes supercoils. also facilitates unwinding at the beginning of replication
2. telomerase uses a short RNA template to add short DNA repeats to the short ends of linear chromosomes when last primer is removed using RNA template