DNA Replication 3.3 U3

Question 1

Prokaryote chromosomes vs Eukaryotes chromosomes?

Answer 1

Pro:
singular, circular
in cytoplasm

Eu:
multiple, linear
more
in nucleus

Question 3

Euk vs Pro Chromosomes?

Answer 3

Pro:
singular, circular
in cytoplasm

Eu:
multiple, linear
more
in nucleus

Question 4

Chromatin vs chromatid vs chromosome?

Question 5

What is DNA coiled around and what does that form?

Answer 5

DNA is tightly coiled around histones, which form nucleosomes

Question 6

What is X-Shape?

Answer 6

duplicated chromosome with supercoiled chromatin

Question 7

What are the main roles of DNA?

Answer 7

Storing information:
Genetic info
Copying information:
Prior to division (during S phase) it has to be copied!
Transmitting information:
Genes are inherited from one gen to the next

Question 8

What are the monomers of DNA

Answer 8

Nucleotides

Question 9

What is the DNA structure?

Answer 9

Double-stranded
Double helix (linear in euk, circular in pro)
Monomers = nucleotides
5’ to 3’ directionality
5’ = phosphate end
3’ = OH end
Antiparallel
Hydrogen bonds between bases

Question 10

What is Chargaffs Rule?

Answer 10

“Chargaff’s Rule”
# of A=T
# of C=G
# of purines = # of pyrimidines

Question 11

What are the Base-Pairing Rules

Answer 11

Adenine with thymine (2 H bonds)
Guanine with cytosine (3 H bonds)

Question 12

Describe the Contents of Nucleotides?

Answer 12

Monomers of DNA
Composed of three chemical groups:
5 Carbon Deoxyribose Sugar
Carbons are numbered for biochemical identification purposes
Phosphate
Attached to the 5’ deoxyribose carbon
1 of 4 Nitrogenous bases

Question 13

Base Pairs?

Answer 13

A-T/U
G-C

Question 14

What are Euk Telomere?

Answer 14

Eukaryotic DNA has ends
Prokaryotic doesn’t because it is stored as a circular chromosome.
These ends can be degraded over time, leading to gene loss.
Eukaryotes have “caps” of long nonsense DNA sequences called telomeres to protect against DNA degradation.
Many scientists speculate that telomere loss is associated with aging in eukaryotes.

Question 15

What is the central dogma?

Answer 15

Describes the flow of information in a cell
DNA–>RNA–>Protein
Proteins carry out cell functions, which is expressed as a physical trait*.

Question 16

What is Semi-Conservative Replication?

Answer 16

Each copy of the DNA will have one template (old) strand and one newly synthesized strand.

Question 17

3 steps to DNA Replication?

Answer 17

Initiation, Elongation, Termination

Question 18

What is Initiation in DNA Replication?

Answer 18

Topoisomerase (A) relaxes the supercoiled DNA near the origin of replication.
DNA Helicase (B) breaks the hydrogen bonds between the template strands.
Strands are kept from re-annealing (fancy word for binding) by single stranded binding proteins (C).

Question 19

What is Elongation in DNA Replication?

Answer 19

Primase puts down RNA primers to help DNA polymerase actually bind to the template DNA Strand
DNA Polymerase binds and synthesizes the new strands from 5’ to 3’.
Replication on the leading template strand is continuous.
Replication on the lagging template strand is discontinuous

Question 20

What is Termination in DNA Replication?

Answer 20

RNA primers are removed
DNA ligase fills in the gaps from the primer removal and between the Okazaki Fragments.
End result: Two Identical Copies of the DNA