DNA Replication 3.3 U3

Question 1

Chromatin vs chromatid vs chromosome?

Question 2

Prokaryote chromosomes vs Eukaryotes chromosomes?

Answer 2

Pro:singular, circularin cytoplasmEu:multiple, linearmorein nucleus

Question 3

What is DNA coiled around and what does that form?

Answer 3

DNA is tightly coiled around histones, which form nucleosomes

Question 4

What is X-Shape?

Answer 4

duplicated chromosome with supercoiled chromatin

Question 5

What are the main roles of DNA?

Answer 5

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

Question 6

What are the monomers of DNA

Answer 6

Nucleotides

Question 7

What is the DNA structure?

Answer 7

Double-strandedDouble helix (linear in euk, circular in pro)Monomers = nucleotides5’ to 3’ directionality 5’ = phosphate end3’ = OH endAntiparallelHydrogen bonds between bases

Question 8

What is Chargaffs Rule?

Answer 8

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

Question 9

What are the Base-Pairing Rules

Answer 9

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

Question 10

Describe the Contents of Nucleotides?

Answer 10

Monomers of DNAComposed of three chemical groups:5 Carbon Deoxyribose SugarCarbons are numbered for biochemical identification purposes Phosphate Attached to the 5’ deoxyribose carbon1 of 4 Nitrogenous bases

Question 11

What are Euk Telomere?

Answer 11

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 12

What is the central dogma?

Answer 12

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

Question 13

What is Semi-Conservative Replication?

Answer 13

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

Question 14

3 steps to DNA Replication?

Answer 14

Initiation, Elongation, Termination

Question 15

What is Initiation in DNA Replication?

Answer 15

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 16

What is Elongation in DNA Replication?

Answer 16

Primase puts down RNA primers to help DNA polymerase actually bind to the template DNA StrandDNA 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 17

What is Termination in DNA Replication?

Answer 17

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