DNA Structure (Lecture 8)

Question 1

What are the parts of a nucleotide?

Answer 1

Phosphate, Base, Sugar

Question 2

What is the difference between a ribose and deoxyribose?

Answer 2

Ribose has two OH while deoxyribose has an OH and an H

Question 3

What are purines and pyrimidines?

Answer 3

Purine has a double ring structure (Adenine and Guanine)

Pyrimidine is a single ring structure (Cytosine, Thymine, Uracil)

Question 4

What does a Phosphate look like?

Answer 4

Question 5

Adenine

Base symbol?

Nucleotide?

Nucleotide symbol?

Nucleoside?

Nucleoside symbol?

Answer 5

Adenine

Base symbol: A

Nucleotide: Deoxyadenosine 5’ monophosphate

Nucleotide symbol: dAMP

Nucleoside: Deoxyadenosine

Nucleoside symbol: dA

Question 6

Guanine

Base symbol?

Nucleotide?

Nucleotide symbol?

Nucleoside?

Nucleoside symbol?

Answer 6

Guanine

Base symbol: G

Nucleotide: Deoxyguanosine 5’ monophosphate

Nucleotide symbol: dGMP

Nucleoside: Deoxyguanosine

Nucleoside symbol: dG

Question 7

Thymine

Base symbol?

Nucleotide?

Nucleotide symbol?

Nucleoside?

Nucleoside symbol?

Answer 7

Thymine

Base symbol: T

Nucleotide: Deoxythymidine 5’ monophosphate

Nucleotide symbol: dTMP

Nucleoside: Deoxythymidine

Nucleoside symbol: dT

Question 8

Cytosine

Base symbol?

Nucleotide?

Nucleotide symbol?

Nucleoside?

Nucleoside symbol?

Answer 8

Cytosine

Base symbol: C

Nucleotide: Deoxycytidine 5’ monophosphate

Nucleotide symbol: dCMP

Nucleoside: Deoxycytindine

Nucleoside symbol: dC

Question 9

What is this strand called?

Answer 9

DNA polynucleotide strand

Question 10

What is this strand called?

Answer 10

RNA polynucleotide strand

Question 11

What kind of bonds do T-A pairs have? How many?

What kind of bonds do C-G pairs have? How many?

Answer 11

T-A pairs have two hydrogen bonds

C-G pairs have three hydrogen bonds

Question 12

What kind of sugar does DNA have?

What kind of sugar does RNA have?

Answer 12

DNA had deoxyribose sugar (no oxygen here)

RNA has ribose sugar (an OH group here)

Question 13

What is a phosphodiester linkage?

Answer 13

A phosphodiester linkage connects the 5’ - phosphate group and the 3’ -OH group of adjoining nucleotides

Question 14

How do the two DNA strands run in correlation to one another?

Answer 14

The strands run in opposite directions; they are antiparallel

Question 15

In RNA what replaces thymine (T)?

Answer 15

In RNA, uracil (U) replaces thymine (T)

Question 16

DNA vs. RNA

Sugar?

Bases?

5’ end?

Size?

Strands?

Answer 16

Sugar

DNA is deoxyribose

RNA is ribose

Bases

DNA: A,T,C,G

RNA: A,U,C,G

5’ End

DNA: Monophosphate,

RNA: Triphosphate

Size

DNA: Very large

RNA: Smaller

Strands

DNA: Double

RNA: Single

Question 17

What is the DNA backbone?

Answer 17

The DNA backbone is deoxyribose sugars linked by a phosphate

Question 18

Eukaryotic Genome Organization

1. DNA duplex is how big in diameter?

Answer 18

DNA duplex 2 nm in diameter

Question 19

Eukaryotic Genome Organization

2. Nucleosome fiber how big in diameter?

Answer 19

Nucleosome fiber 10 nm in diameter

Question 20

Eukaryotic Genome Organization

3. Chromatin fiber how big in diameter?

Answer 20

Chromatin fiber 30 nm in diameter

Question 21

Eukaryotic Genome Organization

4. Coiled chromatin fiber how big in diameter?

Answer 21

Coiled chromatin fiber 300 nm in diameter

Question 22

Eukaryotic Genome Organization

5. Coiled coil is how big in diameter?

Answer 22

Coiled coil 700 nm in diameter

Question 23

Eukaryotic Genome Organization

6. Condensed chromatid is how big in diameter?

Answer 23

Condensed chromatid 1400 nm in diameter

Question 24

How we go from double-stranded DNA into a Metaphase Chromosome? (Or how to pack 2 meters of DNA into the nucleus of a cell)?

Answer 24

Question 25

Histones/Histones removed Info slide

Answer 25

Question 26

DNA is interesting, but we are interested in changes in DNA that results in a new allele. What are these changes referred to as?

Answer 26

DNA is interesting, but we are interested in changes in DNA that results in a new allele. These changes are referred to as mutations.

Question 27

The Importance of Mutations What are mutations?

Answer 27

Mutations: sustainer of life and cause of great suffering * Source of all genetic variation, which further provides the raw material for evolution * Source of many diseases and disorders

Question 28

The Importance of Mutations What are mutations useful for?

Answer 28

* Useful for probing fundamental biological processes * Identifying mutant genes that alter development are useful for identifying the function of that gene. * Example, Wnt genes involved in patterning the vertebrate axis now known to be at the center of colon cancer.

Question 29

Greater than 80% of all colon cancers are caused by mutations in how many genes?

Answer 29

Greater than 80% of all colon cancers are caused by mutations in just one gene, APC.