DNA

Question 1

What is the central dogma of molecular biology

Answer 1

DNA –> RNA –> Protein

Question 2

What are the nucleotide bases

Answer 2

Adenine, guanine, cytosine, thymine

Question 3

Which bases are purines

Answer 3

Adenine and guanine

Question 4

Which bases are pyrimidine

Answer 4

Cytosine and thymine

Question 5

How are nucleotides in a strand connected to each other

Answer 5

Phosphodiester bonds

Question 6

What is Chargaff’s Rule

Answer 6

% A = % T
%C = %G

Question 7

What is the ratio of C+A:G+C?

Answer 7

It varies!

Question 8

How many DNA bp per helical turn?

Answer 8

10

Question 9

What is the most basic level of DNA packaging?

Answer 9

Nucleosome

Question 10

What is a nucleosome

Answer 10

DNA wrapped around octameric histone complex
“beads on a string”

Question 11

What are sister chromatids

Answer 11

Identical copies of a chromosome

Question 12

WHich are larger–purines or pyrimidines

Answer 12

Purines

Question 13

Where is the centromere

Answer 13

In the middle of the replicated chromosome

Question 14

Why is the centromere important

Answer 14

Where the mitotic spindle attaches, densest DNA

Question 15

What is the telomere

Answer 15

Region of DNA at ends of chromatids

Question 16

Euchromatin:

Answer 16

less condensed, more accessible

Question 17

Heterochromatin:

Answer 17

highly condensed, not rich in genes, low levels of gene expression

Question 18

What are the types of heterochromatin

Answer 18

Constitutive and facultative

Question 19

What are the differences between the subtypes of heterochromatin

Answer 19

Constitutive: always tightly packed
Facultative: can be opened up

Question 20

What is a gene?

Answer 20

region of DNA that controls discrete hereditary characteristics, usually corresponding to single protein or RNA

Question 21

What makes up mobile DNA elements

Answer 21

DNA trasposons, retroviral-like retrotransposons, non-retroviral retrotransposons

Question 22

Why di we care about simple sequence repeats?

Answer 22

Help with gene mapping, some are specific to diseases such as Huntingtons

Question 23

About how much fo the human genome is repeated vs unique sequences

Answer 23

50-50

Question 24

Define synteny

Answer 24

The presence of two or more loci on the same chromosome

Question 25

What are the 3 basics of DNA metabolism

Answer 25

Replication, Recombination, Repair

Question 26

What is the mechanism of DNA replication

Answer 26

Semiconservative

Question 27

What catalyzes DNA replication

Answer 27

DNA polymerases

Question 28

What directing does DNA replication happen?

Answer 28

5’-3’

Question 29

Leading strand:

Answer 29

replicated in same direction as helix is being unwound

Question 30

Lagging strand:

Answer 30

Replicated in the opposite direction of unwinding
Many small fragments generated

Question 31

Who connects the fragments of the lagging strand

Answer 31

DNA ligase

Question 32

Who unwinds the DNA

Answer 32

DNA helicase

Question 33

Who prevents the unwound DNA from reconnecting

Answer 33

Single strand DNA binding protein

Question 34

Who makes the RNA primer

Answer 34

DNA polymerase/primase

Question 35

Who synthesizes the new DNA strand

Answer 35

DNA polymerase

Question 36

Draw a schematic of the replication fork

Answer 36

Question 37

What is the problem with ending replication

Answer 37

lagging strand cannot finish replicating the parent strand

Question 38

How is the end replication problem fixed

Answer 38

Telomerase. Uses RNA template to synthesize a DNA copy of telomeric portion

Question 39

What is DNA methylation

Answer 39

Methyl group added to cytosine

Question 40

What does methylation do

Answer 40

Influences regulatory proteins, usually in transcriptionally silent regions

Question 41

Is methylation hereditary

Answer 41

Yes