Chapter 33: Nucleic Acids

Question 1

What is the first level of DNA packaging?

Answer 1

Wrapping of DNA around histones to create a nucleosome structure

Question 2

What is the second level of DNA packaging?

Answer 2

“Beads on a string” form of chromatin
Beads = nucleosomes
String= linker DNA

Question 3

_____ are the major proteins of chromatin

Answer 3

Histones

Question 4

What are the five different histones of most eukaryotic species?

Answer 4

H1, H2A, H2B, H3, & H4

Question 5

Histones are small basic proteins with many _____ and _____ residues

Answer 5

Lysine and arginine

Question 6

Histones are ____ charged particles

Answer 6

Positively

Question 7

DNA is _____ charged

Answer 7

Negatively

Question 8

+ charge of Histone allows interaction with - charged ___

Answer 8

DNA

Question 9

What histones make up a histone octamer?

Answer 9

2 each of H2A, H2B, H3, & H4

Question 10

What does DNA wrap around to form a nucleosome?

Answer 10

Histone octamer

Question 11

Histone modifications can lead to…

Answer 11

Gene activation or gene repression

Question 12

Study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than alterations to the DNA sequence is ____

Answer 12

Epigenetics

Question 13

Histone tails are important in

Answer 13

Epigenetic regulation

Question 14

Epigenetic “marks” tell your genes to

Answer 14

switch on/off & to speak loud/soft

Question 15

What does “beads on a string” consist of?

Answer 15

Nucleosomes connected by linker DNA

Question 16

Chromatosomes are part of the ___ level

Answer 16

Second

Question 17

What is a chromatosome?

Answer 17

Nucleosome (DNA wrapped around histone octamer) with one bound linker histone (H1)

Question 18

H1 binds the ____ and exit/entry of the nucleosome dyad (center DNA of the nucleosome)

Answer 18

Linker DNA

Question 19

Chromatin unfolds when treated with

Answer 19

Low ionic strength solution

Question 20

What is the third level of packaging?

Answer 20

30nm fiber

Question 21

With what can’t the 30nm fiber form?

Answer 21

H1

Question 22

H1 histones from _____ bind to each other

Answer 22

Adjacent nucleosomes

Question 23

What are the two models for the third level?

Answer 23

Solenoid and Zig-Zag

Question 24

What is the fourth level?

Answer 24

Looped domains

Question 25

Looped domains attached to

Answer 25

Chromosome scaffold

Question 26

What can cause loop domains to open up?

Answer 26

Histone, modifying enzymes, chromatin, remodeling complexes, & RNA polymerase

Question 27

In prokaryotes, DNA is ____ and there is no nucleus

Answer 27

Smaller

Question 28

The presence of 2 ___ groups on RNA greatly affects its properties

Answer 28

-OH

Question 29

2-OH can form hydrogen bonds. When treated with 0.1 M NaOH, what are the results?

Answer 29

Rapid degradation. DNA would remain stable.

Question 30

Because RNA has 2-OH groups, it can participate in certain ____ and ____ reactions

Answer 30

Chemical and Enzyme-catalyzed

Question 31

DNA is ____stable than RNA and is ____susceptible to alkaline attack

Answer 31

More, less

Question 32

It is important for DNA to be stable because its role as the primary ____

Answer 32

Genetic material

Question 33

What do nucleases catalyze?

Answer 33

Hydrolysis of phosphodiesters

Question 34

Exonucleases work from the ___

Answer 34

Ends | 5' to 3' or 3' to 5'

Question 35

Endonucleases work ____ the chain

Answer 35

Within

Question 36

What are the 3 properties of restriction endonucleases?

Answer 36

1. Recognition of short sequences on DNA and cleavage of DNA at that site 2. Palindromic sequences 3. Bacteria use these enzymes to destroy invading genomes by cleaving their DNA's

Question 37

What is an example of DNA recognition & cleavage?

Answer 37

EcoR1 Restriction Endonuclease

Question 38

Palindromic means it can be read _____ forward and backward

Answer 38

The same. 5'-GAATTC-3' 3'-CTTAAG-5'

Question 39

Bacteria can protect its own DNA from being cut by

Answer 39

Methylation of adenine residues which prevents EcoR1 cleavage

Question 40

Restriction enzymes are important in

Answer 40

Molecular biology - cloning DNA fingerprinting DNA profiling- forensics and paternity tests

Question 41

You can use restriction enzymes to

Answer 41

Generate fragments of a certain size

Question 42

After digestion of restriction enzymes, fragments are run through a gel. The fragments travel from the ____ end to the ____ end.

Answer 42

Negative, positive

Question 43

Which fragments travel farther in the gel? Long or short

Answer 43

Short

Question 44

For DNA profiling, a band present in the child must be present in either their ___ or ___

Answer 44

Father, mother