DNA Chromosomes & Genomes I

Question 1

What happens to the chemical structure of a gene when it is passed from a cell to daughter cell?

Answer 1

It is mostly uchanged.

Question 2

In the 19th century, it was found that chromsomes contain DNA and protein in ___ amounts.

Answer 2

Equal

Question 3

In a study, S strain cells were fractionated into classes of purified molecules. All of the molecules produced S strain cells except for DNA. What can be concluded from this?

Answer 3

The molecule that carries the heritable information is DNA.

Question 4

What is found at the 5’ end of DNA?

Answer 4

Phosphoryl end

Question 5

What is found at the 3’ end of DNA?

Answer 5

Hydroxyl end

Question 6

How are sugars and bases linked?

Answer 6

Covalently via glycosidic bonds.

Question 7

Are DNA strands arranged parallel or anitparallel?

Answer 7

Antiparallel.

Each strand’s sequence is complementary to the parter.

Question 8

What are the purines?

Answer 8

Adenine and guanine

Question 9

What are the pyrimidines?

Answer 9

Cytosine and thymine

Question 10

How many hydrogen bonds are found between adenine and thymine?

Answer 10

2

Question 11

How many hydrogen bonds are found between guanine and cytosine?

Answer 11

3

Question 12

What is a genome?

Answer 12

A complete set of information in an organism’s DNA.

The entire genome must be duplicated and passed to the daughter cell.

Question 13

Each human cell contains ___ copies of each chromosome

Answer 13

2

Question 14

In humans, there are __ paies of autosomes and __ sex chromosomes

Answer 14

22 pairs of autosomes

2 sex chromosomes

Question 15

When do translocations commonly occur?

Answer 15

During an abnormal recombination event.

Question 16

Translocations commonly occur during abnormal events, such as cancer. Translocation can also be useful for what purpose?

Answer 16

Maintaining the correct amount of genetic material

Question 17

What are genes?

Answer 17

The information-containing elements that determine the characteristics of a species.

Question 18

Does condensation of chromosomes occur during interphase or mitosis?

Answer 18

Mitosis

Question 19

What are three chromosome requirements?

Answer 19

DNA replication origin

Centromere

Telomeres

Question 20

What DNA binding proteins are involved in forming chromosomes?

Answer 20

Histones and non-histone chromosomal proteins.

Question 21

What makes up chromatin?

Answer 21

Proteins and nuclear DNA.

Question 22

What is the most basic unit of chromosome packing?

Answer 22

The nucleosome

Question 23

How is DNA digested?

Answer 23

It is digested by nucleases. It cuts between nucleosomes and degrades exposed DNA between nucleosome core particles.

Question 24

How many proteins are found in each individual nucleosome?

Answer 24

8

Question 25

What are histones?

Answer 25

Small proteins with a hisone fold. They are what DNA wraps around.

They also have an N terminal amino acid tail that extends out from the core and are subject to covalent modifications important for chromatin regulation.

Question 26

What type of bond hods DNA and histones together?

Answer 26

Hydrogen bonds

Question 27

What is the purpose of chromatin remodeling complexes?

Answer 27

They allow loosening of DNA/histone contact.

Question 28

The structure of the nucleosome is temporarily changed in chromatin remodeling. What is the consequence of this?

Answer 28

DNA is less tightly bound to the histone.

Question 29

What is the zig-zag model?

Answer 29

A model in which histones are condensed into a pattern via a zig-zag fashion.

Question 30

What is a primary function of histone tails?

Answer 30

They help to condense chromatin. They are largely unstructured, suggesting they are highly flexible.

The tails can also form interactions with adjacent nucleosomes.

Question 31

What is histone H1?

Answer 31

A linker histone that contacts both DNA and protein. It changes the path of the DNA as it exits the nucleosome.