DNA & Chromosomes (Lec 1)

Question 1

What are genes?

Answer 1

the information containing elements that determine the characteristics of a species

Question 2

What does it mean for DNA strands to be antiparallel?

Answer 2

each strand’s sequence is complementary to partner

Question 3

What are the two purines?

Answer 3

adenine and guanine

note: purines = small name, big ring

Question 4

Name the base pairs

Answer 4

Adenine pairs with Thymine (2 H bonds)

Guanine pairs with cytosine (3 H bonds)

Question 5

What are the two pyrimidines?

Answer 5

Cytosine and Thymine

Question 6

True or False?

At replication, the entire genome must be duplicated and passed to the daughter cell.

Answer 6

True

Question 7

Discovery of the structure of DNA provided a mechanism for this to occur….

Answer 7

complimentary strands allow the genome to be replicated

each strand serves as the template

Question 8

How many different chromosomes is the human genome distributed over?

Answer 8

24

Question 9

What is a chromosome?

Answer 9

a single long linear DNA molecule associated with proteins that fold and pack it into a compact structure

Question 10

Each human cell contains 2 copies of each chromosome except…

Answer 10

germ cells and RBCs

Question 11

How many pairs of autosomes and sex chromosomes are there?

Answer 11

22 pairs of autosomes

2 sex chromosomes

Question 12

Does interspersed DNA contain genes?

Answer 12

no

Question 13

How do you know if a DNA sequence is functional or nonfunctional?

Answer 13

functional sequences are conserved during evolution

nonfunctional sequences mutate randomly without consequence

Question 14

What happens in interphase?

Answer 14

chromosomes are replicated; they are decondensed and can’t be easily distinguished

Question 15

What happens to chromosomes in mitosis?

Answer 15

become highly condensed and separated into two daughter nuclei

Question 16

What does a centromere do?

Answer 16

allows one copy of each duplicated and condensed chromosome to be pulled into each daughter cell when the cell divides

Question 17

What are telomeres?

Answer 17

at the ends of a chromosome, contain repetitive sequences that enable the ends to be efficiently replicated

Question 18

Protein + nuclear DNA = ?

Answer 18

chromatin

Question 19

What are the DNA binding proteins involved in forming chromosomes?

Answer 19

histones and non-histone chromosomal proteins

Question 20

What are nucleosomes?

Answer 20

most basic unit of chromosome packing

Question 21

Each individual nucleosome core particle consists of how many histone proteins?

Answer 21

8

Question 22

What is linker DNA produced?

Answer 22

DNA that is broken down by cutting between nuclesomes and degrading the exposed DNA between nucleosome and core particles

Question 23

Nucleosome particle is disc-shaped with DNA wrapped ____ turns

Answer 23

1.7

Question 24

How is DNA packaged?

Answer 24

interactions between DNA and histone (142 H bonds are formed between DNA and the histone core in each nucleosome)

Question 25

True or False?

Histones are highly conserved; most changes would be lethal

Answer 25

ture

Question 26

What do chromatin remodeling complexes do?

Answer 26

allow further loosening of DNA/histone contact

Question 27

Chromatin remodeling proteins are related to helicases and are ___ depending

Answer 27

ATP

Question 28

What is Histone H1?

Answer 28

linker histone, larger than others, less conserved, contacts both DNA and protein, changes the path of the DNA as it exits the nucleosome