DNA structure

Question 1

Where is chromatin located?

Answer 1

Nucleus

Question 2

When is chromatin seen in the nucleus?

Answer 2

When the cell is not dividing

Question 3

What are the two forms of chromatin?

Answer 3

Heretochromatin

Euchromatin

Question 4

What is the structure of euchromatin?

Answer 4

DNA wrapped around histone protein

to form a nucleosome

Question 5

What is the structure of heterchromatin?

Answer 5

Nucleosomes coil up closer to each others

Question 6

What form of chromatin can gene expression occur with?

Answer 6

Euchromatin

Question 7

How do euchromatin and heterochromatin look different under a light microscope?

Answer 7

Euchromatin appears lighter

heterochromatin appears darker

Question 8

What are chromosomes?

Answer 8

Heterochromatin is much more tightly packaged

to form chromosomes

Question 9

When are chromosomes seen in the nucleus?

Answer 9

When the cell is dividing

Question 10

Can gene expression occur with chromosomes?

Answer 10

No

Question 11

What is a gene?

Answer 11

Section of DNA that codes for a protein

Question 12

Where are genes located?

Answer 12

Each gene has a specific chromosomal location

Question 13

What is the genome? In humans?

Answer 13

Entire DNA sequence

In humans this is 24 chromosomes
22 autosomes + 2 sex chromosomes

Question 14

What are two examples of nucleic acids?

Answer 14

DNA

RNA

Question 15

What is the structure of nucleic acids?

Answer 15

Polynucleotides - lots of nucleotides arranged linearly

Question 16

What is the structure of nucleotide?

Answer 16

Pentose sugar

attached to a nitrogenous base and a phosphate

Question 17

What is the structure of a nucleoside?

Answer 17

Pentose sugar

attached to a nitrogenous base

Question 18

Which pentose sugar is found in DNA?

Answer 18

Deoxyribose

Question 19

Which pentose sugar is found in RNA?

Answer 19

Ribose

Question 20

Which carbon atom of the pentose sugar is joined to the nitrogneous base?

Answer 20

1’ carbon atom

Question 21

Which carbon atom of the pentose sugar is joined to the phosphate group?

Answer 21

5’ carbon atom

Question 22

What is the difference between 2-deoxyribose and ribose?

Answer 22

In 2-deoxyribose, 2’ carbon atom is joined to H

In ribose, 2’ carbon atom is joined to OH

Question 23

What is the bond between the 5’ carbon atom and the phosphate group called?

Answer 23

Phosphate ester bond

Question 24

What are the two types of nitrogneous bases? What do they each mean?

Answer 24

Purines - have two rings

Pyrimidines - have one ring

Question 25

What are some examples of purines?

Answer 25

Adenine Guanine

Question 26

What are some examples of pyrimidines?

Answer 26

Cytosine Thymine Uracil

Question 27

Which bases are found in DNA/RNA?

Answer 27

Adenine Guanine Cytosine

Question 28

Which base is found in DNA only?

Answer 28

Thymine

Question 29

Which base is found in RNA only?

Answer 29

Uracil

Question 30

How are nucleosides named in RNA and DNA?

Answer 30

RNA: base-ine DNA: deoxy-base-ine

Question 31

How are nucleotides named in RNA and DNA?

Answer 31

RNA: base-ine monophosphate DNA: deoxy-base-ine monophosphate

Question 32

How are nucleotides joined together in DNA?

Answer 32

Phosphodiester bond | between 3' carbon of one nucleotide of phosphate group of next nucleotide

Question 33

What is meant by DNA being polar?

Answer 33

Has two distinct ends | phosphate group at one end, 3' OH at other end

Question 34

What is base pairing?

Answer 34

Refers to how complementary bases line up against each other | form hydrogen bonds between them

Question 35

Which bases pair up with each other?

Answer 35

A - T A - U C - G

Question 36

How many hydrogen bonds form between A-T and A-U?

Answer 36

2 hydrogen bonds

Question 37

How many hydrogen bonds form between C-G?

Answer 37

3 hydrogen bonds

Question 38

What is the secondary structure of DNA?

Answer 38

Two strands of DNA come together | wind around each other to form a double-helix

Question 39

How do the two strands of DNA relate to each other?

Answer 39

Complementary Anti-parallel

Question 40

What is meant by the two DNA strands being complementary?

Answer 40

Their bases are complementary to each other | hydrogen bonds form between them

Question 41

What is meant by the two DNA strands being anti-parallel?

Answer 41

Run in opposite directions | one runs from 5' to 3', other runs from 3' to 5'

Question 42

What type of double helix is formed in DNA?

Answer 42

Right-handed double helix

Question 43

What is the sugar-phosphate backbone?

Answer 43

Refers to how the pentose sugar and phosphate line the outside of the double helix bases are inside

Question 44

How is a DNA sequence written?

Answer 44

Top strand - 5' to 3' Bottom strang - 3' to 5'