The genome

Question 1

What does Adenine bind to?

Answer 1

Thymine

Question 2

What does Cytosine bind to?

Answer 2

Guanine

Question 3

What three things make up a nucleotide?

Answer 3

A phosphate, sugar and a base

Question 4

The sugar phosphate backbone is held together by what type of bonds?

Answer 4

covalent

Question 5

what type of bonds form between DNA bases?

Answer 5

hydrogen bonds

Question 6

How many hydrogen bonds forms between Thymine and Adenine?

Answer 6

2

Question 7

How many hydrogen bonds form between Cytosine and Guanine?

Answer 7

3

Question 8

What direction is a gene read in?

Answer 8

5 prime to 3 prime

Question 9

nucleotides are subunits of …….

Answer 9

nucleic acids

Question 10

How many carbons are in the sugar on a nucleotide?

Answer 10

5

Question 11

Ribonuncleic acid is single or double stranded?

Answer 11

Single stranded

Question 12

Why is ribonucleic acid so unstable?

Answer 12

because it is single stranded

Question 13

Deoxyribose is so stable because….

Answer 13

its double stranded, therefore can form a helix

Question 14

Pyrimidine is a single of double ring structure?

Answer 14

single

Question 15

Purine is a single or double ring structure?

Answer 15

double

Question 16

What 2 bases are pyrimidine compounds?

Answer 16

Thymine and Cytosine

Question 17

What 2 bases are Purine compounds

Answer 17

Guanine and Adenine

Question 18

What bonds link nucleotides together?

Answer 18

phosphodiester bonds

Question 19

What is a phosphodiester bond between in DNA structure?

Answer 19

A 3 carbon on a sugar molecule, and the 5th carbon of another sugar

Question 20

describe the beads on a string model?

Answer 20

Lines of DNA wound round histones

Question 21

what is a nucleosome?

Answer 21

a length of DNA coiled around a histone

Question 22

when would you see DNA in the shape of a mitotic chromosome?

Answer 22

during mitosis (replication and division)

Question 23

what histones make up a nucleosome?

Answer 23

8 histones (octamer)
x2 H2A, H2B
x3 H3, H4

Question 24

Are histones positively charged?

Answer 24

yes

Question 25

Is DNA positively charged?

Answer 25

no

Question 26

to go from beads on a string to finer structure of DNA what extra histone do you need?

Answer 26

H1

Question 27

What does H1 do?

Answer 27

allows the DNA to fold back on itself

Question 28

What two methods allow for DNA replication (Allow access to enzymes)?

Answer 28

1. Chromatic remodelling complexes | 2. Histone modifying enzymes (add or remove methyl, acetyl or phosphate)

Question 29

What do histone modifying enzymes do?

Answer 29

They add or remove acetyl, methyl and phosphate

Question 30

How to histone modifying enzymes work? **

Answer 30

They remove the positive charge on the histone group, so the DNA attached no longer has affinity for it. Histone becomes neutral. DNA then is 'unpackaged'

Question 31

Is euchromatin or heterochromatin more coiled?

Answer 31

euchromatin - loosely packed and uncoiled

Question 32

Is heterochromatin genetically inactive?

Answer 32

yes

Question 33

Supercoiling of Beta Globin or the HBB gene causes what blood disorder....

Answer 33

severe anaemia | no mutation- gene just folded up a bit too tightly

Question 34

Supercoiling can affect the way genes are ........

Answer 34

expressed

Question 35

Rubinstein-Taybi Syndrome is a ......... disease

Answer 35

chromatin

Question 36

What are the symptoms of Rubinstein-Taybi

Answer 36

Braod thumbs and broad big toes retardation facial abnormalities

Question 37

how common is Rubinstein-Taybi syndrome

Answer 37

1 in 100,000

Question 38

what causes Rubinstein-Taybi syndrome?

Answer 38

mutation in histone acetyl-transferase - how they fold

Question 39

How many pairs of homologous autosomal chromosomes do we have?

Answer 39

22 pairs | and 2 sex chromosomes (46 in total)

Question 40

Most human cells are diploid or haploid?

Answer 40

diploid (2 copies)

Question 41

What is a karyotype?

Answer 41

an individuals collection of chromosomes

Question 42

Down syndrome affects which chromosome?

Answer 42

21, trisomy