DNA- the genetic material

Question 1

Protein general function

Answer 1

support function of cell

metabolism, function, organisation, regulation, development

Question 2

activation of gene in eukaryotes

Answer 2

may be active in different tissues at different times therefore different function

Question 3

DNA discovery

Answer 3

Friedrich Miescher in 1869

Question 4

Karyotype

Answer 4

full set of chromosomes

Question 5

How is chromosomes been seen - technique used - e.g. dyes

Answer 5

staining with dyes, AT/GC rich region genome showing pattern of bands which is unique to chromosomes

Question 6

Diploid

Answer 6

pair of homologous chromosomes in normal cells

Question 7

Haploid

Answer 7

In gametes

Question 8

Human genome project

Answer 8

started 1990 and published 2003

3 billion base pairs

Question 9

Gene number

Answer 9

correlates with complexity of species

Question 10

correlation between complexity and chromosomes number

Answer 10

has no correlation

Question 11

Junk DNA

Answer 11

DNA of unknown function

Question 12

Function of junk DNA

Answer 12

organising genome and regulating certain functions

transcription, DNA replication

Question 13

condensed vs uncondensed genes

Answer 13

condensed - gene coded

uncondensed - less gene coded

Question 14

Example for the importance of chromosomes determining genetics

• down syndrome
• turner syndrome
• Klinefelter syndrome

Answer 14

down syndrome - 3 copies of chromosomes 21
turner syndrome - only one X chromosomes
klinefelter syndrome - one Y and 2 X chromosomes

Question 15

non-disjunction cause

Answer 15

pair of chromosomes fail to separate during formation of gametes

Question 16

Philadelphia chromosomes (chronic myeloid leukaemia-90%)

Answer 16

Chromosomes 9 fuses to region of chromosomes 22 - modification
by chromosome translocation

Question 17

what is cystic fibrosis (CF) - most common

Answer 17

genetic disorder of cell membrane
cause thick, sticky mucus to build up in air passages and pancreas
most common - DF508

Question 18

most common mutation for CF

Answer 18

^F508 - delete 3 nucleotides (phenylalanine) at position 508

Question 19

cause of CF

Answer 19

prevent Cl ions to move out of cells causing water in by osmosis = mucus outside = infection

Question 20

Sickle cell disease

Answer 20

‘A’ changes to ‘T’ at 17 of gene for beta chain of haemoglobin
Changes to glutamic acid to valine
decreases number for RBC causing pain and infections

Question 21

Experiment - Griffin (1928)

Answer 21

Streptococcus Pneumoniae injected into mice

rough strain becomes a smooth strain when heat-killed smooth strain is mixed in

Question 22

transformation of dead cell into living

Answer 22

Transforming principle

Question 23

rough strain

Answer 23

non-virulent strains

Question 24

smooth strain

Answer 24

virulent strains

Question 25

Avery (1944)

Answer 25

transformation produced by DNA transfer
using different enzymes - Dnase, protease, Rnase
test what happens to the rough strain
injected into mice - Dnase did not kill the mice

Question 26

Dnase

Answer 26

degrades DNA

Question 27

Protease

Answer 27

degrades protein

Question 28

Rnase

Answer 28

degrades RNA

Question 29

Hershey and Chase (1952)

Answer 29

uses bacteriophage T2 and Ecoli
35S - protein coats the virus
32P - DNA inside the virus

Question 30

Method of Hershey and Chase

Answer 30

mixed virus and bacteria and injects DNA into host cell
Shakes off coat = protein ‘ghost’ labelled with 35S
viral chromosomes multiple and produce phages

Question 31

Result of H and C

Answer 31

new phage particles contain unlabelled or 32P labelled DNA

therefore spread of disease is caused by genes