DNA profiling

Question 1

DNA profiling

Answer 1

the production of a visible pattern of fragments (bands) of DNA for comparing samples of DNA

Question 2

Other name for DNA profiling

Answer 2

genetic fingerprinting

Question 3

5 steps in preparing a DNA profile `

Answer 3

1. collect tissue samples
2. cells broken down and DNA extracted
3. DNA is cut into fragments
4. fragments separated
5. profiles analysed

Question 4

3 examples of suitable tissue samples

Answer 4

blood semen or saliva

Question 5

how is the DNA cut into fragments

Answer 5

using restriction enzymes

Question 6

what is restriction enzymes do?

Answer 6

cut DNA at a specific base sequence

Question 7

how are the fragments of DNA separated

Answer 7

by gel electrophoresis

Question 8

the basis upon which the DNA fragments are separated

Answer 8

on the basis of size

Question 9

3 applications of DNA profiling

Answer 9

forensic science/crime
medical/paternity disputes
genetic screening

Question 10

forensic science or crime as an application of DNA profiling

Answer 10

bodily material found at crime scene

used to identify a subject

Question 11

medical/paternity disputes

Answer 11

used to identify the father or mother of a child

Question 12

genetic screening

Answer 12

a test for the presence or absence of genes

Question 13

genetic engineering

Answer 13

the artificial manipulation or alteration of genes or genotype or DNA

Question 14

recombinant DNA

Answer 14

the combination of DNA from different organisms

Question 15

5 processes in genetic engineering

Answer 15

isolation
cutting
ligation
transformation/introduction of base sequence changes
expression

Question 16

isolation

Answer 16

human chromosome with the target gene is removed from a cell
the plasmid (made of DNA) is removed from the bacterium

Question 17

cutting

Answer 17

the human chromosome is cut to remove the target gene using a restriction enzyme
plasmid is cut using same enzyme

Question 18

ligation

Answer 18

human target gene mixed with plasmid, the cut ends of the human DNA and the plasmid DNA are joined by an enzyme called ligase (ligation)
plasmid is now composed of recombinant DNA

Question 19

transformation/introduction of base sequence changes

Answer 19

the uptake of DNA into a cell
bacteria are treated to take up the plasmids with the target gene from the surrounding solution
bacterial DNA now has a different base difference from before

Question 20

expression

Answer 20

bacteria now cultured in bioreactor, reproduce asexually
the target gene is expressed (directs the formation of a protein eg. to make insulin)
extracted and purified

Question 21

application of genetic engineering in plants

Answer 21

weedkiller - resistant crops

Question 22

example of weedkiller - resistant crops

Answer 22

tomatoes with a long shelf life

Question 23

application of genetic engineering in animals

Answer 23

production of a human-blood clotting factor in sheep, produced in their milk
(pharming)
these animals with human genes are said to be transgenic

Question 24

application of genetic engineering in microorganisms

Answer 24

production of human insulin by bacteria

Question 25

dangers of genetic engineering 2

Answer 25

release of GMOs into the environment may lead to the escape of foreign genes into the environment as a food source - possible danger to health, toxic proteins, allergic reactions

Question 26

genetic testing in humans

Answer 26

tests carried out after birth to detect diseases or genes early

Question 27

mutation 2

Answer 27

change in genetic material | change in dna or gene or chromosome structure

Question 28

how do mutations occur

Answer 28

at random in any gene or chromosome

Question 29

number of mutations that survive

Answer 29

very low as cells can often repair damaged DNA

Question 30

mutant genes in DNA

Answer 30

often recessive and don't appear in the phenotype

Question 31

harmful mutations

Answer 31

may increase the rate of mitosis forming tumors

Question 32

can mutations be inherited

Answer 32

yes, may cause genetic defects in the child

Question 33

genetic mutations give rise to

Answer 33

changes in the phenotype and variation

Question 34

if a mutation is inheritable

Answer 34

it can play a part in evolution by allowing natural selection to occur

Question 35

2 types of mutation

Answer 35

chromosome mutation | gene (or point) mutation

Question 36

2 types of chromosome mutation

Answer 36

change in structure of chromosome | change in the number of chromosomes

Question 37

2 examples of change in structure of chromosome

Answer 37

deletion | inversion

Question 38

deletion

Answer 38

a piece of chromosome (DNA) is lost

Question 39

inversion

Answer 39

a piece of chromosome breaks off and turns upside down before rejoining (may cause cancer in humans)

Question 40

change in number of chromosomes

Answer 40

addition or loss of one or more chromosomes eg. Downs syndrome results from presence of an extra chromosome in zygote, i.e. every cell is 2n = 47

Question 41

gene (or point) mutation

Answer 41

sequence of bases in part of a DNA strand is altered

Question 42

4 examples of gene (or point) mutation

Answer 42

albinism haemophilia cystic fibrosis sickle-cell anaemia

Question 43

albinism

Answer 43

can't produce melanin - skin pigment

Question 44

haemophilia

Answer 44

blood won't clot due to lack of clotting factor

Question 45

cystic fibrosis

Answer 45

thick mucus secreted in lungs and gut

Question 46

sickle-cell anaemia

Answer 46

abnormal red blood cells

Question 47

sickle cell anaemia is caused by

Answer 47

a mutant recessive gene - only occurs in someone who is homozygous for the condition

Question 48

sickle cells

Answer 48

have abnormal haemoglobin which makes the red blood cells change into a sickle shape, cells clump together and cause heart failure and damage to brain, kidney, liver etc

Question 49

causes of mutation

Answer 49

mutagenic agents

Question 50

3 examples of mutagens

Answer 50

radiation (X-rays, UV rays) chemicals (tobacco smoke, benzene, asbestos, mercury) viruses

Question 51

if a mutagen causes cancer it is called

Answer 51

a carcinogen