Biology Yr9

Question 1

How is DNA arranged in a nucleus

Answer 1

Long coiled molecules called chromosomes

Question 2

How many chromosomes

Answer 2

46 ( 23 pairs )

Question 3

How many chromosomes does a human sex cells have ( sperm and egg )

Answer 3

23 chromosomes

Question 4

What is a gene

Answer 4

A section of a chromosome that code a particular characteristic

Question 5

What is an example of genetic variation 
A. Blood type
B. Accent
C. Scar on body
D. Eye colour

Answer 5

A. Blood type

D. Eye colour

Question 6

What is an acronym for genetic engineering

Answer 6

S: select
I: isolate
I: insert
R: replication

Question 7

What are the stages of genetic engineering

SIIR

Answer 7

1. Select desired characteristic
2. Isolate the gene responsible for the characteristic ( using enzymes )
3. Insert this gene into another organism ( e.g a bacterium )
4. Replication of the organism ( bacteria replicate every 20mins )

Question 8

What is genetic engineering?

Answer 8

A process that involves:
Changing the genes if an organism by introducing a gene from another organism to give a desired characteristic. An organism whose genes have been altered is called a “ genetically modified organism “

Question 9

What does selective breeding involve

Answer 9

Involves choosing parent that both show a desired characteristic to breed together and produce offsprings with more desirable characteristics

Question 10

Stages of selective breeding

Answer 10

1. Decide which characteristics are important ( desirable characteristics ( eg blue eyes
2. Choose parents that show these characteristics ( phenotypes ) and breed them together
3. Select the offspring that have the desired characteristics to breed the next generation
4. Continue the process ( over a number of years )

Question 11

What are the advantages of selective breeding

Answer 11

1. Increased milk/ yield from cattle ( which may increase profit flr farmers )
2. Can create new varieties of ( good ) crops
3. Disease resistance in food crops or garden plants e.g soya beans
4. Can produce domesticated animals with a gentle nature e.g labradoodle

Question 12

Disadvantages of selective breeding

Answer 12

1. Can lead to breeding where some breeds are particularly prone to disease or inherited defects
2. Smaller gene pool selective bred organism are more likely to pass on harmful recessive alleles
3. They are more likely to be susceptible to disease

Question 13

If you want to selectively breed something what would you have to do?

Answer 13

Find parents that have each of the desired characteristics, long fur and blue eyes e.g
Male: long fur
Female: blue eyes
= offspring with long fur and blue eyes

Question 14

How do you clone a mammal?

Answer 14

1. Take a normal body cell from specimen you want to clone ( DNA ) and remove the nucleus
   2) take an egg cell from another organism, remove nucleus and discard it
   3) insert nucleus from body cell into egg cell
   4) electric shock is given to simulate fertilisation and stimulate cell division
   5) implant embryo into surrogate organism to develop clone