Cell division - cognito

Question 1

(i) Give two advantages of using stem cells.

Answer 1

can grow into any type of tissue / named tissue
* used in medical research
* used to treat human diseases
* large numbers can be grown

Question 2

(ii) Give two disadvantages of using stem cells.

Answer 2

expensive
* grow out of control / ref cancers
* may be rejected
* need for drugs (for rest of life)

Question 3

It is important to sterilise the culture medium and all the apparatus before use.
Explain why.

Answer 3

to kill / destroy other microorganisms / named type
or to prevent contamination

Question 4

All tools should be washed in disinfectant after using them on plants infected with
TMV.
Suggest why.

Answer 4

to kill virus
or
to prevent virus spreading

Question 5

Scientists produced a single plant that contained a TMV-resistant gene.
Suggest how scientists can use this plant to produce many plants with the
TMV-resistant gene.

Answer 5

take (stem) cells from meristem
or
tissue culture

Question 6

Some plants produce fruits which contain glucose.
Describe how you would test for the presence of glucose in fruit.

Answer 6

use Benedict’s solution
1
glucoses turns solution blue to orange

Question 7

Meiosis and mitosis are different types of division in human cells. Compare the two
processes by referring to where each takes place and the kind of products that are made

Answer 7

meiosis mitosis
sexual asexual
gametes growth
ovary or testes all other cells
or gonads
half number same number
of chromsomes of chromosomes
haploid or diploid or
23 chromosomes 46 chromosomes
reassortment or no reassortment
variation possible or no variation
or not identical or identical
4 cells produced 2 cells produced
2 divisions 1 division

Question 8

(ii) Why is it necessary to absorb some food molecules by active transport?

Answer 8

(ii) against a concentration gradient