Genetic Variation ~ B1.7

Question 1

What is genetic information?

Answer 1

The information that results in plants and animals having similar characteristics to their parents. It is carried by genes that are passed on in the sex cells (gametes) from which they develop.

Question 2

Where are chromosomes found?

Answer 2

In the nucleus.

Question 3

What are chromosomes made up of?

Answer 3

Made up of DNA.

Question 4

What is a section of a chromosome called?

Answer 4

A gene

Question 5

What is a gene?

Answer 5

They carry information that control the characteristics of an organism.

Question 6

What do genes control?

Answer 6

The development of different characteristics.

Question 7

How many chromosomes does a human have?

Answer 7

23 pairs (46 altogether)

Question 8

What are differences between individuals of the same species called?

Answer 8

Variation

Question 9

What is asexual reproduction?

Answer 9

When there is only one parent and there is no variation at all (unless due to environmental changes)

Question 10

What is an example of asexual reproduction?

Answer 10

When bacteria reproduces.

Question 11

What are the 3 types of cloning?

Answer 11

Tissue culture
Embryo transplants
Adult cell cloning

Question 12

What is tissue culture?

Answer 12

~the parent plant with the characteristics that you want is selected
~a few cells are scraped/cut off into several beakers containing nutrients and hormones (agar)
~a week or two later there are lots of genetically identical plantlets growing
~the whole process must be aseptic (carried out in the absence of harmful bacteria) otherwise the new plants will rot
*the offspring are genetically identicle to the parents and each other

Question 13

What are embryo transplants?

Answer 13

~parents with desired characteristics are mated (either naturally or in a Petri dish)
~embryo is removed before the cells become specialised
~they are split into several embryos
~these embryos are then implanted into the uterus’ of separate surrogate mothers who will eventually give birth to clones
*the offspring are generically identicle to each other but not the parents

Question 14

What is adult cell cloning?

Answer 14

~A skin cell is taken
~An egg cell is taken
~The nucleus of the skin cell is removed
~The nucleus of the egg cell is removed
~The skin cell nucleus is inserted into the empty egg cell
~An electric shock causes the egg to begin to divide to form embryo cells
~When the embryo has developed, it is inserted into a surrogate who later gives birth
*the child is genetically identical to the parent

Question 15

What are reasons for genetically modifying crops?

Answer 15

~To improve crop yield
~To improve resistance to pests or herbicides
~To extend the shelf life of fast ripening crops

Question 16

What are the concerns about genetically modified crops?

Answer 16

~Genes from GM crops could be transferred via pollen to non GM crops
~The nectar from GM crops can harm the insects that feed on it
~There is uncertainty about the effect of eating GM crops on human health

Question 17

How can you make insulin?

Answer 17

The gene for human insulin is inserted into bacteria, which then reproduced asexually and produced large quantities of genetically engineered insulin.

Question 18

Why could it be good to clone plants animals and humans?

Answer 18

~traditional breeding methods are slow
~can predict characteristics of offspring
~produces genetically superior stock
~could eliminate diseases such as diabetes
~organ donation has matching tissue so it would be able to donate without the risk of rejection

Question 19

Why could it be bad to clone plants animals and humans?

Answer 19

~cloning is unnatural
~human clones will not have ‘parents’
~abnormalities may occur in clone
~cloning does not allow natural evolution