Inheritance

Question 1

How would you create lots of insulin?

Answer 1

• bacteria have short bits of DNA called plasmids- extract and cut using a restriction enzyme
• isolate the human insulin gene and cut using a resitrction enzymes
• stick plasmid and dna together using DNA ligase
• use the plasmid as a vector to get into bacteria, thus inserting the DNA into the bacteria
• put bacteria in fermenter w optimum conditions to replicate, to be harvester

Question 2

How do you clone animals via embryo splitting?

Answer 2

• sperm taken from one animal to artificially inseminate another
• zygote forms and develops into early embryo
• this is split and put into uterus of surrogate mothers
• when animals are born they are clones of each other

Question 3

How does reproductive cloning work?

Answer 3

• take a mature cell and isolate the nucleus
• take an egg cell and remove the nucleus
• join the two together with an electric shock
• mitosis produces embryo
• embryo put in a surrogate mother
• baby born is clone of the animal the nucleus was taken from

Question 4

What does transgenic mean?

Answer 4

Transfer of genetic material from one species to a different species

Question 5

What are reasons for and against cloning?

Answer 5

For: •animals can be given gene to produce large quantities of human antibodies rather than waiting for human itself to find correct antibody and replicate it
• animals could be made w organs similar enough to human ones to transplant ∴ no shortages
• prevents extinction
Against: • lack of variation
• inbreeding
• population issues

Question 6

What are reasons for and against GM plants for food?

Answer 6

For: • can have desired characteristics
• can be made for specific environments
• better yield
• more resistant to pests ∴ you can use one broad range herbicide rather than several smaller ones
Against: • not scientifically proven safe for consumption, e.g. Some people report side effects like allergies and infertility
• if herbicide resistant but escapes and grows in wild, hard to destroy

Question 7

What is the difference between sexual and asexual reproduction?

Answer 7

Asexual: one parent, parents and children genetically identical, faster, requires less energy, no partner needed, in bacteria, protoctista, fungi, plants, some animals
Sexual: two parents, offspring not genetically identical to parents/each other, produces variety, in fungi, plants, animals

Question 8

How do runners asexually reproduce?

Answer 8

Overground aerial plants grow roots and develop into new plants
E.g. Wild strawberries

Question 9

How does micropropagation work?

Answer 9

• small pieces (exoplants) cut from stems or side shoots of plant
• placed in agar growth medium, containing nutrients, minerals, plant hormones, and growth regulators
• when roots grow transferred to greenhouse
• put in pots w conditions like temp and humidity controlled
• small plants are clones

Question 10

What are some of the benefits of micropropagation?

Answer 10

Quicker than seeds
Genetically identical to parent plant
Any time of year

Question 11

What is a gene?

Answer 11

Section of a molecule of DNA

Question 12

Where are chromosomes found?

Answer 12

In the nucleus

Question 13

How many chromosomes do we have?

Answer 13

Diploid (2 sets of chromosomes, normal cells): 46

Haploid (1 set of chromosomes, sex cells): 23

Question 14

What is the structure of DNA?

Answer 14

Two strands coiled to form double helix

A with T and C with G

Question 15

What do dominant and recessive mean?

Answer 15

Dominant- only 1 copy necessary for characteristic to be shown
Recessive- 2 copies necessary for characteristic to be shown

Question 16

What is codominance?

Answer 16

Both alleles contribute to phenotype ∴ both characteristics are shown

Question 17

What is a homologous chromosome?

Answer 17

A set of chromosomes (1 maternal, 1 paternal) with the same type of gene, e.g. Earlobe shape

Question 18

What is the difference between meiosis and mitosis?

Answer 18

Meiosis: to make gametes, in testes and ovaries, 2 rounds of cell division, 4 cells made, chromosome number decreases, cells not identical
Mitosis: for growth and repair, in all body cels, 1 runs of cell division, 2 cells made, chromosome number stays te same, cells identical

Question 19

What can cause genetic variation?

Answer 19

• mutations
• random fertilisation between any egg and sperm
• crossing over and random assortment

Question 20

What is a mutation? What are they caused by?

Answer 20

Rare random change in genetic material that can be inherited. Most harmful, some neutral, a few beneficial
Caused by mutagens:
-ionising radiation(UV, gamma)
-chemicals(tobacco smoke)
-viruses(HIV)
-errors in cell division

Question 21

Why do some people have multiple copies of a chromosome?

Answer 21

• failure to separate

- normal egg fertilised by abnormal sperm

Question 22

What is cystic fibrosis?

Answer 22

Recessive

Persistent coughing, wheezing, breathing difficulties

Question 23

What is haemophilia?

Answer 23

Recessive
Main affects males as on x gene
Prolonged bleeding

Question 24

What is sickle cell anaemia?

Answer 24

Co-dominant
Pain due to sickle cells crisis(abnormal RBCs block small blood vessels), fatigue, heart palpitations, resistance to malaria

Question 25

How are insect and wind pollinating plants adapted for pollination?

Answer 25

Insect- nectar, bright coloured petals, scents, small sticky pollen grains
Wind- anthers stick out, stamen has large SA, pollen grains large and float easily

Question 26

What conditions are needed for germination?

Answer 26

Water
Oxygen
Warmth

Question 27

How does plant fertilisation take place?

Answer 27

• when pollen goes down the style to the ovule in the carpel, the female ovum will be fertilised with the male nucleus from the pollen. Then the ovule forms a zygote (seed), ovule wall forms seed coat and the ovary becomes a fruit

Question 28

How do germinating seeds get energy?

Answer 28

• starchy food reserves in cotyledons- broken down into glucose for aerobic respiration
• after leaves form, use PS