Biology 20Q

Question Answer

1. (Recap) Define sexual and a sexual reproduction Sexual - two parents genes fusing to produce a genetically different cell Asexual - one parent cell producing genetically identical cell

2. (Recap) What are the gametes in animals? Sex cells - Sperm and egg

3. (Recap) State the name of the type of cell division

that produces gametes Meiosis - producing genetically different cells

4. (Recap) How many chromosomes would you find in

human a) body cells b) gametes? a) 46 b) 23

5. (Recap) Define the word clone An organism or cell, produced asexually from one parent, that are genetically identical to parent

6. Define variation The differences in characteristics between individuals of the same species

7. What can cause variation? Genetics and/or Environmental factors

8. Define a species A group of individuals in a population able to breed and produce fertile offspring

9. Who proposed “natural selection” Charles Darwin (and Russell Wallace)

10. Why was it discredited? It lacked evidence, knowledge of DNA as a molecule for inheritance and conflicted with the belief that God and literal creation/Insufficent evidence/process of genetic inheritance (DNA) was unknown

11. Describe genetic screening Genetic screening involves testing people or groups of people for the presence of a particular allele or other genetic abnormality.

12. Explain selective breeding 1. When organisms are deliberately bred so their offspring have the desirable characteristics. 2, Their offspring with these traits are then bred. 3. This process repeats after many generations.

13. Describe potential problems with selective

breeding Future generations will all share very similar genes. An increased risk of genetic disease caused by recessive alleles. More difficulty in producing new varieties in the future.

14. Suggest a use of selective breeding Many e.g. Cows to produce more meat/milk, domesticated pets, Chickens to lay larger eggs

15. Define natural selection Process by which a species changes over time in response to changes in the environment, or competition between organisms, in order for the species to survive.

16. Explain how natural selection causes a useful gene

to increase across a species? Gene (allele) has a benefit. Those species with it are more likely to survive -And more likely to breed -Pass on these useful alleles -Over time more and more species have this competitive advantage until all species in a population have this

17. What is mutation? Random change to genetic material

18. Why can natural selection be more easily shown in

bacteria? They divide-and pass on genes quickly.

19. Define extinction No remaining individuals of a species alive

20. What can be done to reduce the likelihood of

antibiotic resistance in bacteria? -Use antibiotics sparingly. -Ensure prescribed antibiotic courses are completed and not just stopped when people feel better