B5 Flashcards
What is the genome?
The entire genetic material of an organism.
What is an allele?
Different versions of the same gene.
What can affect an organism’s phenotype?
- genotype
- environmental conditions
Explain how your height can be affected by both your genome and the environment.
- your genes control how tall you can grow
- your height also relies on your diet and sleeping hours
How do you classify the term ‘Discontinuous variation’ ?
Discontinuous variation is when there is only two or more distinct categories without intermediates. They aren’t affected by environmental factors.
How do you distinguish mitosis and meiosis?
Mitosis: formation of two identical daughter cells (asexual reproduction)
Meiosis: formation of four genetically non-identical cells (sexual reproduction)
Where does meiosis take place?
The reproductive organs (ovaries and testes) only.
How does meiosis introduce genetic variation?
Some of the father and the mother’s chromosomes go into each new cell when the cell divides. The mixing of chromosomes creates genetic variation.
Explain why gametes has to be haploid.
A male gamete fuses with a female gamete to form a fertilized egg during fertilization.
The gametes need to be haploid so the egg ends up with the diploid number of chromosomes and not twice as many.
What does it mean for the fertilized egg to be diploid?
It has the full set of chromosomes.
List features of sexual reproduction.
- Cells divide by meiosis
- offspring are non-identical
- two parents
- gametes fuse
Give two advantages of sexual reproduction.
- genetic variation
- adaptation and evolution
What are the advantages and examples of asexual reproduction?
- lots of offspring quickly > E. Coli (half an hour)
- only one parent needed (no mate needed) > aphids in the summer when there is plenty of food
Banana plants can produce asexually. Discuss the advantages and disadvantages of this form of reproduction.
Advantages: it can produce a lot of offspring very quickly without any mate
Disadvantage: no genetic variation > whole population can be affected if environment changes
Sperm and egg cells fuse during sexual reproduction. What’s the name of the resultant cell produced?
Zygote.
Name the three levels of organisation in a genome.
Chromosomes, DNA, genes