Reproduction Flashcards
All 10 cards in this deck
What is the role of meiosis in the body, and where does it occur?
It produces gametes (sex cells); it occurs in the reproductive organs (testes and ovaries).
How many daughter cells does meiosis produce, and how do they compare genetically?
Four daughter cells, all genetically different from each other and from the parent cell.
How does the number of chromosomes in a gamete compare with the number in a body cell?
A gamete has half the number (it is haploid), e.g. 23 in a human gamete compared with 46 in a body cell.
True or false? Mitosis and meiosis both produce two genetically identical daughter cells.
False. Mitosis produces two genetically identical diploid cells; meiosis produces four genetically different haploid cells.
How do meiosis and fertilisation together lead to genetic variation in offspring?
Meiosis makes genetically different gametes, and fertilisation randomly combines one gamete from each parent, restoring the diploid number.
Describe the structure of a DNA molecule.
A polymer of two strands coiled to form a double helix, linked by complementary base pairs joined by weak hydrogen bonds.
What are the three parts of a DNA nucleotide?
A sugar, a phosphate group, and one of four bases attached to the sugar.
Which DNA bases pair together?
A pairs with T, and C pairs with G.
e.g. the complementary strand of ACG is TGC
What is a genome, and what is a gene?
The genome is the entire DNA of an organism; a gene is a section of a DNA molecule that codes for a specific protein.
What are the steps to extract DNA from fruit?
e.g. using a strawberry
- Mash the fruit and mix with salt and detergent — detergent breaks down cell membranes, salt makes DNA clump together.
- Filter the mixture to remove insoluble cell debris.
- Add cold ethanol — DNA is insoluble in it and appears as white strands.