4.6.1 reproduction Flashcards
A cell divides in a series of stages called
the cell cycle
What are the initial steps in the cell cycle?
The cell grows and organelle numbers increase, DNA replicates.
In the cell cycle after the DNA has replicated what happens next?
The copied chromosomes separate (mitosis) and then the cell divides into two.
What are the 2 forms of reproduction?
Asexual and sexual
Why is asexual reproduction important?
growth and repair
How many parents are involved in asexual reproduction?
1
How many parents are involved in sexual reproduction?
2
Which form of reproduction involves gametes?
sexual - fusion of egg and sperm
Which form of reproduction brings about variation?
sexual
Name an organism that reproduces asexually
bacteria, daffodil bulbs, strawberry tubers
Name an organism what reproduces sexually
humans
What form of cell division produces gametes?
Meiosis
Where does meiosis occur?
testes and ovaries
Where does mitosis occur?
in all body cells except testes and ovaries
In plants what are the sex cells?
pollen and egg cell
In animals what are the sex cells?
egg cell and sperm
What is another name for a gamete?
sex cell
Why does sexual reproduction bring about variation
Involves FUSION of egg and sperm, creating a unique combination of alleles
How many chromosome pairs are found in human body cells?
23 pairs
How many chromosomes are found in human sex cells
23
Chromosomes are found
in the nucleus
Chromosomes are made up from
DNA
Put the following in order of size starting with the smallest
cell, gene, nucleus, chromosome
gene, chromosome, nucleus, cell
What are genes?
Short sections on DNA found on chromosomes - they code for a particular characteristic
How are mitosis and meiosis different?
Mitosis is used for growth and repair, meiosis makes gametes
How many times does the cell divide in meiosis?
twice
How are the cells produced different from the parent cell in meiosis
they have half the chromosome number
How many cells are produced at the end of meiosis?
4
How many cells are produced at the end of mitosis?
2