AQA GCSE Gender determination(Biology)
Gender determination
Humans have 23 pairs of chromosomes in each body cell. 22 pairs (autosomes) control most characteristics. 1 pair (sex chromosomes) determines whether a person is male or female.
Sex Chromosomes
Females: XX → both sex chromosomes are the same.
Males: XY → sex chromosomes are different.
How Sex is Determined
Egg cells always carry X.
Sperm cells carry either X or Y.
Genetic Crosses
Practice Questions
1.How many pairs of chromosomes are found in a human body cell?
2.Explain why the father determines the sex of a baby.
3.Why is the probability of having a male or female child approximately equal?
Factors affecting the rate of photosynthesis
Measuring & calculating rates of photosynthesis
Inverse square law and photosynthesis
Economics of enhancing the conditions in greenhouses
Investigating the effect of light intensity on the rate of photosynthesis
Data analysis and nervous system
The effect of a factor on human reaction time
Controlling blood glucose concentration
Regulating water and nitrogen levels in the body.
Hormones and human reproduction
Using hormones to treat infertility
Control and coordination in plants using hormones
Investigating the effect of light or gravity on the growth of newly germinated seedlings