Sex Determination (GCSE Biology)

Which chromosome pair determines biological sex in most human males and females?

What is the role of the SRY gene located on the Y chromosome in humans?

What is the expected sex ratio (male : female) at conception in humans under normal conditions?

Which of the following statements about sex-linked recessive traits is correct?

Haemophilia is an X-linked recessive disorder. If a carrier mother (XhX) and a healthy father (XY) have children, what fraction of daughters will be carriers?

In birds, sex is determined by Z and W chromosomes. Which is true?

In human assisted reproduction, preimplantation genetic testing can be used to select embryos without sex-linked disease. What is one ethical concern about using this to choose sex?

In an XY sex-determination system, what gametes do typical human males produce?

A male is color-blind (an X-linked recessive trait) and his wife has normal colour vision but her father was colour-blind. What is the probability their son will be colour-blind?

What term describes the allele or gene found on the X chromosome but not on the Y, causing traits to appear more often in males?

Which environmental sex determination example is correct?