The Role of Chromosomes and Hormones Flashcards
What are chromosomes?
Chromosomes are strands of DNA found in the nucleus of living cells that carry information in the form of genes
What are genes?
Short sections of DNA that determine the characteristics of a living thing
How many chromosomes are there in the human body?
There are 46 chromosomes divided into 23 pairs, the last of these, the 23rd pair, determine biological sex
What are the chromosomal structures for male and female and why?
For females it’s XX whereas for males it’s XY this is because of how they appear when viewed under a microscope
How is a babies sex determined?
All normal egg cells have an X chromosome whereas some sperm cells have an X chromosome some have a Y chromosome. The sex of the baby depends on whether the sperm that fertilises the egg has an X or Y chromosome.
What does the Y-chromosome carry and what does it do?
A gene called the sex determining region Y - this causes testes to develop in an XY embryo - which then produce androgens (male sex hormones) this causes the embryo to develop into a male
What is a hormone?
A chemical substance circulating in the blood that controls and regulates the activity of certain cells or organs
Which are the two key times at which gender development is influenced by hormones?
Prenatally in the room and during puberty
How are hormones influential prenatally in the womb?
They act upon brain development and course development of the reproductive organs
How are hormones influential during puberty?
The best of hormonal activity triggers the development of secondary sexual characteristics such as pubic hair
How does the role of hormones differ in males and females?
Males and females produce many of the same hormones but in different concentrations – some hormones however are exclusive to one gender
What is testosterone?
A hormone from the androgen group that’s produced mainly in the mail testes (and in small amounts in the female ovaries)
When does testosterone become active and what does it do?
It begins to be produced at around eight weeks of foetal development and controls the development of male sex organs
What studies have been done into the effect of testosterone on human behaviour and what did they find?
Nanne Van de Poll et al. 1988 - showed that female rats became more physically and sexually aggressive when injected with testosterone
What is oestrogen?
The primary female hormone, playing an important role in the menstrual cycle and reproductive system