The Role Of Chromosomes And Hormones

Question 1

What are chromosomes?

Answer 1

Made from DNA and found in the nucleus of living cells and carry genetic information in the form of genes; the 23rd pair of chromosomes determines biological sex.

Question 2

What is a hormone?

Answer 2

A chemical substance circulated in the blood that controls and regulates the activity of certain cells or organs

Question 3

What is testosterone?

Answer 3

A hormone from the androgen group that is produced mainly in the male testes (and in smaller amounts in the female ovaries). It is associated with aggressiveness. (Primary male hormone)

Question 4

What is oestrogen?

Answer 4

The primary female hormone, it plays an important role in the menstrual cycle and reproductive system

Question 5

What is oxytocin?

Answer 5

A hormone which causes contraction of the uterus during labour and stimulates lactation

Question 6

What are genes made from?

Answer 6

(Short sections of) DNA

Question 7

How many pairs of chromosomes in the sex cells are there?

Answer 7

23 pairs

Question 8

What pair of chromosomes determines biological sex?

Answer 8

The 23rd pair

Question 9

Which sex cell determines sex: the egg or the sperm?

Answer 9

Sperm. If the fertilising sperm carries an X chromosome it will be a girl, and if it carries a Y chromosome it will be a girl.

Question 10

What is the chromosomal structure for females?

Answer 10

XX

Question 11

What is the chromosomal structure for males?

Answer 11

XY

Question 12

What is the gene called in the Y chromosome that cause male foetal development?

Answer 12

Sex-determining region Y or SRY

Question 13

What does the SRY cause to happen and when does this occur?

Answer 13

After eight weeks it causes testes to develop in an XY embryo through the release of male hormones.

Question 14

What is the difference in sex chromosomes and hormones?

Answer 14

Sex chromosomes contain genetic material that determines a person’s sex but hormones influence the development of gender

Question 15

Name three sex hormones

Answer 15

• Testosterone
• Oestrogen
• Oxytocin

Males and females produce the same hormones but in different concentrations

Question 16

What is testosterone?

Answer 16

Testosterone is a male hormone which controls the development of male sex organs. It is associated with masculinisation of the the brain such as the development of brain areas linked to spatial skills. It is also associated with male type behaviours such as competitiveness and aggression.

Human and animal studies have demonstrated the influence of increased testosterone on aggressive behaviour.

Question 17

What condition is caused by high levels of male hormones?

Answer 17

Congenital adrenal hyperplasia (CAH).

Has been found to result in increased aggression, preference for male toys and increased spatial ability in females.

This suggests that the high levels of testosterone is cause for aggression and spatial ability.

Question 18

What animal study demonstrates the effects of testosterone?

Answer 18

Van de Poll et al found that injecting female rats with testosterone led to an increase in aggression. Also, castrated male rats show reduced aggression.

Suggests that testosterone is the cause of aggression.

Question 19

What is oestrogen?

Answer 19

It promotes the development and maintenance of female characteristics of the body of and to regulate menstruation.

Also has behavioural and psychological effects such as premenstrual tension (PMT) which is associated with emotionality, irritability and irrational behaviour as well as lapses in self-control that can lead to anti-social behaviour and can even result in acts of criminality.

Question 20

What is oxytocin?

Answer 20

Women typically produce it in much larger amounts than men, particularly as a result of giving birth.

It stimulates lactation (making breastfeeding possible). Also reduces the stress hormone cortisol and facilitates bonding. For this reason it has been referred to as the ‘love hormone’, and is released in massive quantities during labour and after childbirth and makes new mothers feel ‘in love’ with their baby.

Also increased five-fold during sex (although drops immediately in males after orgasm, which explains males’ sudden loss of intimacy at this point)

Question 21

EVALUATION OF THE ROLE OF HORMONES AND CHROMOSOMES

Evaluate the role of hormones and chromosomes in terms of it being simplistic

Answer 21

One limitation is that it is simplistic to think of testosterone as being a male hormone and oestrogen and oxytocin being female hormones; research shows all three exert important influences on both males and females.

It is also simplistic to perceive single hormones as having exclusive effects upon sex and gender. Hormones are often part of biological mechanisms that exert complex actions upon the body and behaviour.

Question 22

EVALUATION OF THE ROLE OF HORMONES AND CHROMOSOMES

Is it reductionist?

Answer 22

Biological accounts that reduce gender to the level of chromosomes and hormones have been accused of ignoring alternative explanations for gender development.

The cognitive approach focuses attention on the changing thought processes that explain gender development. In addition, although the biological approach would acknowledge the importance of innate factors in gender development, the psychodynamic approach would also point to the importance of childhood experiences such as interaction within the family.

Question 23

EVALUATION OF THE ROLE OF HORMONES AND CHROMOSOMES

Is there any evidence?

Answer 23

A strength is that evidence supports it such as the case of Bruce Reimer that shows socialisation cannot overcome biology.

Bruce’s penis was accidentally cut off at 7 months, and he was then raised as a girl. At adolescence he was given oestrogen. He later decided to live as a man despite his parents’ efforts to treat him as a girl.

The final outcome suggests that biological influences are more important than socialisation. Bruce was always biologically male with an XY chromosome and treating him as a girl for many years didn’t seem to affect his identity as a male.

Question 24

EVALUATION OF THE ROLE OF HORMONES AND CHROMOSOMES

The role of culture and social influences

Answer 24

One of the classic cases of abnormal gender development illustrates the role of culture along with the effect of testosterone.

The case of the Batista Boys showed that the ‘girls’ accepted their male role without any difficulty. It has been suggested that the ease of transition from female to male highlights the importance of culture.

Research seems to suggest that the eventual outcome for each individual appears to be a complex and unpredictable combination of genes, hormones and socialisation.

Thus gender development is in part biologically determined (nature) but experience, personal qualities and socialisation (nurture) also seem to have a key role.