Biology holiday study

Question 1

how modern technology has increased the production of crop plants

Answer 1

Modern technology such as chemical fertilisers, pesticides, herbicides, modern agricultural machinery, artificial selection… have been used to increase food production

Question 2

how can overuse of fertilisers damage the environment

Answer 2

When the excess nutrients from all the fertilizer we use runs off into our waterways, they cause algae blooms sometimes big enough to make waterways impassable. When the algae die, they sink to the bottom and decompose in a process that removes oxygen from the water

Question 3

Zygote

Answer 3

a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.

Question 4

what are male gametes and where are they made

Answer 4

male gametes are called sperm, they are made in the testicles

Question 5

what are female gametes and where are they made

Answer 5

eggs and ovum, made in ovaries

Question 6

The term used to describe the fusion of gametes

Answer 6

fertilisation

Question 7

What organ of a female parent do offspring develop

Answer 7

uterus

Question 8

Role of the placenta during pregnancy

Answer 8

gas exchange

Provides nutrients

Question 9

Secondary sexual characteristics are

Answer 9

thechanges that occur during pubertyas children become adolescents

Question 10

what are secondary sexual characteristics controlled by

Answer 10

They are controlled by the release ofhormones–oestrogenin girls andtestosteronein boys

Question 11

Sexual changes in puberty

Answer 11

Some changes occur to both boys and girls, includinggrowth of sexual organsandgrowth of body hair
Emotional changesalso occur due to the increased levels of hormones in the body
These include more interest in sex and increased mood swings

Question 12

effects of oestrogen

Answer 12

Breasts develop
body hair grows
Menstrual cycle begins
hips get wider

Question 13

Effects of testosterone

Answer 13

growth of penis and testes 
growth of facial and body hair 
muscles develop 
Voice breaks 
testes start to produce sperm

Question 14

When does the menstrual cycle start

Answer 14

Starts in early adolescence in girls (around age12) and is controlled byhormones
The average menstrual cycle is28 dayslong

Question 15

ovulation

Answer 15

Ovulation(the release of an egg) occurs abouthalfwaythrough the cycle (day14) and the egg then travels down the oviduct to the uterus

Question 16

Menstruation

Answer 16

Failure to fertilise and egg is commonly called a period. To occur – this is caused by thebreakdown of the thickened lining of the uterus

Question 17

how long is mensturation

Answer 17

Menstruation lasts around5 – 7 daysand signals the beginning of the next cycle
After menstruation finishes, the lining of the uterus starts to thicken again in preparation for possible implantation in the next cycle

Question 18

Oestrogen menstural cycle timeline

Answer 18

Oestrogenlevels rise from day 1 to peak just beforeday 14
This causes theuterine wall to start thickeningand theegg to mature
The peak in oestrogen occurs just before the egg is released
Progesteronestays low from day 1 – 14 and starts to rise once ovulation has occurred
The increasing levelscause the uterine lining to thicken further; a fall in progesterone levels causes the uterine lining to break down (menstruation / ‘period’)

Question 19

What does the pituitary gland produce

Answer 19

The pituitary gland producesFSHwhich stimulates the development of afolliclein the ovary

Question 20

what develops inside the follicle

Answer 20

An egg develops inside the follicle and the follicle produces the hormoneoestrogen

Question 21

What maintains the uterus lining

Answer 21

Progesteronemaintains the uterus lining(the thickness of the uterus wall)