Perguntas que eu errei

Question 1

Suggest why a protective substance is necessary in the intestines. (2)

Answer 1

• protect the intestine from pathogens
• physical damage by food passing through intestine

Question 2

What is the ileum?

Answer 2

an organ

Question 3

Define the term chromosome. (2)

Answer 3

strand of DNA (1) that contains genetic material (2)

Question 4

Describe the roles of FSH and LH in the menstrual cycle. (4)

Answer 4

• FSH stimulates, development and maturation of follicles
• FSH stimulates, development and maturation of an egg
• FSH stimulates release of oestrogen from ovary
• LH stimulates ovulation
• LH stimulates release of progesterone (corpus luteum)

Question 5

Describe the changes that occur in the lining of the uterus during one menstrual cycle. (3)

Answer 5

• loss of lining at the beginning of the cycle
• thickening of lining after loss, 2nd week
• last 2 weeks, after ovulation: thickness of lining remains constant

Question 6

Outline how the hormones in contraceptives act as a method of birth control. (3) (mari nao precisa saber disso, saiu do syllabus)

Answer 6

• contraceptives contain progesterone
• prevents release of FSH/LH
• prevents, development of follicles
• prevents ovulation

Question 7

Function of effectors. (1)

Answer 7

carry out response

Question 8

Function of receptors. (1)

Answer 8

detects the stimulus

Question 9

Which organ produces bile? (1)

Answer 9

liver

Question 10

Describe graph for enzyme activity x temp.

Answer 10

decrease after optimum is steeper than increase
line meets x axis at end

Question 11

Explain the effect of a lack of magnesium ions of the colour of plant leaves. (2)

Answer 11

yellow (1) since magnesium is required for making chlorophyll (2)

Question 12

Explain why the sequence of amino acids is important in the production of receptor molecules for neurotransmitters. (2)

Answer 12

• the sequence of amino acids determines the shape of the protein
• a complementary shape required for the receptor molecule to bind to neurotransmitter

Question 13

Describe how artificial selection differs from natural selection. (3)

Answer 13

• humans choose desired features
• humans choose individuals to reproduce
• selection not influenced by environment
• decreases genetic variation
• faster
• for economic reasons

Question 14

State two other sources, besides mutation, for genetic variation in populations. (2)

Answer 14

meiosis/crossbreeding
random fertilisation

Question 15

Explain why vitamin D is important for the nutrition of children. (3)

Answer 15

• needed for development of bones
• needed for development of teeth
• prevents rickets

Question 16

Define the term ‘transmissible disease’. (2)

Answer 16

disease is caused by a pathogen (1) which is passed from one host to another (2)

Question 17

Explain why women should be vaccinated against rubella before they reach reproductive age. (4)

Answer 17

• rubella is caused by a virus
• virus can cross the placenta
• and can affect embryo fetus
• can cause serious damage to baby
• vaccination stimulates long-lasting active immunity in mother, so immunity is gained before they become pregnant (2)

Question 18

Explain why the rate of photosynthesis will decrease if the humidity in the apparatus becomes very low. (3)

Answer 18

• air becomes dry
• diffusion gradient for water vapour increases
• increased rate of transpiration
• stomata close
• CO2 cannot enter

Question 19

Explain why the rate at which CO2 is used in photosynthesis is greater than the rate of its uptake. (2)

Answer 19

• carbon dioxide produced in respiration
• plants respire all the time
• carbon dioxide released by cells is used in photosynthesis

Question 20

Discuss the advantages of growing crops in glasshouses. (6)

Answer 20

• glasshouses can maintain optimum conditions for
  photosynthesis
• maintain optimum light intensity
• by using artificial lights
• maintain optimum temperature
• heater/cooling
• can use CO2 enrichment
  by burning fuels
• supply of nutrients and minerals
• herbicides not required
• control of pollinators for selective breeding

Question 21

Outline the process of artificial insemination (3).

Answer 21

• collect semen
• selecting of sperm
• determine when female is about to ovulate
• insert sperm into female

Question 22

State two main features of fungal cells that are used to distinguish them from cells of prokaryotes. (2)

Answer 22

• nucleus
• mitochondria

Question 23

List 2 nutrients that need to be added to a fermenter to produce penicillin. (2)

Answer 23

• water
• glucose
• amino acids

Question 24

Explain why the nutrients are sterilised before they are added to the fermenter. (1)

Answer 24

to make sure no other microogranisms can grow

Question 25

Explain why the fermenter has a gas outflow pipe. (2)

Answer 25

so that waste gases like CO2, produced during fermentation and respiration, can escape reduce pressure

Question 26

Describe how acid rain destroys forests. (3)

Answer 26

- acidifies soil - acidified soil causes leaching - damage leaves - affects ability of roots to absorb mineral ions

Question 27

Mutations are always inherited in single-celled organisms that reproduce asexually but are not always inherited in organisms that reproduce sexually. Explain why. (4)

Answer 27

- mutations are found in the DNA - asexual reproduction offspring are genetically identical to the parent - so any existing mutations in parent DNA will be inherited - sexual reproduction involves two parents - mutation will only be in some of the gametes - meiosis does not result in genetically identical cells

Question 28

Suggest why amphibians are vulnerable to pollutants such as acid rain. (2)

Answer 28

- permeable skin - they have fragile/thin gills - part of their life only exists in water

Question 29

Describe the structure of a villus and its role in the alimentary canal. (6)

Answer 29

- lacteals absorb fatty acids and glycerol - lymphatic vessel, returns fats to blood - epithelial cell has microvilli - increasing the surface area for absorption - epithelial layer one cell thick for short diffusion distance - epithelial layer is where break down of maltose into glucose occurs

Question 30

Discuss the possible disadvantages of people changing the genes in a plant. (3)

Answer 30

- cross-pollinate into wild populations - expensive GM seeds - ethical concerns - reduced natural biodiversity

Question 31

Predict and explain the effect of high humidity on the stomata. (3)

Answer 31

- stomata will take longer to close - reduced water vapour concentration gradient - so the guard cells do not lose water as quickly - guard cells stay turgid

Question 32

State two types of cell membrane proteins. (2)

Answer 32

carriers enzyme/maltase

Question 33

Explain how bacteria become resistant to antibiotics. (5)

Answer 33

- random mutations in some bacteria - bacteria with resistance survive and reproduce - passing on their resistant gene - increase in frequency of resistant gene in population - natural selection/becoming better adapted for new environment