paper 1 - topic 3

Question 1

what are pathogens

Answer 1

microorganisms that cause infectious disease

Question 2

toxins

Answer 2

released by bacteria

damage tissues which then make us feel ill

Question 3

bacteria

Answer 3

reproduce rapidly in the body

Question 4

viruses

Answer 4

cannot reproduce themselves- only in a host cell

cannot be killed by antibiotics

Question 5

how pathogens are spread

Answer 5

air

water

direct contact

Question 6

how to reduce the spread of pathogens

Answer 6

wash hands

clean water

condom

isolation

vaccination

Question 7

malaria

Answer 7

1) infected person is bitten by mosquito - malaria pathigen passes into mosquito
2) mosquito bites a different person and passes pathogen to them

mosquito is a vector

Question 8

prevention of malaria

Answer 8

stop the vector breeding

insecticide

prevent mosquitos biting humans

Question 9

skin

Answer 9

forms protective layer covering body

Question 10

nose hair and mucus

Answer 10

traps pathogens

Question 11

cilia

Answer 11

on trachea and bronchi

covered in mucus which traps pathogens

cilia wafts mucus up towards throat where it is swallowed in stomach

Question 12

hydrochloric acid

Answer 12

in stomach

kills pathogens before they can get further in the digestive system

Question 13

immune system

Answer 13

white blood cells - ingests pathogens and uses enzymes to destroy pathogens (phagocytosis)

antibodies- stick to pathogens which triggers pathogens to be destroyed

Question 14

tobacco mosaic virus

Answer 14

viral disease

causes leaves to discolour

rate of photosythesis is reduced and growth of plant is reduced

Question 15

rose black spot

Answer 15

caused by fungus

leaves discolour

rate of photosynthesis is reduced and rate of growth is reduced

spread by water or wind

treat by fungicides or remove infected leaves

Question 16

vaccinations

Answer 16

introducing small quantities of dead forms of a pathogen into the body

white blood cells are stimulated to produce antibodies against the dead pathogen

at the same time the white blood cell divides by mitosis to copy itself - these copies means if the same pathogen enters the body the white blood cells can produce the correct antibodies quickly to prevent infection

Question 17

antibiotics

Answer 17

kill infective bacteria inside the body without harming body cells

Question 18

antibiotic resistance

Answer 18

where antibiotics had been overused so the bacteria evolved and the antibiotics no longer worked

Question 19

what drugs are tested for

Answer 19

toxicity

effectiveness

premium dosage

Question 20

drug testing

Answer 20

pre clinincal - in a lab on cells or animals

clinical testing - on humans:

first stage- low doses given to healthy volunteers to see side effects and safety

continues to find optimum dose on people with the disease

double blind - test group recieve drug and control group recieve the placebo. neither the patients nor doctors know who is getting what to prevent bias

Question 21

how monoclonal antibodies are produced

Answer 21

1) inject mouse with antigen so lymphocytes produce antibody against antigen
2) extract lymphocyte
3) fuse lymphocyte with tumour cell to produce hybridoma
4) allow hybridoma to divide by mitosis to form clones of hybridoma cells (monoclonal antibodies)

Question 22

monoclonal antibodies

Answer 22

produced from a single clone of cells

specific to one binding site on one protein antigen

target a specific chemical or cell type in the body

Question 23

uses of monoclonal antibodies

Answer 23

pregnancy tests

measure hormones in bloods

detect pathogens in blood

plant disease testing kit

Question 24

identifying plant diseases

Answer 24

garden manual

take plant to lab to identify pathogens

testing kit

Question 25

plant ion deficiencies

Answer 25

lack of nitrate- causes stunted growth as nitrate is needed for proteinsynthesis

lack of magnesium- causes chlorosis as magnesium is needed to make chlorophyll

Question 26

plant defense responses

Answer 26

cell wall- difficult for microorgansims to penetrate

waxy cuticle- difficult for microorganisms to penetrate

bark- barrier to entry ny microorganisms

release chemicals - kill bacteria

release poisons- deter herbivores

sharp thorns - stop plant from being eaten

hairs- make it difficult to eat

movement when touched - scares herbivores

mimicry - blend into surroundings

Question 27

photosynthesis

Answer 27

light
carbon dioxide + water ——–> glucose + oxygen

CO2 + H20 ———> C6H1206 + 02

plant takes carbon dioxide and water into leaf

light energy is absorbed by chlorophyll

the light energy is then used to convert the carbon dioxide and water into glucose and oxygen is also produced

Question 28

photosynthesis required practical

Answer 28

1) take boiling tube and place it 10cm away from an led light source
2) fill tube with sodium hydrogen carbonate solution as it releases carbon dioxide
3) place pondweed into tube with cut end at top
4) leave for 5 mins for plant to acclimatise to conditions in the boiling tube
5) bubbles should be seen being produced at cut end of pondweed
6) start stopwatch and count number of bubbles produced in one minute
7) repeat two more times to get average of bubbles produced in one minute
8) repeat experiment at 20cm, 30cm and 40cm

Question 29

problems with photosynthesis practical

Answer 29

number of bubbles can be too fast to count accurately

bubbles are not always the same size

Question 30

aerobic respiration equation

Answer 30

glucose + oxygen ——> carbon dioxide + water +
energy

C6H1206 + 02 ———> C02 + H20

Question 31

anaerobic respiration equation

Answer 31

glucose ——–> lactic acid + energy

does not require oxygen

releases much less energy than aerobic as oxidation of glucose is incomplete

Question 32

body changes during exercise

Answer 32

breathing rate and volume increases to provide extra oxygen in the bloodstream

heart rate increases to pump the oxygenated blood around the body

lactic acid build up in muscles causing fatigue and contracting inefficiently and creating oxygen debt

Question 33

metabolism

Answer 33

the sum of all the chemical reactions in a cell or body