Biology paper 1

Question 1

Eukaryotic and Prokaryotic cell differences

Answer 1

Eukaryotic: complex, all plant and animal cells
Prokaryotic: smaller, simpler, single-celled organism e.g. bacteria which doesn’t have chloroplasts or mitochondria or nucleus but has strand of DNA and small rings of DNA called plasmids

Question 2

Mitochondria

Answer 2

These are where most of the reactions for aerobic respiration take place. This transfers energy that the cell needs to work

Question 3

Plant cells have (as extra to animal cells)

Answer 3

Rigid cell wall made up of cellulose, permanent vacuole, chloroplasts

Question 4

How to prepare your slide

Answer 4

Add a drop of water, cut up onion and separate into layers, use tweezers to peel off some epidermal tissue, iodine solution (stain), cover slip

Question 5

Differentiation

Answer 5

A cell changes to become specialised for its job

Question 6

Diffusion

Answer 6

Diffusion is the spreading out of particles from an area of high concentration to an area of low concentration

Question 7

Osmosis

Answer 7

Osmosis is the movement of water particles across a partially permeable membrane from a region of higher water contents to a region of lower water concentration

Question 8

Active transport

Answer 8

Active transport is allows substances to be absorbed into a cell or the blood from a low to high concentration against the concentration gradient which requires energy from respiration

Question 9

Adaptations of exchange surfaces

Answer 9

Thin membrane (short diffusion distance), large surface area, lots of blood vessels, ventilated

Question 10

Artery (first)

Answer 10

Carries blood away from the heart at a high pressure (strong (have muscles) and elastic fibres)

Question 11

Capillary (second)

Answer 11

Involved in the exchange of materials at the tissues.
One cell thick, permeable walls, diffusion

Question 12

Vein (third)

Answer 12

Carries blood to the heart at a lower pressure, bigger lumen, valves

Question 13

Coronary arteries

Answer 13

Branches off the aorta and surrounds the heart making sure it gets all the oxygenated blood it needs

Question 14

Where is the pacemaker

Answer 14

In the wall of the right atrium

Question 15

What does plasma carry

Answer 15

Red blood cells
White blood cells
Platelets
Nutrients (glucose, amino acids etc)
Carbon dioxide
Urea
Hormones
Proteins
Antibodies
Antitoxins

Question 16

Cardiovascular disease- e.g. coronary heart disease

Answer 16

coronary heart disease is when the coronary arteries that supply the blood to the muscle of the heart get blocked by layers of fatty material building up. This causes the arteries to become narrow do blood flow is restricted and there’s a lack of oxygen to the heart which can cause a heart attack

Question 17

Stents and statins

Answer 17

Stents keep arteries open
Statins reduce cholesterol in the blood

Question 18

Phloem

Answer 18

Elongated living cells
Small pores in the end walls to allow cell sap through
Transport food substances (mainly dissolved sugars)
Transport in both directions
Translocation

Question 19

Xylem

Answer 19

Dead cells with no end walls
Strengthened by lignin
Carry water and minerals ions
Transport up from roots to leaves
Transpiration stream

Question 20

What affects transpiration rate

Answer 20

Light intensity
Temperature
Air flow
Humidity

Question 21

Bacteria (and examples)

Answer 21

Very small cells which reproduce rapidly inside the body
Produce toxins that damage cells and tissues to make you feel ill

Salmonella- food poisoning, fever, cramps, vomiting, diarrhoea. Poultry given vaccinations, hygiene

Gonorrhoea- STD, pain when urinating, thick yellow/green discharge from vagina/penis, antibiotics (penicillin) but there are resistant strains if bacteria, barrier methods e.g.condoms

Question 22

Viruses (and examples)

Answer 22

Not cells (tiny) and reproduce rapidly
Live inside cells and replicate themselves, the cell will burst releasing all the new viruses
Cell damage makes you feel ill

Measles (spread by droplets)- red skin rash, fever, can lead to complications, vaccinations

HIV (sexual contact or exchanging bodily fluids)- flu symptoms, treated by antiretroviral drugs, attacks immune system- AIDs

Tobacco Mosaic Virus- plants, mosaic pattern on leaves, discoloured, less photosynthesis

Question 23

Protists (and examples)

Answer 23

Single-celled eukaryotes
E.g. parasites which live on or inside and organism and cause damage, carried by a vector

Malaria- mosquitos 🦟 are vectors and insert it into animal’s blood vessels when feeding on it- repeated fever, death. Stop mosquitos breeding, insecticides, mosquito nets

Question 24

Fungi (and examples)

Answer 24

Some are single-celled, others have a body made up of hyphae which can grow and penetrate human skin and the surface of plants causing diseases, it can also produce spores which spread to other organisms

Rose black spot- purple/black spots on rose leaves- yellow- drop off, less photosynthesis, spreads by water/wind, fungicides to treat it and strip and destroy affected leaves

Question 25

Reducing/preventing spread of disease

Answer 25

Hygiene Destroying vectors (habitat or insecticides) Isolating infected individuals Vaccination

Question 26

Vaccination

Answer 26

Injecting small amounts of dead or inactive pathogens. These carry antigens which cause the body to produce antibodies to attack them so if it infects that person the white blood cells can rapidly mass-produce antibodies to kill off the pathogen.

Question 27

What can become resistant to antibiotics

Answer 27

Bacteria mutate and can become resistant

Question 28

Three Main Stages in Drug Testing

Answer 28

1- (preclinical testing) on human cells and tissues in the lab 2- (preclinical testing) on live animals- test efficacy, find toxicity and dosage 3- (clinical trial) on human volunteers. First healthy to see side effects at a low dosage then increased then tested on people suffering from the illness to find optimum dose, (double) blind trials with placebo (effect), peer review

Question 29

Monoclonal antibodies

Answer 29

Mouse injected with chosen antigen, B-lymphocytes taken from mouse. Fast-dividing tumour cells from the lab fused with B-lymphocyte to make a hybridoma. It divides quickly to produce lots of clones that produce the monoclonal antibodies

Question 30

What mineral ions do plants need

Answer 30

Nitrates - to make proteins and therefore for growth Magnesium ions - for making chlorophyll for photosynthesis

Question 31

Plants use glucose for...

Answer 31

Respiration Main cellulose Making amino acids Stored as oils or fats Stored as starch

Question 32

Plant defenses

Answer 32

Physical- waxy cuticle, cell walls from cellulose, dead cells around stems (bark) Chemical- produce antibacterial chemicals, poisons Mechanical- thorns/hairs, droop/curl when touched, mimicry

Question 33

Body defence system

Answer 33

Skin (secretes antimicrobial substances), hairs, mucus, cilia (waft mucus to back of throat to be swallowed), HCl acid in stomach White blood cells: -engulf & digest (phagocytosis) -produce antibodies (specific to antigen) -produce antitoxins

Question 34

Protruding limiting factors

Answer 34

Light CO2 contents Temperature (Chlorophyll)

Question 35

Inverse square law

Answer 35

Light intensity inversely proportional to distance^2

Question 36

Respiration

Answer 36

Respiration is the process of transferring energy from glucose which goes on in every cell Exothermic

Question 37

What larger molecules are made from smaller ones

Answer 37

Glucose: starch, glycogen, cellulose Lipid: glycerol, fatty acids Glucose: amino acids (proteins), nitrate ions

Question 38

Respiration equations

Answer 38

Aerobic: Glucose + Oxygen → Carbon dioxide + Water Anaerobic: Glucose → Lactic acid Anaerobic in plants: Glucose → Ethanol + Carbon dioxide (fermentation)