biology paper 1

prokaryotes

prokaryotes

smaller and simpler

bacteria

eukaryotes

complex

animal and plant cells

cytoplasm

where most of the chemical reaction happens

mitochondria

aerobic respiration happens

ribosomes

where proteins are made

chloroplasts

where photosynthisis happens

bacterial cell contains

• cell wall

• cell membrane

• cytoplasm

• single loop of DNA

• plasmids

microscopy

magnification = image size/ real size

microscopy practical set up

1) Add a drop of water to the middle of a clean slide
2) Cut up an onion & separate it out into layers. Use tweezers to peel off some epidermal tissue from the bottom of one of the layers
3) Using the tweezers, place the epidermal tissue into the water on the slide
4) Add a drop of iodine solution - a stain used to highlight objects in a cell by adding colour to them
5) Place a cover slip on top - stand the cover slip upright on the slide, next to the water droplet. Then, carefully tilt & lower it so it covers the specimen. Try not to get any air bubbles under there - there'll obstruct your view

microscopy practical using a light microscope

1) Clip the slide you've prepared onto the stage
2) Select the lowest-powered objective lens
3) Use the coarse adjustment knob to move the stage up to just below the objective lens
4) Look down the eyepiece. Use the coarse adjustment knob to move the stage downwards until the image is roughly in focus
5) Adjust the focus with the fine adjustment knob, until you get a clear image of what's on the slide

microscopy practical drawing observations

1) Draw what you see under the microscope using a pencil with a sharp point
2) Make sure your drawing takes up at least half of the space available & that it is drawn with clear, unbroken lines
3) Your drawing should not include any colouring or shading
4) If you are drawing cells, the subcellular structures should be drawn in proportion
5) Include a title & write down the magnification that it was observed under
6) Label the important features of your drawing using straight, uncrossed lines

chromosomes

coiled up lengths of DNA

growth and DNA

1) the cell grows and increases the amount of subcellcular structure like ribosomes
2) DNA is replicated then forms X shaped chromosomes

mitosis

Chromosomes line up at the centre of the cell
Two arms of chromosomes are pulled apart
Nucleus divides
Cytoplasm and cell membrane divides

cell specialisation

nerve cells- carry impulses, so they are long and narrow
Muscle cells - responsible for motion and movement, contain many fibers for movement
Root hair cells - grow long 'hair' that sticks out the soil, large surface area
Phloem- few sub cellular structures
Xylem- hollow
Sperm cell- tail and lots of mitochondria.

diffusion

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

osmosis

the movement of water particles for a partially permeable membrane from a less to more concentrated area

osmosis practical

-Cut up a potato into identical cylinders
- Get some beakers with different sugar solutions in them, one should be pure water and another should be a very concentrated sugar solution and some in between.
- Measure the mass of the cylinders and leave each one in each beaker for a day
- Take them out, dry them and weigh them again
- If water has been drawn in by osmosis they will have increased in mass
- If water has be drawn out they will decrease in mass
- Dependant variable is the chip mass
- Independent variable is the concentration

active transport

lock and key

chemical reactions involved when things split apart or are joined together

every enzyme has an active site with a usual shape

substrates fit into an enzyme and they have an active site

investigating enzymatic activity

1) add iodine to spotting tiles and use a water bath

2) add some amylase and buffer solution

3) add the tube to the bath then add some starch solution and mix

4)put it in the spotting tiles if the solution stays brown then all the starch had been broken down

carbohydrates

starch——— amylase——-sugars

proteases

protein———protease——— amino acids

lipases

lipid——— lipase——— fatty acids

food test benedicts

sugar

heat in water bath

brick red

food test biuret

amino acids

add buiret regent

lilac

food test ethonal

fats/lipids

dissolve fat add water

milky

food test iodine

starch

add iodine solution

blue/black

arteries

work well under pressure

carry blood away from the heart

thick layer of muscle

capillaries

really small

walls are one cell thick diffusion is fast

veins

capillaries join up to form veins

big lumen

stop blood flowing in wrong direction

red blood cells

carry oxygen to the lungs

large surface area

haemoglobin

white blood cell

immune system

produces anti toxins and antiboides

have a nucleus

communicable diseases

diseases that spread from person to person or between animal and animal caused by bacteria, viruses or fungi

non-communicable diseases

cannot spread between person to person for example CHD

benign tumours

masses of abnormal cells that isn’t typically dangerous

malignant tumours

spread round the body and break of in the blood stream

dangerous and can be fatal

lifestyle factors

• smoking

• drinking

• UV exposure

genetic factors

• passed on from parent

• faulty genes

transpiration

xylem- moves in one direction root to leaf

water and ions

translocation

phloem goes up and down to transport

glucose of respiration

transpiration rate

• air flow

• temperature

• humidity

• light intensity

salmonella

type of bacteria causes food poisoning

suffer from; fever, stomach cramps, vomiting,diarrhoea

most poultry is vaccinated

gonorrhoea

caused by bacteria

STD

pain when they urinate

treatment: antibiotics, penicillin

measles

viral disease spread by droplets of people sneeze or cough

red skin rash

vaccinations

HIV

sexual contact or spreading of exchange of bodily fluids

flu-like symptoms

TMV

virus that affects plants

leaves become discoloured with a mosaic pattern

less photosynthesis

Rose black spots

fungus

less photosynthesis

spread by water or wind

strip affected leaves off plants

leaves need to be destroyed

malaria

protist

fever

spread by vectors

immune systems attacking pathogens

white blood cells engulf the pathogen and digest them. Every pathogen invades pathogens have a unique molecule which are called antigens. White blood cells detect a foreign antigen and start to make antibodies. Antibodies lock onto invading pathogen and make a specific antigen to destroy the pathogen

vaccination

involve injecting a weakened pathogen into the body. antigens allow white blood cells to attack pathogen.

drugs: aspirin

painkiller made from willow

drug: digitalis

treating heart conditions

foxglove

drug: penicillin

alexander fleming

antibiotic

photosynthesis

co2+H20————>(light) C6H12O6+O2

plant use glucose for:

• respiration

• making cell walls

• amino acids

• stored as oils or fats

• stored by starch

rate of photosynthesis

• light

• CO2

• temperature

pondweed practical

1)place a boiling tube 10cm away from an LED light source because they don't produce much heat

2) fill boiling tube with sodium hydrogen carbonate solution which releases c02 which is needed for photosynthesis

3) put pondweed into the boiling tube with the cut end at the top- leave for 5 mins, we should start to see bubbles of gas= oxygen

4) start stopwatch and count the number of bubbles produced in 1min- repeat two more times and find an average

5) do the whole experiment again but instead start at 20cm then 30cm, then 40cm

respiration

process of transferring energy from glucose

exercise

causes more respiration

oxygen debt

extra amount of oxygen your body needs after exercise

anaerobic respiration

• no oxygen

• exothermic

• happen in cytoplasm

• releases lactic acid

aerobic respiration

• oxygen

• exothermic

• happens in mitochondria

• releases CO2 +H20

stomata

tiny holes found in the underside of leaves. They control water loss and gas exchange by opening and closing.

what is an enzyme

a biological catalyst