Entire biology paper 1

What is resolution?

Shortest distance between two objects that can be seen clearly.

Microscopy RP:

1. Place slide on the stage.

2. Use the lowest power objective lens to give the largest field of view.

3. Switch light on so it passes through the slide.

4. Use coarse adjustment knob to bring stage up until roughly in focus.

5. Move stage as close to the lens as possible. The slide can be damaged if it touches the lens.

6. Turn the fine focus knob until the image comes into focus.

7. Change the objective lens to higher power for a higher magnification.

8. Calculation the magnification by image size/actual size

9. Calculate total magnification by Objective lens x Eyepiece lens

Characteristic of a strand of DNA

1. polymer

2. double helix

Cell cycle

Interphase:

1. cells grows bigger

2. DNA replicates

3. Organelles increase in number

Mitosis:

1. Chromosomes line up at centre

2. Set of chromosomes pulled to each end

3. Nucleus divides

Cytokinesis:

1. Cytoplasm and cell membrane divide

2. Two identical daughter cells formed

How do you calculate the cell cycle?

Observed number of cells in stage/total number of cells observed x total length of cell cycle

Osmosis RP:

1. use a cork borer to cut 5 identical potato cylinders

2. use a scalpel and ruler to ensure each is the same length

3. measure the mass and length of the potato and record in a table

4. measure 10cm cubed of each sugar solution and pour into each boiling tube and label, one should be distilled water

5. add one potato cylinder to each boiling tube and leave for 24 hours

6. blot the potato dry and record the final mass and length

7. calculate the percentage change by final-initial mass/initial mass

8. Plot a graph for the percentage change

Active transport definition

Movement of substances from an area of low to high concentration against a concentration gradient. The energy for this is provided by respiration.

What does amylase convert and where?

Starch → sugar

1. salivary glands

2. Pancreas

3. small intestine

what does protease convert and where?

Protein → amino acids

1. stomach

2. pancreas

3. small intestine

What does lipase convert and where?

lipids → fatty acids and glycerol

1. pancreas

2. small intestine

What does carbohydrase convert?

Carbohydrates → simple sugars

What is the purpose of the liver?

Emulsifies fat which increases surface area and the rate of digestion by lipase.

Neutralises stomach acid with bile which is alkaline, this neutralises HCL to provide ideal conditions for enzymes in the small intestine.

What conditions causes enzymes to denature?

1. temperature

2. pH

Food tests RP:

Starch:

1. transfer food to test tube

2. add iodine solution and shake

3. turn from orange to blue black

Protein:

1. transfer food to test tube

2. add biuret solution and shake

3. blue to purple

Sugar:

1. transfer food to test tube

2. add benedict’s solution

3. place in water bath

4. blue to green to yellow to orange to brick red depending on amount of sugar present

Lipid (fat):

1. add ethanol

2. shake

3. pour into water

4. milky if present

Effect of pH on enzymic activity RP:

1. add iodine to spotting tiles

2. add amylase and buffer solution to a test tube, mix and then add starch.

3. Start a stopwatch

4. After 30s, add a drop into the spotting tiles

5. Repeat every 30s until the iodine stops changing colour

6. Repeat using a different buffer solution pH

Features of the blood and its functions:

Plasma - transports C02, minerals, glucose, urea and hormones

Red blood cell - transports oxygen

White blood cell - Ingesting pathogen and making antibodies

Platelets - blood clotting

Features of an artery

Carries blood away from the heart

Thick muscular walls

Narrow lumen

Carry blood under high pressure so the walls are very strong and elastic.

Features of a vein

Carries blood to the heart

Thin walls and a wider lumen

Carry blood under low pressure

Valves to prevent the backflow of blood

Features of capillaries

Connects arteries and veins

One cell thick so short distance for diffusion

Very narrow lumen

What is the purpose of digitalis?

Slows down the heart rate, found in floxglove

Process of the heart

The deoxygenated blood enters the heart through the vena cava into the right atrium and ventricle through valves. It is then pumped into the pulmonary arteries through a valve to the lungs. The oxygenated blood flows back into the heart through the pulmonary vein into the left atrium and ventricle through a valve and is pumped into the aorta, which gets pumped to the rest of the body.

What is coronary heart disease? (CHD)

Fatty deposit that builds up on the walls of the coronary artery which restricts the blood flow. This means less oxygen reaches the heart muscle and the heart cannot respire, leading to a heart attack.

Risks of CHD?

Smoking and high blood pressure - damages artery lining leading to a fatty deposit build up

High cholesterol - fatty substances are carried in the blood by proteins

Not enough exercise - Increases blood pressure and cholesterol in blood

What are stents? Positives and negatives

Metal mesh inserted into an artery to maintain blood flow. This keeps the artery open so the heart can receive enough oxygen to be able to function.

P - last a long time, rapid recovery

N - risk of infection, requires surgery, blood clotting may occur

What is statin? Positives and negatives

a drug that lowers harmful cholesterol in the blood and stops the liver from producing too much cholesterol and reduce the rate it is deposited at. Patients should have a healthy diet.

P - increases the blood flow to the heart

N - may forget to take the drug, long term, side effects, can take a while for it to work at first

Positive and Negatives of an artificial heart

P - less waiting time, less chance of immune system rejecting the heart

N - doesn’t always pump blood as efficiently

Compare mechanical valves and biological valves:

mechanical walves:

1. last longer

2. blood clots are more likely after surgery

3. anti clotting medication for rest of life

4. may hear valves open and close

5. 5 years higher survival rate

6. lower percentage of deaths

Biological valves:

1. no additional medication

2. ethical issues with animal tissue

3. may harden over time leading to further operation or a new valve

4. likely rejected by body

Both:

1. readily available

2. little wait time

Measles

Virus

symptoms: fever, rash

Spready by: Sneezing and coughing - inhaling droplets

Treatment: vaccinated as children

HIV

Virus

Symptoms: flu like symptoms, destroys immune system - AIDS

Spready by: sexual contact, sharing needles

Treatment: antiretrovial drug

TMV

Virus

Symptoms: mosaic pattern and discolouration of leaves. Chlorophyll in leaves destroyed - less photosynthesis

Spready by: direct contact with plant infected material

Treatment: remove infected plants

Salmonella

Bacteria

Symptom: Fever, cramp, vomiting, diarrhoea

Spready by: cross contamination in food

Treatment: poultry vaccinated against

Gonorrhoea

Bacteria

Symptom: yellow or green discharge from vagina or penis, pain urinating

Spread by: sexual contact

Treatment: antibiotics

Rose black spot

Fungi

Symptoms: spots of leaves, less chlorophyll - photosynthesis

Spready by: water and wind

Treatment: destroy infected leaves

Malaria

Protist

Symptom: fever, death

Spready by: mosquitos

Treatment: mosquito nets, remove still water

Skin

physical barrier

scabs form over cuts - platelets needed

antimicrobial secretions

kill pathogens

airways

some pathogens spread via air or beathing in

trachea secrets mucus

mucus traps pathogens

mucus moved by cilia

mucus moved upwards and swallowed

Stomach

Pathogens enter stomach with HCL and dies

stomach acid kills pathogen in food

Difference between phagocytes and lymphocytes

P - engulf pathogens and digest them by phagocytosis

L - produce antitoxins and neutralises the toxin, produce antibodies which bind to specific antigens on the pathogens

where are penicillium, digitalis and aspirin found

mould - alexander felming

foxglove

willow bark

Process of a vaccine

Small amount of dead or inactive pathogen injected

Pathogen has a antigen on its surface

White blood cells detect this as a foreign body

white blood cells produce antibodies which lock onto the antigen destroying it

Memory white blood cells are produced

If pathogen renters, antibodies are mass produced very quickly preventing infection

What is the only thing you can cure with antibiotics

bacteria

Difference between benign and malignant

B - abnormal cells and don’t invade other parts of the body, isn’tStructure cancerous and can be removed

M - tumours spread to other parts of the body and tissues through the blood, cancerous and cannot be removed, form secondary tumours.

Structure of a plant

epidermal tissue - single layer of cells that cover the whole plant

Xylem - roots stems and leaves, gives support and transports water and minerals

Phloem - roots stems and leaves, transports sugars

Spongy mesophyll - leaves, helps facilitate gas exchange

Palisade mesophyll - leaves, main site of photosynthesis

Meristem tissue - tip of root and shoot, enables plant growth

Difference between transpiration and translocation

Transpiration - water is transported from roots to the leaves by the xylem and moves upwards (evaporation of water)

Translocation - sugar transported from the leaves to the rest of the plant through the phloem

Photosynthesis word and symbol equation

Carbon dioxide + water → glucose + oxygen

6C02 + 6H20 → C6H1206 + 602

How do you calculate light intensity?

1/distance sqaured

Photosynthesis RP: (why do we use sodium hydrogen carbonate solution and a LED lamp?)

1. fill a boiling tube with sodium hydrogen carbonate solution

2. cut a 10m piece of pondweed and put it in the boiling tube with the cut end at the top

3. Set a LED lamp 10cm to the boiling tube and leave for 5m

4. Start stopwatch and count the bubbles released in 1m

5. repeat steps 1-5 while altering the distance of the lamp

Sodium hydrogen carbonate solution: excess dissolved carbon dioxide for the plant so it isnt a limiting factor

LED lamp: produces less heat and reduces effect of temperature

Aerobic respiration word and symbol equation

glucose + oxygen → carbon dioxide + water

C6H1206 + 602 → 6C02 +6H20

anaerobic respiration in muscles

glucose → lactic acid (energy) which causes muscle fatigue

anaerobic respiration in plants and yeast cells

glucose → ethanol + carbon dioxide + (energy) which creates alcoholic drinks and bread by the process of fermentation

where in the cell does anaerobic respiration take place?

cytoplasm

Why is there less energy released in aerobic respiration than aerobic

oxidisation of glucose is incomplete (not fully broken down)

metabolism

sum of all reactions happening in a cell or organism, where molecules are made or broken down