Biology: Organisation (Paper 1)

What is a specialised cell?

A cell with a specific function

e.g nerve cells

Muscle cells

What is referred to as ‘the building blocks of life’?

Cells

How to form tissues organs etc

Cells > tissues

• A group of similar cells working together for one function

Tissues > organs

• A group of tissues working together for one function

Organs > Organ systems

• A group of different organs working together to perform a function

Test for starch

Iodine solution

Blue - black positive

Refer to ‘iodine solution’ not ‘iodine’

Test for lipids

Sudan III Test

Sudan III stain solution

Fat is stained snd separated from substance

Bright red layer - positive

Test for sugars

Benedicts (reagent) test

Water bath at 75º

Wait 10 mins

Green / Yellow / Brick red positive\

Don’t boil mix for too long as starch will turn to sugars - false positive

Test for proteins

Biuret test

Purple positive

Hold test tube infant of white paper as purple result is hard to see

pH effect on Enzymes

Enzymes work best in their optimum pH level

• If pH is too high or low

• The hydrogen bonds in the active site

• Break down and the active site loses its shape

• It can no longer break down food

• The enzyme had denatured

What can muscle tissue do?

Contract to bring about movement

What can glandular tissue do?

Release hormones and enzymes

What does epithelial tissue do?

Cover all parts of the body

Label the Digestive system

How do Enzymes aid digestion

1. The enzymes pass out of the cells into the digestive system

2. They come into contact with food molecules

3. They catalyse the breakdown of large insoluble food molecules into smaller soluble molecules

Properties of Enzyme Protease

Substrate	Products	Location
Proteins	Amino acids	Small intestine Pancreas Stomach

Properties of enzyme Lipase

Substrate	Products	Location
Lipids (fats)	Fatty acids Glycerol	Pancreas Salivary gland Stomach

Properties of enzyme Carbohydrase

E.g. Amylase

Substrate	Products	Location
Carbs Starch	Sugars Glucose	Pancreas Small intestine Salivary glands

What are the ….. for?

1. Cell membrane

2. Ribosomes

3. Mitochondria

4. Cytoplasm

5. Nucleus

1. Cell membrane - controls what goes in & out

2. Ribosomes - protein synthesis

3. Mitochondria - Respiration for energy

4. Cytoplasm - Site of chemical reactions

5. Nucleus - Holds DNA

What is parastalsis?

The squeezing action in oesophagus and intestines to put food through

What is the optimum pH and temp for enzymes?

pH 5-9

Optimum pH7

Optimum temp 37º

Label the heart

How is the small intestine adapted for absorption?

• Villi, increased surfaced area

• Large surface area (5m long)

• Micro villi, increase surface area

• Villi have thin membrane for a short diffusion path

• Capillaries absorb nutrients

• Rapid rate of diffusion

What is a single circulatory system?

• Blood goes from heart to gills (for oxygen) to organs

• Blood loses lots of pressure passing through gills and loses oxygen before getting to organs.

What is a double circulatory system?

• Blood from heart to lungs for oxygen

• Back to heart

• Pumped around rest of body

• Back to heart

• Blood passes through heart twice which speeds up transport and increases oxygen

Properties of Arteries

• High pressure blood

• From heart to body

• Thick wall and muscle

• Elastic fibres which stretch and recoil in-between surges of blood

Properties of veins

• Blood to the heart

• Deoxygenated

• Low pressure

• Valves to prevent back flow

• THin wall

Properties of capillaries

• Substances from blood diffuse

• E.g CO2 and glucose

What does the pulmonary artery do?

Pumps deoxygenated blood away from heart to lungs

What does aorta do?

Pumps oxygenated blood to body

What does the pulmonary vein do?

Pumps oxygenated blood into the heart to go to the body

What does the vena cava do?

Allows deoxygenated blood from body into the heart

What side has a thicker wall? Why?

• Left side

• Pumps blood to rest of the body so requires thicker muscular wall as the blood is pumped at a greater force

What is found in the blood?

• Plasma - liquid

• Red blood cells, white blood cells

• Plateletes (tiny fragments of cells)

What does plasma transport?

• Plasma transports CO2 from organs to lungs

• Waste product urea from liver to kidneys to be excreted

• Soluble digestion products e.g. glucose

What aaptations do red blood cells have?

• Transport oxygen from lungs to body

• Haemoglobin which carries oxygen (oxyhaemoglobin)

• No nucleus (more room for haemoglobin)

• Concave shape for larger surface area for more haemoglobin

White blood cells features

• Make antibodies

• Contain nucleus ( & DNA)

What are platelets for?

To help clot blood to prevent bleeding out.

Cardiovascular diseases

• Coronary heart disease

• Fatty deposits block coronary arteries. Arteries narrow which limits oxygen to heart

• Statins reduce cholesterol which slows down build up of fat

• Stent

• Can cause liver problems

• Leaky valves

• Artificial increase blood clot risks

Gas exchange in lungs

• Alveoli - large surface area, one cell thick, good blood supply, steep concentration gradient

• Bronchi - tubes into lungs

• Bronchioli - smaller tubes from bronchi

• Trachea contain rings of cartilage preventing collapse

Cancer

• uncontrolled growth and mitosis (tumour)

• Benign tumour - contained a membrane, stay in one place

• Malignant - cancer, spread

• Alcohol - Mouth & throat cancer

• UV light - skin cancer

• Radon - Uncontrolled cell division

Non communicable

Can’t be passed on from person to person

Communicable

Passed on from person to person

What can HPV cause?

Cervical cancer

What polymer is amylase made of?

Amino acids

Evaluate the use of anti-clotting drugs

Advantage:

• Only one per day

• Tablet is easy to swallow / not painful

Disadvantage:

• Could forget to take the drugs

• Could still clot in the first week.

How does an enzyme work?

Lock and key theory

• Starch / substrate binds to active site

• Shape of active site and substrate are complementary

• Bonds between the starch molecules are broken to produce smaller molecules