Edexcel IAL Biology Unit 1 Topic 1

Monosaccharide

single sugar unit

Examples of Monosaccarides

1. Glucose

2. Fructose

3. Galactose

Disaccharides

Two sugar units

Examples of Disaccharides

1. Maltose

2. Lactose

3. Sucrose

Maltose is made up of...

alpha Glucose + alpha Glucose = 1,4 glycosidic bond

Lactose is made up of...

Galactose + B glucose = 1.4 glycosidic bond

Sucrose is made up of...

Fructose + Glucose = 1,2 glycosidic bond

Polysaccharides

Containing three or more sugar units

Examples of Polysaccharides

1. Amylose

2. Glycogen

3. Amylopectin

Amylose

lots of alpha glucose molecules joined together by 1,4 glycosidic bonds

Amylopectin

1,6 and 1,4 glycosidic bonds, has side branches

Glycogen

Made of many monomers of alpha glucose, with 1,4 and 1,6 bonds

Many side branches

Fatty acids

1 Glycerol + 3 fatty acids

Distinguish between the structure of a unsaturated and a saturated fatty acid

1. Saturated fatty acids have no carbon-carbon double bonds, whereas unsaturated fatty acids have at least one carbon-carbon double bond

2. Saturated fatty acid chains are straight, whereas unsaturated fatty acid chains are not straight

Factors affecting diffusion

1. Surface area to volume ratio

2. Concentration gradient

3. Temperature

Blood clotting

1.Platelets are exposed to cut in blood vessel so it releases serotonin and cause smooth muscles in blood vessel to contract.

2.Platelets release a protein Thromboplastin

3.Thromboplastin, activates a series of enzymes that... in the presence of Calcium ions and Vitamin K, convert the protein Prothrombin(insoluble/inactive) into the enzyme Thrombin(soluble/active).

4.Thrombin catalyses the conversion of soluble(inactive) fibrinogen into insoluble(active) fibrin

5.When many fibrin molecules stick together, a mesh is formed, which traps other platelets and red blood cells.

Thromboplastin is a...

Protein

Prothrombin is a...

inactive enzyme

Thrombin is an...

active Enzyme

Fibrinogen is...

soluble

Fibrin is...

insoluble

Athleresclorosis

1. Damage to endothelium by an irritant

2. Inflammatory response occurs

White blood cells/Macrophages move to the site of infection causing atheroma formation

3. Calcium salts, cholesterol and fibrous tissue builds up at the site, forming a hard plaque on the inner wall of the artery

What is the result of Athleresclorosis?

1. The artery loses some elasticity

2. Artery becomes narrower, which makes it more difficult to pump blood around the body

3. High blood pressure

Why does Atheresclorosis only occur in Arteries?

Arteries contain fast flowing blood under very high pressure, therefore there's high chance of damage to the artery wall

Why does Atheresclorosis not occur in veins?

There's much lower pressure in veins, compared to arteries, so less risk of damage

Explain how the structure of an artery is related to its function

1. smooth (endothelium) lining to reduce friction (between

wall and blood)

2. (thick) elastic wall to allow stretch and recoil

3. collagen layer to provide strength / withstand high blood pressure

4. (smooth) muscle in wall to enable artery to change its diameter

Antihypertives function

Reduce/lower high blood pressure

Examples of Antihypertives

1. Beta blockers

2. Diuretics

3. Vasodilators

Risks of Antihypertives

1. coughing

2. Fainting

3. Headaches

3. tiredness /fatigue

Function of Statins

To reduce LDL cholesterol levels in the blood

Risks of using Statins

1. Muscle and joint pain

2. Nausea

3. Digestive problems

Function of Anticoagulants

Reduce blood clot formation

Examples of Anticoagulants

Warfarin & Heparin

Function of platelet inhibitory drug...

Reduce formation of blood clots

Risks of Platelet inhibitory drugs

- Nausea

- Excessive bleeding in stomach

- Diarrohea

Structure Starch

Made up of Amylose & Amylopectin

Structure of Amylose

1. Long, coiled but unbranched chain with 1,4 glycosidic bonds

Structure of Amylopectin

Long, branched chain, with 1,4 and 1,6 glycosidic bonds

Distinguish between structure of saturated fatty acid and unsaturated fatty acid

- saturated fatty acid has no

carbon - carbon double bonds

whereas an unsaturated fatty

acid has at least one carboncarbon

double bond

- saturated fatty acid chains are straight

unsaturated fatty acid chains are not

straight

-ratio of H:C is higher in saturated fatty

acids than unsaturated fatty acids ;

Explain why the human heart is divided into a left side and a right side

1. idea that it keeps oxygenated and deoxygenated blood

separate ;

2. keeps { concentration / diffusion } gradient steep

3. idea that this results in sufficient oxygen being carried

to the {tissues / cells / eq } and CO2 removed from tissues

Explain how a gene mutation affects gas exchange in a person with CF

1. defective CFTR protein

2. chloride ions are not transported out of the cells / sodium ions move into cells ;

3. water does not move out (of cells) / water moves in to cells

4. mucus (on cell surface) { is not diluted / is thicker / is more

sticky } / eq ;

5. reduced rate of gas diffusion / reducing ventilation of alveoli

Explain why different fatty acids have different melting temperatures

1. idea that the greater the number of double bonds the lower

the melting temperature ;

2. (because) the fatty acid chain is more { bent / less linear

ACCEPT double bonds result in

kinks

3. fatty acids do not pack closely together;

4. weaker intermolecular forces

covalent bonds or carbon bonds

or pi bonds

5. less energy needed to separate fatty acid chain molecules

Social and Ethical issues of Genetic screening

- Risk of miscarriage

- false results can provide incorrect information

- Unethical to abort a fetus if it has a genetic disorder

Suggest how cholesterol affects membrane fluidity

1. Cholesterol binds to fatty acid tails of phospholipids

2. Pulling fatty acid tails together, which reduces movement of the phospholipids

Relative risk

The chance of an event occuring, in one group compared to the other group