Topic 1

A level Biology Edexcel A (SNAB)- Topic 1

Solvent

Substances dissolve in it e.g. water+++

dipolar

Having a slightly positive charge and negative charge

Cohesive

They tend to stick together

Cohesion

Attraction between molecules of the same type

Which side of the heart carries oxygenated blood?

left

Why is the left side of the heart thicker?

Because it carries oxygenated blood

Where does blood from the vena cava go to?

Right atrium

Where does blood from the pulmonary vein go to?

Left atrium

Why does the heart have coronary arteries on the surface?

It needs it's own supply of oxygen to pump the blood around the body

What is the valve between the atrium and ventricle?

Atrioventricular valves

What is the valve between the right ventricle and the pulmonary artery?

Semi lunar valve

What is the valve between the left ventricle and aorta?

Semi lunar valve

What do valves do?

Stop the back flow of blood

What are the three blood vessels?

Arteries, veins and capillaries

What do the arteries do?

Carry blood from the heart to the rest of the body

What are features of the artery?

Thick muscle wall, lots elastic fibres, small lumen

What are the features for in an artery

To withstand the high pressure of the blood, to be able to stretch and recoil

What do veins do?

Take blood back to the heart

What are features of veins?

Large lumen, thin muscle wall, little elastic tissue

Why do veins have different features to arteries?

Veins are different because the blood that goes to them are under lower pressure.

what is atheroma?

it is a fatty deposit that makes the lumen get smaller.

How does atherosclerosis occur?

1)there is damage to the endothelial wall

2)this triggers an inflammatory response

3)white blood cells accumulate with chemicals in the blood

4)WBC enlarge with cholesterol and form a atheroma

5)this stretches the artery making it lose elasticity

6)calcium deposits and fibrous tissue build up forming plaque

7)lumen size reduces, higher chance of damage

what does atheroma do?

it produces postive feedback of the lumen getting smaller ad there being a higher chance of damage to the arteries.

Explain the process of blood clotting

• Damaged blood cell releases thromboplastin

• + Ca ions coverts prothrombin to thrombin

• Thrombin catalyses fibrinogen to fibrin (insoluble)

• Fibrin mesh traps RBCs and platelets= clot

what is fibrin used for?

create the mesh that traps red blood cells.

explain the link between atherosclerosis and blood clotting

Atherosclerosis will make the lumen smaller so the chance of blood clotting is increased due to the fatty deposits.

what are the lifestyle factors that affect CVD?

Diet, high blood pressure, smoking and inactivity

explain diet in terms of affecting CVD

High saturated at diet increases blood cholesterol and atheroma formation.

explain high blood pressure in terms of affecting CVD

This increases the risk to the damage of the arterial wall

how does smoking affect CVD?

- CO reduces amount of O2 in the blood so not enough o2 can get to tissue > stroke

- nicotin makes platelets sticky

how does inactivity affect CVD?

This increases blood pressure

what a factors that are beyond control in terms of CVD?

Genetics, age and gender

What are antihypertensives?

drugs that reduce blood pressure

what are benefits of antihypertensives?

- They can be given in combination to reduce blood pressure as they work in different ways

- Blood pressure can be monitored at the home so the patient can see if the drugs are working

what are risks of hypertensives?

Could cause fainting, headaches, drowsiness

What are statins?

They are drugs which lower the amount of 'bad' cholestrol in blood.

benefits of statins

Reduce the risk of developing CVD

Risks of statins

Could cause muscle and joint pain, nosebleeds, headaches and nausea

What are anticoagulants?

Drugs that reduce the ability of the blood to clot

Benefits of anticoagulants

prevent any existing blood clots from getting larger

Risks of anticoagulants

excessive bleeding, fainting, swelling

what are platelet inhibitory drugs?

drugs that reduce the formation of blood clots.

Benefits of platelet inhibitory drugs

can be used to treat someone already with CVD or blood clots.

Risks of platelet inhibitory drugs

Rashes, diarrhoea, excessive bleeding

What is a monosaccharide?

a single sugar unit

what are examples of monosaccharides?

glucose, fructose, galactose

What is a diasaccharide?

a two single sugar unit

what is the bond between a diasaccharide

glycosidic bond

what are examples of diasaccharides

maltose, lactose and sucrose

What is maltose made of?

glucose and glucose

What is lactose made of?

glucose and galactose

What is sucrose made of?

glucose and fructose

what reaction occurs in the formation of a diasaccharide

condensation reaction

how do you break two sugar units

using hydrolysis

What is hydrolysis?

breaking using water

What is a polysaccharide?

polymers of monosaccharides

what are examples of polysaccharides found in food

glycogen in animals and starch and cellulose in plants

what are examples of starch?

amylose and amylopectin

Does amylose or amylopectin have branches?

amylopectin

why is glycogen are source of energy

as it is branched, when it is broken down energy can be released from multiple places on it

What is a triglyceride?

fat

What is a triglyceride made of?

glycerol and 3 fatty acids

what are the fatty acid tails made from?

hyrdocarbons

How is a triglyceride formed?

~ By a condensation reaction between fatty acids and a glycerol

~ Ester bond is formed and a molecule of water is removed

How is a triglyceride broken?

By hydrolysis reactions

what are the two types of lipids?

saturated and unsaturated

saturated lipids

DONT have a double bond between the carbons atoms in their hydrocarbon tail

unsaturated lipids

DO have a double bond between carbon atoms in their hydrocarbon tail

what lipid increases the risk of CVD?

saturated

what is a type of lipid made in the body?

cholesterol

What are lipoproteins?

any kind of fat transporter e.g. LDL, HDL

What is HDL cholesterol?

good cholesterol that is made of mainly protein

what is the function of HDL?

to reduce total blood cholesterol when the level is too high

What is LDL cholesterol?

bad cholesterol that is made from mainly lipid

what is the function of LDL?

to increase the total blood cholesterol when the level is too low

what are twp types of obesity indicators?

waist-to-hip ratio and BMI

What is the BMI formula?

weight (kg) / height (m^2)

What is the waist to hip ratio?

waist circumference / hip circumference

what can stopping smoking do?

reduce the risk of CVD based on scientific research

what can frequent exercise do?

reduce the risk of CVD based on scientific research

what are the consequences of energy imbalance?

weight loss, weight gain and development of obesity

what happens when their is weight gain?

the energy intake is higher than the energy output which could lead to a person becoming obese

what happens when their is weight loss?

the energy intake is lower than the energy output which could lead to a person being underweight

why is a supply of energy needed?

so that organisms can grow. move, reproduce etc

what is energy budget

the amount of energy taken in and used up by an organism

what are the different circulatory systems?

open, single closed and double closed

What do open circulatory systems allow?

substances to diffuse between blood and cells, mass flow of nutrients to cells

what do closed circulatory systems allow?

the blood system to be more efficient at delivering substances around the body.

Single closed circulatory system

Arteries, capillaries and veins surrounding organs and all cell have an equal chance for food.

Double closed circulatory system

mass transport of either oxygenated blood of deoxygenated blood depending on what side.

Limitations of open CS

- struggle to control the velocity of blood

- struggle to vary amount of oxygen they take in

limitations of closed single

-Blood flow is rare

-blood pressure is lower so there is a slower rate of flow

limitations of closed double

-high blood pressure

-more complex so their is a higher chance of errors occuring

What is a cardiac cycle

a sequence of contraction and relaxation of the atrium and ventricle

What is systole?

Contraction

What is diastole?

relaxation

What is atrial systole?

contraction of the atria

what valves are open in artial systole

atrioventricular valves

what is ventricular systole?

ventricular contraction

what happens in atrial systole?

the pressure increase whilst the volume decrease