Edexcel A Level Biology Topic 1 Questions

What is the purpose of having a heart and circulation?

Moving substances around the body

Why do larger organisms need a mass transport system, not an open circulatory system?

Larger diffusion distances: slower transport of substances

Why is water a good transport medium? (3 things)

Dipole, solvent, thermal properties

What is meant by a dipole molecule?

One end is slightly positive and one end is slightly negative.

Why is the dipole nature of water important? (2 things)

Water is cohesive and flows. Good solvent

How is water a good solvent?

Ionic substances will be surrounded by water molecules due to dipole nature

Why are the thermal properties of water so important?

High specific heat capacity allows stability in organisms

Which blood vessels have narrow lumen?

Arteries and capillaries

Which blood vessels have wide lumen?

Veins

Which blood vessels have thicker walls?

Arteries

Which blood vessels have thinner walls?

Veins

Which blood vessels have more collagen, smooth muscle and elastic fibers?

Arteries

Which blood vessels have less collagen, smooth muscle and elastic fibers?

Veins

Which blood vessels have valves?

Veins

Which blood vessels don't have valves?

Arteries

How are capillaries adapted to their function?

permeable walls 1 cell thick, close to every cell

What are the 3 stages of the cardiac cycle?

atrial systole, ventricular systole, diastole

Features of atrial systole

-Atria contract, ventricles relax

-Atrioventricular valves open

-Blood pushed into ventricles

Features of ventricular systole

-Ventricles contract , atria relax

-Semilunar valves open

-Blood pushed into aorta and pulmonary artery

Features of cardiac diastole

-Atria and ventricles relaxed

-Blood returns to heart

-Atria and ventricles fill

features of the heart

-Four chambered, sends blood to the upper and lower body.

-double pump

Atherosclerosis

1- Endothelium damaged or dysfunctional

2-Inflammatory response

3-Calcium salts and fibrous tissues harden, forming plaque

4-Increased blood pressure, positive feedback

Clotting cascade process

1- Platelets and damaged tissue release thromboplastin

2- prothrombin to thrombin

3- thrombin catalyses fibrinogen to insoluble fibrin

4- Fibrin mesh traps platelets and red blood cells

Correlation definition

A change in one variable is reflected by a change in another

Causation definition

A change in one variable is responsible for a change in another

null hypothesis

a statement or idea that can be falsified, or proved wrong

Risks are OVERESTIMATED if:

-involuntary

-not natural

-dreaded

-unfamiliar

-unfair

-very small

Risks are UNDERESTIMATED if:

-Consequences occur in the long term

Cohort studies

Record exposures of a large group of unaffected people throughout time

Case-control study

Compares a group of people with a disease to a group of people without a disease

CVD risk factor: Genetics

-Some alleles increase risk of CVD

-Family history increases risk

CVD risk factor: Diet

-Too much salt increases BP

-Alcohol constricts arteries, increases BP

-Obesity increases risk

-High in sat fat and low in unsat fat increases risk

CVD risk: Blood Pressure

-High BP increases risk of damaging arteries

CVD risk: Smoking

-Lowers HDL

-Increased heart rate and BP

-Toxins damage artery lining

-Increases platelet stickiness

-More free radicals

CVD risk: Inactivity

-Exercise improves coronary circulation

-Increases HDL

-reduces cardiac output and increases heart rate, reducing elasticity of artery walls

What is an oedema?

Fluid build up in tissues causing swelling

How does an oedema form?

High pressure at arterial end of capillary forces lots of fluid into intercellular space.

What is a calorie?

the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius

How many calories are in a kilocalorie?

1000

How many joules are in a calorie?

4.184

What is the general formula of a carbohydrate?

Cx(H2O)n

What elements make up carbohydrates?

carbon, hydrogen, oxygen

What is the name for a long chain of sugar?

Saccharide

What is a monosaccharide?

simple sugar

What is a disaccharide?

two monosaccharides joined together

What is a polysaccharide?

many monosaccharides joined together

What bonds connect monosaccharides?

Glycosidic bonds

In what reactions are glycosidic bonds formed?

Condensation

What is glucose used for?

cellular respiration

What is the formula of glucose?

C6H12O6

Is glucose a monosaccharide, a disaccharide, or a polysaccharide?

monosaccharide

Where does fructose come from?

fruit, honey and some vegetables

What is a use of fructose?

Attracting animals to eat fruit, aiding seed dispersal

Is fructose a monosaccharide, disaccharide, or polysaccharide?

monosaccharide

Where does galactose come from?

lactose

What is the difference between glucose and galactose?

The OH groups on carbon 1 and carbon 4 are on the opposite sides

Is galactose a monosaccharide, disaccharide, or polysaccharide?

Monosaccharide

Where does maltose come from?

the breakdown of starch

What is maltose made of?

2 glucose

Where is maltose commonly found?

germinating seeds

Is maltose a monosaccharide, disaccharide, or polysaccharide?

disaccharide

What is sucrose used for?

Transporting sugar around plants

What is sucrose made of?

glucose and fructose

What type of glycosidic bond is in sucrose?

1,4 glycosidic bond

Is sucrose a monosaccharide, disaccharide, or polysaccharide?

Disaccharide

What is the function of starch?

energy storage in plants

What is starch made up of?

amylose and amylopectin

Is starch a monosaccharide, disaccharide, or polysaccharide?

polysaccharide

What glycosidic bonds does amylose have?

1,4

What glycosidic bonds does amylopectin have?

1,4 and 1,6