Biology knowledge topic 1 lifestyle, health and risk

What are the 4 components in blood and what do they each do?

Red blood cells-carry and transport oxygen around the body by bonding with the haemoglobin.

White blood cells-defend the body against pathogens as part of the immune system.

Platelets-Mediate blood clotting to prevent blood loss and seal wounds.

Plasma-Act as the liquid transport medium that carries cells, dissolved nutrients, hormones, and waste.

Why is water a good solvent?

Water molecules from a layer around the ions and break the ionic substance apart through hydrogen bonds.

What does hydrophilic and hydrophobic mean?

Hydrophilic-water loving

Hydrophobic-water hating

What is the definition of specific heat capacity?

The amount of energy needed to raise the temperature of 1cm3 by 1 degree celsius.

What is cohesion and adhesion?

Cohesion-the attraction between water molecules.

Adhesion-the attraction between water molecules and other molecules.

What is mass flow?

Movement of fluids down a pressure gradient from an area of high pressure to low pressure.

Why do organisms require a mass transport system?

Larger animals have a smaller surface area to volume ratio and a higher metabolic rate. Diffusion alone is insufficient to supply all cells with in the substances they need.

Describe the function of the heart's major blood vessels

Vena cava= brings oxygenated blood from the body to the heart.

Pulmonary artery= takes blood from the heart to the lungs.

Pulmonary vein= brings oxygenated blood from the lungs to the heart

Aorta= takes blood from the heart around the body.

Relate the structure of arteries to their function.

Thick muscular walls to handle high pressure without tearing. Elastic tissue allows recoil. Narrow lumen to maintain pressure

Relate the structure of veins to their function.

Thin walls due to low pressure. Require values to ensure blood doesn't flow backwards. Have less muscular and elastic tissue as they don't have to control blood flow,

Relate the structure of capillaries to their function

Walls only one cell thick for a short diffusion pathway. Very narrow so that permeate tissues and red blood cells can lie flat against the wall, effectively delivering oxygen to tissues

Describe what happens during cardiac diastole

The heart is relaxed. Blood enters the atria, increasing the pressure and pushing open the atrioventricular valves. This allows blood to flow into the ventricles. Pressure in the heart is lower than in the arteries, so semilunar valves remain closed.

Describe what happens during atrial systole.

The atria contracts, pushing any remaining blood into the ventricles.

Describe what happens during ventricular systole.

The ventricle contracts. The pressure increases, closing the atrioventricular valves to prevent back flow, and opening the semilunar valves. Blood flows into the arteries.

Differentiate between correlation and causation

Correlation= Where a change in one variable occurs at the same time as a change in another variable.

Causation= Where a change in one variable causes a change in another variable

Give features of a good scientific study.

• Representative sample.

• Clear aim or hypothesis.

• Valid and reliable results.

• Controlled variables.

Give an ethical issue surrounding the use of invertebrates in research.

Some consider it wrong to harm other living organisms however some argue that they are not complex organisms so shouldn’t suffer with pain.

Definition for metabolism.

The total of all chemical reactions that take place within the cells of a living organism.