Edexcel Biology GCSE - Cellular Respiration and Transport Part 2

A substance broken down by respiration to release energy.

A device used to measure how fast respiration happens in an animal

The volume of blood pumped from the heart with each beat.

The part of the circulatory system that includes the left side of the heart, the rest of the body apart from the lungs, and the blood vessels that connect them together.

Fluid which is derived from blood plasma that passes through the walls of capillaries.

The structure in veins that prevents the backflow of blood.

A blood vessel with valves that transports blood to the heart.

One of the two veins that carries deoxygenated blood to the heart from the body systems.

Breathing in and out.

The lower chamber of the heart that receives blood from the atrium and pumps it into arteries.

Blood transports materials and distributes heat around the body. It also helps to protect against disease.

Plasma is a straw-coloured liquid that makes up just over half the volume of blood. (55%)

Red blood cells Platelets white blood cells

Transporting dissolved carbon dioxide, digested food molecules, urea and hormones; distributing heat

Transporting oxygen

Ingesting pathogens and producing antibodies

Involved in blood clotting

Red blood cells (also called erythrocytes) transport the oxygen required for aerobic respiration in body cells.

They must be able to absorb oxygen in the lungs, pass through narrow blood capillaries, and release this oxygen to respiring cells.

They contain the proteinhaemoglobin, which gives them their red colour They have no nucleus so they can contain more haemoglobin. They are small and flexible so that they can fit through narrow blood capillaries. They have a biconcave shape - they are the shape of a disc that is curved inwards on both sides - to maximise their surface area for oxygen absorption. They are thin, so there is only a short distance for the oxygen to diffuse to reach the centre of the cell.

Haemoglobin can combine reversibly with oxygen. This is important - it means that it can combine with oxygen as blood passes through the lungs, and release the oxygen when it reaches the cells.

phagocytes | - lymphocytes

About 70 per cent of white blood cells are phagocytes. Phagocytes engulf and destroy unwanted microorganisms that enter the blood, by the process of phagocytosis.

Lymphocytes make up about 25 per cent of white blood cells. Lymphocytes produce soluble proteins called antibodies when a foreign body such as a microorganism enters the body.

they bind to pathogens and damage or destroy them they coat pathogens, clumping them together so that they are easily ingested by phagocytes they bind to the pathogens and release chemical signals to attract more phagocytes