Biology Additional Science Topic 2 Notes

What is respiration?

A process used by all living organisms that release the energy in organic molecules.

How does the human circulatory system facilitate respiration? 

The circulatory system

Blood carries oxygen and nutrients to the body's cells,and waste products away from them. The circulatory system consists of:

• The heart, which is the muscular pump that keeps the blood moving
• The arteries, which carry blood away from the heart
• The veins, which return blood to the heart
• The capillaries, which are tiny blood vessels that are close to the body's cells

The diagram outlines the circulatory system. Oxygenated blood is shown in red, and deoxygenated blood in blue. A process called diffusion takes place in the capillaries. Diffusion is where particles of a high concentration move to an area of low concentration. Glucose and oxygen diffuse into the cells from the capillaries. Carbon dioxide diffuses out of the cells into the blood in the capillaries.

What is diffusion? 

Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration. Particles are always moving and net movement is the sum of the movement of all particles.

Aerobic Respiration:

Aerobic respiration uses oxygen from the air to release energy from glucose. This energy obtained is used by the working muscle cells in the process of exercise.

The reactions of aerbic respiration can be shown using a word equation:

glucose + oxygen --> carbon dioxide + water + energy

The effect of exercise on breathing rate and heart rate:

When you exercise, your heart rate and breathing rate increase. The harder you exercusem the more these rates increase.

Heart rate can be measured by taking your pulse at the wrist. It is usually measured as number of beats per minute.

Breathing rate is measured by counting the number of breaths in one minute.

Explanation of why this happens:

During exercise, muscle cells are respiring faster. This means that they need more oxygen and glucose, and release more carbon dioxide:

A faster heart rate means that blood is pumped faster around the body. The blood takes oxygen and glucose to the cells faster and removes carbon dioxide faster.

A faster breathing rate means that oxygen can be taken into the body at a faster rate to allow respiration to occur and carbon dioxide can be released faster to produce energy.

The equation to calculate cardiac output: 

cardiac output = stroke volume x heart rate

Reasons for why the body has to use anaerobic respiration during exercise:

During hard exercise, the oxygen supply may not be enough for the needs of the muscle cells. When this happens, anaerobic respiration takes place, as well as aerobic respiration.

Anaerobic respiration: 

Anaerobic respiration is the release of energy from glucose without using oxygen. This produces lactic acid. Much less energy is released by anaerobic respiration than by aerobic respiration. The lactic acid that forms causes muscle fatigue and pain.

Anaerobic respiration can be shown using a word equation:

glucose -->…