Chapter Three - Living The Life

Question 1

What’s the difference between respiration and the respiratory system?

Answer 1

Respiration is the process that releases chemical energy in living cells. The cells in your body use oxygen to carry out respiration. The respiratory system is responsible for getting this oxygen from the air you breathe into your body.

Question 2

Organisms that are larger than a few millimetres wide have two more life processes, what are they? (MRS CG GREN is a good reminder)

Answer 2

C is for circulation - Living things move move nutrients, gases and wastes around their body
Tiny organisms don’t need a transport system because nutrients and gases can reach each part of the organism through their ‘skin’. If something is small enough, everything inside is close to the surface.
Circulation is an essential life process in larger organisms because the need to transport nutrients and gases to all areas of the body. A transport system is not essential for all living organisms.

G is for gas exchange - most living things need to take oxygen from their environment and release carbon dioxide back into the environment through respiration.
Some organism, such as bacteria and fungi, don’t need oxygen for respiration - this is why gas exchange in not on the life process list.

Question 3

What is energy?

Answer 3

All life processes need energy. Energy is not a substance, but it makes things happen. It can only be detected when it changes from one form to another.

Question 4

Energy is used to power your body, you get energy from food. Ow does your body use that energy?

Answer 4

Energy is used to:

• keep warm
• move muscles
• fight germs
• make chemicals
• keep impulses moving through your brain and nerves
• produce new cells for growth and repair
• Keep blood circulating throughout your body

Question 5

How is energy released from food?

Answer 5

In the human body, a series of reactions in cells cause a mixture of glucose and oxygen to release energy. The process involved in releasing energy is respiration. Most of the time your body carries out aerobic respiration, which uses oxygen. Aerobic respiration occurs inside mitochondria, inside cells. Glucose and oxygen react and release energy inside the mitochondria. Glucose and oxygen go into the cell and carbon dioxide go out. Aerobic respiration only takes place when there is enough oxygen in the body. If oxygen is in short supply anaerobic respiration (respiration without oxygen) takes place. This produces less energy than aerobic respiration and quickly causes a build-up of lactic acid.

Question 6

What is the mitochondria?

Answer 6

Mitochondria are known as the powerhouses of the cell. They are organelles that act like a digestive system which takes in nutrients, breaks them down, and creates energy rich molecules for the cell. The biochemical processes of the cell are known as cellular respiration.

Question 7

What happens when you don’t get oxygen?

Answer 7

If your body does not get enough oxygen for more than a few minutes your brain cells will start to die. This is why checking a patients abc’s ave vital.

Question 8

How the human body works?

Answer 8

The human body works with the help of certain processes. These are called life processes because they are commonly seen in living organisms.

Question 9

What do life processes require?

Answer 9

Energy.

Question 10

Where does energy come from for the human body?

Answer 10

Energy comes from the food you eat. It is release during respiration. Respiration happens inside body cells and, in humans, requires oxygen.

Question 11

What are the main life processes? (Often remembered by using MRS GREN)

Answer 11

1. Movement
   Both animals and plants have the ability to move. Plants are rooted and move slowly as they grow. Their roots move down into the soil and their stems move up towards the light. Animals on the other hand move quickly and can move their entire bodies. They can move in search of food, shelter or to avoid danger.
2. Respiration
   Respiration is the process of extracting energy out of the food we eat. All living things respire because they need energy to grow, to replace worn out parts and to move. Respiration takes place in the mitochondria of the cell. There are two types of respiration, with and without oxygen. Aerobic respiration uses oxygen and releases a large amount of energy. Anaerobic respiration does not require oxygen and releases a smaller amount of oxygen.
3. Sensitivity
   All living organisms are sensitive, this means that they have an awareness of changes in their environment. Animals respond quickly to stimuli such as heat, light, sound, touch and chemicals which have taste and smell. On the other hand plants generally appear less sensitive and their response is slower. Plants respond to light by moving their leaves towards it, the flowers of some plants open in the morning and close at night when it is dark. Some plants, however, do respond quickly such as the Venus flytrap response to touch.
4. Growth
   All living organisms grow. Plants continue growing throughout their lives. Animals stop growing once they reach adulthood. Even when growth stops, materials within an animal’s body are still being replaced from its food.
5. Excretion
   All living things make waste products these can be useless or harmful to it and therefore need to be got rid of. Excretion is the process of getting rid of metabolic waste. Plants store waste substances in their leaves, the waste is removed when their leaves fall off. Animals breathe out waste carbon dioxide, other waste substances leave the body in urine and sweat. Note: Getting rid of faeces or undigested food is not excretion but egestion.
6. Reproduction
   All living things must produce offspring like themselves in order for their species to survive. This is the process known as reproduction. Plants produce seeds that give rise to new plants of the same species. Animals lay eggs or have babies. Reproduction can be of two types, Sexual which involves two parents and the union of two gametes and Asexual where one parent can reproduce itself.
7. Nutrition
   Nutrition is needed for energy and growth, both plants and animals need food. Plants are able to make their own food by photosynthesis. They use sunlight to turn simple molecules like carbon dioxide and water into more complex carbohydrate molecules. Animals are unable to make their own food so rely on other plants and other animals for their nutrition. Animals take in complex substances and break them down into small, simple, soluble molecules which can be used for energy and growth.