Chapter 3: The Energy Of Life

Question 1

Metabolism

Answer 1

Together, all of the chemical reactions that place in the cells of organisms are known as metabolism

Question 2

Enzymes

Answer 2

An enzyme is a bilogical catalyst that speeds up the chemical reactions in cells.

Question 3

Substrate

Answer 3

The substances an enzyme acts on is called a substrate

Question 4

Produce

Answer 4

The enzyme acts on the substrate and changes it into a product

Question 5

Homeostasis

Answer 5

Enzymes are sensitive changes in their environment, and if it changes. It may stop working. A homeostasis makes the condition stay the same

Question 6

Homeostasis examples

Answer 6

On a hot day we sweat to remove heat from the skin.

On a cold day we shiver and these small movements creath warmth

Question 7

Photosynthesis

Answer 7

The way plants make their food is calles photosynthesis

Question 8

Producers

Answer 8

Organisms that can make their own food

Question 9

Reactants needed for photosynthesis

Answer 9

1. Carbon dioxide, comes from the air. It enters the plant through small openings in the leaves called stomata
2. Water, comes from the soil. It enters through the plants roots
3. Chlorophyll, is the green pigment found in the chloroplastof plant cells. It absorbs light energy and changes it into chemical energy.
4. Sunlight, is the energy absorbed by the leaves

Question 10

Products of photosynthesis

Answer 10

1. Glucose, is the food made by the plant. It can be used to provide energy for the plant. Many plants store excess glucose in the form of starch.
2. Oxygen can be used to provide energy for the plant. It is released into the air through stomata. The oxygen released by photosynthesis is important as it then becomes available to all other plants and animals for respiration

Question 11

Photosynthesis

Answer 11

Photo means ‘light’ and synthesis means ‘to make with’. Together, photosynthesis means ‘to make with light’.

Question 12

Respiration

Answer 12

The release of energy from food

Question 13

Consumers

Answer 13

Organisms that must eat food because they cannot make their own are called consumers.

Question 14

Reactants of repiration

Answer 14

1. Oxygen is needed by most living things for respiration. This is called aerobic respiration.
2. Glucose releases energy. This energy is changed into other forms - kinetic energy when you run, sound energy when you talk, or stored as chemical energy in the form of fat if a person consumes more energy than they need.

Question 15

Products of Respiration

Answer 15

1. Carbon dioxide is a waste product of respiration. It passes out of the body through the lungs.
2. Water is also a waste product of respiration.
   Note that some of the energy prodcued by respiration will be ‘lost’ as heat.

Question 16

Respiration in Cells

Answer 16

Respiration takes place inside most plant and animal cells.
Mitochondria are tiny organelles in the cytoplasm. Respiration reactions take place in the mitochondria of cells.
Enzymes carefully control these reactions.