Photosynthesis:

Question 1

What is the Word Equation for Photosynthesis?

Answer 1

carbon dioxide + water -> glucose + oxygen.

Question 2

How do plants take in Carbon Dioxide and Water?

Answer 2

carbon dioxide: this diffuses from the air into the plant through the stomata.

water - from the soil, through the root hair cells of the roots by osmosis.

Question 3

Where does photosynthesis take place?

Answer 3

Photosynthesis takes place inside the plant’s chloroplasts. This means that photosynthesis mainly occurs in the leaf, but a small amount happens in the green stem.

Question 4

Why are leaves and stems green?

Answer 4

They contain the pigment chlorophyll inside their chloroplasts.

Question 5

How does Photosynthesis work?

Answer 5

Light transfers energy from the Sun to chlorophyll, where carbon dioxide and water react to make glucose.
Glucose stores energy within its chemical bonds.

Question 6

State, and describe, the stages of photosynthesis.

Answer 6

The series of photosynthesis reactions are divided into two main stages:
• Stage 1 (light dependent) - energy transferred from light splits water molecules into oxygen gas and hydrogen ions.
• Stage 2 (light independent) - carbon dioxide gas combines with the hydrogen ions to make glucose.

Question 7

Is Photosynthesis exothermic or endothermic?

Answer 7

Photosynthesis is an example of an endothermic reaction. This means that energy must be transferred from the surroundings to keep it going

Question 8

What is Glucose used for?

Answer 8

• The plant uses some of the glucose it makes immediately in respiration.
• Other glucose molecules are converted into other sugar molecules, such as fructose, which is found in high quantities in fruit, and sucrose (table sugar’), which is made up of one molecule each of glucose and fructose and is found in high quantities in stems, such as in sugar cane, as it is the form in which glucose is transported around the plant’s tissues.
• Glucose that is not needed straight away is converted to starch. This provides a store of energy and can be used at night for respiration when the plant is not photosynthesising.

Question 9

List the usage of the substances plants are made up of.

Answer 9

cellulose:
to form cell walls.

starch:
food store.

proteins and nitrogen:
for growth and repair.

sucrose:
stored in fruit.

glucose:
used in respiration.

fats and oils:
food store and growth.

Question 10

What is the Chemical Equation for
Photosynthesis?

Answer 10

6CO2 + 6H2O -> C6H12O6 + 6O2