Photosynthesis Worksheet

Leaves

Plants produce their own food by a process called photosynthesis. The green colour we see in leaves is due to a pigment called chlorophyll. Chlorophyll combines water and a gas (carbon dioxide) using light to make sugar (glucose) and oxygen.

water + carbon dioxide + (light) → glucose + oxygen

Plants are sensitive to light because they need light to photosynthesise.

Which THREE of these observations best describes plants grown in the dark?

Flowers on long stalks

the stem is long

the leaves are brown

the stem is weak and cannot support the leaves

the leaves are pale green

the seed does not germinate

Sugars are produced in which plant cells?

root hairs

cells in the leaf

cells in the stem

carpel

Which part of the plant transports food to all other plant parts?

stamen

sepal

stem

seed

The green pigment in leaves is called...

carbon dioxide

chlorophyll

chlorine

chloroform

Variegated leaf

This is a variegated ivy leaf. The outside is green and the inside is pale yellow.

In which area would you expect sugar to be produced by photosynthesis?

inside

outside

Which gas does the plant combine with water to make sugars?

nitrogen

oxygen

carbon dioxide

chlorine

Which gas is produced as a waste product of photosynthesis?

oxygen

carbon dioxide

methane

hydrogen

What are missing in the equation for photosynthesis?

water

+

A

+

(light)

→

B

+

oxygen

Write your answer below.

	Answer
A
B

The Amazon rainforest is referred to as the 'lungs of the world'.

Which statement best describes this metaphor?

the trees produce a large proportion of the world's oxygen

the rainforest is the same shape as human lungs

the trees produce the largest proportion of the world's carbon dioxide

the trees work harder when the world needs more oxygen

Emily germinates some seeds in soil. She gives them water and warmth, but keeps them in a dark cupboard for several weeks.

From this list, predict what will happen to Emily's plants.

they will have yellow leaves

they will grow tall and weak

they will be healthy and strong

they will die

ANSWERS

Question 1

Plants are sensitive to light because they need light to photosynthesise.

Which THREE of these observations best describes plants grown in the dark?

Flowers on long stalks

CORRECT ANSWER

the stem is long
the stem is weak and cannot support the leaves
the leaves are pale green

EDDIE SAYS

Plants grow towards light and become weak and pale if they are deprived of this energy source.

ANSWERS

Question 2

Sugars are produced in which plant cells?

CORRECT ANSWER

cells in the leaf

EDDIE SAYS

The cells in the leaves are primarily responsible for sugar production. That's one reason that leaves are often broad and take up a lot of the total space occupied by a plant. The cells in many plant stems do contribute to this sugar production, but the bulk of it by far is the job of the leaves.

ANSWERS

Question 3

Which part of the plant transports food to all other plant parts?

CORRECT ANSWER

stem

EDDIE SAYS

The stem carries food around the plant and transports water and minerals from the roots to the leaves and flowers.

ANSWERS

Question 4

The green pigment in leaves is called...

CORRECT ANSWER

chlorophyll

EDDIE SAYS

Chlorophyll (pronounced CLAW-ROW-FILL) is truly one of the most important chemicals on planet Earth. It is single-handedly responsible for food production and oxygen production. I'd called that slightly important!

ANSWERS

Question 5

Variegated leaf

This is a variegated ivy leaf. The outside is green and the inside is pale yellow.

In which area would you expect sugar to be produced by photosynthesis?

CORRECT ANSWER

outside

EDDIE SAYS

The outside of the leaf contains chlorophyll, the pigment in which photosynthesis takes place.

ANSWERS

Question 6

Which gas does the plant combine with water to make sugars?

CORRECT ANSWER

carbon dioxide

EDDIE SAYS

Photosynthesis is amazing: a simple gas from the air plus water make food (sugar)! Carbon dioxide is that gas and all the carbon atoms in our food come from there. Maybe planting more trees might help to remove some of the carbon dioxide that is causing climate change....??

ANSWERS

Question 7

Which gas is produced as a waste product of photosynthesis?

CORRECT ANSWER

oxygen

EDDIE SAYS

IIt is wonderful that the WASTE from photosynthesis is a gas that sustains life! Life, as we know it, would not be possible without plants producing oxygen. Remember that plants also need oxygen to respire (release energy from sugars).

ANSWERS

Question 8

What are missing in the equation for photosynthesis?

water

+

A

+

(light)

→

B

+

oxygen

Write your answer below.

CORRECT ANSWER

	Answer
A
B

EDDIE SAYS

A is the gas carbon dioxide and B is the sugar glucose are missing.
Remember, light is also needed but as this is not a substance it doesn't go in the equation. Sometimes it is written above the arrow sign.

ANSWERS

Question 9

The Amazon rainforest is referred to as the 'lungs of the world'.

Which statement best describes this metaphor?

CORRECT ANSWER

the trees produce a large proportion of the world's oxygen

EDDIE SAYS

Because the Amazon covers a huge area of land (though sadly getting smaller daily because of human activity) oxygen produced by the trees travels all around the world! In addition, the tiny plant plankton living in the top layer of the world's oceans produce an enormous proportion of the world's oxygen.

ANSWERS

Question 10

Emily germinates some seeds in soil. She gives them water and warmth, but keeps them in a dark cupboard for several weeks.

From this list, predict what will happen to Emily's plants.

CORRECT ANSWER

they will die

EDDIE SAYS

Without light after germination, the seedlings will not be able to make food in their yellow leaves. Just like animals, without food, plants die. Some food is stored in the seed, but not enough to sustain the plant for very long - the leaves must begin to photosynthesise which, without light, they cannot do.