W. McConnell 2004 Kinross High School THE WORLD OF PLANTS (C) Making Food.

W. McConnell 2004 Kinross High School

THE WORLD OF PLANTS

(C) Making Food


1.What is meant by photosynthesis?

The process by which green plants make food in the presence of light.


2. Complete the passage below

Photosynthesis takes place in the ………….…… of plant cells.

The ………………. gives the plant its green colour. It traps …….… energy from the sun. Chlorophyll and light are essential for ………………….…. The energy from the sun is used to make the raw materials ………………………… (from the air) and ………… (from the soil) combine. The products from this combination are ………… and …………

chloroplasts

photosynthesis

light

chlorophyll

water

carbon dioxide

oxygen

glucose


3.What conclusion would you come to if only the green areas in a variegated leaf showed the presence of starch?

Chlorophyll is necessary for photosynthesis


4.During photosynthesis carbon dioxide is taken in by plants and converted into a simple carbohydrate [glucose]. How is this carbohydrate then used by the plant?

•Stored as starch

•Used immediately for energy

•Used as building material (cellulose)


5.What is meant by the term ’dry mass’?

The weight of the plant tissue when all the water has been removed.


6. When using the bubbler apparatus, what tells you how fast the plant is photosynthesising?

The number of bubbles of oxygen produced every minute.


7. When using the bubbler apparatus, what are each of the following pieces of equipment used for?

Apparatus What it is used for

lamp

ruler

water at 20oC

source of lightto vary distance of light from apparatusoptimum temp for photosynthesis


8. A typical set of results from a bubbler experiment at 20oC are shown below.light intensity number of bubbles in 3 minutes

10 0

20 6

30 15

40 26

50 35

60 38

70 38

Why does the rate of photosynthesis level off after a while even although the light is getting brighter?

CO2 is the limiting factor – it has run out of CO2

to make the reaction go any faster.


9.Name the 4 things which a plant needs to photosynthesise.

•Light

•Water

•Chlorophyll

•Carbon dioxide


10.If the graph below shows the results of increasing the temperature of elodea in a bubbler apparatus at 20oC what is the limiting factor?

Temp (oC)

Number of bubbles per minute

0

2

4

6

8

10

12

14

16

18

20

0 5 10 15 20 25 30

Light or carbon dioxide


11.What does the enzyme starch phosphorylase do in leaf cells?

Converts excess glucose into starch to be stored in the leaf ?


12.Below is a cross section of a leaf. Identify the xylem and phloem cells.

Xylem

Phloem


13.What is the function of the phloem vessels?

What is the function of the xylem vessels?

To carry the glucose made in the leaves to other parts of the plant.

To carry water and minerals from the soil to the leaves for photosynthesis.


14.Xylem and phloem are together called vascular bundles. Apart from transport, what is the function of vascular bundles?

Support


15.Which cells in the vascular bundles are formed from columns of dead cells whose walls have been impregnated with a woody waterproof substance ?

Name the woody waterproof substance.

Xylem

Lignin


16.

Companion cells

Sieve tubes

Name the 2 different types of cell found with the phloem tubes.


17.

Tiny pores found on the under surface of a leaf.

What are stomata?

When are the stomata open? Open during the day

Closed during darkness


18.Name the process by which water vapour passes out of the stomata to cool the plant.

Transpiration


19. A leaf has a large surface area so that:

A leaf is thin so that :

It increases the area for maximum light absorption

gases can diffuse quickly to and from the cells


20. Type of cell in

leafFunction

Cells found on either side of stomata. They control the size of the stomata.

Guard cells

Palisade mesophyll cells

Top layer of cells. Contain most chloroplasts.

Small holes which can open or close to let air in or out.

Stomata


21.

Carbon dioxide

Which gas does a plant take in through its leaves?


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W. McConnell 2004 Kinross High School THE WORLD OF PLANTS (C) Making Food.

Documents

kinross high school

photosynthesis slide

food slide

darkness slide

support slide

transpiration slide

xylem phloem slide

plant cells