Unit 3

Question 1

What is the role of the phloem?

Answer 1

Carries the products of photosynthesis to other parts of the plant.

Question 2

What are the features and adaptations in an insect-pollinated flower?

Answer 2

-Large, brightly colored petals to attract insects
-Large sticky pollen grains to stick in the insects’ bodies
-Contain nectar as a ‘reward’ for insects

Question 3

What is phototropism?

Answer 3

The growth of a plant in response to the direction of light.

Question 4

Where are ova produced in the flowers?

Answer 4

In the ovules in the ovaries.

Question 5

What are the 2 types of cells found in the mesophyll layer?

Answer 5

spongy and palisade cells.

Question 6

what is geotropism?

Answer 6

The growth of a plant in response to the direction of gravity.

Question 7

How does a pollen grain reach an ovum so fertilisation can take place?

Answer 7

1) Pollen grains from another flower land on the stigma
2) The pollen grain grows a pollen tube down the style into the ovary
3) The tip of the tube dissolves to allow the pollen grain to move out of the tube and into the ovule to fertilise

Question 8

What are the 4 factors that affect transpiration?

Answer 8

-Light intensity (increase)
-temperature (increase)
-Humidity (decrease)
-Wind speed (increase)

Question 9

Which layer forms them main gas exchange surface of the leaf?

Answer 9

Spongy mesophyll layer.

Question 10

How do you test for starch in leaves?

Answer 10

1) Place leaf in boiling water for 30 sec to dewax it
2) Place leaf in boiling ethanol to remove chlorophyll (Bunsen burner off)
3) Wash leaf with cold water and place it on a tile
4) Add a few drops of iodine to the leaf
5) Any parts of the leaf that contain starch will turn blue-black

Question 11

What does turgid mean?

Answer 11

When a plant cell has a high internal pressure, which makes to cytoplasm push against the cell wall.

Question 12

What is the response of the roots to gravity?

Answer 12

Positive geotropism

Question 13

What are the male and female gametes for plants

Answer 13

pollen grains and ova

Question 14

What is the role of the xylem?

Answer 14

Supplies the leaf with water and mineral ions.

Question 15

What is the response of shoots to light?

Answer 15

Positive phototropism

Question 16

What are the features and adaptations in an wind-pollinated flower?

Answer 16

-Small, not brightly colored petals
-Small, smooth grains to be carried in the wind
-Feathery stigma to catch pollen grains in the wind

Question 17

Why is turgor important for plants?

Answer 17

So neighboring cells that have lower water potential can absorb water due to osmosis. This happens to many cells so that water can move across a plant tissue.

Question 18

Where are pollen grains produced in the flowers?

Answer 18

In the anthers of the stamens.

Question 19

What is the role of the cuticle in the upper and lower epidermis?

Answer 19

Reduces water loss by evaporation and acts as a barrier against microorganisms.

Question 20

What are the conditions required for germination?

Answer 20

-Warm temperatures, so that enzymes can work efficiently
-Water, for chemical reactions to take place
-Oxygen, for respiration

Question 21

Why is the upper epidermis transparent?

Answer 21

To allow light to pass through to the chloroplasts in the palisade layer.