Plants

Question 1

Give examples of plant organs?

Answer 1

stems, rooted and leaves

Question 2

What are the 5 tissues in a plant?

Answer 2

• epiderma
• palisade mesophyll
• spongy mesophyll
• xylem and phloem
• meristem

Question 3

What does the epidermal tissue do?

Answer 3

covers the whole plant

Question 4

What does the palisade mesophyll tissue do?

Answer 4

part of leaf where most photosynthesis happens

Question 5

What dies the spongy mesophyll tissue do?

Answer 5

contains big air spaces to allow gases to diffuse in and out of cells

Question 6

What does the xylem and phloem do?

Answer 6

transport things like water, mineral ion and food around the plant

Question 7

What is the meristem tissue?

Answer 7

found in growing tips of shoots and roots and is able to differentiate into different types of plant cells allowing the plant to grow

Question 8

What are the four tissues in a plant?

Answer 8

epidermal, mesophyll, xylem, phloem

Question 9

structure of a plant from top to bottom?

Answer 9

• waxy cuticle
• epidermal tissue
• palisade mesophyll tissue
• spongy mesophyll
• epidermal tissue
• stomata

Question 10

How is the epidermal tissue related to its function?

Answer 10

covered with waxy cuticle, reduces water loss by evaporation

Question 11

How is the upper epidermis related to its function?

Answer 11

transparent so light can pass through to the palisade layer

Question 12

How is the palisade layer related to its function?

Answer 12

lots of chloroplasts, near the top so can get lots of light

Question 13

How are the xylem and phloem related to their function?

Answer 13

network of vascular bundles which deliver water and other nutrients to the entire leaf and take away glucose produced in photosynthesis

Question 14

How are some tissues adapted for efficient gas exchange?

Answer 14

• lower epidermis has stomate which let C02 diffuse directly into the leaf
• air spaces in spongy mesophyll tissue increase rate of diffusion of gases

Question 15

What do the phloem do?

Answer 15

transport food substances ( mainly dissolved sugars) made in the leaves to the rest of the plant for immediate use or storage

Question 16

What direction fo the phloem flow?

Answer 16

both directions

Question 17

What is the process which takes place in the ploem?

Answer 17

translocation

Question 18

What do the phloem tubes look like?

Answer 18

columns of elongated living cells with small pores in the end walls to allow cell sap to flow through

Question 19

What do the xylem do?

Answer 19

carry water and mineral ions from the roots to the stem and leaves

Question 20

What direction of the xylem?

Answer 20

up

Question 21

What do the xylem look like?

Answer 21

dead cells joined end to end with no end walls between them and a hole down the middle - strengthened with lignin

Question 22

What is the process which takes place in the xylem?

Answer 22

transpiration stream

Question 23

What is transpiration?

Answer 23

loss of water from the plant

Question 24

What is transpiration caused by?

Answer 24

evaporation and diffusion of water from a plants surface

Question 25

Where does most transpiration happen?

Answer 25

leaves

Question 26

explain the transpiration stream?

Answer 26

• evaporation creates slight shortage of water in leaf so more water is drawn up from the rest of the plant through the xylem vessels to replace it
• means more water is drawn up from the roots and so there is a constant transpiration stream of water through a plant

Question 27

What is transpiration a side effect of?

Answer 27

the way leaves are adapted for photosynthesis

Question 28

What is transpiration rate effected by?

Answer 28

• light intensity
• temperature
• air flow
• humidity

Question 29

How does light intensity effect transpiration rate?

Answer 29

brighter the light, greater transpiration rate

stomate begin to close as it gets darker

Question 30

How does temperature effect transpiration rate?

Answer 30

warmer it is, faster transpiration rate

Question 31

How does airflow effect transpiration rate?

Answer 31

better air flow, greater transpiration rate

If air flow is bad, water vapour sits around leaf and doesnt move around. high concentration of water particles inside and outside leaf so diffusion doesnt happen as quickly. If high air flow, water vapour is swept away maintaining a low concentration of water in air outside leaf and then diffusion happens quickly

Question 32

How does humidity effect transpiration rate?

Answer 32

• drier the air, faster transpiration

need a high concentration gradient

Question 33

How can you estimate rate of transpiration?

Answer 33

measuring uptake of water from plant - measuring distance bubble moved

Question 34

What are guard cells adapted to do?

Answer 34

open and close stomata

Question 35

What happens when the guard cells have lots of water?

Answer 35

guard cells fill with water and go plump and turgid making the stomata open so gases can be exchanged for photosynthesis

Question 36

What happens when a plant is short of water?

Answer 36

guard cells loose water and become flaccid making the stomata close helping to stop water vapour from escaping

Question 37

What are guard cells also sensitive to?

Answer 37

light at night - close to save water

Question 38

Where do you find most stomata?

Answer 38

undersides of leaves as its cooler and shaded so less water lost

Question 39

What have guard cells adapted for?

Answer 39

gas exchange and controlling water loss in leaf