Photosyntheis

Question 1

Where does photosynthesis take place

Answer 1

In the chlorophyll in chloroplasts

Question 2

What does chlorophyll do

Answer 2

Absorbs light

Question 3

What is the word equation for photosynthesis

Answer 3

Carbon dioxide + water = glucose + oxygen

Question 4

What is the symbol equation for photosynthesis

Answer 4

6Co2 + 6H2O=C6H12O6 + 6O2

Question 5

What type of reaction is photosynthesis

Answer 5

Endothermic reaction

Question 6

Define endothermic reaction

Answer 6

Where energy is transferred from the environment to chloroplasts by light

Question 7

What is the first reason why plants want glucose

Answer 7

For cellular respiration

Question 8

What does cellular respiration do

Answer 8

It breaks glucose apart to release energy

Question 9

What is the second reason plants want glucose

Answer 9

To make cellulose

Question 10

What is cellulose and how is it made

Answer 10

Its a complex carbohydrate that strengthens cell walls and its made by glucose molecules combining together

Question 11

What is the 3rd reason plants want glucose

Answer 11

To make starch

Question 12

How does starch help plants

Answer 12

It breaks down into glucose when there is less photosynthesis (e.g winter) and it is used as long term storage

Question 13

What is the 4th reason for why plants need glucose

Answer 13

To make amino acids

Question 14

How are amino acids made in plants

Answer 14

By combining glucose and nitrate ions (from soil)

Question 15

Why do plants want to make amino acids

Answer 15

Because amino acids combine to make proteins

Question 16

What is the 5th reason why plants want glucose

Answer 16

To make oils and fats

Question 17

Why do plants want oils and fats

Answer 17

So they can be stored as a future energy source

Question 18

What are the 4 factors affecting the rate of photosynthesis

Answer 18

1. Light intensity
2. Temperature
3. Concentration of carbon dioxide in the air
4. Chlorophyll

Question 19

Where is the stomata in a plant

Answer 19

Scattered in the lower epidermis

Question 20

What happens in the lower epidermis

Answer 20

Co2 diffuses through the holes to then move up the leaf into the spongy mesophyll tissue

Question 21

Why does the spongy mesophyll tissue have lots of air gaps between the cells

Answer 21

So the gas can easily diffuse through the the next layer - paliside mesophyll layer

Question 22

What layer does the most photosynthesis happen and why

Answer 22

The palisade mesophyll layer because palisade cells are packed full of chloroplasts

Question 23

What does the upper epidermis layer do

Answer 23

Has transparent cells to allow sunlight to pass through to get to the chloroplasts in palisades beneath

Question 24

How are sugar molecules carried to the rest of the plant after photosynthesis

Answer 24

By the phloem

Question 25

What does the xylem do

Answer 25

Continually brings water up from the roots for the palisade cells to use in photosynthesis

Question 26

What adaptation does the leaf have to prevent water loss

Answer 26

A waxy cuticle on top

Question 27

What is a waxy cuticle

Answer 27

A thin waterproof layer of lipids that water cant get through

Question 28

Why do leaves keep the stomate open for as short a time as possible

Answer 28

So they can maximise Co2 absorption but minimise water loss

Question 29

How is each stoma formed

Answer 29

From the gap between 2 guard cells

Question 30

What happens to the guard cells when a plant has lots of water

Answer 30

Guard cells will be well hydrated (turgid) which makes gap between them larger allowing more co2 to diffuse through

Question 31

What happens to the guard cells when a plant is short of water

Answer 31

The guard cells lose water due to osmosis and become flaccid

Question 32

What happens to the stomata when guard cells become dehydrated(flaccid)

Answer 32

The stomata close meaning the plant no longer takes in Co2 but will conserve its water vapour

Question 33

What happens to guard cells at night and why

Answer 33

They close at night when photosynthesis isnt taking place and they dont need Co2 because they’re sensitive to light

Question 34

Why are stomatas on the lower side of the of the leaf

Answer 34

Because its more shady which makes it cooler so less water will evaporate

Question 35

Where is meristem tissue found

Answer 35

Found at growing tips of roots and shoots

Question 36

What can meristem tissue do

Answer 36

It can differentiate into loads of different cell types so that the plant can grow

Question 37

Define translocation

Answer 37

Movement of cell sap up and snd down the plant

Question 38

How is translocation achieved

Answer 38

Achieved by phloem cells

Question 39

What are phloem tubes

Answer 39

Phloem cells that are arranged end to end to form long columns

Question 40

Why do phloem cells have pores in their walls

Answer 40

To allow cell sap to pass along the phloem tube

Question 41

Why are xylem tubes ans what do they form

Answer 41

Dead xylem cells with no ends between them so they from 1 long hollow tube

Question 42

What strengthens xylem tubes

Answer 42

Lignin

Question 43

What is the role of xylem tubes

Answer 43

They transport both water and mineral ions from the roots up the stem to the leaves where water can be hsed in photosynthesis

Question 44

Define transpiration

Answer 44

Evaporation of water through the leaves

Question 45

What is a transpiration stream

Answer 45

A chain of water molecules

Question 46

What are the 4 factors that influence the rate of transpiration

Answer 46

1. Light intensity 2. Temp 3. Air flow 4. Humidity

Question 47

How does light intensity increase the rate of transpiration

Answer 47

The stomatas open wider to let more carbon dioxide into the leaf for photosynthesis

Question 48

How does temperature affect the rate of transpiration

Answer 48

Particles of water will have more energy in warmer temperatures so theyre more likely to evaporate and diffuse out of stomata

Question 49

How does air flow affect the rate of transpiration

Answer 49

Higher air flow means there is a higher concentration gradient which increases rate of transpiration

Question 50

How does humidity affect the rate of transpiration

Answer 50

Higher humidity means there is a lower concentration gradient which decreases the rate of transpiration