photosynthesis

Question 1

algae

definition

Answer 1

A group of organisms that photosynthesise but lack the complex range of cell types and organs found in land plants. Most algae are aquatic. All have chloroplasts.

Question 2

biomass

definition

Answer 2

The dry mass of an organism.

Question 3

carbon dioxide

definition

Answer 3

A gaseous compound of carbon and oxygen, which is a by-product of respiration, and which is needed by plants for photosynthesis.

Question 4

cell

definition

Answer 4

Basic unit of life. Unicellular organisms only have one cell. Multicellular organisms have many cells.

Question 5

chlorophyll

definition

Answer 5

The green chemical inside the chloroplasts of plant cells. It enables photosynthesis to take place.

Question 6

chloroplast

definition

Answer 6

Contains the green pigment chlorophyll; the site of photosynthesis.

Question 7

denature

definition

Answer 7

If a substance is denatured, its structure and function is altered. This can be caused by heat, altered pH or by chemical agents.
enzymes.

Question 8

endothermic

definition

Answer 8

Reaction in which energy is taken in from the surroundings.

Question 9

enzyme

definition

Answer 9

A protein which catalyses or speeds up a chemical reaction.

Question 10

glucose

definition

Answer 10

A simple sugar used by cells for respiration.

Question 11

light

definition

Answer 11

Visible electromagnetic radiation.

Question 12

limiting factor

definition

Answer 12

A factor which, if in short supply limits or reduces the rate of photosynthesis, eg temperature, light intensity and carbon dioxide concentration.

Question 13

organ

definition

Answer 13

A group of different tissues that work together to carry out a particular function, eg heart and lungs.

Question 14

photosynthesis

definition

Answer 14

A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic.

Question 15

respiration

definition

Answer 15

The chemical change that takes place inside living cells, which uses glucose and oxygen to release the energy that organisms need to live. Carbon dioxide is a by-product of respiration.

Question 16

stomata

definition

Answer 16

Tiny holes in the epidermis (skin) of a leaf. They control gas exchange by opening and closing and are involved in loss of water from leaves. Singular is stoma.

Question 17

xylem vessels

definition

Answer 17

Narrow, hollow, dead tubes with lignin, responsible for the transport of water and minerals in plants.

Question 18

Photosynthesis

overview

Answer 18

Green plants and algae use light energy to make glucose and oxygen from carbon dioxide and water. Temperature, carbon dioxide concentration and light intensity can affect the rate of photosynthesis.

Question 19

Photosynthesis

Algae

Answer 19

Algae can also make their own food by the process of photosynthesis. Plant biomass will increase as a result of photosynthesis.

Question 20

Photosynthesis equation

Answer 20

Carbon dioxide + water →(light)→ Glucose + oxygen

Question 21

Is photosynthesis a endothermic or exothermic reaction?

Answer 21

Photosynthesis is an endothermic reaction as it requires light energy to react carbon dioxide and water to produce glucose and oxygen.

Question 22

Photosynthesis

Chlorophyll

Answer 22

The light energy required is absorbed by a green pigment called chlorophyll in the leaves. Chlorophyll is located in chloroplasts in plant cells.

Question 23

What is the main organ for photosynthesis?

Answer 23

Plant leaves are the main organ for photosynthesis.

Question 24

Photosynthesis

carbon dioxide

Answer 24

The carbon dioxide required for photosynthesis comes from the air. It enters leaves through the stomata. Water enters the plant through the roots, and is transported to the leaves in the xylem.

Question 25

Photosynthesis | oxygen

Answer 25

Oxygen is formed as a product. Some is used for respiration. During the day, provided the rate of photosynthesis is high enough, plant and algae give out oxygen.

Question 26

Photosynthesis | glucose

Answer 26

Glucose is the starting point for making the materials that plants need to live. These materials are used to make cell walls and other cell components and will enable the plant to growth and increase in biomass.

Question 27

The glucose not used for respiration is used in the following ways:

Answer 27

- cellulose - starch - Amino acids→Proteins - Lipids (fats/oils)

Question 28

Cellulose in plants

Answer 28

Many glucose molecules joined together makes cellulose which is to build cells walls and adds strength to cell walls

Question 29

Starch in plants

Answer 29

Many glucose molecules joined. insoluble storage form of carbohydrate

Question 30

Lipids (fats/oils) in plants

Answer 30

Used for storage in seeds

Question 31

Amino acids and proteins in plants

Answer 31

Glucose plus nitrates absorbed from the soil makes amino acids. many amino acid molecules joined makes proteins.

Question 32

There are several ways of measuring the rate of photosynthesis in the lab. These include:

Answer 32

- the rate of oxygen production (number of bubbles or volume of oxygen gas given off in a set time) - the rate of carbon dioxide uptake - the rate of glucose production

Question 33

Several factors can affect the rate of photosynthesis:

Answer 33

- light intensity - carbon dioxide concentration - temperature

Question 34

Light intensity

Answer 34

Without enough light, a plant cannot photosynthesise very quickly - even if there is plenty of water and carbon dioxide. Increasing the light intensity increases the rate of photosynthesis, until some other factor - a limiting factor - becomes in short supply. The rate of photosynthesis is directly proportional to the light intensity until another factor becomes limiting. At very high light intensities, photosynthesis is slowed, but these light intensities do not occur in nature.

Question 35

Carbon dioxide concentration

Answer 35

Carbon dioxide is one of the reactants in photosynthesis. If the concentration of carbon dioxide is increased, the rate of photosynthesis will therefore increase. At some point, another factor may become limiting

Question 36

Direct proportion

Answer 36

As light intensity increases the rate of photosynthesis also increases. This is because photosynthesis is an energy requiring reaction, endothermic. More light energy will increase the rate at which oxygen is given off so more bubbles of oxygen will be produced per minute.

Question 37

Inverse proportion

Answer 37

There is an inverse relationship between distance and light intensity - as the distance increases, light intensity decreases. This is because as the distance away from a light source increases, light energy becomes spread over a wider area.

Question 38

Features of leaves | Name the purpose of the adaptation large surface area

Answer 38

To absorb more light

Question 39

Features of leaves | Name the purpose of the adaptation thin (leaves)

Answer 39

Short distance for carbon dioxide to diffuse into leaf cells

Question 40

Features of leaves | Name the purpose of the adaptation chlorophyll

Answer 40

Absorbs sunlight to transfer energy into chemicals

Question 41

Features of leaves | Name the purpose of the adaptation Network of veins

Answer 41

To support the leaf and transport water and sugars

Question 42

Features of leaves | Name the purpose of the adaptation Stomata

Answer 42

Allow carbon dioxide to diffuse into the leaf and oxygen to diffuse out

Question 43

Structure of leaves | Name the purpose of the adaptation Epidermis is thin and transparent

Answer 43

To allow more light to reach the palisade cells

Question 44

Structure of leaves | Name the purpose of the adaptation Thin cuticle made of wax

Answer 44

To protect the leaf from infection and prevent water loss without blocking out light

Question 45

Structure of leaves | Name the purpose of the adaptation Palisade cell layer at top of leaf

Answer 45

To absorb more light and increase the rate of photosynthesis

Question 46

Structure of leaves | Name the purpose of the adaptation Spongy layer

Answer 46

Air spaces allow carbon dioxide to diffuse through the leaf

Question 47

Structure of leaves | Name the purpose of the adaptation Palisade cells contain many chloroplasts

Answer 47

To absorb all the available light

Question 48

What is the rate of photosynthesis directly proportional to?

Answer 48

Rate of photosynthesis is directly proportional to light intensity.

Question 49

What is light intensity proportional to?

Answer 49

Light intensity is proportional to 1/d^2.

Question 50

What is light in tensity inversely proportional to?

Answer 50

d^2