photosynthesis Flashcards

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1
Q

algae

definition

A

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.

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2
Q

biomass

definition

A

The dry mass of an organism.

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3
Q

carbon dioxide

definition

A

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

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4
Q

cell

definition

A

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

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5
Q

chlorophyll

definition

A

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

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6
Q

chloroplast

definition

A

Contains the green pigment chlorophyll; the site of photosynthesis.

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7
Q

denature

definition

A

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

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8
Q

endothermic

definition

A

Reaction in which energy is taken in from the surroundings.

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9
Q

enzyme

definition

A

A protein which catalyses or speeds up a chemical reaction.

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10
Q

glucose

definition

A

A simple sugar used by cells for respiration.

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11
Q

light

definition

A

Visible electromagnetic radiation.

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12
Q

limiting factor

definition

A

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

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13
Q

organ

definition

A

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

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14
Q

photosynthesis

definition

A

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.

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15
Q

respiration

definition

A

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.

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16
Q

stomata

definition

A

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.

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17
Q

xylem vessels

definition

A

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

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18
Q

Photosynthesis

overview

A

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.

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19
Q

Photosynthesis

Algae

A

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

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20
Q

Photosynthesis equation

A

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

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21
Q

Is photosynthesis a endothermic or exothermic reaction?

A

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

22
Q

Photosynthesis

Chlorophyll

A

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

23
Q

What is the main organ for photosynthesis?

A

Plant leaves are the main organ for photosynthesis.

24
Q

Photosynthesis

carbon dioxide

A

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.

25
Q

Photosynthesis

oxygen

A

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.

26
Q

Photosynthesis

glucose

A

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.

27
Q

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

A
  • cellulose
  • starch
  • Amino acids→Proteins
  • Lipids (fats/oils)
28
Q

Cellulose in plants

A

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

29
Q

Starch in plants

A

Many glucose molecules joined.

insoluble

storage form of carbohydrate

30
Q

Lipids (fats/oils) in plants

A

Used for storage in seeds

31
Q

Amino acids and proteins in plants

A

Glucose plus nitrates absorbed from the soil makes amino acids.

many amino acid molecules joined makes proteins.

32
Q

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

A
  • 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
33
Q

Several factors can affect the rate of photosynthesis:

A
  • light intensity
  • carbon dioxide concentration
  • temperature
34
Q

Light intensity

A

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.

35
Q

Carbon dioxide concentration

A

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

36
Q

Direct proportion

A

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.

37
Q

Inverse proportion

A

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.

38
Q

Features of leaves

Name the purpose of the adaptation large surface area

A

To absorb more light

39
Q

Features of leaves

Name the purpose of the adaptation thin (leaves)

A

Short distance for carbon dioxide to diffuse into leaf cells

40
Q

Features of leaves

Name the purpose of the adaptation chlorophyll

A

Absorbs sunlight to transfer energy into chemicals

41
Q

Features of leaves

Name the purpose of the adaptation Network of veins

A

To support the leaf and transport water and sugars

42
Q

Features of leaves

Name the purpose of the adaptation Stomata

A

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

43
Q

Structure of leaves

Name the purpose of the adaptation Epidermis is thin and transparent

A

To allow more light to reach the palisade cells

44
Q

Structure of leaves

Name the purpose of the adaptation Thin cuticle made of wax

A

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

45
Q

Structure of leaves

Name the purpose of the adaptation Palisade cell layer at top of leaf

A

To absorb more light and increase the rate of photosynthesis

46
Q

Structure of leaves

Name the purpose of the adaptation Spongy layer

A

Air spaces allow carbon dioxide to diffuse through the leaf

47
Q

Structure of leaves

Name the purpose of the adaptation Palisade cells contain many chloroplasts

A

To absorb all the available light

48
Q

What is the rate of photosynthesis directly proportional to?

A

Rate of photosynthesis is directly proportional to light intensity.

49
Q

What is light intensity proportional to?

A

Light intensity is proportional to 1/d^2.

50
Q

What is light in tensity inversely proportional to?

A

d^2