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BIOLOGY UNIT 2 > 1. Photosynthesis and ATP synthesis > Flashcards

1. Photosynthesis and ATP synthesis Flashcards

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1
Q

Humans, like all animals and fungi, are

A

heterotrophs

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2
Q

heterotrophs are

A

organisms that obtain energy from the food they eat

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3
Q

autotrophs are

A

organisms that can capture energy from sunlight or chemicals and use that energy to produce food

they are primary producers

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4
Q

heterotrophs means that we need to eat food containing

A

organic molecules, especially carbohydrates, fats and proteins.

These organic molecules are our only source of energy

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5
Q

Plants do not need to take in any organic molecules at all.

plants obtain their energy from

A

sunlight

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6
Q

plants can use this energy from the sunlight to build

A

their own organic molecules using simple inorganic substances

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7
Q

how plants build their own organic molecules using simple inorganic substances

A

1) they produce carbohydrates from carbon dioxide and water, by photosynthesis.
2) use these carbohydrates + inorganic ions such as nitrate, phosphate and magnesium, to manufacture all the organic molecules that they need.

Organisms that feed in this way are autotrophs

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8
Q

heterotrophs depend on autotrophs for

A

the supply of organic molecules on which they feed

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9
Q

how some heterotrophs feed (2)

A

1) directly on plants

2) further along a food chain

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10
Q

eventually all of an animal’s or fungus’s food can be traced back to (2)

A

1) plants

2) energy of sunlight

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11
Q

Respiration is

A

The process by which cells break down simple food molecules to release the energy they contain.

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12
Q

Respiration involves

A

the oxidation of the energy-containing organic substances, forming another energy-containing substance called ATP

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13
Q

Every cell has to make its own

A

ATP

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14
Q

Photosynthesis happens in what organisms (3)?

A

1) plants
2) algae (phytoplankton)
3) some bacteria (autotrophs)

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15
Q

Phytoplankton are

A

tiny organisms that float in the upper layers of the sea and lakes

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16
Q

photosynthesis in green plants takes place in

A

the chloroplasts of several plant tissues, especially the palisade mesophyll and spongy mesophyll tissues of leaves

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17
Q

diagram of the structure of a leaf (#18)

A

check notebook #18

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18
Q

diagram of the structure of inside a leaf (#19)

A

check notebook #19

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19
Q

The ultimate source of almost all of our food is

A

photosynthesis

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20
Q

Overall equation for photosynthesis

A

6CO2 + 6H2O ——> C6H12O6 + 6O2

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21
Q

Algae are

A

A diverse group of aquatic organisms that have the ability to conduct photosynthesis

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22
Q

what bring water to the photosynthesizing cells of the leaf

A

The xylem tissues of roots, stems and leaf vascular bundles

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23
Q

how carbon dioxide diffuses into the leaf

A

1) through stomata,
2) then diffuses through air spaces and into mesophyll cells
3) and finally into chloroplasts, where photosynthesis takes place

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24
Q

Chloroplasts are

A

organelles within the cells of plants and certain algae that is the site of photosynthesis.

it has a double membrane and contains chlorophyll to absorb light energy

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25
Q

what is the site of photosynthesis

A

chloroplasts

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26
Q

Xylem tissues transports

A

water

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27
Q

stomata are

A

the tiny holes/pores usually found in the lower epidermis of the leaf through which diffusion of gases occurs, including carbon dioxide

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28
Q

physical features of a leaf (4)

A

1) a broad, thin lamina
2) a midrib
3) a network of veins
4) a leaf stalk (petiole)

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29
Q

photomicrograph of a section of a typical leaf from a mesophyte

A

quizlet or chegg

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30
Q

A mesophyte is

A

a plant adapted for normal terrestrial conditions

(it is adapted neither for living in water nor for withstanding excessive drought).

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31
Q

for the mesophyte to perform its function, the leaf must (3)

A

1) contain chlorophyll and other photosynthetic pigments arranged in such a way that they can absorb light;
2) be able to absorb carbon dioxide and dispose of the waste product, oxygen;
3) have a water supply and be able to export manufactured carbohydrate to the rest of the plant.

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32
Q

The large surface area and thinness of the lamina of the leaf allows it to

A

absorb a lot of light

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33
Q

The thinness of the lamina of the leaf

A

minimizes the length of the diffusion pathway for gaseous exchange

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34
Q

The Lamina of the leaf is

A

the green flat part of a leaf that is specialized for photosynthesis

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35
Q

The arrangement of leaves on the plant helps the plant to

A

absorb as much light as possible

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36
Q

the Leaf mosaic is

A

The arrangement of leaves on the stem of a plant

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37
Q

The upper epidermis of the leaf is made of

A

thin, flat, transparent cells which allow light through to the cells of the mesophyll below, where photosynthesis takes place

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38
Q

A waxy transparent cuticle, which is secreted by the epidermal cells, provides a

A

watertight layer preventing water loss other than through the stomata, which can be closed in dry conditions.

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39
Q

The waxy transparent cuticle and epidermis together form

A

a protective layer against microorganisms and some insects.

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40
Q

The structure of the lower epidermis in mesophytes is similar to that of the upper, except that

A

most mesophytes have many stomata in the lower epidermis. (Some have a few stomata in the upper epidermis also.)

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41
Q

Each stoma is bounded by

A

two sausage shaped guard cells

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42
Q

guard cells are

A

The two cells that flank the stomatal pore and regulate the opening and closing of the pore.

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43
Q

diagram of a photomicrograph of stomata and guard cells in Tradescantia leaf epidermis (#45)

A

check notebook #45

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44
Q

Changes in the turgidity of these guard cells cause them to

A

change shape so that they open and close the pore

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45
Q

explain when guard cells gain or lose water

A

When the guard cells gain water, the pore opens

When the guard cells lose water, the pore closes

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46
Q

explain the walls in guard cells

A

guard cells have unevenly thickened cell walls.

The wall adjacent to the pore is very thick, whilst the wall furthest from the pore is thin

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47
Q

what is arranged as hoops around each guard cell

A

Bundles of cellulose microfibrils are arranged as hoops around each guard cell

as the cell becomes turgid, these hoops ensure that the cell mostly increases in length and not diameter

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48
Q

cellulose microfibrils are

A

Long, thin strand of cellulose that helps strengthen plant cell walls.

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49
Q

what makes guard cell curve

A

Since the ends of the two guard cells are joined and the thin outer wall bends more readily than the thick inner one, the guard cells become curved.

This makes the pore between the cells open

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50
Q

Guard cells gain and lose water by

A

osmosis

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51
Q

what is needed before water can enter the cells by osmosis

A

A decrease in water potential is needed before water can enter the cells by osmosis.

This is achieved by the active removal of hydrogen ions, using energy from ATP, and then intake of potassium ions (indirect active transport)

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52
Q

diagram of a photomicrograph of palisade cells (#54)

A

check notebook #544

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53
Q

The main site of photosynthesis is the

A

palisade mesophyll because there are more chloroplasts per cell in the palisade mesophyll than in the spongy mesophyll.

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54
Q

spongy mesophyll is a

A

layer of loose tissue found beneath the palisade mesophyll in a leaf

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55
Q

palisade mesophyll is a

A

Layer of tall, column-shaped mesophyll cells just under the upper epidermis of a leaf

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56
Q

how Palisade cells show several adaptations for light absorption (3)

A

1) They are long cylinders arranged at right-angles to the upper epidermis.
2) The cells have a large vacuole with a thin peripheral layer of cytoplasm.
3) The chloroplasts can be moved (by proteins in the cytoplasm, as they cannot move themselves) within the cells,

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57
Q

how Palisade cells having long cylinders arranged at right-angles to the upper epidermis show adaptations for light absorption

A

This reduces the number of light-absorbing cross walls in the upper part of the leaf so that as much light as possible can reach the chloroplasts.

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58
Q

how Palisade cells having a large vacuole with a thin peripheral layer of cytoplasm show adaptations for light absorption

A

This restricts the chloroplasts to a layer near the outside of the cell where light can reach them most easily

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59
Q

how chloroplasts being able to move within Palisade cells is a adaptations for light absorption

A

it absorbs the most light or to protect the chloroplasts from excessive light intensities.

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60
Q

How palisade cells show adaptations for gaseous exchange (2)

A

1) The cylindrical cells pack together with long, narrow air spaces between them.
2) The cell walls are thin and moist, so that gases can diffuse through them more easily.

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61
Q

how palisade cells having cylindrical cells pack together with long, narrow air spaces between them show adaptations for gaseous exchange

A

This gives a large surface area of contact between cell and air.

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62
Q

how palisade cells having thin and moist cell walls show adaptations for gaseous exchange

A

gases can diffuse through them more easily.

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63
Q

how living organisms gain their energy?

A

1) from light or
2) they use the energy transferred from reactions involving elements, simple inorganic compounds or complex organic compounds

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64
Q

Phototrophs are

A

organisms that gain their energy by absorbing light

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65
Q

how Chemotrophs gain their energy

A

from chemical reactions

not from light reactions

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66
Q

The simplest form of carbon that organisms can use is

A

carbon dioxide.

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67
Q

energy flows through living systems and is not

A

recycled

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68
Q

Metabolic pathway is

A

a series of small reactions controlled by enzymes

e.g. respiration and photosynthesis

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69
Q

Life depends on continuous transfers of

A

energy

how this energy enters an organism depends on its type of nutrition
eg- In plants, energy in light is absorbed by chlorophyll and then transferred into the chemical energy of the molecules formed during photosynthesis

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70
Q

Spongy mesophyll is mainly adapted as

A

a surface for the exchange of carbon dioxide and oxygen.

because it contain chloroplasts, but in smaller numbers than in palisade cells

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71
Q

why photosynthesis don’t often occur in the spongy mesophyll

A

the spongy mesophyll has smaller numbers of chloroplasts compared to the palisade mesophyll

Photosynthesis occurs in the spongy mesophyll only at high light intensities.

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72
Q

Photosynthesis occurs in the spongy mesophyll only at

A

high light intensities.

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73
Q

xylem brings in the water necessary for (2)

A

1) photosynthesis

2) cell turgor

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74
Q

what the phloem does

A

the phloem takes the products of photosynthesis to other parts of the plant.

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75
Q

adaptations of the leaf for it to bring together the three raw materials of photosynthesis (water, carbon dioxide, and light and remove its products (oxygen and glucose)

A

large surface area that absorbs as much sunlight as possible and thin for diffusion

an arrangement of leaves on the plant that minimizes overlapping

transparent cuticle and epidermis that let light through to the photosynthetic mesophyll cells beneath

long, narrow upper mesophyll cells packed with chloroplasts that collect sunlight numerous stomata for gaseous exchange

stomata that open and close in response to changes in light intensity

many air spaces in the lower mesophyll layer to allow rapid diffusion in the gas phase of carbon dioxide and oxygen

a network of xylem that brings water to the leaf cells, and phloem that carries away the sugars produced during photosynthesis

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76
Q

lifetime of leaves

A

Leaves have a limited lifetime – they are replaced at growing seasons

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77
Q

Plants usually have numerous leaves and they are borne at

A

the nodes of a stem

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78
Q

The leaf blade is connected to the plant stem by a

A

petiole

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79
Q

Leaves have different shapes and sizes and may be modified to suit particular functions. For example

A

they may be modified with spines as protection for a plant, or for climbing as tendrils in vines

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80
Q

Leaves are arranged on plant stems in three major patterns called (3)

A

alternate opposite or whorled

81
Q

The arrangement of the leaves on the plant is organised so as to

A

maximise the capability of the plant to capture sunlight

82
Q

Leaves consist of different types of cell with particular functions. The major types of cell in a leaf are (4)

A

epidermal cells,

parenchyma cells,

mesophyll cells and

guard cells

83
Q

epidermal cells are

A

a single layer of dermal tissue with covers the outside of a plant.

84
Q

parenchyma cells are

A

a relatively unspecialized plant cell that carries out

various functions

85
Q

Leaves have an outer layer of epidermal cells which are covered with a cuticle that is designed to

A

limit water loss

86
Q

Trichomes are

A

Epidermal hairs

87
Q

Epidermal hairs (trichomes) may be present where?

A

on the upper and lower surfaces of the leaf and these can also help retard water loss

88
Q

In dicotyledonous leaves, stomata are normally restricted to

A

the lower epidermis

89
Q

The guard cells regulate the opening of the stomata according to

A

environmental conditions

e.g. hot, dry or humid

90
Q

The mechanism for the opening and closing of the stoma is dependent on

A

changes in the osmotic concentration of the vacuoles of the guard cells

91
Q

Radioactive water is injected into the stem of a plant that is actively photosynthesising. Outline the route that a water molecule travels before exiting through a stoma

A

Stem into petiole, veins, mesophyll cells or palisade cells, intercellular spaces, exit stomata

92
Q

Open stomata allow what? (3)

A

the carbon dioxide necessary for photosynthesis to enter the leaf and

let out the oxygen produced by photosynthesis.

Water vapour which has evaporated from the surfaces of the mesophyll cells into the intercellular spaces also exits the leaves

93
Q

The irregular shapes of spongy mesophyll in the lower epidermis result in

A

large intercellular air spaces which make for efficient gaseous exchange

94
Q

The mesophyll layer has numerous veins (vascular bundles) consisting of

A

xylem and phloem

that are continuous with the vascular system of the stem and the entire plant

95
Q

The vascular tissues of the leaf veins are surrounded by

A

parenchyma cells that have a small number of chloroplasts and they form a structure called the bundle sheath

96
Q

The bundle sheaths extends where?

A

right to the end of the smallest veins making sure that no parts of the veins are exposed to the air in the intercellular spaces

97
Q

what must happen for substances entering or leaving the vascular bundle?

A

All substances (water, mineral ions, photosynthesis products, metabolic products) must pass through the bundle sheath when entering or leaving the vascular bundle

98
Q

The leaves of most dicotyledonous plants have more stomata on the lower surface than on the upper.

Many have none at all on the upper epidermis.

However, leaves that float on water have

A

almost all their stomata on the upper surface

99
Q

what would happen if leaf cells were arranged in layers horizontally rather than vertically

A

Light would be scattered by cell walls

100
Q

advantage of having large air spaces in leaves

A

Diffusion through air is much faster than diffusion through cell walls and cytoplasm

101
Q

what do chloroplast in the palisade mesophyll cells do on hot, bright days

A

chloroplasts move around in the cell so that they are not all exposed to the most intense light

102
Q

the palisade mesophyll providing a large surface area of moist cell wall for gaseous exchange is due to (2)

A

1) irregular packing of the cells and the large air spaces thus produced
2) The veins in the leaf that help to support the large surface area of the leaf. They contain xylem and phloem

103
Q

photosynthesis is a complex

A

metabolic pathway

104
Q

a metabolic pathway is a

A

series of chemical reactions linked to each other that either builds a complex molecule or breaks down a complex molecule into simpler compounds.

metabolic pathway are catalysed by enzymes

105
Q

Photosynthesis reactions takes place in 2 stages

A

light dependent stage and the light independent stage

106
Q

where do both the light dependent and light independent stage of photosynthesis takes place

A

inside chloroplasts within cells of the leaves and often stems of plants

107
Q

diagram showing the stages of photosynthesis

A

chegg

108
Q

diagram showing the Electron micrograph of a chloroplast

A

chegg

109
Q

Diagram of a chloroplast

A

chegg

110
Q

diagram showing the electron micrograph of part of a chloroplast

A

chegg

111
Q

how many chloroplasts does each cell in a photosynthesising tissue have inside it

A

each cell in a photosynthesising tissue may have ten or even 100 chloroplasts inside it.

112
Q

A chloroplast is surrounded by

A

two membranes, forming an envelope

113
Q

There are membranes inside the chloroplast, which are arranged so that

A

they enclose fluid-filled sacs between them.

The membranes are called lamellae and the fluid filled sacs are thylakoids

114
Q

membranes found inside chloroplasts are called

A

lamellae

115
Q

A thylakoid or lamellae is

A

a membrane-bound compartment inside chloroplasts

116
Q

singular and plural of lamellae and lamella

A

lamella is singular and

lamellae is plural

117
Q

the membranes chloroplast have are (2)

A

1) a double membrane

2) a lamellae

118
Q

Grana are

A

A stacked portion of the thylakoid membrane in the chloroplast. (stacked up like a pile of pancakes)

119
Q

grana function in

A

the light reactions of photosynthesis

120
Q

Stroma is

A

The ‘background material’ inside the chloroplast

121
Q

Embedded tightly in the thylakoid membranes inside the chloroplast are

A

several different kinds of photosynthetic pigments

122
Q

photosynthetic pigments are

A

coloured substances that absorb light energy from certain wavelengths (colours) of light and use it to carry out photosynthesis.

123
Q

The most abundant photosynthetic pigment is

A

chlorophyll

124
Q

the 2 forms of chlorophyll

A
  • chlorophyll a

- chlorophyll b

125
Q

why the stacked thylakoid membranes inside the chloroplasts can capture light very efficiently

A

they have a large surface area so their photosynthetic pigments can capture light very efficiently.

126
Q

The transformation of light energy into chemical energy in the thylakoid membranes is carried out by

A

other chemicals in the membranes closely associated with the photosynthetic pigments

127
Q

thylakoid membranes of chloroplasts functions (2)

A

1) holds chemicals allowing them to function correctly

2) create the thylakoid spaces.

128
Q

thylakoid lumen is

A

the fluid-filled space inside a thylakoid created by the thylakoid membrane

129
Q

the thylakoid lumen is needed for

A

the accumulation of hydrogen ions, H+, used in the production of ATP

130
Q

Chloroplasts often contain starch grains, because

A

starch is the form in which plants store the carbohydrate that they make by photosynthesis

131
Q

the form that plants store the carbohydrate that they make by photosynthesis

A

starch

132
Q

Chloroplast contains (9)

A

1) outer and inner membrane
2) lipid droplet
3) lamella
4) thylakoid
5) granum
6) stroma
7) starch grains
8) ribosomes
9) small circular strand of DNA

133
Q

Chloroplasts are thought to have evolved from

A

Bacteria that first invaded eukaryotic cells over a thousand million years ago

134
Q

Thylakoids (fluid-filled sacs) are stacked up in the chloroplast into structures called

A

rana (singular = granum).

The grana are linked together by bits of thylakoid membrane called lamellae (singular = lamella).

135
Q

Chloroplasts are found in

A

cotyledons, leaves, stems, fruits, and flowers, depending on the plant species and its stage of development from seedling to mature plant

136
Q

Dicotyledonous refers to

A

the group of flowering plants that have embryos with two cotyledons.

Many also have broad leaves with a net like pattern of veins

137
Q

Chloroplasts are green because

A

they contain the pigment chlorophyll, which is vital for photosynthesis

138
Q

the major pigments found in higher plants and green algae are

A

Chlorophyll a and b

139
Q

The most advanced photosynthetic bacteria are

A

the cyanobacteria

140
Q

Chloroplasts are distinguished from other types of plastids by

A

their green colour, which results from the presence of two pigments, chlorophyll a and chlorophyll b

141
Q

Plastids are

A

cytoplasmic organelles that often contain photosynthetic pigments.

142
Q

What is a complex organ composed of several tissues organized to optimize photosynthesis?

A

the leaf

143
Q

What type of cells surround the stomata?

A

guard cells

144
Q

A pigment is a

A

a substance whose molecules absorb some wavelengths (colours) of light, but not others.

(absorbs light and has colour)

145
Q

The wavelengths pigments does not absorb are either

A

reflected or transmitted through the substance.

These unabsorbed wavelengths reach our eyes, so we see the pigment in these colours.

146
Q

the color of pigments arises because they

A

absorb only certain wavelengths of visible light

147
Q

Plants contain many pigments, giving rise to

A

the various colors we see.

Flowers and fruits obviously contain a large number of organic molecules that absorb light.

Leaves, stems and roots also contain a variety of pigments

148
Q

organisms that contain pigments which give them their colors (3)

A

1) Flowers
2) corals
3) animal skin

149
Q

Photosynthetic pigments are the only pigments that have the ability to

A

absorb energy from sunlight and make it available to the photosynthetic apparatus.

150
Q

In land plants, the two classes of photosynthetic pigments are

A

1) chlorophylls

2) carotenoids

151
Q

In plants, algae, and cyanobacteria pigments are the means by which

A

the energy of sunlight is captured for photosynthesis

152
Q

difference between chlorophyll a and chlorophyll b absorb

A

Both chlorophyll a and chlorophyll b absorb similar wavelengths of light, but chlorophyll a absorbs slightly longer wavelengths than chlorophyll b.

This can be shown in a graph called an absorption spectrum

153
Q

diagram showing the absorption spectra for chlorophyll and carotene

A

chegg

154
Q

function of carotenoids, such as carotene and xanthophylls (5)

A

1) absorb a wide range of short wavelength light, including more blue-green light than the chlorophylls.
2) being accessory pigments.
3) help by absorbing wavelengths of light that would otherwise not be used by the plant.
4) pass on some of this energy to chlorophyll.
5) probably also help to protect chlorophyll from damage by very intense light.

155
Q

Carotenoids are

A

Accessory pigments that broaden the spectrum of colors that can drive photosynthesis.

156
Q

Carotene are

A

Carotenes are yellow-orange photosynthetic pigments important for photosynthesis

157
Q

xanthophylls are

A

xanthophylls are yellow/brown pigments important for photosynthesis

158
Q

What is located between the upper and lower epidermis packed with chloroplast, and photosynthetic parenchyma?

A

Mesophyll

159
Q

What are the two sublayers of mesophylls?

A

Palisade and Spongy

160
Q

What type of mesophyll is the main sight of photosynthesis within a leaf?

A

Palisade mesophyll

161
Q

What type of mesophyll functions primarily for gas exchange?

A

Spongy mesophyll

162
Q

What opens during the day for gas exchange needed for photosynthesis and closes during the night to conserve water when photosynthesis is not occurring?

A

stomata

163
Q

explain why chlorophyll looks green

A

Green plants are green because they contain a pigment called chlorophyll

As shown in detail in the absorption spectra, chlorophyll absorbs light in the red (long wavelength) and the blue (short wavelength) regions of the visible light spectrum.

Green light is not absorbed but reflected, making the plant appear green

164
Q

The plasma membrane of the chloroplast is arranged so that the

A

outer membrane separates the inside of chloroplast from the cytoplasm of the plant cell

165
Q

Immature chloroplasts develop into mature chloroplasts due to

A

factors like light availability, chloroplast gene transcription and proteins.

166
Q

chloroplasts have their own DNA and can

A

produce some of their own proteins as well as multiply independently inside the cell in which they live

167
Q

Where does the light dependent stage of photosynthesis take place

A

on the thylakoids inside the chloroplast

168
Q

The light dependent stage of photosynthesis involves

A

the absorption of light energy by chlorophyll, and

the use of that energy and the products from splitting water to make ATP and reduced NADP

169
Q

The chlorophyll molecules are arranged in clusters called

A

photosystems in the thylakoid membranes

170
Q

Photosystems are

A

large complexes of proteins and pigments (light-absorbing molecules) that are optimized to harvest light, play a key role in the light reactions

171
Q

Each photosystem contains what?

A

200 molecules of a green pigment called chlorophyll and

50 molecules of another family of pigments called carotenoids

172
Q

diagram showing a photosystem in a thylakoid membrane showing photoactivation of chlorophyll

A

Energy is captured from photons of light that hit the photosystem, and is funnelled down to a pair of molecules at the reaction centre of the photosystem complex.

173
Q

each photosystems in the thylakoid membranes spans the membrane and contains

A

protein molecules and pigment molecules

174
Q

reaction centre is

A

The site in the chloroplast that receives the energy trapped by chlorophyll and accessory pigments and initiates the electron transfer process.

175
Q

The two different sorts of photosystem are

A

photosystem I (PSI) and

photosystem II (PSII),

both with a small number of molecules of chlorophyll a at the reaction centre

176
Q

The light-dependent reactions of photosynthesis

produce

A

ATP and NADPH

177
Q

NADPH is a

A

reducing agent used in metabolic reactions

178
Q

reduction is the

A

addition of electrons

179
Q

oxidation is the

A

removal of electrons

180
Q

what is both a reactant and a product of photosynthesis

A

water

181
Q

The full name for NADP is

A

nicotinamide adenine dinucleotide phosphate

NADP has one more phosphate molecule than NAD.

182
Q

In PSI the chlorophyll molecule has a maximum absorption at

A

700nm

183
Q

In PSII the chlorophyll molecule has a maximum absorption at

A

680nm

184
Q

photosystems are responsible for capturing the solar energy to be used in the light-dependent reactions.

The photosystems pass electrons from one molecule to another and some of this electron flow is used for

A

ATP synthesis

185
Q

The reaction centre chlorophyll a of PSII is called

A

P680 because this pigment is best at absorbing light with a wavelength of 680 nm

186
Q

The reaction centre chlorophyll b of PSI is called

A

P700 because this pigment is best at absorbing light with a wavelength of 700 nm

187
Q

Electron transport within the chloroplast can follow either

A

a cyclic pathway or a non-cyclic pathway.

The cyclic electron pathway generates ATP and is called cyclic photophosphorylation because light is necessary.

The non-cyclic electron pathway generates ATP and NADPH.
The production of ATP from the non-cyclic electron pathway is called non-cyclic photophosphorylation

188
Q

NADPH is used to provide

A

energy for biosynthetic pathways that occur in cells.

189
Q

The reduction of NADP is catalysed by

A

NADP reductase, which is on the outer surface of the thylakoid membrane

190
Q

Photophosphorylation means

A

‘phosphorylation using light’.

It refers to the production of ATP, by combining a phosphate group with ADP, using energy that originally came from light:

ADP + phosphate ➝ ATP

191
Q

Photophosphorylation happens when

A

an electron is passed along a series of electron carriers, forming an electron transport chain in the thylakoid membranes.

The electron starts off with a lot of energy, and it gradually loses some of it as it moves from one carrier to the next.

The energy is used to cause a phosphate group to react with ADP

192
Q

electron carriers (electron shuttles) are

A

small organic molecules/proteins that can easily accept electrons (i.e., be reduced) or lose them (i.e., be oxidized)- transfer electrons

The electron carriers take the electrons to a group of proteins in the inner membrane of the mitochondrion, called the electron transport chain.

193
Q

what happens as electron move through the electron transport chain

A

they go from a higher to a lower energy level and are ultimately passed to oxygen (forming water)

194
Q

electron carriers provide a

A

controlled flow of electrons that enables the production of ATP

195
Q

what would happen without electron carriers

A

the cell would cease to function

196
Q

eg of two electron carriers are

A

NAD+ and FAD, which are both derived from B vitamins

197
Q

electron transport chain is a

A

cluster of proteins through which electrons flow

that transfer electrons through a membrane within mitochondria to form a gradient of protons that drives the creation of adenosine triphosphate (ATP).

198
Q

Cyclic photophosphorylation involves what photosystem?

A

only PSI, not PSII

199
Q

Cyclic photophosphorylation results in

A

the formation of ATP, but not reduced NADP

BIOLOGY UNIT 2 (7 decks)

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