chapter 17- energy for biological processes Flashcards
1
Q
what do cells require energy for (4)
MRS NERG
A
synthesis of molecules (eg protein)
transport of molecules or ions
cellular movement
synthesis of sugar by photosynthesis
2
Q
what is the cycle of energy
A
radiation from the sun fuels all metabolic reactions and processes neccessary to keep organisms alive, and then it is transferred back to the atmosphere as heat.
3
Q
respiration is the process by which….. (add egs)
A
organic molecules like glucose are broken down into smaller inorganic molecules like co2 and water
4
Q
breaking the bonds of the organic molecules in respiration is used to….
A
sythesise atp (energy is stored in the bonds of eg glucose)
5
Q
respiration involves organisms breaking down …. to provide…… to drive the ……
A
biomass to provide the atp needed to drive the metabolic reactions that take place in cells
6
Q
what is the overall reaction/chemical equation for photosynthesis
A
6CO2 + 6H2O <> C6H12O6 + 6O2
7
Q
what is the overall reaction for respiration
A
C6H12O6 + 6O2 > 6CO2 + 6H2O
8
Q
energy is released when bonds are
A
formed
9
Q
what is the bond energy
A
the energy that is needed to break or released when a bond is made (it is equal)
10
Q
whether an overall reaction is exothermic or endothermic depends on the total number…..
A
and strength of bonds that are broken or formed during the reaction
11
Q
are the atoms in small inorganic molecules joined by strong or weak bonds? wmt
A
strong bonds that are covalent (they have high bond energies) wmt they release a lot of energy when they form but require a lot of energy to break
12
Q
example of small inorganic molecules
A
carbon dioxide and water
13
Q
example of large(r) organic molecules
A
glucose and amino acids
14
Q
do organic molecules contain more or less bonds than small inorganic molecules
A
more
15
Q
are the bonds in organic molecules stronger or weaker than the bonds in small inorganic molecules? wmt
A
weaker bonds wmt they release less energy when they form and require less energy to be broken
16
Q
apply bond energy to respiration
A
the total energy required to break all the bonds in a complex organic molecule is less than the total energy released in the formation of all the bonds in the smaller inorganic products.
the excess energy released by the bond formation is used to synthesis atp
17
Q
do organic molecules contain many or few carbon-hydrogen bonds
A
many/large numbers of
18
Q
which organic molecule has particularly many large numbers of carbon-hydrogen bonds
A
lipids/triglycerides
19
Q
explain the importance of atp to living organisms (4)
(why is atp good)
A
universal energy currency, quick energy transfer, energy is in a usable quantity, atp can be resynthesised
20
Q
describe the properties of cell membranes neccessary for the formation of a proton gradient
(3/4)
A
impermeable to ions/protons, there can be different conc of protons on each side of membrane, contains integral proteins, eg atp synthase responsible for atp synthesis
21
Q
describe a carbon-hydrogen bond
A
a covalent bond/share the electrons almost equally in the bonds that form between them.
the bond is nonpolar therefore it does not require a lot of energy to break (bond energy is low)
22
Q
in respiration what happens when carbon-hydrogen bonds break
A
the carbon and hydrogen released form strong bonds with oxygen atoms forming carbon dioxide and water (small inorganic molecules) resulting in the release of large quantities of energy
23
Q
photosynthesis is the process by which small inorganic molecules make
A
organic molecules and the energy required to build these comes from the sun
24
Q
explain why it is incorrect to say that energy is produced (2)
A
energy cannot be created or destroyed only transferred (1) atp is produced however (1)
25
explain why atp is not a good energy storage molecule but why organic molecules like lipids and carbs are (4)
atp is not very stable (1) as it is easy to remove the phosphate group (1) organic molecules are more stable (1) organic molecules are more energy dense (1)
26
explain the interrelationship between respiration and photosynthesis of organisms (5)
what happens in each:
-.....molecules converted into .... molecules
-reactants and products
-transfers of energy
in P light energy is converted into chemical energy (1) inorganic molecules are converted into organic molecules (1) water and co2 are converted into glucose (and oxygen) (1)
R uses oxygen produced in photosynthesis (1) organic molecules are broken down into inorganic molecules (1) energy released is used to synthesise atp (1) carbon dioxide produced is used in photosynthesis(1)
27
light energy is transferred to ........... energy stored in ............ molecules such as .
chemical (potenial)
organic
glucose
28
does photosynthesis trap or release energy
trap energy
29
is photosynthesis an endo or exothermic reaction exp why
endothermic because energy is absorbed in the form of light
30
does respiration trap or release energy
release energy
31
is respiration an endo or exothermic reaction exp why
exothermic because it released energy from glucose this energy is transferred to adp and pi when atp is made
32
is photosynthesis a catabolic or anabolic reaction
anabolic
33
is respiration a catabolic or anabolic reaction
catabolic
34
what are the components of oxidation
loss of electrons, gain of oxygen, loss of hydrogen ions
35
what are the components of reduction
gain of electrons, loss of oxygen, gain of hydrogen ions
36
what is a redox reaction
a reaction where oxidation and reduction takes place
37
photosynthesis and respiration are both ..... reactions
redox reactions
38
where does oxidation occur in respiration
glucose loses electrons (and hydrogen) to become carbon dioxide
39
where does reduction occur in respiration
oxygen gains electrons (and hydrogen) to become water
40
where does oxidation occur in photosynthesis
water is oxidised to produce oxygen
41
where does reduction occur in photosynthesis
carbon dioxide is reduced into glucose
42
a palisade mesophyll cell may contain up to .. chloroplasts
50
43
chloroplasts transduce light into
chemical energy as either atp (light dependent) or organic compounds (light independent)
44
in which cells are chloroplasts found (3)
in the mesophyll cells of leaves, in the guard cells of stomata, cells of the outer part of green plant stems (cortex)
45
what is the shape of a chloroplast
biconvex disc
46
the chloroplast is surrounded by a.....
double membrane (envelope) with an inner bilayer membrane and an outer bilayer membrane
47
instead of a cytoplasm the chloroplast contains the ........ which is... and what does it do
the stroma a jelly like matrix, enclosing the liquid of the chloroplast, it is the site of many chemical reactions resulting in the formation of complex organic molecules
48
in a chloroplast the space between the outer and inner membrane is called the
intermembrane space
49
what does the stroma contain
contains the appropriate enzymes and suitable pH for calvin
50
the outer and inner membrane on a chloroplast is evidence for
endosymbiosis
51
what do the stroma lamellae do
connect and separate thylakoid stacks/granum
52
what are granum and what do they do
flat membrane stacks that increase sa:v ratio for light absorption/light dependent stage
53
apart from sa:v how is grana adapted to its function
contains photosystems and electrons carriers/etc
54
what do thylakoids have
has an etc and atpsynthase for photophosphorylation
55
the thylakoid membrane is the site of
light dependent reactions of photosynthesis with the photosynthetic pigments embedded directly in the membrane
56
what are the adaptations, for photosynthesis, of a dicotyledonous leaf
broad, thin, flat, large sa
57
why are the apical surfaces of the upper and lower mesophyll moist
for gas exchange the gases dissolve, enzymes cant work in gas
58
why do the lower or spongy mesophyll have air spaces
large sa to let gases circulate
co2 has dissolved so creates low conc in the air sac so conc gradient is created and the co2 needed for photosynthesis diffuses in
59
why is the cuticle on a leaf waxy
to let the light (max amount)
60
why is the upper epidermis on a leaf thin and have no chloroplasts
short diffusion pathway
not block any light
61
how many plasma membranes does a chloroplast have
2 (outer and inner)
62
what is the lamellae for in chloroplasts
holds the grana together (intergranal)
63
how is a large sa of thylakoid membranes achieved in a chloroplast
they are flattened sacs and then stacked into grana
64
what other things to chloroplasts contain
circular dna
ribosomes
lipid droplets
65
what do the ribosomes in chloroplasts make
enzymes, pigments and pigments binding protein
66
what is the enzyme in chloroplasts
rubisco (the most abundant enzyme in the world)
67
where is the chlorophyll located in a chloroplast and how is it arranged
in the grana, sanwiched between the lipids and proteins of the thylakoid membranes
68
with the pigments are what else...
enzymes and electron carrier molecules/proteins
69
why are there so many pigment molecules
becasue they absorb and reflect different wave lengths = different colours
absorption is low in the green spectrum
70
what is the reason for the different shades and colours of leaves
different combinations of pigments
71
which colours are absorbed by chlorophyll a
red and blue
72
which colours are reflected by chlorophyll a
blue and green
73
what does chlorophyll b reflect
yellow and green
74
when there is a peak in the graph of absorption what does it indicate
that that is the wavelength that is most strongly absorbed
75
what is indicated on a dip on an absorption graph
that that is the wavelength that is reflected
76
nm is what is standard form
x10-9m
77
where is chlorophyll a located
in the reaction centre (bound to chlorophyll a/b binding protein), where reactions involved in photosynthesis take place
78
what is the reaction centre surrounded by
the anetnnae complex
79
where are the secondary photosynthetic pigments located, what do they combine with and do (antennae complex)
embedded in the thylakoid membrane, bound to proteins, they form a light harvesting system (antennae complex). the system absorbs/harvest light energy of different wavelengths and transfers the energy to the reaction centre
80
which colours are reflected by chlorophyll a
green
81
what is the role of the anntenae complex
to channel light energy to the reaction centre
82
as light hits the accessory pigments what happens in terms of electrons
electrons become excited to a higher energy level
83
the absorption spectrum indicates...
the wavelengths of light absorbed by each pigment
84
the action spectrum indicated
the overall rate of photosynthesis at each wavelength of light
85
does chlorophyll a lose or gain electrons
lose
86
at the start of photosynthesis, plant cells need to make ........ from ..... and .....
atp from adp and pi
87
what is atp synthase and what does it do
it is an enzyme that catalyses the formation of atp using adp and an inorganic phosphate
also lowers activation energy
88
what is a photosystem
pigment-protein complexes are arranged into arrays of hundreds of pigment molecules called photosystems
the light harvesting system (antennae complex) and reaction centre make up the photosystem
pigments with chlorophyll A at the centre
What name is given to the arrangement of accessory and primary pigments grouped together to gather and use light energy?
89
photosystems can also be called
pigment systems
90
in a photosystem what does the spatial and geometric organisation cause
most of the pigments to function as light harvesters and transfer the excitation energy to other pigments before unwanted photochemistry occurs
91
in photosystems what role do accessory/antenna pigments play
form a light harvesting system which absorbs light energy and transfers it to the reaction centre
92
What name is given to the specific types of pigment that surround chlorophyll?
accessory pigments
93
in photosystems what do electron acceptors do
synthesise atp via chemiosmosis
94
where are photosystems located
in thylakoid membranes
95
in photosynthesis light excites......
chlorophyll electrons (in photosystems) and they become energised/excitied
96
in photosynthesis the electrons are released when ..... and where do they go
chemical bonds are broken and they pass into an etc and are used to generate a proton gradient
97
in photosynthesis excited electrons pass through
electron transport chain making atp via chemiosmosis
98
atp synthase also requires ..... to ensure that the reaction occurs in the forward direction
energy
the reaction would normally proceed in the reverse direction
99
where are electron transport chain located
between the intermembrane space and the matrix of mitochondria
100
electron transport chains establish .... gradient
the proton gradient across the inner mitochondrial membrane
101
how is the energy supplied for adp + pi making atp (in respiration and photosynthesis)
the protons diffuse back into the matrix by diffusing through atp synthase -chemiosmosis
the flow of protons through the channels provides the energy for synthesis of atp
102
atp synthase is linked with....
hydrophilic membrane channel proteins
facilitated diffusion
103
what is the difference in protons across the inner mitochondrial membrane called
electrochemical gradient
104
in lose terms chemiosmosis is the
diffusion of protons/movement of ions across a partially permeable membrane down their electrochemical gradient/from a region of high conc to a region of low conc
105
energy is needed for chemiosmosis, where does it come from
high energy electrons/excited electrons
106
eg of respiratory substrate molecule
glucose
107
what are the 2 ways electrons can become excited
electrons in pigment molecules (eg chlorophyll) are excited by absorbing light from the sun
high energy electrons are released when chemical bonds are broken in rsm (eg glucose)
108
an etc is made up of a series of ... each with progressively
electron carriers each with progressively lower energy levels
109
what enters an etc
a high energy electron/excited electron
110
as high energy electrons move from ...... to ....... , ...... is released
one carrier to another carrier energy is released
111
what is the energy released in an etc used for
pumping protons across the membrane creating a proton gradient (electrochemical)
112
when the protons are pumped across the membrane because of the etc, where do they go
into the inter-membrane space of the mitochondrion
113
how is the proton gradient maintained
as a result of the impermeability of the membrane to hydrogen ions
114
in an etc how do the protons move back across the membrane down the gradient (chemiosmosis)
through the hydrophilic membrane channels which atp synthase is linked with
115
what is the name of organisms that photosynthesise
autotrophic organisms
116
in respiration the high energy electrons that go into the etc come from reduced
nad and fad
117
what is the enzyme called that hydrolyses atp producing adp and pi
atpase
118
atpase and atpsynthase is the same enzyme how is this possible
the reaction is reversible and happens depending on the conc of substrates and products of either side of the reaction
it is possible because the active site is complementary to both substrates and products
119
how many photosystems are there
2
120
light hits which photosystem first
photosystem 2
121
what happens at photosystem 2 and what is the process called
photolysis
water is broken down into oxygen, H+ and electrons
122
what happens to the electrons that come from photolysis
they go through electron carrier molecules
123
what happens to the H+ from photolysis
they go to resynthesise ATP
124
what does thin layer chromatography use as the solvent
silica gel or
125
what would happen if the gel layer in thin layer chromatography was thick
the spot wouldnt travel as far/fast so it would take longer to achieve the desired result
126
what can you do if you only get 1 spot in tlc and yk theres more than 1 solute
rotate the chromatagram 90degrees and use a different solvent
127
describe 2 ways in which the grana are adapted to their function (2)
contains pigments for the absorption of light (dependent reactions)
contains etc, contains atp synthase
has a large sa for light absorption
128
are the phospholipid bilayers within the chloroplast permeable or impermeable to protons
impermeable
129
do thylakoid membranes contains etc proteins
yes
130
is there atp synthase embedded in thylakoid membranes to maintain chemiosmotic gradients
no
131
outline the role of membranes WITHIN a cell (2)
separates cell into compartments/compartmentalisation
for example mitochondria and resp eznymes
132
why is it important that the leaf extract is dried before mixing with the organic solvent in tlc
the water may have affected the Rf value, solvent became too dilute
133
134
in tlc which spot has the least polar (pigment)
the one that is most soluble in the mobile phase and least attracted to the stationary phase
135
in tlc why is it important that the plate is carefully held by the edges to avoid damaging the surface of the plate
so movement of spots not affected by damage
so that plates are not contaminated by fingerprints/oils from skin
136
in tlc why is it important that the plate doesnt touch the sides of the jar or anywhere else
condensation on sides of jar may affects movement of spots
to avoid spots travelling in the wrong direction
137
suggest an advantage of working as quickly as possible when extracting pigments for tlc
to reduce damage, contamination of pigments
to avoid evaporation of solvent
138
What is the primary pigment which is used to absorb light in chloroplasts?
chlorophylla.
139
What name is given to the arrangement of accessory pigments used to absorb light energy from a wide range of wavelengths?
light harvesting system
140
What name is given to the arrangement of proteins containing the primary pigment which carries out the reactions of the light-dependent stage?
reaction centre
141
What name is given to the arrangement of accessory and primary pigments grouped together to gather and use light energy?
photosystem
142
What are the three products of photolysis?
Protons, electrons and oxygen
143
What are the two useful products of the light-dependent reaction?
ATP, NADH
144
In the light-dependent reaction, excited electrons lost from photosystem I are replaced from where?
From the electron transport chain starting from photosystem 2
145
Which photosystems are involved in non-cyclic photophosphorylation?
photosystem 2
photosystem 1
146
Which photosystem is involved in cyclic photophosphorylation?
photosystem 1
147
What is the name of the five-carbon compound combined with carbon dioxide in the first stage of the Calvin Cycle?
rubp
148
Which enzyme catalyses the production of an unstable six-carbon compound in the first stage of the Calvin Cycle?
rubisco
149
What substance is produced by the breakdown of the unstable six-carbon compound in the first stage of the Calvin Cycle?
gp
150
What substance is produced by the reduction of glycerate 3-phosphate in the Calvin cycle?
tp
151
What happens to the majority of the triose phosphate produced by the Calvin cycle
rubp
152
What is meant by the term fixation of carbon dioxide?
Incorporating carbon dioxide into an organic compound.
153
Triose phosphate can be used to synthesise which organic molecules
Carbohydrates, amino acids and lipids.
154
where is the site of light independent reactions/metabolic pathways involving co2
stroma
155
156
name 2 different polysaccharides that can be synthesised from the end products of the light independent stage of photosynthesis
cellulose, starch, amylose and amylopectin
157
what compound it regenerated in the calvin cycle so that more co2 canbe fixed
RUBP
158
what is the first stable product of carbon dioxide fixation
gp
159
suggest 2 ways i which the ultrastructure of the chloroplast can be altered by high temperatures
with explanations
damage to chlorophyll which will reduce the light dependent stage
damage to membranes in chloroplast which will reduce the light dependent stage
damage to membranes in chloroplast reduction is reaction sites for electron transfer which will reduce photophosphorylation/atp production in the light independent stage
damage to membrane around chloroplast which will reduce light independent stage
160
assess the impact of moderate high temp stress on the processs of photosynthesis
deactivation of rubisco will reduce carbon fixation/ldr
ldr will reduce when supply of nadp is reduced
reduction is stomatal aperture will recude carbon dioxide available for fixation
161
state the advantage of the plant having a range accessory pigments in photosystems
able to absorb/use range of different/more wavelengths of light
162
nad is reduced by acccepting hydrogen atoms true or false
true
163
coA delivers the 3 carbon atoms of pyruvate to the krebs cycle in the form of an acetyl group true or false
false
164
nad and fad are examples of enzymes true or false
true
165
atp synthase embedded in the thylakoid membrane maintains chemiosmotic gradients true or false
false
166
phospholipid bilayers within the chloroplast are impermeable to protons true or false
true
167
thylakoid membranes contains etc proteins true or false
true
168
what factors limit photosynthesis
light intensity
temperature
co2 conc
169
List three ways farmers can overcome some of the limiting factors of photosynthesis.
Use artificial lighting to maintain a high light intensity.
Re-use carbon dioxide waste to maintain a high carbon dioxide concentration.
Use greenhouses kept at specific temperatures.
170
Potassium ions diffusing across the cell membrane into the cytoplasm is an example of what...
chemiosmosis
171
