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MISS ESTRUCH FLASHCARDS > TOPIC 5: ENERGY TRANSFERS IN AND BETWEEN ORGANISMS > Flashcards

TOPIC 5: ENERGY TRANSFERS IN AND BETWEEN ORGANISMS Flashcards

1
Q

Location of light
dependent
reaction

A

Thylakoid membranes of
chloroplast

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2
Q

Location of light
independent
reaction

A

Stroma of chloroplast

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3
Q

Thylakoid
membranes

A

Folded membranes containing
photosynthetic proteins
(chlorophyll)
embedded with transmembrane
electron carrier proteins
involved in the LDRs

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4
Q

Chlorophyll

A

Located in proteins on thylakoid
membranes
mix of coloured proteins that
absorb light
different proportions of each
pigment lead to different
colours on leaves

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5
Q

Advantage of
many pigments

A

Each pigment absorbs a
different wavelength of visible
light
many pigments maximises
spectrum of visible light
absorbed
maximum light energy taken in
so more photoionisation and
higher rate of photosynthesis

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6
Q

Light-dependent
reaction (LDR)

A

First stage of photosynthesis
occurs in thylakoid membranes
uses light energy and water to
create ATP and reduced NADP
for LIR
involves photoionisation of
chlorophyll, photolysis and
chemiosmosis

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7
Q

Photolysis

A

Light energy absorbed by
chlorophyll splits water into
oxygen, H+ and e
H2O -> 1/2O2 + 2e- +2H+

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8
Q

Products of
photolysis

A

H+
Picked up by NADP to form
reduced NADP for LIR
e
passed
along chain of
electron carrier proteins
oxygen
used in respiration or
diffuses out leaf via stomata

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9
Q

Photoionisation
of chlorophyll

A

Light energy absorbed by
chlorophyll excites electrons so
they move to a higher energy
level and leave chlorophyll
some of the energy released is
used to make ATP and reduced
NADP

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10
Q

Chemiosmosis

A

Electrons that gained energy
move along a series of electron
carriers in thylakoid membrane
release energy as they go along
which pumps proteins across
thylakoid membrane
electrochemical gradient made
protons pass back across via
ATP synthase enzyme producing
ATP down their conc. gradient

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11
Q

What happens to
protons after
chemiosmosis

A

Combine with co-enzyme NADP
to become reduced NADP
reduced NADP used in LIR

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12
Q

Products of
LDR

A

ATP (used in LIR)
reduced NADP (used in LIR)
oxygen (used in respiration /
diffuses out stomata)

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13
Q

Light
independent
reaction (LIR)

A

Calvin cycle
uses CO2, reduced NADP and
ATP to form hexose sugar
occurs in stroma which
contains the enzyme Rubisco
temperature-sensitive

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14
Q

RuBP

A

Ribulose Bisphosphate
5-carbon molecule

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15
Q

GP

A

Glycerate-3-phosphate
3-carbon molecule

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16
Q

TP

A

Triose phosphate
3-carbon molecule

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17
Q

Producing
hexose sugar
in LIR

A

Takes 6 cycles
glucose can join to form
disaccharides (sucrose) or
polysaccharides (cellulose)
can be converted to glycerol to
combine with fatty acids to
make lipids

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18
Q

Limiting factor

A

A factor which, if increased, the
rate of the overall reaction also
increases

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19
Q

Limiting
factors of
photosynthesis

A

Light intensity
CO2 concentration
temperature

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20
Q

How light
intensity limits
photosynthesis

A

If reduced, levels of ATP and
reduced NADP would fall
LDR limited - less photolysis
and photoionisation
GP cannot be reduced to TP in LIR

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21
Q

How temperature
limits
photosynthesis

A

LIR inhibited - enzyme
controlled (Rubisco)
up to optimum, more collisions
and E-S complexes
above optimum, H-bonds in
tertiary structure break, active
site changes shape - denatured

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22
Q

How CO2
concentration limits
photosynthesis

A

If reduced, LIR inhibited
less CO2 to combine with RuBP
to form GP
less GP reduced to TP
less TP converted to hexose and
RuBP regenerated

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23
Q

Agricultural
practices to
maximise plant
growth

A

Growing plants under artificial
lighting to maximise light
intensity
heating in greenhouse to
increase temperature
burning fuel to release CO2

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24
Q

Benefit of
agricultural
practices for plant
growth

A

Faster production of glucose ->
faster respiration
more ATP to provide energy for
growth e.g. cell division +
protein synthesis
higher yields so more profit

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25
Q

Products of LIR

A

Hexose sugar
NADP - used in LDR

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26
Q

Stages of
aerobic
respiration

A

1) Glycolysis
2) Link reaction
3) Krebs cycle
4) Oxidative phosphorylation

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27
Q

Location of
glycolysis

A

Cytoplasm

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28
Q

Glycolysis

A

Substrate level phosphorylation
- 2 ATP molecules add 2
phosphate groups to glucose
glucose phosphate splits into
two triose phosphate (3C)
molecules
both TP molecules are oxidised
(reducing NAD) to form 2
pyruvate molecules (3C)
releases 4 ATP molecules

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29
Q

Coenzymes

A

A molecule which aids / assists
an enzyme
NAD and FAD in respiration both
gain hydrogen to form reduced
NAD (NADH) and reduced FAD
(FADH)
NADP in photosynthesis gains
hydrogen to form reduced NADP
(NADPH)

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30
Q

Products of
glycolysis

A

Net gain of 2 ATP
2 reduced NAD
2 pyruvate molecules

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31
Q

How many ATP
molecules does
glycolysis produce

A

2 ATP molecules used to
phosphorylate glycose to
glucose phosphate
4 molecules generated in
oxidation of TP to pyruvate
net gain 2 ATP molecules

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32
Q

Location of the
link reaction

A

Mitochondrial matrix

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33
Q

Link reaction

A

Reduced NAD and pyruvate
are actively transported to
matrix
pyruvate is oxidised to
acetate (forming reduced
NAD)
carbon removed and CO2
forms
acetate combines with
coenzyme A to form
acetylcoenzyme A (2C)

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34
Q

Products of the
link reaction per
glucose molecule

A

2 acetylcoenzyme A molecules
2 carbon dioxide molecules
released
2 reduced NAD molecules

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35
Q

Location of
the Krebs
cycle

A

Mitochondrial matrix

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36
Q

Krebs cycle

A

Acetylcoenzyme A combines
with 4C molecule to produce a
6C molecule - enters cycle
oxidation-reduction reactions

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37
Q

Products of the
Krebs cycle per
glucose

A

8 reduced coenzymes
6 reduced NAD
2 reduced FAD
2 ATP
4 carbon dioxide

38
Q

Location of
oxidative
phosphorylation

A

Cristae of mitochondria

39
Q

Mitochondria
structure

A

Double membrane with inner
membrane folded into cristae
enzymes in matrix

40
Q

Role of reduced
coenzymes in
oxidative
phosphorylation

A

Accumulate in mitochondrial
matrix, where they release their
protons (H+) and electrons (e-)
regenerate NAD and FAD to be
used in glycolysis/ link reaction
/ Krebs cycle

41
Q

Role of electrons
in oxidative
phosphorylation

A

Electrons pass down series of
electron carrier proteins, losing
energy as they move
energy released actively
transports H+ from
mitochondrial matrix to intermembranal
space
electrochemical gradient
generated

42
Q

How is ATP made
in oxidative
phosphorylation

A

Protons move down
electrochemical gradient back
into matrix via ATP synthase
ATP created
movement of H+ is
chemiosmosis

43
Q

Role of oxygen
in oxidative
phosphorylation

A

Oxygen is the final electron
acceptor in electron transport
chain
oxygen combines with protons
and electrons to form water
enables the electron transport
chain to continue

44
Q

How would lack
of oxygen affect
respiration

A

Electrons can’t be passed along
the electron transport chain
the Krebs cycle and link
reaction stop because NAD and
FAD (converted from reduced
NAD/FAD as they release their H
atoms for the ETC), cannot be
produced

45
Q

Oxidation

A

Loss of electrons
when a molecule gains
hydrogen

46
Q

Reduction

A

Gain of electrons
a reaction where a molecule
gains hydrogen

47
Q

Location of
anaerobic
respiration

A

Cytoplasm
glycolysis only source of ATP

48
Q

Anaerobic
respiration in
plants & microbes

A

Pyruvate produced in glycolysis
is reduced to form ethanol and
CO2
pyruvate gains hydrogen from
reduced NAD
reduced NAD oxidised to NAD so
can be reused in glycolysis
2 ATP produced

49
Q

Anaerobic
respiration
animals

A

Pyruvate produced in glycolysis
is reduced to form lactate
pyruvate gains hydrogen from
reduced NAD
reduced NAD oxidised to NAD so
can be reused in glycolysis
2 ATP produced

50
Q

Other
respiratory
substances

A

Fatty acids and amino acids
can enter the Krebs cycle for
continued ATP synthesis

51
Q

Lipids as
respiratory
substances

A

Glycerol from lipid hydrolysis
converted to acetylcoenzyme A
can enter the Krebs cycle

52
Q

Proteins as
respiratory
substances

A

Amino acids from protein
hydrolysis can be converted to
intermediates within Krebs
cycle

53
Q

Producers

A

Plants
produce their own
carbohydrates from carbon
dioxide (autotrophs)
start of a food web

54
Q

Energy transfer
between trophic
levels

A

Biomass and its stored energy
is transferred through trophic
levels very inefficiently
most energy is lost due to
respiration and excretion

55
Q

Consumers

A

Heterotrophs that cannot
synthesise their own energy
obtain chemical energy through
eating

56
Q

Biomass

A

Measured in terms of:
mass of carbon
dry mass of tissue per given
area

57
Q

How is dry mass
of tissue
estimated

A

Sample of organism dried in
oven below 100C (avoiding
combustion + loss of biomass)
sample reweighed at regular
intervals
all water removed when mass
constant

58
Q

Why is dry mass a
representative
measure of biomass

A

Water content in tissues varies
heating until constant mass
allows standardisation of
measurements
for comparison

59
Q

Calorimetry

A

Laboratory method used to
estimate chemical energy
stored in dry biomass

60
Q

Calorimetry
method

A

Sample of dry biomass is burnt
energy released used to heat
known volume of water
change in temperature of water
used to calculate chemical
energy

61
Q

Gross primary
production

A

Chemical energy stored in plant
biomass, in a given area /
volume
total energy resulting from
photosynthesis

62
Q

Net primary
production

A

Chemical energy stored in plant
biomass after respiratory losses
available for plant growth and
reproduction - create biomass
available to other trophic levels

63
Q

Calculating net
primary
production

A

NPP = GPP - R
R = respiratory losses to the
environment

64
Q

Calculating net
production of
consumers (N)

A

N = I - (F + R)
I = chemical energy store in
ingested food
F = chemical energy store in
faeces / urine
R = respiratory losses

65
Q

Units of
productivity
rates

A

kJ Ha-1 year-1
kJ is the unit for energy

66
Q

Why is
productivity
measured per area

A

Per hectare (for example) is
used because environments
vary in size
standardises results so
environments can be compared

67
Q

Why is
productivity
measured per year

A

More representative of
productivity
takes into account effects of
seasonal variation
(temperature) on biomass
environments can be compared
with a standardised amount of
time

68
Q

Why is energy
transfer
inefficient from
sun -> producer

A

Wrong wavelength of light - not
absorbed by chlorophyll
light strikes nonphotosynthetic
region (bark)
light reflected by clouds / dust
lost as heat

69
Q

Why is energy
transfer inefficient
after producers

A

Respiratory loss - energy used
for metabolism (active
transport)
lost as heat
not all plant / animal eaten
(bones)
some food undigested (faeces)

70
Q

Farming practices
to increase energy
transfer for crops

A

Simplifying food webs to reduce
energy / biomass
herbicides kill weeks -> less
competition
fungicides reduce fungal
infections
results in more energy used to
create biomass
fertilisers such as nitrates to
promote growth

71
Q

Farming practices
to increase energy
transfer for
animals

A

Reducing respiratory losses
(more energy to make biomass)
restrict movement
keep warm
slaughter animal when young
(most energy used for growth)
selective breeding to produce
breeds with higher growth rates

72
Q

Saprobionts

A

Feed on remains of dead
organisms and their waste
products (faeces / urea) and
break down organic molecules
secrete enzymes for
extracellular digestion

73
Q

Mycorrhizae

A

Symbiotic relationship between
fungi and roots of plants
fungi act as extensions of roots
increase surface area of system
- increasing rate of absorption
mutualistic relationship as
plants supply fungi with
carbohydrates

74
Q

Importance of
nitrogen to
organisms

A

Used to create
amino acids / proteins
DNA
RNA
ATP

75
Q

Nitrogen cycle
stages

A

Nitrogen fixation
nitrification
denitrification
ammonification

76
Q

Nitrogen
fixation

A

Nitrogen fixing bacteria break
triple bond between two
nitrogen atoms in nitrogen gas
fix this nitrogen into
ammonium ions

77
Q

Nitrogen fixing
bacteria

A

Fix nitrogen gas into
ammonium ions
free living in soil
or form mutualistic relationship
on root nodules of leguminous
plants
give plants N in exchange
for carbohydrates

78
Q

Nitrification

A

Ammonium ions in soil are
oxidised to nitrite ions
nitrite ions are oxidised to
nitrate ions
by nitrifying bacteria

79
Q

Denitrification

A

Returns nitrogen in compounds
back into nitrogen gas in
atmosphere
by anaerobic denitrifying
bacteria

80
Q

Ammonification

A

Proteins / urea / DNA can be
decomposed in dead matter and
waste by saprobionts
return ammonium ions to soil -
saprobiotic nutrition

81
Q

Importance of
phosphorius

A

Used to create:
DNA
RNA
ATP
phospholipid bilayers
RuBP / GP/ TP

82
Q

Fertilisers

A

Replace nutrients (nitrates and
phosphates) lost from an
ecosystem’s nutrient cycle when
crops are harvested
livestock removed
can be natural (manure) or
artificial (inorganic chemicals

83
Q

Natural
fertilisers
advantages

A

Cheaper than artificial
fertilisers
often free if farmer has own
animals - recycle manure
organic molecules have to be
broken down first by
saprobionts so leaching less
likely

84
Q

Artificial
fertilisers
advantages

A

Contain pure chemicals in exact
proportions
more water-soluble, so more
ions dissolve in water
surrounding soil.
higher absorption

85
Q

Natural
fertilisers
disadvantages

A

Exact minerals and proportions
cannot be controlled

86
Q

Artificial
fertilisers
disadvantages

A

High solubility means larger
quantities can leach away with
rain
risking eutrophication
reduce species diversity as
favour plants with higher
growth rates e.g., nettles

87
Q

Leaching

A

When water-soluble compounds
are washed away into rivers /
ponds
for nitrogen fertilisers, this can
lead to eutrophication

88
Q

Eutrophication

A

When nitrates leached from
fields stimulate growth of algae
algal bloom
can lead to death of aquatic
organisms

89
Q

How does
eutrophication lead
to death of aquatic
organisms?

A

Algal bloom creates blanket
surface of water blocking light
plants cannot photosynthesize
and die
aerobic bacteria feed and
respire on dead plant matter
eventually, aquatic organisms
die due to lack of dissolved
oxygen in water

90
Q

Mutualistic
relationships

A

A type of symbiotic relationship
where all species involved
benefit from their interactions

91
Q

Role of
saprobionts in
nitrogen cycle

A

They use enzymes to
decompose
proteins/DNA/RNA/urea
releasing ammonium ions

MISS ESTRUCH FLASHCARDS (8 decks)

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