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A level biology > Topic 5 > Flashcards

Topic 5 Flashcards

1
Q

What are the different forms of cellular respiration?

A

-aerobic: requires oxygen, produces carbon dioxide

-anaerobic : oxygen not required, produce ethanol / lactate , carbon dioxide & little ATP

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2
Q

What are the 4 stages of aerobic respiration?

A
  1. Glycolysis
  2. Link reaction
  3. Keen cycle
  4. Oxidative phosphorylation
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3
Q

What are is the procces of glycolysis ?

A

1) glucose made more reactive by gaining two phosphate molecules ,that come from hydrolyses of 2 ATP molecules in a proccess called phosphorylation which lowers activation energy for enzymes controlled reaction (forms fructose 1-6 bisphosphate)

2) glucose split into two 3 carbon molecules called triode phosphate

3) hydrogen removed from each triode phosphate molecule and transferred to NAD to form reduced NAD. [oxidising triose phosphate] and inorganic phosphate added

4) enzyme controlled reaction convert triose phosphate into pyruvate. Whilst 2 ADP are regenerated to ATP by gaining a phosphate via substrate level phosphorylation

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4
Q

What is the yield of glycolysis?

A

2 ATP, 2 reduced NAD and 2 pyruvate molecules

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5
Q

Where does glycolysis occur?

A

In cytoplasm

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6
Q

What is the process of the link reaction?

A

-pyruvate molecules actively transported into mitochondria matrix

-pyruvate oxidises to acetate (pyruvate loses carbon dioxide [decarboxylation] molecule and hydrogen[dehydrogenation])

NAD gain hydrogen = reduced NAD

-acetate combines with co enzyme A to produce acetylcoenzyme

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7
Q

What is the equation for the link reaction?

A

Pyruvate + NAD + Coa = acetyl CoA + reduced MAD + carbon dioxide

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8
Q

What is the Kreb cycles procces ?

A

-acetyl-coenzyme A combined with 4 carbon to produce 6 carbon molecules

-6 carbon molecules loses carbon dioxide& hydrogen in series of reactions to give 4 carbon molecules & ATP from substrate level phosphorylation

-the 4 molecule of carbon dioxide combines with new acetyl-coenzyme to repeat cycle

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9
Q

What is the yield from the Kreb cycle?

A

Reduced NAD, reduced FAD, ATp,

2 molecules of carbon dioxide

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10
Q

What is the significance of the Kreb cycle?

A

•breaks down macromolecules into smaller ones
• produce hydrogen carried by NAD to electron transfer chain and provides energy for oxidative phosphorylation
• regenerates 4 carbon molecules which combine to acetyl-co enzyme A
• an intermediate compound source used by cells to manufacture other important substances (acetyl-CoA used as substrate for fatty acid synthesis )

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11
Q

What are Co-enzymes?

A

Molecule some enzyme require to function

They carry hydrogen atoms

Examples : NAD, FAD, NADP

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12
Q

Where does oxidative phosphorylation occur?

A

In mitochondria

Between the matrix and the inner membrane

Where the cristae that contains enzymes & proteins required for the procces

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13
Q

What is the procces of oxidative phosphorylation?

A

-hydrogen atoms from previous stage combine with FAD & NAP transforming them into reduced co-enzymes

-reduced NAD & FAD donate electrons from there hydrogen atoms to first molecule in electrons transfer chain [rNAD produce 3ATP molecules in chain and rFAD only make 2]

-electrons pass along electron transfer chain In oxidative-reduction reaction series. Energy released causes protons to be actively transported accross inner mitochondria members into inter membranal space

-protons accumulate in inter-membranal space, then diffuse out into matrix through ATP synthase channels in inner mitochondrial membrane (help stimulate reaction of ATP

-end of electron transfer chain, electrons combine with protons (hydrogen) & oxygen to form water

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14
Q

What is the electron transfer chain and how is it used in oxidative phosphorylation?

A

Involves transfer of electrons down electron carrier series

NAD & FAD pass electrons along electron transfer carrier molecules (they are at lower energy levels. So move down energy gradient, allowing energy to be gradually released

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15
Q

What alternate respiratory substrates aside from glucose can be used for respiration ?

A

-lipids: when hydrolysed produce glycerol, that’s phosphorylated & converted to trios phosphate , which proceeds along the stages. The fatty acid is broken down into 2 carbon and converted into acetyl Co-enzyme

-protiens: hydrolysed to constituent amino acids, that undergo deamination in before undergoing respiration. 3 carbon compounds converted to pyruvate, whilst 4-5 carbon compound converts to intermediates in Kreb cycle

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16
Q

What is anaerobic respiration like in plants?

A

• pyruvate loses carbon dioxide molecules and accepts hydrogen from reduced NAD to produce ethanol

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17
Q

What is the equation for anaerobic respiration in plants?

A

Pyruvate + reduced NAD-> ethanol + carbon dioxide + oxidised NAD

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18
Q

What is anaerobic respiration respiration like in animals?

A

Pyruvate molecule takes up 2 hydrogen atoms from reduced NAD
to form lactate and oxidised NAD

(Lactate is oxidised into pyruvate and oxidised further to release energy/ convert to glycogen when oxygen is avalible . Where it’s then taken to liver )

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19
Q

What is the equation for anaerobic respiration in animals?

A

Pyruvate + reduced NAD-> lactate + oxidised NAD

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20
Q

How does lactate affect rate of reaction for respiration?

A

Lactate is acidic which changes the PH . This then affect the enzymes actions and structural function

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21
Q

What is an direct method for energy yields in organisms ?

A

Kreb cycle & glycolysis

Anaerobic respiration (pyruvate into ethanol/lactate) so only utilises glycolysis

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22
Q

What is an indirect method for energy yields in organisms?

A

Oxidative phosphorylation

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23
Q

How is the lead structure adapted for photosynthesis?

A

• has large surface area that absorbs sunlight
• leaves arrangement which minimises overlapping & avoids shadowing of other leafs
• thin to provide short diffusion distance & light absorbed in first few micrometers of leaf
• transparent cuticle & epidermis letting light through to mesophyl cells
• long narrow upper mesophyl cells with chloroplast to collect sunlight
• lots of stomata for gaseous exchange= short diffusion pathway to mesophyl cells
• stomata open and close to respond to light intensity
• air space in lower mesophyl layer allow rapid diffusion in gas phase of co2 and 02
• has xylem and phloem

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24
Q

What is the equation of photosynthesis?

A

6C0(2) + 6H(2)O -> C(6)H(12)O(6) + 6O(2)

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25
What are the the three main stages of photosynthesis?
1, capturing light energy from chloroplast pigments 2, light dependant reaction 3, light independent reaction
26
What is biomass?
Total mass of living (renewal organic like carbon) material in a specific area at a given time (Can change in different seasons-exp, leaf falls in winter) [Measured using dry mass per given area ] [area: gm( negative squared)] [volume: gm(negative cubed)]
27
What are producers?
Photosynthetic organisms which manufacture organic molecules (glucose) from smaller inorganic molecules (co2, H2O) (Chemosynthetic organism [mainly in blue green algae])
28
What are consumers?
Organisms which obtain their energy by consuming other organisms -primary, secondary, tertiary consumer -first consumer, second consumer
29
What are saprobions (decomposers)?
Fungi/ bacteria that breaks down complex organic molecules from dead organisms into simpler molecules/ irons. Important in recycling nutrients Then they can release materials that can be then recycled and absorbed by plants
30
What are food chains?
Describe feeding relationships between organisms at each tropic level
31
What are trophic levels?
Each stage in a food chain/ web/ pyramid of numbers/ biomass (Producer), (consumer,1,2,3,4)
32
What are food webs?
All of the food chains in habitat. They are better than food chains as they show all linked feeding relationships
33
What is a niche (ecological)?
Describes what species is like Includes where it occurs. How it behaves and interactions with other species . How it responds to the environment
34
What is an ecosystem ?
All the living & non living components of a particular area (rainforest, tropical seas, desert)
35
What is calorimetry?
A method to measure biomass
36
What is the process of bomb calorimetry?
Sample of dry material (mass) weighed and burnt In Pure oxygen in a sealed chamber called bomb so heat released can’t escape Bomb is surrounded by water bath and the heat of combustion causes small temperature to rise in water (Use value is specific heat capacity of water and water volume to calculate energy released )
37
How much sun energy is captured by green plants?
1-3% of suns energy is available to convert in the plant into organic matter
38
How much net primary production is absorbed from plant for primary consumer growth
10% energy
39
How much net primary production is consumed between consumers?
Up to 20% transferred
40
What are the reasons for suns energy not converting?
• 90% sun energy reflected back into space • not all wave lengths of light can be absorbed • light doesn’t fall on chlorophyll molecule • low co2 level limit rate of photosynthesis
41
What is gross primary production?
Total quantity of chemical energy stored in plant biomass in given area/ volume (Plants use 20-50% of this energy for respiration )
42
What is net primary production?
Chemical energy store that’s left after respiration usage if energy (avalible for plant growth, repoduction and decomposers)
43
What are the reasons for low percentage of energy transfer at each stage?
• some parts of organisms are not consumed • some parts consumed but not digested • some energy lost in excreted material (urine) • energy lost from heat from respiration, so lost to environment (common in mammals)
44
What is the equation of net production of consumers?
N=I-(F+R) N= net production I = chemical energy store of ingested food F= energy lost in feaces/ urine R= energy lost in respiration
45
What are the consequences of ineffecticiency of energy transfers?
• food chains usually have 4-5 trophic levels • total mass of organisms in particular place (biomass) less at higher trophic levels • total energy avalible less at each level as one moves up food chain
46
What is the energy , from light, used for in the light dependent reaction?
-add phosphate to ADP to make ATP -split water into H(+) ions [protons] and OH(-) ions under procces of photolyses
47
What is oxidation?
Substance - gains oxygen - Loses hydrogen - Loses electron
48
What is reduction?
Substance: -loses oxygen -gains hydrogen -gains electrons
49
How is ATP made in light dependent reaction?
-Electron chain -chemiosmotic theory
50
How is ATP made in. Light dependant reaction using electron chains?
St1-[photoionisation] chlorophyll absorbs light energy= boost energy in pair of electrons in chlorophyll = electrons leave chlorophyll = chlorophyll become ionised/ oxidised St2- electrons are taken up by electron carrier (reduced) and pass along electron carriers via oxidation-reduction reactions that form electron chain in thyakloid membrane St3- the energy priced in this chain is then used to convert to ADP + p to ATP (Chains energy levels lower as it passes through electron carriers)
51
What is the chemiosmotic theory?
An precise mechanism for ATP production • thylakoid is a enclosed chamber where protons (H+) pumped to from strong via protein carriers in membrane that gains energy from photolysis to mobilise this process. And protons from photolysis of water is added to the proton concentration in thylakoid space -this creates high concentration of protons in thylakoid & low in stroma. So protons then travel back through the membrane via ATP substrates channel /[stalked granules] as rest of membrane is impermeable -when traveling through ATP synthase they change enzymes structure that catalyses ADP with inorganic phosphate to form ATP
52
What is the photolysis of water?
Splitting of water molecule -producing electrons that replace lost electron in chlorophyll and provide protons for chemiosmotic theory Equation 2H(2)O -> 4H(+) protons + 4e(-) electrons + O(2)
53
What are the products of the light dependent reaction?
[reduced NADP] protons passed through ATP synthase taken up by NADP, and it carries electrons from chlorophyll molecules -oxygen produced is used for respiration or is removed as a waste product -ATP
54
What does the light independent reaction require?
Products from light depends reaction
55
How does the light independent reaction produce organic molecules?
Calvin cycle
56
What is the process of the Calvin cycle?
1) carbon dioxide diffuses from atmosphere, throughout into the leaf into the stroma of the chloroplast 2) carbon dioxide reacts with ribuloose bisphosphate (RuBP) catalysed by rubisco [ribukose bisphopshate carbotylase] and produces 3 carbon glycerine 3-phosphate (GP) . That is then reduced to triose phosphate using reduced NADP and energy supplied by ATP 3) NADP then goes back to light- dependant reaction to be reduced again and triosphate converted to organic substances (glucose) or regenerates ribuse bisphosphate using ATP from light dependent reaction
57
How is the chloroplast adapted for efficient photosynthesis in the light dependent reaction?
-Thyakloid membranes have large surface area for chlorophyll, electron carriers and enzymes attachment -protein network in grana hold chlorophyll precisely to allow maximum light absorption -grana membrane have ATP synthase that catalyse ATP production. Is selectively permeable to allow establishment of protein gradient -chloroplast has DNA & ribosomes that efficiently manufacture proteins used in reaction
58
How is the chloroplast adapted for efficient photosynthesis in the light Independent reaction?
-fluidity of stroma has all enzymes needed, its membrane bound so enzymes & substrates can be maintained -products of light dependent reaction in grana can diffuse into stroma -has DNA & ribosomes efficiently manufacture protein in light Independant reactions
59
What is the simple sequence of a nutrient cycle?
-nutrient is taken up by producers as inorganic molecules -producers incorporate nutrients into complex organic molecules -nutrients pass into consumers when producers are eaten -nutrient pass along food chain when animals eaten by other consumers -saprobiontic microorganisms breakdown complex molecules of nutrients in animal/plant that has died. Into original simple form. To ensure nutrients are released for re-use
60
What are the stages of the nitrogen cycle?
-nitrogen fixation -animal nutrient transference to decomposition -ammunification -nitrification -denitrification
61
What is nitrogen fixation?
-process nitrogen gas converted into nitrogen containing compound Types: -industrial fixation: -atmospheric fixation: lighting passes through atmosphere makes nitrate soil -biological fixation
62
What are the two types of biological fixation?
-free living nitrogen fixing bacteria -symbiosis( mutualistic nitrogen fixing bacteria)
63
What is free living nitrogen fixing bacteria?
Example: (Aztobacter) Nitrogen gas diffuses into bacteria (root nodules) Inside the nitrogenese catalyses its reduction to ammonia by using ATP . Ammonia is then used to make amino acids. Then when they die nitrogen rich compounds are released (convert nitrogen in air or nitrate in soil)
64
What is mutualistic nitrogen fixing bacteria?
Exp: (Rhizobium) Two organism living together that benefit each other When bacteria produces amino acids, some is converted into the plant, where the plant in exchange gives the bacteria, carbohydrates to use for respiration (Either plant / legumes )
65
Why do root modules contain leg haemoglobin?
Binds oxygen in nodules, to protect (reduction reaction for ammonium ions) from oxidation
66
What happens after biological fixation?
Plants absorb nitrates in soil by active transport via the roots & animals that eat the plants .
67
How are ammonia ions formed in nitrogen cycle?
Plant and animal excrete ammonia ions They die and decay in soil from saprobiontic microorganisms which undergo procces of ammonificatiom where protease that digest proteins into amino acid and deamonases reduce amino acid to ammonium ions So produces ammonium ions from organic nitrogen containing compounds into the soil
68
What is the procces of nitrification?
- an oxidation reaction carried out by nitrifying bacteria - 1) nitrosomonas convert’s ammonium ions to nitrite ions in oxidation reaction - 2) nitrobacter converts nitrite ions to nitrate ions via an oxidation reaction (This process requires oxygen for bacteria, so requires aerobic soil conditions)
69
What is the process of denitrification?
-reduction reaction, occurs in anaerobic conditions (waterlogged soil) so uses anaerobic denitrification bacteria Converts soil nitrate into nitrite into gaseous nitrogen Reduces availability for nitrogen containing compounds for plants
70
What is mycorrhiza fungi?
Association of fungi & roots of plants An mutualistic relationship: plant benefits from improved water & inorganic ion uptake . Whilst fungus receives organic components ( sugars & amino acids)
71
What is mycorrhizae fungi role in nutrient cycle?
• Acts like extensions of plant root system, vastly increasing total surface area for water & mineral absorption • holds water and mineral near the roots. So plant can resist droughts & take up inorganic ions more readily ( scarce ions like phosphate ions)
72
What is the process of the phosphorus cycle?
1) phosphate exists as phosphate ions in sedimentary rock deposits in the sea. That are brought to the surface by geological uplifting 2) weathering and erosion of rocks dissolves phosphate ions to be absorbed by plants (incorporate into biomass as complex molecules) 3) these ions are either fed by animals passing phosphate , who excrete excess phosphate ions In form of waste material (guano) or along with animals die. Where decomposers break down organisms and release phosphate into soil / water [ phosphate ions in bones/ shells are slow to break down] 4) phosphate ions In excreta, released by decomposition or dissolved out of rocks by leaching. Transported by streams & rivers into lakes and oceans where they form sedimentary rocks
73
Why are fertilisers needed?
- replenish mineral ions in intensive food production (agricultural ecosystems) where land is used repeatedly - mineral ions intensively used on land and not replaced. From crops being taken away, so no death , so don’t decay -dead remains / urine / faeces of consumers not often returned to farmland -reduced concentration of mineral ions became a limiting factor
74
What are natural (organic ) fertilisers?
-(materials of animal /plant origin naturally produced) dead & decaying plants/animals remains and animal waste
75
What are Artificial (inorganic) fertilisers?
-mined from rock/deposits and converted/ blended to give appropriate balance of minerals for crops (Has nitrogen , phosphates and potassium)
76
What happens if there’s excess fertilisers on land? (Affect on agriculture)
Increased inefficient production
77
What are the positive consequences for using fertilisers?
Plants grow taller, have greater leaf area, so increase photosynthesis and improve crop productivity
78
What are the negative effects of nitrogen containing fertilisers?
-reduce species diversity -leaching -eutrophication
79
How does nitrogen containing fertilisers cause reduction in species diversity?
Increases growth for nitrogen rich in soil plants like certain grasses, nettles that outcompete species. Causing other species death. (Species only survive if nitrogen concentrations are low enough)
80
What is leaching?
Nutrients removed from soil Rainwater dissolves soluble nutrients, carrying them deep into soil, beyond plants reach. They then find there way into rivers & streams
81
What are the issues with leaching?
-Pollutes water-courses [high nitrate concentrations prevents efficient oxygen transport in babies if they drink it or cause illness like stomach cancer] -eutrophication
82
What is eutrophication?
Nutrient concentration increases in water body’s
83
What are the consequences of eutrophication? (step by step)
-1) low concentration nitrate so nitrate is limiting factor for plant growth -2) increase concentration nitrate from leaching = not limiting factor -3) algae grows on surface , so upper water layer densely populated with algae ‘algal boom’ -4) dense surface absorbs light, prevents it penetrating lower depths . So light became limiting factor = lower algae die -5) dead plants non limiting factor for saprobiontic bacteria growth= grow= increase oxygen demand for bacteria -6) reduce oxygen in water, so oxygen limiting factor for aerobic response in organisms. =less competition for anaerobic organisms -7) increases decomposing dead material and= release toxic wastes (hydrogen sulphate) (nitrates and sulphur containing compounds) that make water putrid

A level biology (8 decks)

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