topic 5 Flashcards
how is atp created
in a hydrolysis reaction where the 3rd phosphate bond is broken (energy is released)
reaction catalysed by ATPase and ADP is the product
what is autotroph
what is heterotroph
an organism that can convert abiotic sources (light) of energy into energy stored in organic compounds
Can’t produce its own food eat plants or animals
respiration equation
respiration is the process by which
glucose + oxygen —-> carbon dioxide + water
organisms produce ATP
what is a redox reaction
oxidation is the loss of H2 or e- from a compound
reduction is the gain of H2 or e- from a compound
-a redox reaction involves oxid AND reduc
how can respiration be measured
respirometer
-02 is used up but co2 is produced in the meanwhile, co2 absorbed by KOH causing pressure in specimen tube to reduce, this pressure difference causes fluid to move up in the tube, , higher fluid moves = faster respiration rate
What is glycolysis
-takes place in the cytoplasm , sugar splitting, , involves splitting of a 6 carbon glucose molecule into 3 carbon pyruvate molecules
glycolysis 1
Where does it take place
glucose=made more reactive by the hydrolysis of 2 atp mols which are converted to ADP and are added to the glucose to form phosphorylated glucose
-phosp glucose is then split into 2 mols of glycerate-3-phosphate GP
Cytoplasm
glycolysis 2
whats the net gain and whats the final product og glycolusis
each GP mol oxidised TO FORM PYRUVATE by releasing 2H atoms which are accepted by NAD co enzyme , 2 NADH Mols formed which carry e- to etc
-2 atp mols used but 4 r produced , net gain of 2 atp
Pyruvate produced can become involved in anaerobic respiration, what happens ?
-Reduced NAD/NADH used to convert pyruvate into lactate
-Pyruvate reduced (accepts H atoms from reduc NAD)
-lactate lowers pH of blood
-as a result muscles become fatigued
2
After exercise lactate converted back to Pyruvate , Pyruvate is oxidised which can then enter the kerbs cycle anextra oxygen is needed
How does the energy released by the electrons moving down the ETC drive atp synthesis
Chemiosmosis
What’s substrate level phosphorylation
Direct transfer of a phosphate group
where does the link reaction take place and what happens
what are the products
-mitochondrial matrix
-pyruvate is decarboxylated (looses co2 mol)
-acetate formed combines with co enzyme A to make acetyl co enzyme
-NAD + is reduced to NADH as it gains H atoms from pyruv
overall products of link r : 2 mols Co2 , NADH , acetyl co enzyme
the 2 carbon acetyl co enzyme mols enter krebs cycle
what happens in the krebs cycle
1. formation of citrate
2. formation of a 5C compound
3. formation of a 4C compound
Acetyl coenzyme (2C compound) combines with a 4 carbon compound to produce citrate (6 carbon comp)
citrate = decarboxylated (releases a co2 mol)
citrate goes thru dehydrogenation (reducing NAD+ to NADH
forming a 5c compound)
5C comp goes thru another round of decarboxylation and dehydrogenation, resulting in ur 4C comp
4C comp goes thru more steps: FAD = reduced to FADH, NAD+ is reduced to NADH, one mol ATP produced
krebs cycle net products per glucose molecule
4 CO2 , 6 NADH, 2 mols reduced fad, 2 mols atp
the reduced NAD and FAD carry e- to the e- tc where atp is produced thru oxidative phosphorylation
what happens in the e- transport chain and where does it occur
inner mitochondrial membrane
the reduced NAD and FAD carry e- to the e- tc where atp is produced thru oxidative phosphorylation
At the end of the ETC
Electrons are passed to the final electron accepter oxygen along with protons to form water
H+ ions in the etc
Whereas the e-
Move into the inter membrane space (causing the conc of H+ ions to increase and creating a proton gradient), H+ diffuse back into the matrix thru the stalked particle. The energy released thru the movement of protons is used to combine ADP + Pi to form ATP
As e- pass between carriers energy is released as ATP
Explain the role of Krebs cycle
Completely oxidises Pyruvate
Releasing as much energy as possible to generate atp
To produce NADH
In a chloroplast what is the
Granum
Stroma
-Stacks of thylakoid membrane which contain chlorophyll
-fluid surrounding granum
What’s the absorption spectrum
The range of diff wavelengths of light a photosynthetic pigment absorbs
Action spectrum
The rate of photosynthesis against the wavelength of light absorbed
What is chlorophyll
What’s an adv
A mixture of photosynthetic pigments that absorb different wavelengths of light
More than one pigment means more wavelengths of light and thus more energy absorbed, faster rate of photosynthesis
What is oxidative phosphorylation
- electrons passed along etc
- Oxygen is the final acceptor
- Process called chemiosmosis
Compare and contrast the structure of a prokaryotic cell with a mitochondrion
- both have plasmids
-both have ribosomes
-prokaryotes don’t have a cell wall
Describe the fate of reduced nad in aerobic respiration
- reduced nad from gylcolysis moves into mitochondria
- Moves to inner mitochondrial membrane (etc)
- Becomes oxidised
- Electrons transferred to etc
- H+ ions pumped into membrane space
Describe the link between ATP and H+ ions
-H+ ions pass thru stalked particles
-energy released to join adp+pi to produce atp
-chemiosmosis
How is NAD formed
NAD forms when reduced NAD releases its electrons
-the electrons r taken to the etc
Whilst the H + ions move into intermebrane space
where does the light dependent stage of photosynthesis occur
what happens in the first stage of the ‘light dependent stage’
-thylakoid membranes
-photolysis of water, light splits water into H+ and e- and oxyg which is made from water
What is photo phosphorylation
The process of generating atp from adp and pi using energy from light during photosynthesis, occurs in thylakoid membranes,
Cyclic photosphorylation - just involves ps1 (light dependent)
-In photosystem 1 light excites electrons raising them to a higher energy level
e- emitted from chlorophyll move through a series of e- carriers
-e- are passed along etc, as they move down energy lvls the energy lost is used to synthesise atp
-e- return to photosystem 1
Non cyclic photophosphorylation
- Light energy hits chlorophyll in ps1, emits e- which are picked up by NADP co enzy,e
- NADP accepts H+ ion from water, becomes reduc
- At the same time an electron emitted from chlorophyll In PS2 is picked up by an elec acceptor and passed along etc synthesising atp, this e- picked up by ps1 to replace the one lost
Photolysis replaces lost e- from ps2
What is the light independent reaction
Calvin cycle, uses ATP and reduced NADP to produce glucose , occurs in stroma
What are the stages of the Calvin cycle
- CO2 bonds with RuBP a 5C compound to produce a 6C compound, catalysed by RUBISCO enzyme (CARBON FIXATION)
- 6C compound splits into 2 GP mols
- Redu NADP & ATP used to convert GP to GALP
(ATP hydrolysed into ADP+Pi , reduc NADP is oxidised to NADP as it donates a H to GP) - Some GALP used to make glucose , some reform RuBP by ATP
What’s a limiting factor
How can the rate of photosynthesis be measured
A variable that limits the rate of a chemical reaction
-volume of o2 produced or vol of co2 taken in
Light -
Low lvls light reduce the amount of ATP and NADP produced in the light dependent stage so will limit the rate of the light independent reactions
Co2
A lack of co2 means less RuBP can be converted into GP and then GALP
-some growers deliberately enrich the atmosphere with c02 to increase production
Temperature
many reactions in photosynthesis involve enzymes, which need sufficient KE to collide with substrates and form enzyme sub complexes . But at temps above optimum enzymes will denature as active site changes shape
What molecule is produced by photophosphyrlation
Oxygen
GALP can be used as…
A raw material in the production of monosaccharides and amino acids
Thylakoid membranes
Provide a space for the accumulation of H+ ions
The mirdrib is the part of a plant which contains branches of vessels from the stem why would this part be important for the production of carbohydrates in photosynthetic cells
Transport in the xylem of water to the leaves , the water is used a source of hydrogen ions
How can GALP be used to synthesis cellulose in plant cell walls
Galp converted to glucose
Beta glucose
Formation of 1,4 glycosidic bonds in condensation reactions
How is a high conc of H+ mainitnaed in the intermembrane space
H+ from reduced NAD
H+ ions pumped into intermembrane space
Energy needed fpr pump
Movement of electrons on etc
The light dependent reactions produces…
Reduced NADP and ATP which is used in the Calvin cycle to convert GP to GALP
Photolysis of water takes place where
In the chloroplast
