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What do plants need energy for?
Photosynthesis, Active Transport, DNA replication, Cell division, Protein synthesis
What do animals need energy for?
Muscle contraction, Body temp maintenance, Active Transport, DNA replication, Cell division, Protein synthesis
What is an autotroph?
Organism able to produce it's own food from inorganic substances using a source of energy E.g. plants and glucose via photsynthesis
How is energy stored and released in a plant?
Stored as glucose, released via respiration
What's the overall equation of respiration?
The reverse of photosynthesis
What are the 3 components of ATP?
The base adenine, ribose sugar and 3 phosphate groups
How is ATP made?
ADP + Pi via ATP synthase
How is energy released from ATP?
Phosphate bonds break
Name 5 reasons as to why ATP is a good energy source.
1) Releases smal, manageable amounts of energy
2) Small and soluble - easily transported
3) Broken down easily - energy easy to release
4) Possible to transfer energy to another molecule by transferring a phosphate group
5) ATP wont pass out of a cell, so the cell always has an immediate source of energy
What is the conezyme used in photosynthesis?
NADP (transfers hydrogen from one molecule to another - therefore can be reduced or oxidised)
Name 3 coenzymes used in respiration.
NAD, coenzyme A and FAD
Describe the structure of a chloroplast.
They have a double membrane known as cholroplast envelope
Thylakoids are fluid filled sacs that are stacked w/in the chloroplast, forming grana
Grana are linked by large thylakoids called lamellae
The stroma is a gel substance containg enzymes, sugars, organic acids etc that surrounds the structures in a choloroplast.
What's the difference b/w a primary and accessory pigment?
Primary pigments are at the centre of photsystems, excited e- are released from them.  Accessory pigments transfer light energy to primary pigments.
What wavelength of light does PSI best absorb?
700nm
What wavelength of light does PSII best absorb?
680nm
How are carbohydraes produced by photosynthesis stored?
As starch grains suspended in the stroma
Outline the light dependant stage of photosynthesis.
Requires light energy
Takes place in thylakoid membranes
Light energy absorbed by photosynthetic pigments in photosystems - converted to chemical energy
H lost from H2O, O2 diffuses out
Light energy used to add phosphate group to ADP to form ATP, and to reduce NADP to form red NADP.
How are energy and hydrogen transferred to the light independent reaction?
ATP transfers energy.
NADP transfers Hydrogen.
Outline the light independent reaction.
(The calvin cycle)
Relies on products of LI reaction
Takes place in Stroma!
ATP and Hydrogen from LD reaction are used to make glucose from CO2
Name 3 things light is used for in the LD reaction.
Forming ATP from ADP and Pi (photophosphorylation)
Splitting H2O into protons, electrons and oxygen (photolysis)
Makind red NADP from NADP (adding an H+)
How are photosystems linked?
Electron carriers! Proteins that transfer electrons. Photosystems and electron carriers form an electron transport chain
What happens to the e- in PSII during non-cyclic photophosphorylation?
Light energy absorbed by PSII
Energy excites electron in Chlorophyll
This moves electron to a higher energy level
High energy electron moves along the electron transport chain to PSI
How is the electron lost from PSII replaced?
Light energy splits water, the proton reduces NAD, the oxygen forms O2 and diffuses away. The electron left from the proton is used to replace the one being passed along the electron transport chain
What happens to the energy of electrons being passed along the electron transport chain?
They lose energy
Thsi is used to ACTIVELY pump H+ ions into the thylakoid, forming a concentration gradient
As these protons diffuse down the gradient via ATP synthase ATP is formed by combining ADP and an inorganic phosphate - Chemiosmosis
How is red NADP formed in non-cyclic photophosphorylation?
Light energy is absorbed by PSI, exciting the electron again.
Eventually the electron is transferred to NADP w/ a proton from the stroma - forms red NADP
What is cyclic photphosphorylation?
Photophosphorylation involving on PSI, no red NADP or O2 is produced as the electron is continually passed back - no need to replace it.
Some ATP is produced.
Outline the Calvin cycle.
Takes place in stroma
Makes triose phosphate from carbon dioxide and ribulose bisphosphate (5C compound). TP can be used to make glucose and other useful organic substances.
It reuires protons and ATP to keep it spinning
RuBP is regenerated to keep the cycle going.
What's the 1st step of the CC?
CO2 diffuses into sroma via stomata
Joins with RuBP  (5C) to form a 6C intermediate.
This breakes down into 2x glycerate 3 phosphate (3C)
The enzyme Rubisco catalyses this reaction
What's the second step of the CC?
2x ATP from the light independent reaction provide energy and 2x red NADP provide H+ ions to convert GP into triose phosphate.
How many TP molecules are used to make RuBP?
5/6.
It requires TP and an ATP
How are hexose sugars made out of products of the Calvin cycle?
2 triose phosphates join.
How are lipids made out of products of the Calvin cycle?
Glycerol, synthesised from TP, and fatty acids, synthesised from glycerate 3 phosphate
How many turns of the CC does it take to form one hexose sugar?
6.
3 turns form 6 TPs, 5/6 of these are used to regenerate RuBP, one is used to form a Hexose sugar.
A further 3 turns produces the second necessary TP.
These 6 turnes need 18 ATP and 12 red NADP
How are choloroplasts well adapted?
Large SA of thylakoids let lots of light in
Stroma contins all necessary reactants for light independent reaction.
Lots of ATP synthases proteins in thylakoid membrane equates to lots of ATP production
What are the ideal conditions for photosynthesis?
High light intensity of useful wavelengths
Temp around 25 degress, as it involves enzymes, and stomatat close at high temps to reduce water loss
0.4% conc. of CO2 (atmospheric level)
How does light intensity affect photosynthesis?
Less red NADP and ATP produced in light dependent stage, so GP to TP conversion is slowed.
What are limiting factors?
Factors which limit the rate of photosynthesis - light intensity for example, at night.  When a factor reaches it's point of saturation, it is no longer the limiting factor.
How is temp a limiting factor?
A non ideal temp affects how enzymes operate
How is CO2 a limiting factor?
Low conc. of carbon dioxide means less GP formed, as there is less CO2 available to join with RuBP
What are the 4 stages of aerobic respiration?
Glycolysis, link reaction, Krebs cycle, oxidative phosphorylation
Outline glycolysis
One molecule of glucose (6C) is split into two Pyruvate molecules (3C)
Occurs in cytoplasm
It's an anaerobic process - no oxygen needed
What's the first stage of glcolysis?
Phophorylation- glucose is phosphorylated by adding 2 phosphate from 2 ATPs
Creates 2x hexose bisphosphates (plus 2 ADP)
hexose bisphosphate is split into 2x triose phosphates
What's the second stage of glycolysis?
Oxidation - TP is oxidised to form 2x pyruvate
NAD collects the 2 released protons, forming red NAD
4 ATPs are also produced, net gain of 2 ATP
What happens to the products of glycolysis?
Pyruvate used in link reaction
red NAD used in oxidative phosphorylation
What happens to Pyruvate in the link reaction?
It's decarboxylated, CO2 removed.
Pyruvate is converted to acetate by having NAD take one H atom.
Acetate + coenzyme A form acetyl coenzyme A
NO ATP PRODUCED

 
For every glucose molecule, how many times must the link reaction take place?
2 pyruvates are formed from glycolysis, so twice.
What happens to the acetyl coenzyme A produced in the link reaction?
It's used in the Krebs cycle
How are mitochondira well adapted for respiration?
Folded cristae (inner membrane) increases SA to maximise respiration.
Lots of ATP synthase molecules in inner membrane produce lots of ATP in oxidative phosphorylation
The matrix contains all the necessary reactants for the Krebs cycle
What is the waste product of the link reaction?
Carbon dioxide
What type of reactions does the Krebs cycle use?
REDOX
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