C17 Photosynthesis Flashcards
Limiting factor
One factor needed in photosynthesis and is in short supply, reducing the rate of photosynthesis.
Light intensity affect on photosynthesis
Light needed, energy source, as light intensity increases, ATP and reduced NADP production increases, increasing rate of photosynthesis
CO2 conc affect on photosynthesis
Needed, source of carbon, increases CO2 conc increases rate carbon fixation, therefore increasing rate TP production
Temperature affect on rate of photosynthesis
As temp increases, rates of enzymes controlled reactions increase.
When do stomata close and how does this effect the rate of photosynthesis
Dry spells (when plants undergo water stress) to avoid water loss.
Preventing diffusion of CO2, decreasing rate light-independant reaction and eventually stopping photosynthesis
Is water a limiting factor in photosynthesis and why
Never, because by the time the water potential to become low enough to limit the rate, the plant would have already closed stomata and ceased photosynthesis processes.
Law of limiting factors states…
Rate of physiological process will be limited by factor in shortest supply
Effect reducing light intensity on Calvin Cycle
-Reduces rate light dependant stage
-Reducing quantity ATP and Reduced NADP
-Conc GP therefore increases and conc TP decreases, less TP generates less RuBP
-Reverse happens when light intensity increases
Effect temperature on Calvin Cycle
-All reactions Calvin Cycle catalysed by enzymes
-Lower temp, enzyme and substrate lower KE, less successful collisions, decreases rate reaction
-Decreases conc GP, TP, RuBP
-Same effect high temp, denaturing, irreversible
Effect Carbon Dioxide on Calvin Cycle
Low conc CO2, decreases conc GP (as there’s less CO2 to be fixed)
-Decreases conc TP
-Conc RuBP increases, still being formed from TP, but not being used to fix CO2
What does an ecosystem composition depend on
The amount of energy
Provide some ways energy consumption is used up
Homeostasis
Respiration
Growth and reproduction
How is ADP formed
ATP and an inorganic phosphate
The Calvin Cycle is the starting point of what
Making all the organic substances plants need (e.g glucose)
What are TP and GP used to make
Carbohydrates, lipids and amino acids
Carbohydrates (what they made up off)
Hexose sugars made joining 2 TP mols.
Larger carbohydrates (sucrose, starch, cellulose) made by joining hexose sugars different ways
Amino acids (what are they made from)
Some are made from GP
Lipids (what are they made from)
Made using glycerol, whichs synthesised from TP and fatty acids, whichs synthesised from GP
Whats chronography used for
Separating different pigments
Mobile phase
Solution containing mixture of pigments
Stationary phase
Think layer of silica gel applied to glass
Why do the pigments move at different rates up the TLC paper
Different solubilities in mobile phase and differing interactions with stationary phase leads to them moving different rates through silica gel
Retention value (Rf)
Distance travelled by component / Distance traveled by solvent
Name 5 different chlorophyll pigments
Carotene
Phaeophylin
Xanthophyll
Chlorophyll a
Chlorophyll b
What conclusion can you make from the ‘investigating photosynthesis pigments’ PAG
That plant leaves consist of different types of pigments that utilise various sunlight wavelengths for photosynthesis and TLC was able to separate these different pigments.
What does the Calvin Cycle use to convert carbon dioxide into sugars
ATP and Reduced NADP
In the light dependant reaction, what is the light energy absorbed by photosystem used for
-Photphosphorylation (making ATP from ADP and inorganic phosphate)
-Making reduced NADP from NADP
-Splitting water into protons (H+ ions), electrons and oxygen (Photolysis) .
What are the two types of phosphorylation
Cyclic
Non cyclic
(Both part of the light dependant stage)
Non cyclic phosphorylation produces…
ATP
Reduced NADP
Oxygen
Cyclic phosphorylation produces…
Only small amounts ATP
Oxidation
is lose of hydrogen atoms or electrons
Reduction
gain of hydrogen atoms or electrons
what type of molecule is NAD and NADP
coenzymes
What are chloroplasts, where are they found and what occurs in them
organelles
found in plant cells
photosynthesis occurs
What are chloroplast surrounded by
double membrane envelope, each a phospholipid bilayer
The outer membrane of chloroplast is permeable to what
range of ions and small molecules
the inner membrane contains what, allows what kind of substances through
contains transport proteins,
allows certain mol/ ions to enter and leave
What is the chloroplast filled with
Cytosol-like fluid (stroma)
CO2, sugars, enzymes and other mols dissolved in it
Membrane system in the stroma
Series flattened fluid-filled sacs, known as thylakoids
Structure of thylakoids
And what do they contain
Series flattened fluid-filled sacs, containing pigments, enzymes and election carriers
How are grana formed
Thylakoids stack up
How are grana connected
By membrane channels known as lamellae
What do the lamellae ensure
Ensures the stacks of sacs are connected, but distanced from each other
What does the membrane of a grana create
Large SA to Vol ratio
What does the membrane system of chloroplast provide
Large number of pigments mols, ensures as much light as possible absorbed. Pigment mols arranged in light-harvesting clusters, known as photosystems
What makes up a photosystem
Different pigment mol, arranged funnel-like structures in thylakoid membrane.
Each pigment mol passes energy down to the next, eventually reaching primary pigment reaction centre.
What does the stroma contain
-Small ribosomes
-A loop of DNA (codes for chloroplast proteins, that are produced at the 70S ribosomes)
-Starch grains
What are the sugars formed during photosynthesis stored as
Starch
Where are the sugars formed during photosynthesis stored
Inside starch grains
What are the 2 classification of pigments
Primary and Accessory pigments
What surrounds the primary pigments molecules
Several hundred accessory pigments
How does the light energy reach the reaction centre
Light energy is absorbed by accessory that pass/ channel down the energy to the primary pigment mol.
The primary pigment mol act as a reaction centre
Photosystem 1
-Photosystem arranged around mol of chlorophyll a
-Peak absorption 700nm
-Reaction centre known as P700
Photosystem 2
-Arranged around mol chlorophyll a
-Peak absorbtion 680nm
-Reaction centre known as P680
Equation for Photolysis
2H2O —(light)—-> O2 + 4H+ + 4e-
Role of water in photolysis
Water requires 4 photons of light, energy equivalent to split one H2O
The O2 produced diffuses out chloroplast and eventually into air
How is reduced NADP formed
H+ ions combine with electrons from PS1 and NADP to give reduced NADP
When does photolysis of light occur
During non-cyclic phosphorylation
What does PS2 have for the photolysis of light (makes it possible)
Water splitting enzymes which catalyses the breakdown of water into H+ ions, O2 and electrons.
Water is the by product
Electeons fill the electron hole in PS2
