Ap Bio- Cell energetics

CO2 is reduced to form glucose.

Test whether they release O2 in the light.

green and yellow

wavelengths of light and the rate of photosynthesis

a. water

to produce simple sugars from carbon dioxide

No pull on water into the plant from evaporation will slow down the photosynthesis rate.

d. In photosynthesis, water and carbon dioxide are reactants. GA3P and oxygen are products.

a. chloroplasts

c. sugars/carbohydrates and oxygen

b. stroma

What is photosynthesis

the process in which light energy is converted to chemical energy in the form of sugars.

The glucose molecules provide organisms with two crucial resources:

1) Energy

2) Fixed Carbon 

The chemical energy in glucose can be harvested through processes like ____

Cellular respiration and Fermentation

Fixed carbon

Carbon taken from inorganic molecules to become apart of a organic molecule through carbon fixation 

Photoautotrophs

organisms that make their own food via light to make sugars

Heterotrophs

organisms that can’t convert carbon dioxide to organic compounds themselves

Mesophyll

The cells in a middle layer of leaf tissue

Primary site of photosynthesis

Mesophyll

Stomata 

Small pores called-singular, stoma-are found on the surface of leaves in most plants, and they let carbon dioxide diffuse into the mesophyll layer and oxygen diffuse out.

Whats in what order

Thylakoid space, chlorophyll →Thylakoid → Granum → Stroma → Chloroplast → Cell → Mesophyll → Leaf → Plan

Each mesophyll cell contains organelles called_____

chloroplasts

Thylakoids

disc-like structures arranged in piles known as grana within each chloroplast

Chlorophyll

Pigments in the membrane of each thylakoid

Stroma

fluid-filled space around the grana

the stage of photosynthesis

1) Light-dependent reactions

2) Calvin cycle

Where do light-dependent reactions take place

thylakoid

Light dependent equation 

light + 2H2O + 2NADP+ +3 ADP + 3Pi → O2 + 2NADPH + 3ATP

Light dependent reaction input

light + 2H2O + 2NADP + ADP + Pi

Light dependent reaction output

O2 + 2NADPH + ATP + 2H+

ATP

A energy storage molecule 

NADPH

A electron carrier, used for reducing stuff later

where does the calvin cycle take place

Stroma

Calvin cycle inputs

ATP + NADPH + Co2

G3P

sugars made from calvin cycle that join up to make glucose

ATP and NADPH are used to?

fix Co2 to make G3P

Calvin cycle outputs

ADP + Pi + NADP+ + G3P

Redox reactions

reactions involving electron transfer

Photosystems

large complexes of proteins and pigments that are optimized to harvest light. They can contain chlorophyll 

non-cyclic photophosphorylation

Process where electrons are removed from water to pass through PSI and PSII before ending up in NADPH

1st step of light reactions

• A photon is absorbed by PSII, excites electrons of pigments that make up PSII

• Excited electrons emit photons that are passed around by the pigments within PSII like a pinball machine

• Eventually a photon may hit the reaction center complex (RCC)

• one of the electrons in one of the chlorophyll of the RCC, instead of going back to ground state, is transferred into the primary electron acceptor

• a enzyme supplies a electron to a pigment that is missing one through breaking down a water molecule into O2, 2H+, and 2e-
  
  basically: PSII absorb light, water is broken down into o2, H+, and e-

2nd step of light reactions

• Electrons travel down electron transport chain (compounds that are embedded in thylakoid membrane)

• H+ move against concentration gradient

• Proton pumps bring protons into the thylakoid space (inside thylakoid)

3rd step of light reactions

• H+ gradient goes through ATP synthase and ATP is made (something to do with H+ spinning the protein motor)

• PSI absorbs light to excite electrons again (electrons lose energy as they travel down chain)

4th step of light reactions

• As electrons move through PSI,  NADP+ to make NADPH

Net outputs of Light reactions

ATP and NADPH

2 ways electrons flow in photosynthesis

Linear electron flow and cyclic electron flow

Linear electron flow

electrons go from 

PSII → electron transport chain → PSI → NADPH

Ratio of ATP and NADPH made in light reactions

1:1

cyclic electron flow

PSI → electron transport chain
makes ATP without making NADPH, important in Calvin cycle cuz there will be an uneven ratio of ATP and NADPH

ATP and NADPH ratio in calvin cycle

9ATP:6NADPH

1st step of calvin cycle

• CO2 comes in through stoma and rubsico attaches it to a 5-carbon sugar (ribulose bisphosphate) → makes a unstable 6 carbon molecule → splits into two 3-PGA
  
  (Carbon Fixation)

2nd step of calvin cycle

• 9ATP and 6NADPH from light reaction are used to reduce 3carbons to become G3P

• Each 3-PGA receives a phosphate from ATP and reduced by NADPH to make G3P

3rd step of calvin cycle

• Some G3P stay in cycle, and are used to regenerate more Rubsico to start the cycle again

• Some G3P leave the cycle to other pathways to make glucose and other compounds

net products of calvin cycle

G3P + NADP+ + ADP

Photosynthesis overall equation

light + H2O + Co2 → C6H12O6 + O2

Light reaction basically

convert light energy (photons) into chemical energy (ATP, NADPH)

Calvin cycle basically

uses chemical energy made from light reactions to make G3P (precursor to glucose)

there are around how much chloroplasts per plant cell?

30-40

1 G3P requires how much ATP and NADPH?

9 ATP, 6 NADPH

The light reactions are basically a sequence of _

redox reactions

How many calvin cycles to make 1 glucose?

6 cycles

Where is ATP made?

outside of thylakoid membrane in stroma (ATP synthase embedded in membrane)

How do H+ travel against the H+ gradient?

They get energy from electrons that lose energy as they travel down the electron transport chain

Chlorophyll 680

P680 is the specialized chlorophyll in Photosystem II (PSII) that absorbs light at 680 nm

how much Co2 to make 1 G3P

3

When a molecule gains an electron, did it gain or lose energy?

gained

waves with shorter lengths have more

energy

wavelength of UV

~400nm

wavelength of infrared

~700nm

 phosphorylation

chemical process that involves the addition of a phosphate group to a molecule, which can either activate or inactivate it