March 3rd - Mon

EXAM 2 -- MARCH 10 (Next Monday)

Q & A: Sunday, 2pm.

Chapter 10: Questions 1-5, 7, 9-10

Fermentation: 

• Glycolysis -- doesn't need O2
• Glucose --> 2 pyruvate + 2 ATP + 2NADH
• If O2 present -- can go into Krebs Cycle -- Oxicative Phosphorylation

• if O2 is temporary stopped -- Oxidative phosphorlyation is stopped.

we can take Pyruvate & do Fermentation -- Alcohol or Lactic acid lactate

NADH is used + we get NAD+ 

So we have some regeneration of NAD+ so glycolysis can continue, and 2ATP can be produced in the breakdown of glucose

It's not efficient, but it keeps the cell alive.

FERMENTATION -- Specifically in abscence of alcohol

1.) Alcohol fermentation -- beer, wine.

pyruvate ---> recycle NADH & get NAD+--> Co2 + ethanol

2.) Lactic acid fermentation -- muscle cells of animals. Some bacteria --> yogurt & cheese

(3carbon) pyruvate --> lactic acid   by using NADH molecules & regenerating NAD+

glycolysis --> 2ATP (we lost electrons from NADH

respiration --> 38 ATP

we get 19 times more ATP using respiration than using glycolysis only.

---------------------END OF CH 9-----------------------------------

Photosynthesis: Chapter 10

• anabolic process for the formation of sugars (carbohydrates) from CO2 and + H2O using light energy & releasing oxygen (O2).

• CO₂ H₂O ---> ~~~light energy~~  -->[CH₂O ]_n + O₂

  
  

  
  

  
  

C02 contribues C, O for carbohydrate

H2O provedes e- and protons (H+) for carbohydrate

Oxygen is a biproduct

e- from water -- low energy. provided --- IN FIGURE NOTES ONLINE!

Supplies most of energy for life on earth.

• Only plants, algae, blue-green algae, etc...
• occurs in chloroplasts - (only)
• chloroplast are present in all green tissues of plants.
•  there are ~ 200 chloroplasts per cell
  

Photo - synthesis: (Overview)

• occurs in 2 main processes -- divided up into the photo part and the synthesis part.

Photo-light reactions

1. 
   
   occur in the thylakoids
2. light energy is captured & used to split H₂O into H+ and electrons (releasing O₂ as a biproduct)
3. the e- move through an electron transport chain, produces ATP by chemiosmosis.

4. Two electrons & protons (orignally fromH₂O are used to reduce NADP+ to NADPH.

   • NADP+ is an electron shuttle like NAD+
   • NAD+ is used for catabolic reactions.
   • NADP+ is used for anabolic reactions.
5.  Overall - Light energy has been converted to the chemical energy of ATP + NADPH.

 

Part II : Synthesis part is a process called = Calvin Cycle.

1. Occurs in the chloroplast stroma. (parts between the thylakoids on the outside.
2. CO₂ is captured (fixed) from the air by attaching it to a 5-carbon sugar.
3. ATP + NADPH from the light reactions are used to reduce CO₂to carbohydrate ( CH₂O ).

 

Both light reactions and calvin cycle are necessary to work together to produce carbohydrates.

 

Light reactions :

Light Characteristics :

• electromagnetic radiation
• ~ has a specific wavelength
• visible light =  ~400 nm to ~700 nm
• the shorter the wavelength -- the more energy. (think of blue flames -- wow, as opposed to easy to attain Red/orange flames ---eh.)
• 
  longer wavelengths = shorter energy -- ie, long wavelengths Red, but no substance.
• light also behaves as a particle
  
• photon-- one light packet
  
• pigments -molecules that can absorb light energy (in the form of photons).

 

• e- absorbs light energ and becomes excited. it can allow electrons to jump to a higher energy orbital, but its unstable.
• when light is taken away -- the e- drops back to its previous level -- which causes it to release energy in the form of light and/or heat.
  
• this property of giving off light and/or heat = fluorescence.

 

• photosynthesis -- excited e- can be picked up by an electron acceptor.
• instead of dropping back down, there's something that can take that electron - so it gets rid of the electron by losing it (not spending it)
• The "lost" e- (excited by light energy) are used to make NADPH & ATP.

 

• 1st electron acceptor = primary e- acceptor (energized e-).

 

• Chlorophyll -- is the most important pigment in photosynthesis.  NEW ABBREV : CHL is now Chlorophyll.
• CHL and other synthetic pigments are hydrophobic molecules and that occur in thylakoid membranes ( hydrophobic things are often found in membranes)
• CHL absorbs light. (red&
  bluelight) only
• Green light is reflected / transmitted by CHL
  

Final Bits on Notes  (you get a blood red color when isolating chlorophyll -- neat-O!)

 

Chlorophyll a absorbs blue light -- A

Chlorophyll