Download Week 4:

Biology 160
Week 4 Class notes
Monday 4/25:
catch up on Cellular function: Cytoskeleton (see video)
Review of “concentration gradient” and associated potential energy.
Review of Enzymes: structure and function, induced fit, inhibitors (induced bad fit)
Introduction to Cellular Respiration:
Process
Glycolysis
Location
Cytoplasm
Carbon
Glucose2 pyruvate
Transition
Cytoplasm
Citric Acid Cycle
Mitochondria
Electron Transport
Chain
Inner membrane of
mitochondria (which
has 2 membranes)
PyruvateAcetic Acid
(2C)
Acetic Acid joins 4C
“acceptor molecule”
2 xCO2 given off, 4C
acceptor molecule is
recycled.
No carbon inputs or
outputs
Energy
Use 2 ATP, gain 4 ATP
(net gain of 2 ATP)
Energy neutral
2 ATP, 6 NADH, 2
FADH2
Approximately 34 ATP
(from NADH and
FADH2)
Fermentation: when oxygen is taken away, yields only the energy associated with glycolysis (2ATP) and
yields one of several products that are generally harmful to living organisms at high concentrations: e.g.
ethanol, lactic acid.
Tuesday 4/26: We mentioned the terms oxidation, reduction, and “redox” chemistry
We balanced the equation for cellular respiration: 6 O2 + C6H12O6  6 CO2 + 6 H2O (plus energy) and
pointed out that cellular respiration allows for inputs other than glucose, including fats, proteins, and
other sugars.
Introduction of Photosynthesis: Reverse equation of Respiration, and can be divided into two phases:
“Light reactions” and “Calvin cycle.”
Anatomy of a chloroplast: double membrane, like mitochondria. Thylakoid sacs stacked into Grana.
Stroma filling the space outside of the grana.
Light reactions can be divided into 2 “photosystems”: “Water splitting” and “NADPH producing”. These
two photosystems both take in light energy, one produces ATP via electron transport chain, the other
produces NADPH. These products are both used in the calvin cycle to take CO2 and attach it to larger
carbon chain molecules, which then are “reduced” to make a 3 carbon sugar. This 3 carbon sugar (G3P
sugar) can be used to synthesize glucose, or other bio-molecules elsewhere in the cell.
Adaptations that take advantage of the separation of light reaction and calvin cycle were discussed: C4
and CAM photosynthesis. These adaptations both allow plants that use them to take in CO2 either
through an extra cell (C4) or at night (CAM) in order to avoid excessive water loss in dry climates.