Transcript Energy - My CCSD

Energy
I. Metabolic Pathways
A.
B.
C.
D.
Energy = the ability to do work
Metabolic processes use chemical
E (ATP)
E released when chemical bonds
break (e- pulled apart)
Each step is regulated by
enzymes
II. Enzymes
A. = proteins essential for
cells to function
B. Act as catalysts
1. Speed up reactions
without being changed
2. Attach to substrate
molecule and weaken it
3. Enzyme is not altered
C. Enzymes ….
1. Lower activation energy
(= energy that must be added to a
reaction to cause molecules to
react)
2. Form enzyme-substrate
complexes
3. Allow reactions to proceed at
certain temperatures and pH
D. Every enzyme catalyzes only
one reaction or one type of
reaction
E. Enzymes ….
1. break down toxins (a lot in liver)
2. speed up digestion
Catalase
III. Factors That Affect Enzyme Speed
A.
Enzymatic reactions are rapid
1. Most occur 1000 times/sec
Ex: 2H2O2  2H2O + O2
(600,000 times/sec with catalase).
B.
Temperature
1. Increase temp
Increase molecular collisions
Increase enzyme activity
2. Temp too high (or low?)…..
breaks down (denatures)
enzyme
3. Human enzymes
function best at is 35o-40oC
Catalase
C. pH
1. Each enzyme
has optimal pH
2. Large change in pH may
denature the enzyme
3. Optimal in humans
pH 6-8
D. Other factors: radiation,
electricity, chemicals.
I. Photosynthesis and Nature
A. Sunlight provides energy to produce
carbohydrates.
B. Equation:
Light
6CO2 + 6H2O
C6H12O6 + 6O2
Chlorophyll
C. Autotrophs (make their own food)
1. Algae, plants, some bacteria
2. Ultimate source of food for life
3. Photoautotrophs…..
use light energy
4. Chemoautotrophs……
use chemical energy
D. Photosynthesis produced the oxygen
in the atmosphere of our planet.
II. Structures of Photosynthesis
A.
Chloroplasts
1. = the organelle of
Photosynthesis
2. Stroma –
fluid-filled inner space
3. Thylakoidsinternal membranes
within stroma
4. Organized into stacks
called grana.
B.
Chlorophylls and other
pigments are embedded
within thylakoid membranes.
C.
Pigments absorb solar
energy.
III. Photosynthetic Pigments
A. Major pigments are
chlorophyll a and b.
1. Both absorb violet, blue, and
red wavelengths best.
2. Most green is reflected back.
B. Carotinoids = yellow-orange
pigments ; absorb light in violet,
blue, and green regions
C. In fall, chlorophyll breaks down and
the yellow-orange pigments show
through.
D. Accessory pigments capture light
when sun changes positions.
IV. Cell Respiration
A. Breaks down glucose and builds up ATP.
B. C6H12O6 + 6O2  6CO2 + 6H2O + ATP Energy
C. Begins in cytoplasm with Glycolysis
1. Turns glucose into pyruvic acid
2. Produces 2ATP
D.
Fermentation
1. Processes that keep
glycolysis going without
oxygen
2. Lactic Acid fermentation
a) Converts pyruvic acid
into lactic acid
b) Occurs in muscle cells
when oxygen not
available; causes pain
c) Used by bacteria that
make yogurt, cheese,
pickles
3. Alcoholic Fermentation
a) Converts pyruvic acid into
ethyl alcohol and CO2
b) Occurs in bacteria and
yeasts
c) Used to make beer, wine,
and bread
E.
Aerobic Respiration
1. Need Oxygen
2. Energy from Pyruvic Acid is
transferred to ATP
a) In the Krebs Cycle
b) In the Electron Transport
Chain
3. Breakdown of glucose
yields 36 ATP
4. If O2 is not available to the
cell, fermentation occurs.
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