Transcript energy and the cell

ENERGY AND THE CELL
Chloroplast
Plant cell organelles which
are the site of photosynthesis.
Chloroplast contains
chlorophyll pigment which
traps the energy in sunlight.
Photosynthesis
 Process by which light energy is
converted to chemical energy.
 Light energy is used to rearrange CO2
and H2O into C6H1206 (glucose).
 Waste products from this reaction
include Oxygen.
 Autotrophs- organisms that make their
own energy.
Photosynthesis: Stage 1 (light reaction)
 Chlorophyll a and b (green) and Carotenoid
pigments (yellow and orange) absorb different
wavelengths of light.
 Pigments are stored within disk like structures in
chloroplast called Thylakoids. Energy is captured
when sunlight strikes the thylakoid causing
electrons to become excited.
Stage 2: Conversion of light energy
 Excited electrons are passed down a series
of molecules called an electron transport
chain producing new molecules including
ATP and NADPH which temporarily stores
chemical energy.
Stage 3: Storage of Energy (dark
reaction)
 Calvin cycle fixates carbon dioxide to form
glucose in a series of enzyme assisted
chemical reactions.
Mitochondria
Organelle which is the site of
cellular respiration in the
cell.
Provides available energy to
the cell in the form of
adenosin triphosphate (ATP).
Cellular Respiration
 Sugar molecules combine with oxygen
to produce usable energy molecules
called ATP.
 ATP provides cells with energy needed
to carry out life activities. It is a
portable form of energy “currency”
inside cells.
ATP
 Adenosine triphosphate is a ribose sugar
molecule with a tail of phophate groups.
 These phophate groups repel each other
because they are negatively charged. They
store energy like a compressed spring.
 A small input of energy breaks the bonds
releasing a large output of energy.
 Water +ATPADP+P+energy
Stage 1 : Glycolysis
 Enzyme assisted anaerobic process that
breaks down glucose to form pyruvate and
NADH molecules.
 Four ATP molecules are also produced.
Stage 2: Krebs Cycle
 Oxygen and Pyruvate enter the
mitochondrian. An electron transport chain
and enzymes are used to produce carbon
dioxide and energy molecules in the form of
ATP.
 At the end of the chain leftover H ions and
Oxygen combine to form water.
Fermentation
Respiration in the absence of
oxygen.
Prokaryotes carry out more than a
dozen forms of fermentation to
produce energy.
Lactic Acid Fermentation
 During vigorous exercise the muscles run
out of oxygen and begin to produce energy
using fermentation.
 This produces lactate as a by product.
 The buildup of lactate causes muscle
soreness.
Alcoholic Fermentation
 Organisms, like yeast, produce energy
without the use of oxygen producing
ethanol as a by product.
 We use this to produce alcoholic beverages
and foods.
 The carbon dioxide given off by yeast
fermentation causes bread to rise.