atp, cellular respiration and photosynthesis · photosynthesis & respiration are opposites...
TRANSCRIPT
ATP, Cellular
Respiration and
Photosynthesis
Energy for Cells
Free Energy: the energy available to do
work
Types of Reactions
Endergonic Reactions: require an input of energy
Exergonic Reactions: release energy (energy EXits)
ATP
Adenosine Triphosphate
3 Phosphate Groups
Goes into endergonic reactions
Released from exergonic reactions
Energy source
ATP + H2O ADP + P + Energy When the last phosphate bond (high energy bond)
is broken, energy is released
Hydrolysis reaction
Cellular Respiration
The process by which energy is made
available for biological work
C6H12O6 + 6O2 6CO2 + 6H2O + Energy
Exergonic
Occurs in both autotrophs & heterotrophs
Reactions occur in the cytoplasm and
mitochondria
Aerobic Respiration
Aerobic Respiration: cellular respiration
that uses O2
Releases 38ATP
Anaerobic Respiration
Anaerobic Respiration: cellular
respiration that occurs in the absence of
oxygen
Fermentation: another term used to
describe anaerobic respiration
Types:
Lactic Acid Fermentation
Alcoholic Fermentation
Anaerobic Respiration
Lactic Acid Fermentation: glucose is
broken down into 2 lactic acid molecules
in the absence of O2
Releases 4ATP
Occurs in human muscle cells
Allows muscles to keep working without oxygen,
but produces MUCH LESS ATP than aerobic
respiration
Anaerobic
Alcoholic Fermentation: glucose is broken down into 2 ethanol molecules and 2 carbon dioxide molecules in the absence of oxygen Releases 4ATP
Carried out by plant cells and microorganisms
Yeast in bread breaks down carbohydrates in the dough by alcoholic fermentation, the CO2 released causes the bread to rise
Yeast are used to produce ethanol in beer & wine
Photosynthesis
Process by which producers store energy
from sunlight as chemical energy in
organic molecules (glucose)
6CO2 + 6H2O + Energy C6H12O6 + 6O2
Endergonic (takes in sunlight)
Occurs in producers only (autotrophs)
Light
Light: radiant energy travels in waves
Visible Spectrum: the range of colors that make up white light Longest R O Y G B I V Shortest
Colors we see depend on what wavelengths are reflected
Chlorophyll & Other
Pigments
Organisms that carry out photosynthesis
contain colored pigments that absorb
light energy and convert it to chemical
energy
Chlorophyll
Most important pigment in photosynthesis
Eukaryotes: chlorophyll is in the chloroplasts
Prokaryotes: chlorophyll is in the cytoplasm
Chlorophyll
Appears green = reflects green & yellow wavelengths of light
Absorption Spectrum: a graph that shows the wavelengths of light absorbed
Absorbed wavelengths are transformed from light energy to chemical energy during photosynthesis
Absorbed wavelengths are USED
Carotenoids
Yellow, orange, and red pigments in chloroplasts
Absorb blue & green wavelengths
Pass energy to chlorophyll
Present in other plant parts (flowers, fruits)
Become visible in autumn because chlorophyll production stops
Chloroplasts
Contain chlorophyll & other pigments
Thylakoid membranes Internal membranes
Fluid mosaic
Chlorophyll & carotenoids embedded in bilayer with proteins
Where the light reactions occur
Grana: stacks of thylakoids
Stroma: fluid part of chloroplast Where the Calvin Cycle occurs
Light Reactions
Involve a series of changes that convert
light energy to chemical energy
“photo” means light – this is the “photo” in photosynthesis!
Occur in the thylakoid membranes
H2O split into Hydrogen ions (H+),
electrons, and O2
The Calvin Cycle (“Dark” Reactions)
Synthesis of sugars by the stroma &
molecules within it
“Synthesis” of photosynthesis
Produces 3 Carbon sugars
2 can be combined to form 6 Carbon sugars,
like glucose
Lack of Free Glucose in
Plants
Most plants contain little free glucose
because:
Glucose + fructose sucrose
Glucose + glucose starch
Glucose used for cellulose
Energy Relationships
Photosynthesis & Respiration are opposites &
interdependent
Respiration = exergonic
Photosynthesis = endergonic
One cannot occur without the
other – products of one are the
reactants of the other
6CO2 + 6H2O + Energy C6H12O6 + 6O2
C6H12O6 + 6O2 6CO2 + 6H2O + Energy
Photosynthesis only in autotrophs
Respiration in autotrophs AND heterotrophs