Post on 23-Mar-2018
Lecture Outline
• Importance of energy in living organisms
• Photosynthesis• Process of photosynthesis
• Purpose of photosynthesis
• Respiration• Purpose of respiration
• Process of respiration
• Fermentation
Importance of Energy
• Living organisms need energy to do everything.• Move
• Grow
• Reproduce
• Photosynthesis & respiration are needed for living organisms to get energy.
Photosynthesis vs. Respiration
• Photosynthesis- turns energy into sugars
• Respiration- turns sugars into energy
Energy Sugars
Photosynthesis
Respiration
How do plants meet their
energy needs?
Remember, science is a process…..
…..a brief history lesson is in order
The process of understanding
photosynthesis
Until almost 350 years ago, plants were thought to feed on soil
Jan Baptista van Helmont
Planted willow tree in pot
Allowed tree to grow for 5 years
Compared weight of tree and soil to original weight
Tree gained 74kg, soil lost 57g
The process of understanding
photosynthesis
100 yrs later we learned that plants
release oxygen into the atmosphere
Joseph Priestly
Candles “damaged” air
Sprigs of mint “restored” air
The process of understanding
photosynthesis
Finally, ~1800 Jan Ingenhousz
determined:
Air was “restored” only in the presence of
sunlight
Only by a plant’s green leaves, not by it
roots
But, he suggested that the source of the
oxygen was CO2
Process of photosynthesis
• Process by which a cell captures energy and uses it to make food.
• Photosynthesis is a 2 step process:1. Capture energy
2. Turn energy into food
Step 1: Capturing Energy
• Plants capture the light energy from the sun.
• Chlorophyll absorbs the light energy.• Pigment that is good at absorbing a certain wavelength of light.
• Located in the chloroplast.
• Organelle located ONLY in plant cells.
• The light energy captured by the chlorophyll is needed to turn energy into food.
Step 2: Turning energy into food
• Plant cells use the captured light energy to produce “food.”
• Water (H2 O) and carbon dioxide (CO2 ) are needed to make the food. • Roots absorb water from the soil.
• Carbon dioxide enters the plant through stomata.
• Light energy changes the water & carbon dioxide into glucose and oxygen (O2).
Process of photosynthesis
•6 CO2 + 6H2 O C6H12O6 + 6O2
•6 carbon dioxide molecules and 6 water molecules produces 1 glucose molecule and 6 oxygen molecules.
light
Photosynthetic Organisms
Carried out by a variety of organisms,
ranging from simple bacteria, to algae
and complex plants.
Any organism that is able to
photosynthesize is known as a
“producer” or “autotroph.”
Importance of
Photosynthesis
Releases oxygen into the atmosphere.
Dead plant matter is a source of fossil
fuels.
Most living things obtain energy either directly or indirectly from the sun’s energy captured during photosynthesis.
Importance of Photosynthesis
Without photosynthesis, living organisms would not get energy!!!
Energy enters the ecosystem through photosynthesis.
Plants use the sun’s energy to make glucose.
All other organisms consume glucose from the producers as a source of energy.
CO2 + H2O + heatfuel
(carbohydrates)
O2
“Burn fuels” to make energy• Combustion - making heat energy by burning fuels
in one step
ATP
ATP + CO2 + H2O (+ heat)
• Aerobic respiration - making ATP energy (& some
heat) by burning fuels in many small steps
food
(carbohydrates)
O2
Energy needs of life• Animals are energy consumers
•What do we need energy for?• synthesis (building for growth)
• reproduction
• active transport
• movement
• temperature control (making heat)
Where do we get energy?•Energy is stored in organic molecules
•carbohydrates, fats, proteins
•Animals eat these organic molecules food• digest food to get
• fuels for energy (ATP)
• raw materials for building more molecules
• carbohydrates, fats, proteins, nucleic acids
ATP
Harvesting energy stored in food• Cellular respiration
• breaking down food to produce ATP
• in mitochondria
• using oxygen
• “aerobic” respiration
• usually digesting glucose
• but could be other sugars, fats, or proteins
C6H12O6 6O2ATP 6CO2 6H2O+ + +
glucose + oxygen energy + carbon + waterdioxide
O2
food ATP
What do we need to make energy?•The “Furnace” for making energy
• mitochondria
•Fuel• food: carbohydrates, fats, proteins
•Helpers• oxygen
• enzymes
•Product• ATP
•Waste products• carbon dioxide
• water
O2
food
ATP
Make ATP!Make ATP!All I do all day…And no oneeven notices!
enzymes
CO2H2O
Can’t store ATP too unstable
only used in cell
that produces it
only short term
energy storage carbohydrates & fats
are long term
energy storage
Using ATP to do work?
A working muscle recycles over
10 million ATPs per second
ATP
ADP
workAdenosine DiPhosphate
Adenosine TriPhosphate
make energyA Body’s Energy Budget
eat
food
synthesis
(building)
• energy needed
even at rest
• activity
• temperature
control
{• growth
• reproduction
• repair{storage
• glycogen
(animal starch)
• fat{
ATP
1
2
3
What if oxygen is missing?• No oxygen available = can’t complete aerobic respiration
• Anaerobic respiration• also known as fermentation
• alcohol fermentation
• lactic acid fermentation
• no oxygen or no mitochondria (bacteria)
• can only make very little ATP
• large animals cannot survive
O2
yeast
bacteria
Anaerobic Respiration• Fermentation
• alcohol fermentation
• yeast
• glucose ATP + CO2+ alcohol
• make beer, wine, bread
• lactic acid fermentation
• bacteria, animals
• glucose ATP + lactic acid
• bacteria make yogurt
• animals feel muscle fatigue
O2
Respiration is a 2 step process:
1. Glucose is broken into smaller molecules.• Occurs in the cytoplasm.
• Oxygen is not needed.
• A small amount of energy (ATP) is released.
Respiration is a 2 step process:
2. Small molecules are broken into even smaller molecules.• Occurs in the mitochondria.
• Oxygen is required.
• A lot of energy (ATP) is released.
Process of respiration
C6H12O6 + 6O2 6CO2 + 6H2 O + ATP
•One molecule of glucose and six molecules of oxygens make six molecules of carbon dioxide, six water molecules, and ENERGY.
ATP = Energy Universal energy storage molecule.
All organisms break down ATP to get
energy.
Energy is
released when
the chemical
bonds in ATP
are broken.