Cellular Energy

Photosynthesis & Respiration

Energy Flow

• Sun Glucose (photosynthesis) ATP (Respiration)

Cell Energy

• Energy ~ The ability to do work.• Main source of energy in living things: Glucose!

C6H12O6– Glucose is a monosaccharide.– Glucose is made by photosynthesis for autotrophs.– Glucose is part of food eaten by heterotrophs.– Glucose is powerful – it must be turned into a gentler form

of energy called ATP to be used by a cell.

Glucose

C6H12O6

How do you get glucose?

• Autotroph ~ Organism that makes its own food (glucose) by photosynthesis.– Ex: plant

• Heterotroph ~ Organism that must eat food (glucose) from an outside source.– Ex: human

Energy Storing Compounds

• NADPH• ATP

ATP

• Adenosine Triphosphate• ATP is an energy storing compound made in

the mitochondria. It is made when glucose is broken down.

ADENOSINE PO 4 PO4 PO4

ATP

• http://www.biologyinmotion.com/atp/index.html

• Be sure to watch!

Cellular Organelles

• Chloroplasts: plant cells; energy from the sun is converted into glucose

• Mitochondria: glucose is converted into ATP

Chloroplast Structure

• Outer and Inner membranes contain and protect the inner parts

• Stroma: area where reactions occur and sugars are created

• Thylakoids: have chlorophyll molecules on their surface• Chlorophyll – pigment that uses sun’s energy to create glucose

• Stroma lamella: act like the skeleton of the chloroplast, keeping all of the sacs a safe distance from each other and maximizing the efficiency of the organelle.

Mitochondria

• Outer membrane• Cristae: the folds• Matrix: contains high number of enzymes;

several steps of cellular respiration are performed here

• DNA• Ribosomes

Photosynthesis

• A chemical reaction in which light energy is converted into bond energy stored in a glucose molecule.

Photosynthesis Reaction

2612622 666 OOHCLightOHCO lChlorophyl

Requirements for photosynthesis:

• Carbon dioxide (CO2)

• Water (H2O)• Light• Chlorophyll

Products of photosynthesis:

• Glucose (C6H12O6)

• Oxygen (O2)

Plant Pigments

• Chlorophyll - green• Xanthophyll - yellow• Carotene - orange• Anthocyanins

*Plant Pigments absorb energy and pass on to chlorophyll

Chlorophyll

• Chlorophyll is green in color, meaning that green light is reflected, not absorbed.

• Chlorophyll absorbs primarily red and blue light for photosynthesis.

What is happening?

Red Light: Green Light:

Light Reactions

• Starting molecules: CO2, H2O• Ending molecules: O2, NADPH,

ATP

e-

Dark Reactions (Calvin Cycle)• Starting molecules:• Ending molecules:

C6H12O6CO2 C5

Cellular Respiration

• Chemical reactions that convert glucose into ATP.

• May or may not use oxygen.• Occurs in mitochondria.

Aerobic Respiration

Materials Needed:– Oxygen– Glucose

Materials Made:

– 36 ATP– Water– Carbon dioxide

ATPOHCOOOHC 36666 2226126

Anaerobic Respiration

•Breaks down glucose without using oxygen.•Produces a poisonous waste product.•Only produces 2 ATP molecules from one glucose molecule.•Two types of anaerobic respiration: • Alcoholic fermentation • Lactic acid fermentation

Lactic Acid Fermentation

• C6H12O6 CO2 + lactic acid + 2ATP Produces lactic acid as

a waste product. Carried out by bacteria. Causes milk to go sour. Carried out by human muscle cells (reason you are sore

after a workout)

Used in industry to make cheese and yogurt.

Alcoholic Fermentation

• C6H12O6 CO2 + alcohol + 2ATP• Yeasts and other microorganisms carry out

alcoholic fermentation• Formation of ethyl alcohol and carbon dioxide

as wastes• Causes bread dough to rise

Aerobic vs. Anaerobic Respiration

Aerobic

• Uses O2.• Breaks down glucose.• Produces 36 ATP.• Carried out by plants and

animals.

Anaerobic

• Does not use O2.• Breaks down glucose.• Produces 2 ATP.• Alcoholic fermentation is

carried out by yeast.• Lactic acid fermentation is

carried out by bacteria.

Aerobic organisms

• An organism that requires oxygen

Anaerobic organisms

• An organism that does not require oxygen

Photosynthesis vs. Respiration

Photosynthesis• Produces C6H12O6 (glucose).• Occurs in the chloroplasts.• Produces O2 (oxygen gas).• Carried out by autotrophs.

Respiration• Produces ATP.• Occurs in the mitochondria.• Produces CO2 (carbon

dioxide).• Carried out by heterotrophs

and autotrophs.• Aerobic respiration

produces 36 ATP, anaerobic 2 ATP.