Photosynthesis• The process autotrophs use to make

glucose sugars from carbon dioxide, water, and light energy

6CO2 + 6H2O C6H12O6 + 6O2

sunlight

Photosynthesis and Respiration are complementary cycles

6CO2 + 6H2O → C6H12O6 + 6O2

C6H12O6 + 6O2 → 6CO2 + 6H2O

Energy inSunlight

Energy outATP

Enzymes

Enzymes

Radiant energycarbohydrates

Respiration

How energy flows through the ecosystem

Photosynthesis

HeterotrophsHeterotrophs

Autotrophs

heat

How organisms get energy

1. Autotrophs: able to produce own glucose – Ex: plants, algae, cyanobacteria– Also called: producers

2. Heterotrophs: must take in glucose from outside source

– Ex: animals, fungus, most bacteria, protozoans

– Also called: consumers

Why is food so important?• The energy from carbon based molecules

(food) are needed to charge ATP molecules, which provide energy for metabolic reactions.

Adenine Ribose 3 Phosphate groups

ADP and ATP• To get energy out of ATP, the bond

between the last two phosphate groups is broken.

ADP ATP

Energy

EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)

Partiallychargedbattery

Fullychargedbattery

Importance of energy

• Cells need energy to be able to carry out important metabolic functions to sustain life.

– Ex: Active transport, cell division, movement of flagella or cilia, and the production, transport, and storage of proteins

Where and how are sugars made?Light Energy

Chloroplast

CO2 + H2O Sugars + O2

Pigments

• Chlorophyll is a pigment, a molecule that can absorb light energy.

• Unused light is reflected.

• What is the color of the wavelength least used by chlorophyll?

Absorption of Light byChlorophyll a and Chlorophyll b

V B G YO R

Chlorophyll b

Chlorophyll a

Photosynthesis pigments

• A. chlorophyll (reflects light green)

• B. chlorophyll b(reflects dark green)

• C. xanthophyll(reflects yellow)

• D. carotenoid(reflects orange)

Chromatography

• The process of separating colored solutions to determine the number of pigments in the solution

• The smaller and more soluble the pigment the further it is carried by the solvent

How does photosynthesis work?

1. Light dependent reaction

2. Calvin cycle

ChloroplastLight

Sugars

CO2

Light-Dependent Reactions

CalvinCycle

NADPH

ATP

ADP + P

NADP+

Chloroplast

H20

O2

Step 1: Light dependent reaction

HydrogenIon Movement

Photosystem II

InnerThylakoidSpace

ThylakoidMembrane

Stroma

ATP synthase

Electron Transport Chain Photosystem I ATP Formation

Chloroplast

Light dependent reaction

• Pigments (chlorophyll) inside of the chloroplasts are arranged into photosystems (PS II and PS I).

• Photosystems absorb sunlight.

• Electrons become energized and help to produce ATP & NADPH.

Step 1: LightDependent reactions• location:

grana of chloroplast

• Photosystem II: – energized chlorophyll splits water into

Oxygen (released) and Hydrogen (carried by NADP to be used later)

• Photosystem I: – energized chlorophyll makes ATP (to be

used later)

Light Dependent reactions

• The products of the light reactions will move on to the Calvin cycle:

• ATP

• NADPH

Step 2: Calvin cycle

ChloropIast

CO2 Enters the Cycle

Energy Input

5-CarbonMoleculesRegenerated

Sugars and other compounds

6-Carbon SugarProduced

Light Independent Reactions(Calvin Cycle)

• Location: stroma (fluid) of chloroplast

• CO2 is “fixed” by RuBP & begins the cycle becoming PGA, then PGAL after hydrogen (from NADP) and energy (from ATP) are added.

• Products: Glucose (sugar/food) is made (from 6 turns of cycle) – RuBP is recycled for next time

6CO2 + 6H2O C6H12O6 + 6O2

Calvin cycle

• The NADPH supplies the energy needed to change the CO2 taken into the cell into a 6 carbon molecule.

• This 6 carbon molecule is made into sugars.

glucose

What happens to the sugar?

• Plants can store the sugar in roots or stems (ex: potatoes, turnips, carrots, sugar cane)

• Heterotrophs such as humans must eat or consume (ex. Carrots, potatoes) foods in order to make ATP by cellular respiration.

• Sugars & starches are used to make ATP by cellular respiration as needed.

• ALL living organisms need and use energy.

• Therefore ALL organisms need ATP

• ALL organisms plants and animals, fungi, bacteria and protists make their ATP through respiration

Photosynthesis and Respiration are complementary cycles

6CO2 + 6H2O → C6H12O6 + 6O2

C6H12O6 + 6O2 → 6CO2 + 6H2O

Energy inSunlight

Energy outATP

Enzymes

Enzymes

Cellular respirationReleases energy for cell metabolism

Two types of respiration

• Aerobic respiration: Organisms that require oxygen use aerobic respiration to make ATP but switch to fermentation when oxygen is not available.

• Anaerobic respiration: Organisms that live without oxygen use anaerobic respiration to make ATP and die in the presence of oxygen.

Where cell respiration takes place

• Prokaryotes: cell membrane

• Eukaryotes: mitochondria organelle

Overview of cellular respiration

Glucose

Glycolysis Krebs cycle

Electrontransport

Fermentation (without oxygen)

Alcohol or lactic acid

Overview of aerobic respiration

GlucoseGlycolysis

Cytoplasm

Pyruvic acid

Electrons carried in NADH

Krebs Cycle

Electrons carried in

NADH and FADH2 Electron

Transport Chain

Mitochondrion

Mitochondrion

Steps of aerobic respiration1. Glycolysis

2. Krebs cycle

3. Electron transport chain

4. ATP synthase

Step 1: Glycolysis

• Glucose molecules are broken down into two molecules of pyruvic acid.

Glucose

To the electron transport chain

2 Pyruvic acid

GLYCOLYSIS

– Anaerobic stage (occurs without oxygen)– Location: cytoplasm

– Carbons? Glucose (6 C) is split into two 3-Cs by the force of 2 ATP molecules

– Products? Hydrogen is saved by NAD to be used later & 4 ATP (net gain of 2) are produced

Step 2: Krebs cycle

• The pyruvic acid is altered to produce NADH, an electron carrier.

Citric Acid Production

Mitochondrion

KREBS CYCLE• Location: mitochondria

(fluid matrix)• Carbon compounds join &

break apart several times during the cycle, making lots of CO2

• Products: small amount of ATP & large amount of NADH (used later)

Step 3: Electron transport chain

Electron TransportHydrogen Ion Movement

ATP Production

ATP synthase

Channel

Inner Membrane

Matrix

Intermembrane Space

• Location: mitochondria (cristae, inner membrane)

• Energy from Hydrogen atom’s electrons is utilized to charge ADP into ATP

• Hydrogen ultimately joins oxygen to make water as a waste product

Electron transport chain

Electron transport chain

• NADH supplies the electron needed to start the ETC.

• Hydrogen ions (protons) are released.

• The protons flow through the ATP-making enzyme (ATP synthase), activating the enzyme to add a phosphate group to ADP to make ATP.

Electron transport chain video

Click on image to play video.

What happens if there is no oxygen available and the organism is aerobic?

1. Glycolysis

2. Fermentation: lactic acid or alcohol

Glucose Pyruvic acid

Fermentation (anaerobic respiration)

• Without enough oxygen present, an “alternate route” is taken, producing other products & much less ATP

• In yeast: Alcohol and CO2 are produced

• Ex: in bread-making & the alcohol industry

Alcohol industry

• Yeast undergo alcohol fermentation when they do not have oxygen to make ATP.

• The alcohol industry uses specific yeast to convert fruit sugars into alcohol.

Sore muscles• When a person exercises,

the muscle cells use up oxygen faster than a person can breathe in.

• The muscle cells need O2 to make ATP.

• The cells perform lactic acid fermentation instead producing lactic acid in the cells and when in higher concentrations, makes muscles feel sore.

US Swim Team members 2004

water

oxygen

Hydrogen

NADP ATP

Light

CO2

glucose

Photosynthesis

glucose

Glycolysis

Krebs cycle

Electron transport

CO2

oxygen

water

3 C comp

NADH

38ATP

Cell Respiration

Endosymbiotic Theory

•Lynn Margulis proposed that certain organelles evolved from a symbiotic relationship between a host cell and early prokaryotes

•Mitochondria were chemosynthetic aerobic prokaryotes

•Chloroplasts were photosynthetic prokaryotes