III. Cells and Energy

A. Energy Transfer in Cells

1. Carbohydrates such as glucose provide energy for the cell. However, they cannot be used directly, They must be converted to ATP

2. ATP Adenosine Triphosphate is the energy molecule of the cell.

Adenosine Triphosphate

3. How ATP works ATP links Anabolism (building molecules) and catabolism (breaking down molecules)!!!!!

Catabolism

ATP is formed from ADP and Pi when energy is released by breaking the bonds of fuel molecules during cellular respiration

Anabolism

When ATP is broken down forming ADP and Pi energy is released to build molecules such as proteins

4. How ATP is Produced: Respiration

IN Out

Glucose

Oxygen

ADP

Free Phosphate(Pi)

Carbon Dioxide

Water

Mitochondrion

The ATP can be used directly to power life processes

ATP

B. Capturing Light Energy: Photosynthesis

1. Requirements and products of photosynthesis

IN OutCarbon Dioxide

Water

Light Energy

Glucose

Oxygen

Water

Chloroplast

2. Stages of Photosynthesis

A) Light Reaction- traps light energy to make ATP– Light strikes chlorophyll and electrons are boosted to a high

energy state

– Electrons flow down the electron transport chain and convert ADP to ATP

B) Water is split– NADP captures hydrogen and becomes NADPH

– Oxygen is given off as waste

C) The ATP and NADPH are used in the Dark reaction

A photon of light strikes chlorophyll and a water molecule is split

As electrons move down the electron transport chain, hydrogen ions are pumped into thylkoid

Light boost the electron to a NADP forming NADPH Hydrogen

ions flow through ATPsyntase forming ATP from ADP

3. 2nd Stage of Photosynthesis: Dark Reaction- Uses the ATP from the light reaction to join the carbon dioxide (from the atmosphere) and hydrogen (from NADPH) to form glucose in a series of reactions called the Calvin Cycle

IN

Out

Calvin

Cycle

Carbon Dioxide

NADPH

ATP

Glucose

NADP

ADP + Pi

The Calvin Cycle

Carbon dioxide joins with RuBP to form a six carbon molecule

The six carbon molecule splits forming 3 carbon molecule called 3-PGA

Energy from ATP and hydrogen from NADPH are added forming G3POne molecule of 3GP exits

The remaining molecule are converted to RuBP

C. Energy Release1. Anaerobic Respiration- the breakdown of

glucose to produce 2ATP without using oxygen.

a) Glycolysis- breaking glucose in two. This produces 2 ATP and Lactic acid

1) Lactic acid causes muscle fatigue

2) Lactic Acid produced by bacteria gives food a sour taste. Vinegar, sour cream, pickles etc

Bacteria

IN OUT

Glucose

2(ADP + Pi)

Lactic Acid

2 ATP

Anaerobic Respiration

b) Fermentation- breaking down glucose into Alcohol and Carbon Dioxide to produce 2 ATP

1) Fermentation produces beer and wine

2) Fermentation causes bread to rise

Yeast

IN Out

Glucose AlcoholCarbon Dioxide

2ATP2(ADP + Pi)

Aerobic Respiration

2. Aerobic Respiration- The break down of glucose with oxygen to produce 38 ATP. Involve 4 Steps:

Step 1: Glycolysis (Occurs in cytoplasm)

Glucose is broken in half producing Pyruvic Acid and 2 ATP

Step 2: Pyruvic Acid Conversion (in Mitochondria)

Pyruvic acid is converted to Carbon Dioxide and Acetyl groups

Carbon Dioxide

Acetyl Groups

Pyruvic Acid

Step 3: Kreb’s Cycle

The Acetyl groups have their hydrogen stripped away releasing CO2 and 2 ATP

Acetyl groups

Hydrogen

NADNADH

Carbon Dioxide

2 ATP

Kreb’s

Cycle

Step 4: Electron Transport ChainHydrogen moves down the electron transport chain producing 34 ATP. The hydrogen then joins with oxygen to form water

ADP + Pi

34 ATP