CELLULAR RESPIRATION• Let’s take a look back!

– Photosynthesis: light energy makes glucose• Occurs only in plants or organisms with chloroplasts

and chlorophyll• Carbon dioxide is taken in• Oxygen is given off• Requires light

CELLULAR RESPIRATION• Cellular Respiration: chemical process

where carbohydrates are broken down to be a quick source of ATP– Location: mostly within Mitochondria– Food ATP

CELLULAR RESPIRATION• Two Types:

1. Aerobic: needs Oxygen2. Anaerobic: does NOT need

Oxygen

• 3 Stages:1. Glycolysis2. Citric Acid Cycle (Kreb’s

Cycle)3. Electron Transport Chain

CELLULAR RESPIRATION• 3 Stages:

1. Glycolysis = ANAEROBIC2. Citric Acid Cycle (Krebs Cycle) = AEROBIC3. Electron Transport Chain = AEROBIC

CELLULAR RESPIRATION1. Glycolysis: means “breaks down glucose”

• Occurs in cytoplasm• Costs 2 ATPs to start reaction• Breaks glucose down to Pyruvic Acid • Makes total of 4 ATPs• At end of reaction, net of 2 ATP, and NADH

(energy carrier)• NOT EFFICIENT

CELLULAR RESPIRATION

CELLULAR RESPIRATION2. Citric Acid Cycle (Kreb’s Cycle)

• Occurs in Mitochondria• Aerobic• 2 Cycles occur at same time• Each cycle produces 1 ATP

CELLULAR RESPIRATION2. Citric Acid Cycle (Kreb’s Cycle)

• Yields (Produces):• 2 Net ATP• NADH and FADH2

• Carbon Dioxide

CELLULAR RESPIRATION

CELLULAR RESPIRATION3. Electron Transport Chain

• NADH & FADH2 from Citric Acid Cycle unloads electrons at ETC

• Result: 32 ATP is made• H2O also made

CELLULAR RESPIRATION• END RESULT:

– 36-38 ATP made from all 3 Stages– Oxidative Phosphorylation

• Oxygen is final electron acceptor• ADP is converted to ATP by adding phosphate

group

• But wait! What if there was not enough oxygen? Could cellular respiration still have taken place?

CELLULAR RESPIRATION• YES! Anaerobic Respiration or

FERMENTATION takes place!

CELLULAR RESPIRATION• FERMENTATION

– 2 Kinds:1. Lactic Acid2. Alcoholic

• Both kinds only use GLYCOLYSIS– How many ATPs does that mean they make?

CELLULAR RESPIRATION1. Lactic Acid Fermentation

• Anaerobic• Produces burning feeling in

muscle cells• Occurs when body worked to

point that more oxygen being used than taken in

• Produces LACTIC ACID and 2 ATP

CELLULAR RESPIRATION2. Alcoholic

• Anaerobic• Carried out by some bacteria

and yeast• Used to bake bread and make

wine• Produces CO2, Ethyl Alcohol,

and 2 ATP

Let us do some comparisons!• Photosynthesis vs. Cellular Respiration

Photosynthesis Cellular RespirationFood synthesized Food broken downEnergy from sun stored in glucose Energy of glucose releasedCarbon dioxide taken in Carbon dioxide given off

Oxygen given off Oxygen taken in

Produces sugars from PGAL Produces CO2 and H2O

Requires light Does not require light

Occurs only in presence of chlorophyll

Occurs in all living cells

Let us do some comparisons!• Fermentation vs. Cellular Respiration

Comparison of Fermentation to Cellular RespirationLactic Acid Alcoholic Cellular respiration

glucose

glycolysis (pyruvic acid)

lactic acid

2 ATP

glucose glucose

glycolysis (pyruvic acid) glycolysis (pyruvic acid)

carbon dioxide

alcohol

2 ATP 36 ATP

water

carbon dioxide

Check It!

D. the Calvin cycle

C. the light-independent reaction

B. cellular respiration

A. photosynthesis

1. The process by which mitochondria break down food molecules to produce ATP is called ________.

Check It!

B. glycolysis, the citric acid cycle, and the electron transport chain

A. Carbon fixation, the Calvin cycle, and the electron transport chain

2. The three stages of cellular respiration are ________.

D. the light-dependent reactions, the citric acid cycle and the electron transport chain

C. glycolysis, the electron transport chain, and the citric acid cycle

Check it!3. Which of the following yields the greatest net

ATP?

D. Cellular respiration

C. Calvin cycle

B. Alcoholic fermentation

A. Lactic acid fermentation