CELLULAR RESPIRATION Let’s take a look back! –Photosynthesis: light energy makes glucose Occurs...

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


• Two Types:1. Aerobic: needs Oxygen

2. Anaerobic: does NOT need Oxygen

• 3 Stages:1. Glycolysis

2. Citric Acid Cycle (Kreb’s Cycle)

3. Electron Transport Chain


• 3 Stages:1. Glycolysis = ANAEROBIC

2. Citric Acid Cycle (Krebs Cycle) = AEROBIC

3. Electron Transport Chain = AEROBIC


1. 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• NOT EFFICIENT


2. Citric Acid Cycle (Kreb’s Cycle)• Occurs in Mitochondria• Aerobic• 2 Cycles occur at same time• Each cycle produces 1 ATP


2. Citric Acid Cycle (Kreb’s Cycle)• Yields (Produces):

• 2 Net ATP

• NADPH and FADH2

• Carbon Dioxide


3. Electron Transport Chain• NADH & FADH2 from Citric Acid Cycle

unloads electrons at ETC• Result: 32 ATP is made

• H2O also made


• END RESULT:– 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?


• YES! Anaerobic Respiration or FERMENTATION takes place!


• FERMENTATION– 2 Kinds:

1. Lactic Acid

2. Alcoholic

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


1. 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


2. 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 down

Energy from sun stored in glucose Energy of glucose released

Carbon 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 Respiration

Lactic Acid Alcoholic Cellular respirationglucose

glycolysis (pyruvic acid)

lactic acid

2 ATP

glucose glucose

glycolysis (pyruvic acid) glycolysis (pyruvic acid)

carbon dioxide

alcohol

2 ATP 38 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

CELLULAR RESPIRATION Let’s take a look back! –Photosynthesis: light energy makes glucose Occurs...

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