Cellular Respiration

Harvesting

Chemical Energy

ATP

CO2 + H2O + heatfuel

(carbohydrates)

O2

“Burn fuels” to make energycombustion

making heat energy by burning fuels in one step

ATP

ATP + CO2 + H2O (+ heat)

aerobic respiration

making ATP energy (& some heat) by burning fuels

in many small steps

food

(carbohydrates)

O2

Energy needs of life• Animals are energy consumers

• What do we need energy for?

• synthesis (building for growth)

• reproduction

• active transport

• movement

• temperature control (making heat)

Where do we get energy?• Energy is stored in organic molecules

• carbohydrates, fats, proteins

• Animals eat these organic molecules food

• digest food to get

• fuels for energy (ATP)

• raw materials for building more molecules

• carbohydrates, fats, proteins, nucleic acids

ATP

ATP

What is energy

in biology?

Whoa!HOT stuff!

Adenosine Triphosphate

Harvesting energy stored in food• Cellular respiration

• breaking down food to produce ATP

• in mitochondria

• using oxygen = “aerobic” respiration

• usually digesting glucose

• but could be other sugars, fats, or

proteins O2

food

ATP

C6H12O6 6O26CO2

ATP

6H2O

Glucose Oxygen Carbon

DioxideWater

ATP

What do we need to make energy?

• The “Furnace” for making energy

• mitochondria

• Fuel

• food: carbohydrates, fats, proteins

• Helpers

• oxygen

• enzymes

• Product

• ATP

• Waste products

• carbon dioxide

• water

O2

food

ATP

Make ATP!Make ATP!

All I do all day…And no oneeven notices!

enzymes

CO2 H2O

Mitochondria are everywhere!!

animal cells plant cells

Cannot store ATP too unstable

only used in cell that produces it

only short term energy storage carbohydrates & fats are long term energy storage

Using ATP to do work?

A working muscle recycles over

10 million ATPs per second

Whoa!Pass me the

glucose & oxygen!

ATP

ADP

workAdenosine DiPhosphate

Adenosine TriPhosphate

How organisms turn fuel into ATP

Fuel(carbohydrates, lipids, proteins)

Anaerobic

Cellular Respiration

Oxygen present?

no yes

Alcoholic

FermentationLactic Acid

Fermentation

Makes only a little

Aerobic

Cellular Respiration

ATP

ATP

ATP ATP ATP

ATP

ATP

ATP

ATPATPATP

ATP

Makes a LOT of

Let’s first look at Aerobic Respiration

Aerobic Cellular Respiration

3 Major Steps:

1. Glycolysis

2. Kreb’s Cycle / Citric Acid Cycle

3. Electron Transport Chain

1. Glycolysis

• Glyco = glucose lysis = splitting

• Where: in the cytoplasm

• Uses : glucose but NO oxygen

• Makes:

• Pyruvate (passed to Kreb’s Cycle)

• A little ATP

• NADH (electron bus… headed to the

Electron Transport Chain)

Glycolosis (no O2 required)

Glucose

G3P

2 Pyruvate

2. Krebs Cycle

• Where?

• in the mitochondrial matrix

• Uses:- pyruvate (from glycolysis)

• Makes:

• NADH (electron bus)

• FADH2 (electron bus)

• A little ATP (energy)

• Carbon Dioxide (waste product)

Krebs Cycle

• Two Acetyl CoA

enter cycle to

form Citric Acid

one at a time

3. Electron Transport• Where?

• Inner mitochondrial membrane

• Uses:

• NADH & FADH2

• Remember these are like “electron buses” that drop off electrons to the ETC

• Oxygen

• Pulls electrons down the ETC and accepts them at the end of the ETC

• This is why we die if we don’t get oxygen!

• Makes:

• Water (waste product)

• A BUNCH of (whoohooo… big energy!)ATP

How does the ETC make so much

energy ?

Answer = chemiosmosis

Sound familiar?

• We learned it in photosynthesis too!

ATP

1. NADH & FADH2 drop off electrons

1. Oxygen pulls electrons down the ETC

2. Chemiosmosis = Hydrogen ions diffuse

from an area of high concentration

(outside the membrane) to an area of

low concentration (inner-membrane

space) through ATP synthase.

• Hydrogen ions then help to bond a

third phosphate group to ADP creating

lots of ATP

Electron Transport

Electron Transport

1 32

Anaerobic Respiration

We know that aerobic cellular

respiration requires oxygen. But

what happens if there is no oxygen

available?

Answer = Anaerobic Cellular Respiration

O2

Anaerobic respiration

• The anaerobic pathway that follows glycolysis

• If there is no oxygen present and an organism needs energy, the cell may use anaerobic respiration to continue producing ATP

O2

Anaerobic Respiration

• also known as fermentation

• alcohol fermentation

• lactic acid fermentation

• no oxygen or

no mitochondria (bacteria)

• makes very little ATP

• large animals cannot survive

using only fermentation

O2

yeast

bacteria

Anaerobic Respiration• Fermentation

• alcohol fermentation

• yeast

• glucose ATP + CO2+ alcohol

• make beer, wine, bread

• lactic acid fermentation

• bacteria, animals

• glucose ATP + lactic acid

• bacteria make yogurt

• animals feel muscle fatigue

O2

Tastes good…but not enoughenergy for me!

Questions!

Number your paper 1 to 4

What is the overall purpose of cellular

respiration?

A. to make ATP

B. to produce H2O

C. to store glucose

D. to deliver oxygen

Which represents the general sequence of

cellular respiration?

A. TCA cycle chemiosmosis glycolysis

B. glycolysis Krebs cycle electron transport

C. electron absorption catalysis

phosphorylation

fermentation

D. aerobic pathway anaerobic pathway

Which stage of cellular respiration is the

anaerobic process?

A. glycolysis

B. Krebs cycle

C. electron transport

Which molecule generated by the Krebs

cycle is a waste product?

A. CoA

B. CO2

C. FADH2

D. NADH

Answers

1. A

2. B

3. A

4. B