Cellular Respiration

Overview

• Heterotrophs obtain

glucose from plants and

plant matter.

• The goal is to convert food

energy (glucose) into

chemical energy! (ATP)

• Why would we do this?

The process by which glucose molecules

(food) are broken down and converted it

into chemical energy (ATP) is called

cellular respiration.

Cellular respiration is a series of chemical

reactions that produces ATP.

The cell can then use that ATP whenever

it needs it!

Two types or categories for the chemical

reactions that make up cellular

respiration:

Aerobic respiration: requires

oxygen

• Produces 36 ATP molecules from each

glucose molecule.

Anaerobic respiration: does not

require oxygen

• Produces 2 ATP molecules from each

glucose molecule.

• Some organisms are only capable of

anaerobic respiration, however; others

are capable of both

Check for Understanding

• What is the primary difference between

aerobic and anaerobic respiration?

• Which one makes more ATP?

• Respiration breaks down glucose,

where do our bodies get the glucose?

The type of cellular respiration that

occurs most commonly in your body cells

is aerobic respiration

Think about this…

Think of one specific piece of evidence

that supports that your cells are aerobic.

Be ready to share!

Three chemical reactions

make up cellular respiration

There are 3 reactions as we

have 3 goals.

1)Break sugar down

2)Collect Hydrogens

3)Build lots of ATP!

Glycolysis: • Both aerobic and

anaerobic

respiration begin

with glycolysis

• Glycolysis is the

process by which

glucose is

converted

(changed) by

being broken

apart. That

catabolizing

releases energy

we can use!

Vocab Tip!

• Glyco is a prefix that means “sugar”

(glucose) in Latin!

• And lysis is a suffix that means “to split”

in Latin

• So…put it all together…Glyco-(sugar)

lysis-(breaks)

• When glucose breaks we call the new

compounds made; Pyruvate.

• Pyruvate is a three-carbon molecule

that can be further broken down in the

next reaction.

• Glycolysis occurs in the cytoplasm of

the cell

• Glycolysis does NOT require oxygen so

we call this process anaerobic.

Most of the energy is contained in the

pyruvate molecules is released in the next

stage.

Think about this….

When we say “ energy is released” where

does that energy actually come from in a

molecule or compound?

Be ready to share!

A single glucose molecule that has

undergone glycolysis will produce 3

things; NADH, 2 ATP and 2 pyruvate

molecules.

Check for Understanding

• Where does glycolysis happen?

• Is it aerobic or anaerobic?

• What is needed for glycolysis?

• Where do those things come from?

• What is produced in glycolysis?

• Where do those things go?

Citric Acid Cycle (Also known

as the “Kreb’s Cycle”)

The pyruvate molecules produced by

glycolysis are moved into the

mitochondria and are the reactants

(ingredients) for the Citric Acid Cycle.

• Remember, we broke (catabolized) the

glucose into 2 pyruvates and so now,

in the Citric Acid Cycle we can break

(catabolize) those pyruvates down

even more!

• The Pyruvates are catabolize into

NADH, ATP (from ADP+P) and CO2

Notice second taxi! Why is this needed here? AND

how do our H taxis differ from those in a plant?

Check for understanding

• Where does Krebs Cycle occur?

• What is the other name for Krebs cycle?

• What is needed for Krebs cycle

• Where do those things come from?

• What is produced in Krebs cycle?

• Where do those things go?

Electron Transport Chain

The process by which energy is

transferred from NADH and

FADH2 to ATP.

The movement of electrons on Hydrogen

from NADH and FADH2 occurs along a

special inner membrane of the

mitochondrion, called the cristae.

•The hydrogen & its electron connect to

oxygen across the membrane and in so

doing makes water molecules.

•The electron transport chain generates

about 36 ATP molecules produced from each

original glucose molecule.

Think about this….

Why can’t we leave hydrogen alone?

Be ready to share!

Check for understanding

• Where does the ETC happen?

• Is it aerobic or anaerobic?

• What is needed for the ETC?

• Where do those items come from?

• What is the ultimate electron and

hydrogen acceptor?

So think about this…for 1 glucose

you get about 36 ATP! That is an

investment that pays off big!!!

Waste products of Cellular

Respiration

• Carbon Dioxide

• Water

• Heat

• Where do each of these end up?

Anaerobic Respiration

Certain cells in our body can produce energy without oxygen, mainly our

muscle cells. And only if we run low on oxygen for them!

Anaerobic respiration is the process that releases energy from food molecules in

the absence of oxygen.

Through fermentation, anaerobic organisms and your cells can exist w/o oxygen by using the small amount of

energy supplied by glycolysis.

Fermentation:The breaking

of glucose in

glycolysis

and the

recycling of

NAD in the

absence of

oxygen.

Only

produces 2

ATP.

Two types of Fermentation:

• Alcoholic fermentation (alcohol is a

waste product)

• Lactic acid fermentation (lactic acid is

a waste product)

Quick check of understanding: Name a type of organism who does

alcohol fermentation. And name an organism who does lactic acid fermentation.