Do our cells breathe?

…Using glucose to make energy (ATP)

If plants need ATP (energy) to form glucose, how can glucose be a source of energy for plants and animals?

How does our body use glucose to make energy?

Why do your muscles get really sore when you exercise intensely, but not when you pace yourself?

How do you get wine from grapes?

Plants get energy from the sun and store it in the bonds of ___________.glucose

• How do we get energy?– by eating food.

• What types of food provide the most energy?– Carbs (sugars or glucose)

have the most energy • e.g. candy bars, wheat,

potatoes, rice, pasta

• What does your body do to the food you eat?- Our body digests our food (breaks apart bonds), releasing energy

Breaking bonds releases energy! Energy is “stored” in the glucose bonds;

breaking them releases the energy What form of energy do our cell (and our

body) use? the molecule ATP

So.. our body breaks downglucose and uses it to make ATP (ENERGY!) Which organelle is responsible for producing energy for our cells?

The MITOCHONDRIA

ATP (adenosine triphosphate) is a nucleic acid that can transfer energy within the cell.

Ex: a small amount of energy from a glucose molecule can be used directly…

The extra energy is transferred to ATP.

The energy in ATP is stored in the bonds between the phosphates (ATP has 3 phosphates).

http://www.brooklyn.cuny.edu/bc/ahp/LAD/C7/graphics/C7_atp_2.GIF

Remember…cellular respiration is using glucose to make energy

Step 1: glycolysis glyco = refers to glucose lysis = break apart Glycolysis = break down 1 glucose into 2 pyruvic acid molecules, which have three carbons each (splits glucose in half)

Also makes 2 ATP! Takes place in the cytoplasm

Why would we need to break down glucose in the cytoplasm first before we use it in the mitochondria? (think transport)

Glucose molecules are too large to move into the mitochondria, so glycolysis makes them smaller to get through the mitochondria’s membranes

After glycolysis, there are two possible paths:

Aerobic respiration – requires oxygen Anaerobic respiration – does not require

oxygen; happens if oxygen is lackingOxygen?

NO

Anaerobic

Respiration

Aerobic Respirati

on

YE

S

An aerobic process (requires oxygen). Reaction releases energy from the chemical

bonds of carbohydrates. Takes place in the mitochondria. Equation:6O2 + C6H12O6 6H20 + 6CO2 +

36ATPOxygen + Glucose Water + Carbon Dioxide

+ Energy

Equation for photosynthesis:Energy + 6H2O + 6CO2 C6H12O6 +

6O2

Equation for aerobic cellular respiration:6O2 + C6H12O6 6H20 + 6CO2 +

36ATP

http://www.channelislandsrestoration.com/photos/images/IslandFox1.jpg http://www.rhs.org.uk/chelsea/2005/exhibitors/plants/images/

GlebeCottagePlants.jpg

http://www.ucmp.berkeley.edu/fungi/basidio/mushroomsismall.jpg

Plants Animals Fungi Protists Some bacteria …almost everything alive!

Recap: Step 1 = glycolysis 2 ATP molecules are produced in cytoplasm and enter mitochondria.

For aerobic respiration, in mitochondria: Step 2 = Krebs Cycle (Citric Acid Cycle) – in

matrix Step 3 = Electron Transport Chain – in inner

membrane ATP is generated in each step, but most of

the ATP is made in the Electron Transport Chain

Right before the Krebs Cycle, the Pyruvate from glycolysis is converted to Acetyl-CoA.

During Krebs, the Acetyl-CoA is broken down into CO2 & electrons (H+).

2 ATP are created. The electrons then move on to the Electron Transport Chain.

We start with one molecule of glucose and end up with 6 CO2 molecules, a handful of electrons (H+) and 4 ATP molecules.

The CO2 is waste that will move out of the cell (and which you exhale).

The 4 ATP molecules can be used by the cell as energy.

What about the other 32 ATPs from our equation?

Embedded in the mitochondria inner membrane are proteins called electron carriers.

The electrons (H+) from Glycolysis and the Krebs Cycle are passed from electron carrier to electron carrier (like a bucket brigade).

With every pass, energy is released from the electrons, and ATP is made. As a result, 32 ATP are made in the Electron Transport Chain.

C6H

12O

6 + 6O

2 → 6CO

2 + 6H

2O + 36 ATP

Glucose + Oxygen → Carbon dioxide + Water + ATP

(Krebs Cycle)

What happens with respiration of lipids, proteins, and nucleic acids?

Starch: broken down into glucose, which enters glycolysis

Fats: broken down into fatty acids and glycerol; fatty acids are cut into 2-carbon compounds, converted to Acetyl-CoA, and enter the Krebs Cycle

Proteins: broken down into amino acids, which can be converted into Acetyl-CoA or other compounds that enter the Krebs cycle at various points The amino group is removed & excreted as urea.

Nucleic Acids Proteins Carbohydrates Lipids

Amino Acids SugarsFatty Acids/

Glycerol

Pyruvate

Acetyl-CoA

KrebsCycle

Urea H2O CO2

Nucleotides

During aerobic respiration, where do the electrons (H+) end up as they are passed from protein to protein?

They end up in the loving arms of oxygen. When oxygen accepts electrons, water is made. If oxygen wasn’t there to accept the electrons,

the Electron Transport Chain would get backed up, and no energy would be produced.

What type of respiration happens when there is no oxygen? …and where does it happen?

AKA: fermentation An anaerobic process

(does not require oxygen)

Two types of fermentation: Alcohol fermentation Lactic acid fermentation

Both take place in the cytoplasm.

http://www.schmohz.com/images/beer-fermenter.jpeg

Pyruvic acid + NADHNAD+ +alcohol +CO2 +

2 ATP

Yeast perform alcohol fermentation in the absence of oxygen.

The alcohol produced is the type that we drink.

The CO2 produced is used to make bread rise.

http://www.utoronto.ca/greenblattlab/images/a/yeast%201.jpg

Pyruvic acid + NADHNAD+

lactic acid2 ATP

*Lactic acid is what makes your muscles sore when you exercise.

Humans (and other animals) - when they are exercising and their muscles aren’t getting enough O2 to keep up with the energy demand.

The build up of lactic acid is what makes your muscles start to burn.

http://www.donlemmonsknowhow.com/img/exercise-session.jpg

You get way more ATP from aerobic cellular respiration than you do from anaerobic cellular respiration (fermentation).

Fermentation is mostly used to provide organisms with short-term bursts of energy when oxygen is not available.

http://www.athleticsireland.ie/content/wp-content/uploads/2006/08/washington.jpg