RespirationBy C. Kohn, Waterford WI

Chickens and CHICKENS

Last year, Mr. Kohn’s class grew two kinds of chickens The first kind were layers. They are bred to

lay eggs and grow slowly. The second kind are broilers. They are bred

for meat production and grow quickly. Why would two breeds of the same bird

grow at very different rates? Think, Pair, Share – what causes the

differences in growth? See next slide first.

Scientific Questions

You might be tempted to respond with short answers like “genetics” or “diet”. Avoid these kinds of answers – they do not

help us to solve a problem. Instead, try to suggest a hypothesis

that might explain this.What might be different about their

bodies, organs, or cells that could cause one kind of chicken to grow twice as fast?

Answers…not yet.

So why does one kind of chicken grow so much faster than the other?

Answering this question requires an understanding of the most universal aspects of agriculture.

To begin, let’s focus on the simplest unit of life – the cell.

The Cell

The cell is the smallest unit of life This means that the smallest something can be

and still be alive is a cell Molecules can’t be alive, but they can be part

of something alive The smallest thing that can be alive is one cell

There are two kinds of cells Prokaryotic – bacteria – simple and basic Eukaryotic – the cells of complex organisms

that have organelles (cellular structures)

Eukaryotic Cells

Eukaryotic cells all have similar key ingredients . Some are… Nucleus w/ DNA instructions Cell membrane to maintain constant

conditions Mitochondria – powerhouse of the cell Ribosomes – protein factories Vacuoles – storage and waste removal Plants Only: Chloroplast (sugar

production), Cell Wall (a plant’s “skeleton”)

The Animal Cell

Nucleus – DNA Instructions

Mitochondria – Cell Powerhouse

Cell Membrane – A

Barrier to

the

Outside

The Mitochondria

In this part of the class, we’ll focus on the mitochondria.

The mitochondria are the “POWERHOUSES” of the cell.

They create the energy that powers the cellular activity of all living things. Your body uses the energy created by your

mitochondria. All plants, animals, and fungi use mitochondria to

create their cellular energy.

The Mitochondria

ATP

ATP is the energy of the cell (not sugar!) ATP stands for Adenine TriPhosphate

ATP consists of…1. Three phosphate molecules2. A ribose sugar molecule3. An amino acid – Adenine

A simpler way to remember ATP is:A Triple Phosphate

1 2 3

ATP = A rechargeable battery ATP is like a rechargeable battery

It is re-used over and over again and can be re-charged each time in the mitochondria

When ATP gives up its “charge”, it becomes ADP and Pi. ADP is the same thing as ATP except that it only

has 2 phosphates▪ Pi is the third unattached phosphate. It has to be

“smashed” back on to re-charge ATP ADP = “A Double Phosphate” = ‘uncharged

battery’

Summary: 5 Key Points

1. Eukaryotic Cells are the cells of complex organisms like plants, animals, and fungi.

2. Eukaryotic Cells all have Mitochondria, the powerhouse of the cell

3. Mitochondria produce ATP, the energy of the cell. 1. ATP powers all cellular activity in any kind of cell

4. ATP carries energy; when it gives up its energy, it becomes ADP and Pi

5. ATP must be re-charged in the mitochondria 1. ATP becomes “re-charged” when ADP and Pi are smashed

together

ATP Synthase – the Smasher Wheel

ADP and Pi are ‘smashed’ together in a special structure in the mitochondria called ATP Synthase. ATP Synthase is a tiny molecular structure that

turns

ATP Synthase is just like a water wheel on a dam. As water flows over the dam, the

waterwheel turns ATP Synthase turns when hydrogen

flows past it

ATP Synthase

``

ATP Syntha

se

Stored Hydrogen

Mitochondrial Inner

Membrane

Mitochondrial Lumen (inside)

Flow

ing

Hyd

roge

n

ATP Synthase

Just like water flowing over a dam powers a waterwheel, hydrogen flowing through ATP Synthase turns its “wheel” The turning of this wheel combines ADP

and Pi into the energy-carrying ATP

The walls of the mitochondria contain many ATP Synthase structures, each producing charged ATP from ADPand Pi

Hydrogen-Powered ATP Synthase

The wheel of ATP Synthase requires constantly flowing hydrogen

This hydrogen comes from the food you eat

Carbohydrates provide most of this hydrogen

Carbohydrates include simple sugars, starches, and fiber

Carbohydrates = Chains of Sugar Starches, simple sugars, and fiber are all

made from chains of sugar molecules.

In order for your body to use a carbohydrate, it must be broken down into individual sugar molecules – glucose

White bread tastes sweeter than whole grain bread because it is made of shorter chains of sugar that break down more easily (the shorter the chain, the easier to break it)

Carbohydrate Digestion

When you eat carbohydrates, they are broken down into individual glucose molecules (click)

These molecules are absorbed into the blood and are absorbed by cells.

Once in the cell, the individual glucose molecules are broken down. The hydrogen is moved inside the mitochondrial

membranes to power ATP Synthase Carbon Dioxide (CO2) is the waste created from respiration.

To Blood

Removal of Hydrogen after ATP Synthase

In the mitochondria, the stored hydrogen powers the wheels of ATP Synthase.

After it powers the wheel, each hydrogen atom must be removed from the mitochondria. If hydrogen was not continuously removed, it would

stop flowing. (Imagine if people stopped inside a revolving door!)

To remove the hydrogen, we breathe in oxygen The oxygen binds to two hydrogen molecules to

make H2O

H2O and CO2 are breathed out when we exhale

Summary – 5 key points

1. ATP Synthase is the “wheel” that “smashes” ADP and Pi back into charged ATP

2. Flowing hydrogen from the mitochondrial membrane powers this wheel.

3. The hydrogen comes from the food we eat, particularly carbohydrates

4. Carbohydrates must be broken down into individual glucose molecules to be used by cells.

5. Hydrogen is taken from glucose to power ATP Synthase.

Both H2O and CO2 are exhaled when we breathe out. CO2 and H2O are the waste products of respiration.

Application – ATP Synthase & Brown Fat

Babies have lots of what is called brown fat. Fat typically is used to store energy for ATP

production.

Brown fat is found in babies and animals in cold climates. Brown fat is brown because it has a large

number of mitochondria It is actually created from muscle, not fat.

ATP Synthase & Brown Fat Brown fat produces heat. It does this

because it has leaky mitochondria The hydrogen atoms stored in mitochondria can

leak out instead of going through ATP Synthase This creates friction, which creates heat

Brown fat doesn’t just insulate babies and cold-climate mammals, it heats them!

Brown fat & weight loss? Why might this work?

Growth, Mitochondria, & Oxygen

Growth and Mitochondrial Respiration of Mungbeans (Phaseolus aureus Roxb.) Germinated at Low Pressure 1

Mary E. Musgrave, et. al.

Beans grew more with higher oxygen levels. Why? TPS Why would oxygen improve

growth? How does oxygen affect ATP

production?

CO2 and Mitochondrial Conc. Plant growth in elevated CO2

alters mitochondrial number and chloroplast fine structure. Kevin L. Griffin, et al

Increasing CO2 concentrations led to increased mitochondrial concentrations in plants

Increased CO2 led to an…Increased amount of mitochondria, leading to…

Increased plant productivity.

Why? TPS

Broiler Chicks vs. Layers

“Heat production and lipid metabolism in broiler and layer chickens during embryonic development.” Momoka Sato, et. al.

Consumption of the yolk sac was faster in broilers than in layers. Note: The egg yolk is the food for

the baby chick Why might broiler chickens consume

their egg yolk faster than a layer?

Chickens

How could we use mitochondria, ATP, or ATP synthase to improve chicken growth and performance?

On your whiteboards, write 5 ways in which we could change the cells of a chicken so that it grows faster. Be prepared to defend why your

treatment might work.