Topic 2Organisms and Energy

1. Aerobic Respiration 2. Exercise3. Anaerobic Respiration 4. Photosynthesis5. Limiting factors6. Water Transport

• Recall that respiration is a process used by all living organisms that releases the energy in organic molecules

• Explain how the human circulatory system facilitates respiration,including:

a) glucose and oxygen diffuses from capillaries into respiring cells

b) carbon dioxide diffuses from respiring cells into capillaries• Define diffusion as the movement of particles from an

area of high concentration to an area of lower concentration

• Demonstrate an understanding of how aerobic respiration uses oxygen to release energy from glucose and how this process can be modelled using the word equation for aerobic respiration

Aerobic RespirationLearning Objective:

Explain what respiration is with a description of bodily processes that support the process.

Learning Outcomes

C: Define aerobic respiration and state the word equation

B: Explain why respiration is important in living organisms.

A: Model and explain the role of diffusion in supporting respiration.

StarterWhat is

Respiration?

How is it different from

breathing?

Two important life process

• Eat- From eating we get out vitamins, minerals, proteins, fibre and energy! Today we are interested in the energy, this comes from carbohydrates, we break down carbohydrates into a sugar called glucose.

• Breath- take in oxygen and breath out carbon dioxide.

Aerobic respiration: summarySummarize the process of aerobic respiration in a sentence.

Aerobic respiration is a chemical reaction so it can also be summarized in a word equation.

What is the word equation for this vital chemical reaction?

Aerobic respiration is a chemical reaction that takes place in all living cells,

in which glucose reacts with oxygen to produce carbon dioxide and water

and stored chemical energy is released.

Aerobic respiration• Aerobic – needs oxygen!!• Word equation for aerobic

respiration: Glucose Oxygen Carbon

DioxideWater Energy + + +

carbondioxideglucose oxygen water

carbondioxide

wateroxygenglucose

energy

energy

Structures of the respiratory system

Lets look at how we breath

• Air is breathed in through the nose and mouth, and through the ________

• The trachea divides into the two __________ which branch out into narrower tubes called ____________.

• The bronchioles end in tiny air sacs called ____________ that have very thin walls, which makes the exchange of gas easier.

The Respiratory System

Trachea Bronchi Bronchioles Alveoli

• Air is breathed in through the nose and mouth, and through the TRACHEA.

• The trachea divides into the two BRONCHI, which branch out into narrower tubes called BRONCHIOLES.

• The bronchioles end in tiny air sacs called ALVEOLI, that have very thin walls, which makes the exchange of gas easier.

The Respiratory System• TASK: Use these

words to label• Alveoli • Bronchi • Bronchioles• Trachea

http://www.online-stopwatch.com/eggtimer-countdown/full-screen/

TASK: Breathing Task Worksheet• You have 2

Minutes to put the statements in order!

http://www.online-stopwatch.com/eggtimer-countdown/full-screen/

How does the gas Exchange Happen?

• Does it need energy?

• How does the carbon dioxide and the oxygen know where to go?

What is diffusion?

Dissolved substances have to pass through the partially permeable cell membrane to get into or out of a cell. Diffusion is one of the processes that

allows this to happen..

What substances are we talking

about?

How does smell travel to our nose?

In this example a sock is 2 metres away from the person.1. Where is the smell strongest?2. How does the smell travel from the

sock to the person?

Breathing involves the exchange of gases in the lungs, a process which occurs by diffusion.

What is the vital gas that you breathe in?

Diffusion and breathing

The lungs have a huge surface area to maximize the exchange of oxygen and carbon dioxide with each breath.

Where in the lungs does gas exchange take place?

oxygen

carbon dioxide

What is the waste gas that you breathe out?

Diffusion in action: one gas

Diffusion in action: two gases

Changing concentrations

The rate of diffusion depends on several factors, such as the distance the particles have to travel and the difference in concentration.

Molecules diffuse until they are evenly spaced apart and equilibrium is reached.

During diffusion molecules move from an area of high concentration to an area of low concentration. They are said to move down a concentration gradient.

Diffusion is a passive process which means that no energy is needed.

highconcentration

lowconcentration

What happens in the alveoli?

How are alveoli adapted?Alveoli have several adaptations that help to make gas exchange very efficient: They are very thin – only one cell thick. They are covered by a network of fine capillaries, enabling

gases to pass almost directly between the lungs and bloodstream.

They are moist, encouraging gas molecules to easily dissolve.

They have a large combined surface area, allowing large amounts of gases to be exchanged with each breath.

Cross-section through an alveolus

deoxygenated blood (from body tissues)

oxygenated blood (to body tissues)

air in/out

Alveoli are the tiny air sacs at the end of the bronchioles, in which gas exchange occurs.

alveolus

capillary

red blood cell

Gas exchange animation

Inhaling increases the concentration of oxygen molecules in an alveolus.

At this point, how does this compare with the concentration of oxygen in deoxygenated blood in the capillary?

Diffusion and breathing – oxygen

deoxygenated blood from the body

oxygenated blood to the body

When you inhale,the concentration of oxygen inside each alveolus ishigher than in deoxygenated

blood.

oxygen into alveoli

How is the concentration of oxygen in the blood increased?

Oxygen molecules diffuse across the lining of the alveolus into the blood in the capillary, moving from higher to lower concentration.

Diffusion and breathing – oxygen

oxygenated blood to the body

deoxygenated blood from the body

oxygen into alveoli

diffusion

When you inhale,the concentration of oxygen inside each alveolus ishigher than in deoxygenated

blood.

Deoxygenated blood from the body is low in oxygenbut has high levels of carbon dioxide.

How does this compare with concentration of carbon dioxide in the alveolus?

Diffusion and breathing – carbon dioxide

deoxygenated blood from the body

oxygenated blood to the body

The concentration of carbon dioxide in deoxygenated blood is higher

than in thealveolus.

How is the concentration of carbon dioxide in the blood reduced?

Carbon dioxide molecules diffuse from the blood in the capillary into the alveolus, moving from higher to lower concentration.

Diffusion and breathing – carbon dioxide

deoxygenated blood from the body

oxygenated blood to the body

The concentration of carbon dioxide in deoxygenated blood is higher

than in deoxygenated

blood.

carbon dioxide out of alveoli

diffusion

Aerobic respiration is a chemical reaction shown by the equation:________ + oxygen → carbon dioxide + ________ (+ energy)

Aerobic means needing __________. __________ comes from carbohydrates in food. It is carried to the cells of the body in the bloodstream. Oxygen is absorbed by the blood in the lungs and travels to the __________ of the body. Both substances enter a cell by a process called __________. Carbon dioxide leaves the cells and travels in the blood to the __________, where it is lost from the body. Respiration provides the cells with __________, which can be used for other things such as __________ of muscles, and sending messages through nerves.

energy cells glucose contraction diffusion oxygen water lungs glucose

Diffusion: true or false?

Questions

• Describe one adaptation of the alveoli that that allows them to do there job.

• Where does the oxygen you breath come from?

• Carbon Dioxide moves into the capillaries during breathing. True or false?

• Why is it important that the cells get the appropriate amount of oxygen?

• The alveoli of a smoker are often flatter with a smaller surface area, how will that effect the diffusion of gases?

Plenary

description linking the following points • high concentration (in air sacs) to lower

concentration ( in blood) (1) • by diffusion (1)