0 How will our year 7 work help us with this topic?

1 Cells and What they need

2 A Balanced Diet

3 Energy in food

4 The digestive system

5 Enzymes and digestion

6 Absorption

7 The Skeletomuscular System

8B1 Cells and body systems

In pairs draw a plant cell on one mini whiteboard and an animal cell on the other. Label them and discuss what each of the parts does.

Copy these diagrams into the space on page 8

Essential Core Knowledge Test

• Collect an essential core knowledge test workbook
• Complete the front cover with your name and class (8E3) and my name.
• Write today’s date in the column against P1, forces and motion.
• Wait for further instructions.
• Turn to the P1 questions (the third page of questions)
• IN SILENCE and working ON YOUR OWN answer these questions.

Add them together.

Subtract them from each other.

pressure = force ÷ area

pascals (Pa) or newtons per metre squared (N/m²)

As height increases pressure decreases.

As depth increases so does pressure.

An object remains stationary or moving at a constant speed in a straight line unless a resultant force acts on it.

Relative motion

Mark each answer then write your total score at the bottom and then write it onto the front cover, ready to be handed in.

What are the 7 life processes?�Write all 7 on your whiteboards. �Let’s ask MRS GREN

MRS GREN

Remember organisms do these things, but so do the individual cells that they are made of.

Movement

In animals muscles contract and parts of the body move.

​

Plants can grow towards or away from stimuli (gravity, water, light)

Life processes

Amber

A person walking.

Louis

A fish swimming.

Nadia

A Venus flytrap closing.

Jack

A bird flying.

Movement

​

Some children suggest examples of movement animals and plants.

Zoe

Grass bending in the wind.

Respiration

A chemical reaction in cells which uses oxygen to release energy from glucose.

​

Write the reaction for respiration in the space below the table.

Sensitivity

The ability to sense and respond to stimuli.

Life processes

How would you know that a living thing has “sensitivity”?

A

It can be hurt.

B

It can feel emotions.

C

It can respond to changes in its surroundings.

D

It is kind to other living things.

Growth

​

The increases in cell size and number that take place during the life of an organism.

�

Reproduction

To produce offspring by sexual or asexual reproduction.

Excretion

 To get rid of waste material from the blood, tissues and organs.

Nutrition

Taking in food and converting it into energy and other vital nutrients.

​

Answer the 2 questions about nutrition in plants below.

Life processes

1. Whose example shows that the animal or plant is alive?

A

Only Amber.

B

Amber, Jack and Louis.

C

Amber, Jack, Louis and Nadia.

D

All of them.

Amber

A person walking.

Louis

A fish swimming.

Nadia

A Venus flytrap closing.

Jack

A bird flying.

Zoe

Grass bending in the wind.

Life processes

2. How would you explain your answer to question 1?

A

Animals can move but plants cannot move.

B

The animals and plants are moving themselves.

C

Only walking is a movement that shows something is alive.

D

Any kind of movement shows that something is alive.

Amber

A person walking.

Louis

A fish swimming.

Nadia

A Venus flytrap closing.

Jack

A bird flying.

Zoe

Grass bending in the wind.

The hierarchical structure of organisms

ORGAN SYSTEM

Life processes

Respiration

Respiration is one of the processes carried out by living things.

Complete the sentences in the box.

You should only use respiration or breathing to fill each gap.

​

Moving air into and out of your lungs is called ………………………… .

Getting energy from food is called ………………………… .

………………………… happens in all living things.

………………………… only happens in some living things.

………………………… does not happen in plants.

………………………… provides living things with oxygen for ………………………… .

Oxygen

Some children discuss their ideas about how oxygen moves around the human body.

Ali

Air tubes carry oxygen from the lungs to the heart, where it mixes with the blood.

Jacob

I think air diffuses from the lungs into the blood.

Naomi

Oxygen diffuses from the air in the lungs into blood in blood vessels.

Chloe

I think oxygen mixes with the blood in the lungs.

Grace

Oxygen diffuses through the body from the air in the lungs.

Who gives the best explanation of how oxygen moves around the human body?

On your mini whiteboards – who gives the best explanation of how oxygen moves around the body?

Answer the questions at the bottom of page 9

0 How will our year 7 work help us with this topic?

1 Cells and What they need

2 A Balanced Diet

3 Energy in food

4 The digestive system

5 Enzymes and digestion

6 Absorption

7 The Skeletomuscular System

8B1.1 What do Cells Need

Name two reactants for respiration that ALL cells need.

1.

2.

Name two reactants for photosynthesis that plant cells need.

1.

2.

Name two waste products that must be removed from respiring animal cells.

1.

2.

How do these substances enter and leave cells?

​

oxygen

glucose

carbon dioxide

water

carbon dioxide

water

diffusion through the cell membrane

Answer the questions on page 10

Write the letter for the correct answer to the questions on the next few slides on your mini whiteboards.

​

We’ll look at the answers after you’ve written them onto your whiteboards.

Brain cell

brain

Oxygen

A human brain is made up of billions of cells.

Every cell in the brain needs oxygen to stay alive and function.

​

1. How does a cell in the brain get oxygen?

A

It makes its own oxygen.

B

It takes oxygen from the air.

C

It takes oxygen from the lungs.

D

It takes oxygen from the blood.

Brain cell

brain

Oxygen

A human brain is made up of billions of cells.

Every cell in the brain needs oxygen to stay alive and function.

​

1. How does a cell in the brain get oxygen?

A

It makes its own oxygen.

B

It takes oxygen from the air.

C

It takes oxygen from the lungs.

D

It takes oxygen from the blood.

Brain cell

brain

Oxygen

A human brain is made up of billions of cells.

Every cell in the brain needs oxygen to stay alive and function.

2. How would you explain your answer to question 1?

A

The lungs absorb oxygen from air we breathe in.

B

The circulatory system carries oxygen from air in the lungs to all cells in the body.

C

Oxygen is made by cellular respiration.

D

Oxygen from air diffuses through the body to all of its cells.

Brain cell

brain

Oxygen

A human brain is made up of billions of cells.

Every cell in the brain needs oxygen to stay alive and function.

2. How would you explain your answer to question 1?

A

The lungs absorb oxygen from air we breathe in.

B

The circulatory system carries oxygen from air in the lungs to all cells in the body.

C

Oxygen is made by cellular respiration.

D

Oxygen from air diffuses through the body to all of its cells.

Brain cell

brain

Food

A human brain is made up of billions of cells.

Every cell in the brain needs glucose from food to stay alive and function.

​

1. How does a cell in the brain get glucose?

A

It takes glucose from food in the mouth.

B

It takes glucose from the stomach and intestines.

C

It takes glucose from the blood.

D

It makes its own glucose.

Brain cell

brain

Food

A human brain is made up of billions of cells.

Every cell in the brain needs glucose from food to stay alive and function.

​

1. How does a cell in the brain get glucose?

A

It takes glucose from food in the mouth.

B

It takes glucose from the stomach and intestines.

C

It takes glucose from the blood.

D

It makes its own glucose.

Brain cell

brain

Oxygen

A human brain is made up of billions of cells.

Every cell in the brain needs oxygen to stay alive and function.

2. How would you explain your answer to question 1?

A

Glucose is made by cellular respiration.

B

The digestive system absorbs glucose from digested food.

C

The circulatory system carries glucose from digested food to all cells in the body.

D

Glucose from digested food diffuses through the body to all of its cells.

Brain cell

brain

Oxygen

A human brain is made up of billions of cells.

Every cell in the brain needs oxygen to stay alive and function.

2. How would you explain your answer to question 1?

A

Glucose is made by cellular respiration.

B

The digestive system absorbs glucose from digested food.

C

The circulatory system carries glucose from digested food to all cells in the body.

D

Glucose from digested food diffuses through the body to all of its cells.

We need to get oxygen and glucose to every cell in our bodies so they can respire.

Cell membrane

Blood vessel

Cell

Glucose molecule

1. The breathing system

Our bodies use 3 organ systems to get oxygen and glucose to every single cell in your body.

What does this system do to get the reactants of respiration to all your cells?

The breathing system takes air into our lungs, where oxygen is taken into the blood and carbon dioxide is released from the blood to breathe out.

2. The digestive system

What does this system do to get the reactants of respiration to all your cells?

The digestive system breaks our food down into small molecules, like glucose, which can be absorbed into the bloodstream.

3. The circulatory system

What does this system do to get the reactants of respiration to all your cells?

The circulatory system moves oxygen from the lungs and glucose from the gut to all our cells, so they can be used in respiration.

Think, Pair, Share�Think about each of these questions for two minutes. Then discuss each one with your neighbour for a few minutes

• Note down your thoughts/answers in the space provided.
• Have an answer ready for each question ready to share with the class.

​

• Where does the oxygen we need for respiration come from?
• Where does the glucose we need for respiration come from?
• Where do other substances our cells need (like protein and vitamins) come from?
• How does the oxygen get inside our body?
• How do the glucose and protein etc. get inside our body?
• How does the oxygen and glucose and protein etc. get to every single cell in our body?
• What about waste products like carbon dioxide? How are they removed from our cells?
• How do the waste products exit our bodies?

​

0 How will our year 7 work help us with this topic?

1 Cells and What they need

2 A Balanced Diet

3 Energy in food

4 The digestive system

5 Enzymes and digestion

6 Absorption

7 The Skeletomuscular System

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Answer the first 4 questions on page 14 and then see if you can list the 5 major food groups.

A Balanced Diet

4. What do you think is meant by a ‘balanced diet’?

5. What food groups do you think go into a balanced diet?

Fats and sugars

Milk and dairy products

Meat, fish and eggs

Bread, cereals and potatoes

Fruit and vegetables

A balanced diet contains each of the 5 major food groups in the right proportions.

Fats and sugars

Milk and dairy products

Meat, fish and eggs

Bread, cereals and potatoes

Fruit and vegetables

How much of each do you need?

1

2

3

4

5

Nutrition

Nutrition is the process of absorbing the nutrients we need. It is how living things get chemical energy (food) and substances for making new cells and repairing damaged ones.

There are 7 types of nutrient (not food groups) our bodies need. How many can you name?

Nutrition

Nutrition in humans and other animals

Look at the statements below about nutrition. True or false?

1. Eating is an example of nutrition.
2. Drinking is an example of nutrition.
3. Going to the toilet is an example of nutrition.
4. Breathing is an example of nutrition.
5. Nutrition takes place in all humans and animals.

Nutrition in plants

Look at the statements below about nutrition. True or false?

1. Plants taking in nutrients from the soil is an example of nutrition.
2. Plants taking in water is an example of nutrition.
3. Plants taking in oxygen from the air is an example of nutrition.
4. Plants absorbing sunlight is an example of nutrition.
5. Nutrition does not take place in plants.
6. Nutrition takes place in all living things.

Let’s answer the true / false questions on page 14.

✔

x

✔

x

✔

✔

✔

✔

✔

x

x

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Answer questions 1 – 5 about your breakfast on (bottom of page 15 / top of 16).

Back to your breakfast

What nutrients do the food groups mainly provide?

What nutrients do the food groups mainly provide?

What is each nutrient used for?

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Fatty and sweet food

Milk and dairy products

Meat, fish and eggs

Bread, cereals and potatoes

Fruit and vegetables

What do these food groups mainly provide?

Carbohydrate

Protein

Fat

Minerals

Vitamins

Fibre

Water

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Carbohydrate

Protein

Fat

Minerals

Vitamins

Fibre

Water

What do these nutrients do for you?

For maintenance, growth and repair

To provide stored energy and insulation

To provide energy

For cytoplasm and body fluids

Needed in small amounts to maintain health

Helps the food to move through the gut and keep intestines healthy

Needed in small amounts to maintain health

52

Have a look at your ideal breakfast.

1. Which food groups does it contain?
2. Which groups are missing?
3. Which nutrients does it provide?
4. Which are missing?
5. What could you add to your breakfast so it contains all nutrient groups?

New Information: Energy in food

• The most important thing that our food provides is energy
• Carbohydrates are food molecules made of which three elements?

Fill in the gaps in questions 1 – 3 on pages 16 – 17 as we go through the next few slides.

New Information: Energy in food

• The most important thing that our food provides is energy
• Carbohydrates are food molecules made of which three elements?
• Carbohydrates are made from carbon, hydrogen and oxygen atoms.
• The clue is in the name, like many compounds. Remember yr 7 chemistry!

​

New Information: Energy in food

• There are two types of carbohydrates: sugar and starch
• Sugars are smaller carbohydrate molecules.
• There are many different sugars, but the simplest one is glucose.
• Glucose is a reactant in respiration and our cells need lots of it.
• Starch is a larger carbohydrate molecule made from a long chain of glucose molecules joined together. More on this later.

What are carbohydrates?

Starchy foods contain carbohydrates which are made of long chains of identical small sugar molecules.

carbohydratemolecule

The long chains of carbohydrates are broken down into the smaller sugar molecules by the body.

​

The small molecules from carbohydrates are used by the body to release energy and make the body work.

New Information: Energy in food

• Lipids are stored in fat cells to provide energy if we don’t have any carbohydrates to use.

What are fats?

Fats are made up of fat molecules which contain fatty acids and glycerol.

fat

molecule

glycerol

Fat molecules have to be broken down by the body so that they can be used for energy storage.

Fats are also used by the body to keep heat in and to make cell membranes.

fatty acids

New Information: Building blocks in food.

Our food also provides us with molecules for growth and repair

Proteins are used in our cells to:

• build new cells
• Repair damaged cells
• Carry out important chemical reactions in the cells
• Maintain our cells and keep them alive

What are proteins?

Proteins, like carbohydrates, are made of long chains of small molecules. In proteins, these small molecules are

not identical.

protein

molecule

one

amino acid

Proteins are made up of chains of small molecules called amino acids. There are over 20 different kinds of amino acid.

Proteins are used by the body for growth and repair.

Nutritional values for bread

Collect 5 food labels.

Answer questions 1 – 7 on page 19 about your foods.

Each group is going to test 1 food for 4 different nutrients. �Record your results on 1 line in the table on page 18, then onto the whiteboard:

Benedict’s test for sugar

1. Write your initials onto a boiling tube.
2. Mash up the food sample.
3. Put into a boiling tube.
4. Add an equal amount of water.
5. Add 10 drops of blue Benedict's solution (blue)
6. Place in water bath and wait for any change in colour.

Turns blue- green red if sugar is present.

Iodine test for starch

1. Mash up the food sample.
2. Use a spatula to put in a boiling tube.
3. Add an equal amount of water.
4. Add a 10 drops of iodine solution and stir.
5. If starch is present it will turn black.

Thursday, 10 October 2024

Biuret test for Protein

1. Mash up the food sample.
2. Use a spatula to put the food in a boiling tube.
3. Add equal amount of water.
4. Add a 10 drops of Biuret solution, put in a bung and shake gently
5. If there is protein present the solution turns purple.

Make sure you are wearing goggles

No

protein

protein

Thursday, October 10, 2024

Ethanol Emulsion test for fat

1. Take a sample of food using a spatula.
2. Place it in a test tube.
3. Add a small volume of ethanol and seal the tube with a bung.
4. Shake the tube vigorously for a few seconds.
5. If fat is present an “emulsion” will form – the mixture will be milky.

Benedict’s test for sugar

1. Collect your sample from the water bath.
2. Was there any change in colour?

​

​

Turns from blue to green red if sugar is present.

Learn the food tests!

0 How will our year 7 work help us with this topic?

1 Cells and What they need

2 A Balanced Diet

3 Energy in food

4 The digestive system

5 Enzymes and digestion

6 Absorption

7 The Skeletomuscular System

5 quick questions

Recalling key information

1. Which nutrients in food provide us with energy?
2. Name the sugar that is used in cells for respiration.
3. How can we test food for starch?
4. How can we test food for sugar?
5. How can we test food for lipids (fats)?

Recalling key information

1. Which nutrients in food provide us with energy?

Carbohydrates (starch and sugars) and lipids (fats and oils)

2. Name the sugar that is used in cells for respiration.

Glucose

3. How can we test food for starch?

Iodine test: blue/black means starch is present

4. How can we test food for sugar?

Benedict’s test: green/yellow/brick red means sugar is present

5. How can we test food for lipids (fats)?

Ethanol emulsion test: milky white shows lipids are present.

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Wednesday, 27 July 2022

8B1.3 Energy in food

Energy in food

Key words:

• Joules (J): the unit of energy.
• Kilojoules (kJ): 1000 Joules
• Thermal energy: heat energy
• Respiration: a chemical reaction that happens in cells to release energy from food
• Calorie (cal): another unit of energy, often used to show how much energy is in food. (We don’t use it in the lab. We use Joules.)
• Kilocalorie (kcal): 1000 calories
• Calorimetry: technique used to find out how much energy is transferred from something when it burns

​

75

Different people need different amounts of energy from their food.

​

​

​

​

List the factors you think might affect the amount of energy we need.

The amount of energy we need tends to increase as we approach adulthood.

Pregnancy

people in their 50s need about 17% less energy in their diet than people in their 30s.

an adult office worker might need 10,000 kJ per day, but a manual worker might need 15,000 kJ per day

a woman’s energy needs increase when she is pregnant because she is carrying extra mass and new cells are being made as the foetus grows.

the greater a person’s mass, the more energy they need. Men tend to need more energy than women,

What do we use energy for?

• M
• R
• S
• G
• R
• E
• N

ovement

espiration

ensitivity

rowth

eproduction

xcretion

utrition

Who do you agree with and why?

Who do you disagree with and why?

Is anyone partially right?

​

​

Jemima: I think food is burned in our tummies and that’s how we get energy

Reggie: I think food is burned all over our bodies and that is why we are warm.

Priya: All our cells need energy from our food.

Pablo: I think that our cells use a chemical reaction to get energy

Bob: the carbohydrates and lipids in food contain the energy our cells need

Akiko: I don’t think that nutrients actually get burned in our cells at all

​

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What do we mean when we talk about burning fat?

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Wednesday, 27 July 2022

Doing exercise uses the fat that is stored in your body.

Luckily it not actually burnt although it does produce waste heat energy.

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You would need to eat an extra portion of chips for every hour of cycling you do.

​

​

​

​

​

What would happen if you ate food containing more energy than you used?

5 quick questions

We are going to burn some food using the apparatus above.

Can you remember the different energy stores?

What can’t we do to energy?

How is energy stored in our food?

What happens to the energy in the food when we burn it (where has it gone)?

Stand your cork upright on your heat proof mat and ignite your food.

Health and safety

Put the method in the correct order

7

​

1

​

​

5

​

​

2

​

4

​

6

​

3

10cm3

Set up your apparatus as shown.

Record your results in the results table on page 25.

We are going to use the amount of energy transferred from the food to the hot water to find out how much energy is in different food types using this equation:

The mass of 1cm³ water = 1g

energy transferred (J)

mass of water (g)

× 4.2

temperature

increase (°C)

×

=

When you have done a calculation, write your results into this table on the board. Then answer the questions on p25

Which food had the most energy?

What did we do to make this a fair test?

What didn’t we do that we should have?

Which nutrients give us energy?

What is the important sugar our cells need?

How do our cells use glucose for energy?

Is food burnt in our cells?

​

New information

​

Every cell in your body needs energy for chemical reactions to take place.

You need energy just to stay alive this is known as BMR

BMR stands for Basic Metabolic Rate; the number of kilojoules you use to stay alive each day.

The bigger you are the more cells you have and the more energy you will need to stay alive.

The body needs also needs energy to repair damaged tissue and for you to grow.

​

​

​

​

​

​

Check point

​

For every kg of body mass you need 5.4 kJ of energy every hour. This is the basic metabolic rate (BMR) needed to maintain essential bodily functions.

​

To calculate the daily BMR (kJ/day) of a 60kg person

​

​

​

WE: Calculate the daily BMR (kJ/day) of a 80kg person

​

​

​

​

​

​

Check point

For every kg of body mass you need 5.4 kJ of energy every hour. This is the basic metabolic rate (BMR) needed to maintain essential bodily functions.

​

To calculate the daily BMR (kJ/day) of a 60kg person

​

Daily BMR = energy required per hour x no of hours x body mass

​

WE: Calculate the daily BMR (kJ/day) of a 80kg person

​

Daily BMR = energy required per hour x no of hours x body mass

​

​

​

​

New information

​

You need energy to do physical activity this is known as PAL

​

PAL stands for Physical Activity Level and is the number of kilojoules you use to fuel all of your physical activity.

​

Athletes in endurance events and hard training need more energy for PAL.

​

​

​

​

Check Point

If you are more active you will need more energy e.g:

a 60kg person will use 400kJ walking for half an hour

and 1500kJ running for half an hour.

To find out how much energy you need in a day you have to add together your daily BMR and the extra energy you use in your activities (PAL).

​

​

I

If the daily BMR (kJ/day) of a 60kg person is 7776kJ/day calculate the daily energy requirement if this person spent half an hour walking and half an hour running?

​

​

Daily BMR is = 7776kJ

Walking half an hour requires 400kJ of energy

Running for half an hour requires 1500kJ of energy

​

Daily energy requirement is

​

Apply your knowledge

We:

If the daily BMR (kJ/day) of a 60kg person is 7776kJ/day calculate the daily energy requirement if this person spent 2 hours walking and an hour running?

​

Daily BMR is 7776kJ

Walking 2 hours requires 400kJx 4= of energy

Running for an hour requires 1500kJx2= of energy

Daily energy requirement is =

​

​

​

​

Review

• A typical man needs 11,500kJ per day
• A typical woman needs 9,500kJ per day
• Teenagers need a bit more and pensioners need a bit less energy

​

• Why do men and women need different amounts of energy each day?

​

​

• Why does a teenager need more energy than a pensioner?

​

​

Review

• A typical man needs 11,500kJ per day
• A typical woman needs 9,500kJ per day
• Teenagers need a bit more and pensioners need a bit less energy

​

• Why do men and women need different amounts of energy each day?
• Men tend to be taller and heavier than women so need more energy.

​

• Why does a teenager need more energy than a pensioner?
• A teenager is growing and more active than a pensioner.

​

0 How will our year 7 work help us with this topic?

1 Cells and What they need

2 A Balanced Diet

3 Energy in food

4 The digestive system

5 Enzymes and digestion

6 Absorption

7 The Skeletomuscular System

Thursday, 10 October 2024

Topic 8.1 Food and the Digestive System

The Digestive System

Retrieval Practice

​

Last lesson: What is BMR?

​

Last week: Name 5 nutrients in our food

Last year: What is diffusion?

Key stage 2: why do we chew our food?

The Digestive System

Last lesson: What is BMR?

BMR stands for Basic Metabolic Rate; the number of kilojoules you use to stay alive each day.

​

Last week: name 5 nutrients in food

Carbohydrates, proteins, vats, vitamins, minerals, water, fibre

​

Last year: What is diffusion?

The net movement of molecules from an area of high concentration to one of low concentration.

​

Key stage 2: why do we chew our food?

To break it apart and to make it easier to swallow.

What happens to the food we eat?

1. What happens to the food we eat?

A

All of it stays in the body.

B

Some of it stays in the body and some of it leaves the body.

C

All of it leaves the body.

What happens to the food we eat?

2. How would you explain your answer to question 1?

A

Goodness is taken out of the food, then we get rid of the rest.

B

The food is digested and nutrients are absorbed, then we get rid of the rest.

C

The food is broken down and turned into poo, which we get rid of.

D

The food is used to make us grow bigger and taller.

Digestion

• To stay alive, cells need a constant supply of energy and molecules for chemical reactions.
• In a multicellular organism the cells are organised into tissues, organs and organ systems that work together to support the life processes of cells to keep the organism alive.
• The digestive system breaks large food molecules into smaller ones.
• The small food molecules then diffuse through the wall of the small intestine into the blood.
• The food molecules diffuse out of the blood into all of the cells in the body.

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How does food get into the body so you can use it?

With the person next to you describe the route you think food takes from your plate to waste in the toilet.

Gums to Bums

​

​

​

​

​

​

​

​

​

​

​

https://www.youtube.com/watch?v=0gY-zXsUYgs

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Mouth

The mouth breaks down food by chewing (physical digestion).

​

Enzymes also chemically break down the food (chemical digestion).

​

Label the diagram on page 30 as we go through the parts of the digestive system.

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Oesophagus

The tube connecting you mouth to your stomach.

​

Food is moved down by peristalsis

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Thursday, 10 October 2024

Stomach

The food is broken down by stomach acid and enzymes into smaller chemicals that can be absorbed.

(Chemical digestion)

The enzymes in the stomach work best in low pH (acidic)

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Thursday, 10 October 2024

Liver and gall bladder

Why isn’t your poo acidic?

The liver produces alkaline bile which neutralises the acid and emulsifies fats.

​

The gall bladder stores bile until it is needed.

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Thursday, 10 October 2024

Small intestine

More enzymes work in the small intestine to chemically digest food.

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The small intestine is where the broken down food molecules are absorbed into the blood to be take where they are needed.

Only small molecules can be absorbed. Anything too large carries on.

Aylsham High School

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Thursday, 10 October 2024

Large intestine

Here the body absorbs any water into the blood. Undigested material continues its journey.

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Rectum

Faeces (undigested food) is stored here until you go to the toilet.

Aylsham High School

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Thursday, 10 October 2024

Anus

Your anus is a ring of muscles that controls when your faeces come out.

The human digestive system

The boxes below contain the names of some human organs.

Which organs are part of the human digestive system?

Organ

Stomach

Intestines

Oesophagus

A

C

D

Lungs

B

Whiteboards

The human digestive system

How would you join the boxes to connect each organ you have chosen to its main function?

Function

To digest food and absorb nutrients.

To transport food from the mouth.

To absorb oxygen.

B

D

F

To store and churn food.

C

To dissolve food and absorb nutrients.

A

To release energy from food.

E

Organ

Stomach

Intestines

Oesophagus

A

C

D

Lungs

B

Answer the questions on page 30

1. What is the difference between dissolving and digesting?
2. Why do we chew food?
3. Where is food digested?
4. What is mechanical digestion and where in the digestive system does it happen?
5. What is chemical digestion and where in the digestive system does it happen?
6. Where is food absorbed into the blood?
7. Where does the food we absorb end up?
8. What is an enzyme?
9. Why do we have enzymes in the digestive system?
10. Where in the digestive system do enzymes digest food?

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Answers to the questions on page 310

1. Digesting is breaking larger molecules into smaller ones, dissolving is when a substance mixes into a liquid.
2. To make the food swallow-able and increase the surface area for enzymes to work on.
3. Mouth, stomach, small intestine.
4. Physically breaking big lumps of food into smaller pieces. It takes place in the mouth.
5. Chemical digestion is where chemicals (enzymes, bile and HCl) in the body break food down into smaller molecules. It happens in the mouth, stomach and small intestine.
6. In the small intestine.
7. In our cells.
8. A biological catalyst.
9. To digest our food, chemically breaking large molecules into smaller ones (eg starch to glucose).
10. In the mouth, stomach and small intestine.

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1

2

3

4

5

1

2

3

4

5

6

2

3

7

4

5

6

1

E

BLOOD

X

D

0 How will our year 7 work help us with this topic?

1 Cells and What they need

2 A Balanced Diet

3 Energy in food

4 The digestive system

5 Enzymes and digestion

6 Absorption

7 The Skeletomuscular System

Y

M

C

A

respire

1/3

Cells use nutrients from our food to?

build new cells

repair themselves

all of the above

Click again for answer

Y

M

C

A

swallowing food

2/3

What is digestion?

making poo

breaking large molecules of food into smaller ones

absorbing nutrients into the blood

Click again for answer

Y

M

C

A

the accidental consumption of chemicals

3/3

What is chemical digestion

when food molecules are broken into smaller ones by enzymes

when food molecules are pulled apart by cells

when food molecules are dissolved in stomach acid

Click again for answer

Why do we need food?

• Movement: muscle cells contain two proteins that slide across each other to make muscle tissue move
• Respiration: food molecules are broken down by proteins in cells to release energy
• Sensitivity: receptors are made of protein. So are neurotransmitters.
• Growth: Cells need to make more cells and they need lots of protein to do this
• Reproduction: see above
• Excrete: Waste products are broken down by proteins and removed from cells
• Nutrition: cells take in molecules from food that allow them to make their own proteins. These molecules come from digested protein in our food.

All of these processes happen because chemical reactions happen inside cells.

Protein in the cells is necessary for all these processes to happen.

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What is digestion?

The body carries out digestion of food to convert large insoluble food molecules …

carbohydrate

molecule

protein

molecule

fat

molecule

… which are small enough to pass through the walls of the small intestine and then dissolve into the blood.

… into smaller soluble ones.

Enzymes and Digestion Keywords

Cells are like factories

Inside there are lots of tools and machines that do particular jobs, like releasing energy from food and carrying out other important chemical reactions.

These cellular ‘tools and machines’ are called enzymes.

New Information

The job of enzymes is to make the chemical reactions in cells happen faster. If the chemical reactions don’t happen fast enough, the cell won’t work properly and it will die.

Some examples of chemical reactions that cells need to perform are:

• Breaking large molecules into smaller ones
• Joining small molecules together to make larger ones
• Changing molecules from one type to another

A protein that makes a chemical reaction happen faster is called an enzyme.

RULE: all enzymes are proteins, but not all proteins are enzymes.

What are carbohydrates?

Starchy foods contain carbohydrates which are made of long chains of identical small sugar molecules.

Carbohydrate

molecule

The long chains of carbohydrates are broken down into the smaller sugar molecules by the body.

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The small molecules from carbohydrates are used by the body to release energy and make the body work.

What are proteins?

Proteins, like carbohydrates, are made of long chains of small molecules. In proteins, these small molecules are

not identical.

protein

molecule

one

amino acid

Proteins are made up of chains of small molecules called amino acids. There are over 20 different kinds of amino acid.

Proteins are used by the body for growth and repair.

What are fats?

Fats are made up of fat molecules which contain fatty acids and glycerol.

fat

molecule

glycerol

Fat molecules have to be broken down by the body so that they can be used for energy storage.

Fats are also used by the body to keep heat in and to make cell membranes.

fatty acids

Why do we need enzymes in our digestive system?

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• BBC bitesize: enzymes and absorption

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• Useful summary of new information, plus two video clips to watch and summary quiz.

Digestive enzymes

How do digestive enzymes help the process of digestion?

Digestive enzymes are the chemicals that break large insoluble food molecules into smaller soluble molecules.

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Complete the table on page 37 whilst we look at the three different types of digestive enzyme:

Enzymes and carbohydrate digestion

Carbohydrates are chains of identical sugar molecules.

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The digestive enzymes called carbohydrases break the chemical bonds between the individual sugar molecules in each carbohydrate chain.

carbohydrase

long carbohydrate molecule

sugar

molecules

Enzymes and protein digestion

Proteins are made up of amino acids. There are 20 different types of amino acids.

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Proteins are digested by digestive enzymes called proteases. These enzymes work in an acidic environment to break proteins into smaller amino acids.

protease

long

protein molecule

amino acid molecules

Enzymes and fat digestion

Fats are digested in two stages:

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• Firstly, bile (released by the gall bladder) allows the fat to “mix” with water by breaking the fat into smaller droplets. This is called emulsification.

• Secondly, the digestive enzyme lipase breaks each fat molecule into the smaller glycerol fatty acid molecules .

bile

lipase

+

fat molecule

glycerol

fatty acids

Complete this table on page 36

Activity: Digestion of starch by amylase

1. Set up four test tubes of starch solution. Label them 1-4.
2. Add amylase to tubes 1 and 2 only.
3. Incubate all tubes at 37C.
4. Test samples 1 and 3 for starch using iodine.
5. Test samples 2 and 4 for sugar using Benedict’s solution and a 250ml beaker of boiled water as a waterbath.

1 2 3 4

Starch Starch Starch Starch

and and only only

amylase amylase

Results

1 2 3 4

Starch Starch Starch Starch

and and only only

amylase amylase

Cells use nutrients from food to:

Respire

Build new cells

Repair themselves

All of the above

Click again for answer

A

B

C

D

What is digestion?

Swallowing food

Making poo

Breaking large molecules of food into smaller ones

Absorbing nutrients into the blood

Click again for answer

A

B

C

D

What does protease digest?

carbohydrates

protein

lipids

fats

Click again for answer

A

B

C

D

What does carbohydrase digest?

carbohydrates

protein

lipids

fats

Click again for answer

A

B

C

D

Where is amylase produced?

stomach

small intestine

mouth

large intestine

Click again for answer

A

B

C

D

What is chemical digestion?

The accidental consumption of chemicals

When food molecules are broken into smaller ones by enzymes

When food molecules are pulled apart by cells

When food molecules are dissolved in stomach acid

A

B

C

D

What is an enzyme?

A protein produced by living cells to make chemical reactions happen faster

Something people put in washing powders

A chemical found in saliva that breaks down starch

A substance in the digestive system that chemically digests food

A

B

C

D

What can enzymes do?

Break large molecules into smaller ones

Make respiration happen fast enough for cells to live

Join small molecules together to make larger ones

All of the above

A

B

C

D

8B1.7 Absorbing Nutrients in the Digestive System

A model of digestion

Imagine that:

• the brick models you have been given are pieces of food in the digestive tract

To talk about in your group

1. Which types of food can be absorbed through the wall of the digestive tract into the body?
2. Which types of food need to be digested by an enzyme before they can be absorbed?
3. Which types of food cannot be absorbed, and why?

• the piece of card is the wall of the digestive tract
• you are a digestive enzyme in the digestive tract.

How do nutrients get into the blood?

Digestive enzymes are produced by specialized cells in the pancreas and digestive tract.

These enzymes are produced by cells in the stomach and small intestine.

This happens in the small intestine in structures called villi.

They are specialised to allow small molecules to be absorbed into the blood quickly.

Here the enzymes help to break down large food molecules into smaller molecules that are more easily absorbed into the blood.

Check point

Digestive enzymes are produced by specialized cells in the pancreas and digestive tract.

These enzymes are produced by cells in the stomach and small intestine.

This happens in the small intestine in structures called villi.

They are specialised to allow small molecules to be absorbed into the blood quickly.

Here the enzymes help to break down large food molecules into smaller molecules that are more easily absorbed into the blood.

Folds in the small intestine wall are covered in villi. Each villus is lined with epithelial (surface) cells that have microvilli. So the surface area is massive.

Adaptations of the small intestine

• Huge surface area through which nutrients can be absorbed
• Villi increase the surface area
• Each villus has many capillaries into which nutrients diffuse
• The walls of the villi are one cell thick to allow for efficient diffusion
• The cells lining the villi have microvilli to increase the surface area still further.

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Use this information to complete the table on page 40

Model Digestive Gut

It is very difficult to do practical work with a real small intestine but we can make a model of how it works. Visking tubing is used as it has very tiny holes in it that are too small to see.

Model Digestive Gut

Water molecule

Starch molecule

Sugar molecule

Visking tubing has tiny holes in which allows sugar and water through

​

In this model the Visking tubing has tiny holes in which allows sugar and water through but not large molecules such as starch, proteins and fats

Model Digestive Gut Thumbs

Water molecule

Starch molecule

Sugar molecule

Visking tubing has tiny holes in which allows sugar and water through

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​

Can large molecules, like starch, proteins or fats pass through the Visking tubing?

​

Can small molecules such as sugars, amino acids, fatty acids and glycerol pass through the Visking tubing?

​

​

​

Apply your knowledge

Starch and amylase is placed in the Visking tubing.

​

Can the starch move out of the Visking tubing? Explain why?

No because it is a large molecule that cannot pass through the Visking tubing.

What happens to the starch in the Visking tubing?

It is broken down in to sugar by amylase.

Will the sugar remain in the Visking tubing? Explain why?

The sugar will not stay in the Visking tubing as it is small enough to get through the holes in the visking tubing.

What test would you use to test for sugars outside the Visking tubing?

Benedicts Test.

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​

​

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Demonstration

1. Starch and water
2. Amylase and water
3. Starch, amylase and water

1 2 3

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​

​

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Which test tube will contain sugar outside the Visking tubing?

Explain why?

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​

​

​

​

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1 What do the following things represent in your model small intestine?

a the Visking tubing The small intestine

b the liquid inside the tubing solution Food inside the small intestine

c the water outside the tubing Our blood

2 Name one way in which this model is not like a real small intestine.

The Visking tubing doesn’t have villi, there are more nutrients that are absorbed into the blood, the body’s conditions are warmer and perhaps have a different pH

Faster workers What do you think would happen if the boiling tube was put into a warm water bath?

As the body’s temperature is 36°C and enzymes work quicker at this temperature

Try to explain the results.

The large starch molecules cannot pass through the small holes in the Visking tubing. Amylase is an enzyme that breaks down the starch into smaller sugar molecules which can pass through the Visking tubing.

Model Digestive Gut-Review

Small Intestine

In pairs summarise what happens inside the small intestine. Use the following keywords:

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small intestine, villi, small molecules, blood, large molecules, starch, proteins or fats, small molecules, sugars, amino acids, fatty acids, glycerol, Enzymes, nutrients, absorbed

​

Then complete this EWT

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Describe what happens to either carbohydrates, fats or protein when it reaches the small intestine (6). Make sure you use the key words above.

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Small Intestine

Describe what happens to either protein, fats or carbohydrates when it reaches the small intestine(6). Make sure you use the key words above.

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• Nutrients e.g. proteins, fats or carbohydrates are broken down
• By enzymes
• In the small intestine
• In to smaller molecules amino acids, fatty acids/glycerol or sugars
• Name an enzyme that breaks down the larger molecule e.g, protease breaks down proteins, lipase breaks down fat, carbohydrase breaks down carbohydrates.
• The small molecules can then be absorbed by the small intestine in to the blood stream
• That have villi on the inside to increase the surface area

Applying knowledge: a student set up this investigation. The visking tubing is semi-permeable, just tlike the wall of the small intestine; only small molecules can pass through

Make a prediction: which solutions will test positive for starch and which for sugar? Explain why

What observations will the student make? Complete the table using your predictions.

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0 How will our year 7 work help us with this topic?

1 Cells and What they need

2 A Balanced Diet

3 Energy in food

4 The digestive system

5 Enzymes and digestion

6 Absorption

7 The Skeletomuscular System

Quick questions:

1. What are all living and previously living organisms made of?
2. What do we call the starting materials in a chemical reaction?
3. Does sound travel fastest through solids, liquids or gases?
4. What percentage of our atmosphere is oxygen?
5. What happens to waste energy?

8E3 Start here

Absorption

Recap:

1. What are the molecules called that help to digest food?
2. What is the scientific word for fats?
3. Why do we need enzymes in our digestive system?

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a protein made in cells to help a chemical reaction to happen faster

the breaking down of large food molecules into smaller food molecules

to break down large food molecules into small soluble ones which can be used in chemical reactions in the body

they are absorbed into the bloodstream

Page 39

https://youtu.be/_qq_Dh9EWsw?feature=shared

Operation Ouch - Digestion | Biology for Kids - YouTube

even larger surface area for molecules to diffuse across

even larger surface area for molecules to diffuse across

once molecules have diffused, they can be taken away quickly

molecules have a short distance to diffuse (this makes diffusion faster!)

no

yes

no, it is too large

it is digested by amylase

no, it will diffuse into the water (from high concentration in the tubing, to low concentration in the water)

Benedicts test (blue to brick red)

yes

no

no

yes

no

no

no

yes

0 How will our year 7 work help us with this topic?

1 Cells and What they need

2 A Balanced Diet

3 Energy in food

4 The digestive system

5 Enzymes and digestion

6 Absorption

7 The Skeletomuscular System

Practical work ordering

Practical work risk assessment

Are muscles and bones alive?

What do these before and after images show?

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Muscle and bone cells are alive.

What would happen if we had no bones?

Draw straight lines to join each description with an explanation.

Joints

You have joints in your skull, hip, elbow and spine.

​

Discuss with your neighbour how the joints in these four places might be different from each other.

Write down what you think is different about them.

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Joints

• Where two bones meet.
• Some allow movement, some none at all.

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Joints

BALL AND SOCKET JOINT

The joints at the __________ and ____ are ball and socket joints.

SHOULDER

HIPS

They allow movement in different directions

IMMOVABLE JOINTS

The _______ of an adult is made up of joints that have fused together, so they cannot move

SKULL

FUSED JOINTS

The _______ is made up of joints that only have a small amount of movement

SPINE

HINGE JOINTS

The joint at the _______ is a hinge joint.

It allows movement up and down, but not side to side.

ELBOW

Checkpoint – joint structure and function

Synovial fluid

Triceps

Humerus

Cartilage

Ulna

Radius

Tendon

Biceps

Ligament

Chicken wing dissection

Chicken wing dissection

TAKE CARE WITH SCALPELS, WEAR GLOVES AND WASH YOUR HANDS AND THE BENCH AFTERWARDS.

Try to find the following structures in the chicken wing:

• Muscles – see how they work together to bend and straighten the limb
• Nerve fibres and blood vessels
• Tendons
• Ligaments
• Bone
• Cartilage
• Bone marrow

Method:

1. Put on pair of gloves, and use the scalpel or scissors to carefully peel the skin from the wing. Notice where feathers used to be attached to the skin. Observe the layer of fatty tissue underneath the skin.
2. Remove the connective tissue to reveal the muscles underneath
3. Use a probe to separate the muscles. Notice that they are arranged on opposite sides of the bone.
4. Try to straighten the wing as much as you can, then pull one of the muscles with the probe. Observer how the muscle pairs work together to cause motion.

Method:

5. Locate where the tendons attach to the bone (tendons are the white durable tissue)

6. Look for small white nerves that are embedded within the muscle tissue. Find and identify blood vessels within the muscle

7. Remove muscles from the bone to expose the joints. Identify the cartilage (shiny, white coverings on the end of the bones)

8. Break the elbow joint by twisting

9. Your teacher can snap the long bone to expose the inside of the bone.

1. Muscles are connected to bones by ________________, these do not stretch, if they did the muscle would be more / less effective.
2. Lift up your bag. Complete the following sentences.
• My biceps feels ___________ it has contracted / relaxed.
• My triceps feels ___________ it has contracted / relaxed.
3. Now stretch out your arm. Complete the following sentences.
1. My biceps feels ____________ it has contracted / relaxed.
2. My triceps feels ___________ it has contracted / relaxed.

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Muscles

1. To bend the knee the _____________ muscle contracts and the _____________muscle relaxes
2. To straighten the knee the _____________ muscle contracts and the _____________ muscle relaxes.
3. To bend the ankle the shin muscle _____________ and the calf muscle _____________.
4. To straighten the ankle the shin muscle _____________ and the calf muscle _____________.

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Muscles

Biomechanics

Use the formula below to work out how much force would be needed to lift the can of coke.

Lifting force = distance B x weight distance A

biceps muscle

can of coke,

weight = 250N

elbow

pivot

A = 3cm

B = 30cm

= 30 x 250

3

= 2500N