Multicellular Organisms

Key Area 2.1 Producing new cells

Cell Specialisations

We are learning to

• Understand what cell specialisation is and its importance.

I can

• Identify different cell specialisms

• Describe how cell specialisms are related to function in a number of examples

Starter Activity

• In your pair, discuss the structures found in a typical animal cell and their functions

• Discuss the structures found in a typical plant cell and their functions

• Name three other types of cell that you have studied so far

Twig: What is a cell?

Think, Pair, Share

• What is a unicellular organism?

• What is a multicellular organism?

• Give two examples of each

Unicellular organisms

Bacteria

Euglena Paramecium Yeast

Amoeba

Multicellular organisms

Multicellular organisms

• Multicellular organisms are made up of more than one cell.

• These cells can be organised into tissues and organs.

What do all of these cells have in common?

Cell specialisations The cells on the previous slide all have

typical structures such as: – cytoplasm

– cell membrane

– cell wall

– nucleus (not including RBC)

– chloroplasts

However, the structure each type of cell is different so that it can carry out a particular function.

What is a specialised cell?

• Plants and animals consist of many cells and so are known as multicellular.

• They contain many different types of cell.

• Each type of cell is designed to carry out a particular job or function.

• This is known as cell specialisation.

Twig: Different types of cell

Did You Know?

• There are over 100 different types of cell in the human body!

• These are just a few examples………..

Head contains nucleus and mitochondria

Tail

Sperm cells swim towards the egg to carry out fertilisation. They have a tail to enable them to swim and many mitochondia for producing energy.

Sperm cell

• Made in the ovaries of

mammals.

• An egg cell is large compared to sperm.

• Contains a food store in the cytoplasm for nourishing the embryo.

Cytoplasm containing food store

Nucleus

Egg cell (ovum)

• Help to prevent dust and bacteria entering lungs

• Line the windpipe (trachea)

• Have tiny hairs called cilia

• Cilia sweep mucus with trapped dust and bacteria up to mouth to be swallowed

nucleus

cilia

Ciliated cell

• Longest cells in the body

•Transmit electrical nerve impulses in body

Nerve cell (neurone)

nucleus

extension of the cytoplasm (axon)

Twig: Nerve cell

• No nucleus • Contain haemoglobin to carry oxygen

around the body • “Biconcave” shape for large surface area

Red blood cell

Twig: Blood

• Found in leaves of plants

• Packed with chloroplasts

to trap light for photosynthesis

nucleus

chloroplasts

Palisade mesophyll cell

thin cell wall

Root hair cell

• Root hair increases surface area for uptake of water and minerals from soil

• Thin cell wall so water can move in easily

vacuole

cell membrane

root hair

Cell Specialisations Task

• Use your knowledge of cells to name each cell opposite.

• Write how the structure of each cell allows it to carry out a particular function

Cell Specialisations Task • Check your work using the table opposite

• You may have remembered additional information!

Cell Specialisations

I can

• Identify different cell specialisms

• Describe how cell specialisms are related to function in a number of examples

Starter

• Card sort task/Who am I

Cell Organisation

We are learning to

• Describe how cells are organised in multicellular organisms and explain the importance of cell organisation.

Success Criteria:

• View tissues using a light microscope

• Be able to identify and name different types of tissue

• Explain the importance of cell organisation.

Tissues

1. What are tissues?

2. Can you give some examples of tissues in the human body?

3. Can you give some examples of tissues in plants?

4. What is the difference between tissues and organs?

Tissues

• Tissues are groups of cells that perform the same function.

• Examples of human tissues include epithelial tissue and muscle tissue.

• The study of tissue is known as histology or, in connection with disease, histopathology.

Tissues

Epithelial tissue • Epithelial tissue covers body surfaces

and lines cavities and tubes.

• These include the airways and digestive tract.

• Some epithelial tissue is specialised to form glands like oil and sweat glands in the skin.

Muscle tissue

• Muscle tissue helps in body movement because it can contract and relax.

• There are three different types of muscle tissue: - cardiac

- skeletal

- smooth

Smooth muscle tissue

• The structure of these cells allows them to perform a specific function

• Are spindle shaped

• Can contract and relax

• This allows the cells to slide easily across one another

Smooth muscle tissue

Plant tissues

• Plants also have different types of cells that are grouped together into tissues.

• In each case, the structure of each cell is related to its function.

• Plant tissues include epidermal, palisade mesophyll and spongy mesophyll.

Epidermal tissue • Epidermal cells fit together like a

jigsaw

• From Greek word meaning “over-skin”

• Create a strong and protective layer on the outside of leaves, roots and stems

epidermal

Palisade mesophyll tissue

• These cells have many chloroplasts to trap light for photosynthesis

• Are column shaped so that they can be densely packed near the surface of the leaf

palisade mesophyll

Spongy mesophyll tissue

• These cells have a rounded shape

• This allows them to be loosely arranged so that they can take up carbon dioxide by diffusion

• Carbon dioxide can then be used for photosynthesis

spongy mesophyll

Cross section through a leaf

Organs

• A group of tissues working together form an organ.

• Examples of animal organs include the heart, lungs, brain and kidneys.

• Examples of plant organs include roots, stems, flowers, seeds and fruits.

Systems

• A group of related tissues and organs eg. blood, heart, arteries, capillaries and veins make up a system.

• The tissues an organs above make up the circulatory system.

Systems

• Examples or organ systems in animals include:

• skeletal

• muscular

• digestive

• respiratory

• nervous

• circulatory

Systems

• Examples of organ systems in plants include the vascular system in the roots and shoots.

Summary • Cells have different ___________ that allow

them to carry out a particular__________.

• These are known as cell specialisations.

• Many __________ cells working together form a __________.

• A group of tissues that work together form an ___________.

• Organs are found in both _______ and plants. A group of related tissues and organs form a __________.

animal

specialised

organ

tissue

structures

function system

Summary • Cells have different _________ that allow

them to carry out a particular__________.

• These are known as cell specialisations.

• Many __________ cells working together form a ______.

• A group of tissues that work together form an _______.

• Organs are found in both _______ and plants.

• A group of related tissues and organs form a __________.

animal

specialised

organ

tissue

structures

function

system

Key Area 2.1 Consolidation Tasks…

You must complete…

In the back of your notebook: Exercise 1 & 2 from the new unit 2 homework booklet.

Review your KA 2.1 cells, tissue & organs key words.

Review your KA 2.1 cells, tissues & organs learning outcomes.

You should complete…

N5 Text book: Read page 114 – 118

In the back of your notebook: complete Activity 2.1.1 (p116) & Activity 2.1.3 (p118)

You could complete…

On plain A4 paper: Activity 2.1.2 (p116) & Activity 2.1.4 (p118)

Collect 4 study cards and create quiz cards (questions & answers) about cells, tissues & organs.

Stem Cells

We are learning to

Explain what a stem cell is and how they are used for research and treating illnesses

I can

• Define the term „stem cell‟

• Describe the role of stem cells in animals

• Be able to describe the advantages and disadvantages of using stem cells for research and treating illnesses.

Think, Pair, Share

• Have you heard of the term “stem cell”?

• What do you know about them?

• Discuss your ideas with your partner and be ready to share them with the class!

Stem Cells

• Stem cells can divide to produce more stem cells or can differentiate into specialised cells.

• Some stem cells have the ability to turn into any type of body cell and are involved in growth and repair of body tissues.

Twig Clip: Stem Cells

Self Renew Specialise

Types of stem cells

• Scientists are researching treatments for certain illnesses that involve the use of stem cells.

• There are two main types of stem cells: – Embryonic stem cells

– Adult stem cells

(Image: Miodrag Stojkovic/Science Photo Library) (Image: Steve Gschmeissner / SPL)

Coloured scanning electron micrograph of human embryonic stem cells

Embryonic stem cells

• These are found in embryos (the blastocyst)

• Stem cells that come from embryos can develop into any type of body cell.

• This allows the organism to grow from an embryo into a fully formed individual.

Adults stem cells • Adult stem cells can be found among other

specialised cells in a tissue or organ.

• Adult stem cells are like built-in repair kits, regenerating surrounding cells damaged by disease, injury and every day wear and tear. They can only differentiate into a limited number of types of cell.

Adult stem cells

• Adult stem cells are found throughout the body in different tissues and organs.

• They do not have the same properties as embryonic stem cells as they are slightly more specialised.

Starter

• What are stems cells?

• Where are they found?

Medical uses of stem cells

Learning Intention:

• Learn about how stem cells are used and the ethical issues involved with their use

Success Criteria:

• State the medical uses of stem cells

• Describe the ethical issues surrounding the use of stem cells

• Describe the advantages and disadvantages of using stem cells for research and treating illnesses.

Use the cards and the video clips to answer the following questions

1. How are stem cells used to treat patients now?

2. How might stem cells be used to treat

patients in the future?

3. How else could stem cells be used?

(Hint: Two ways are described on the cards)

Medical applications Stem cells have important medical applications.

Some of these include:

Source of stem cell Medical use

Marrow in the centre of bones Treating leukaemia, a type of cancer caused by abnormal blood cells

Skin Growing new layers of skin that can be used to treat burn victims

Heart muscle Repairing damaged heart muscle after a heart attack (still being tested)

Bladder Building a new bladder in a laboratory for a patient whose bladder has been damaged by injury or disease

Future medical applications

• In the future, scientists hope that stem cells will be used to cure conditions such as Alzheimer‟s disease, diabetes, spinal-cord injuries and stroke.

• Stem cells may also provide a useful alternative to animals for testing experimental drugs.

Twig Clip: Uses of Stem Cells

BBC Learning Zone: Stem Cell Research and Medicine

Stem cell debate

• Sort the cards into those statements that are fact, opinion and not relevant

• Sort the cards into those statements that are for stem cell research annd those that are against.

Ethical issues with embryonic stem cells • Embryonic stem cell research gives us a moral dilemma. It

forces us to choose between two moral principles important to humans. The first is the duty to prevent or ease suffering by doing all we can to improve medical treatments for illness. The second is our duty to respect the value of human life.

• In the case of embryonic stem cell research, it is very difficult to respect both of these moral principles.

• Embryonic stem cell research could lead to new medical treatments, which could save human lives and relieve human suffering. On the other hand, to obtain embryonic stem cells, an early stage embryo has to be destroyed meaning the loss of a potential human life.

• Which moral principle should be followed in this situation? Does the answer lie in our attitude to the embryo – does it have the status of a person?

• What do you think about this issue?

Advantages Disadvantages

Embryonic Stem Cells

Advantages Disadvantages

Adult Stem Cells

First Task… Discuss your advantages and disadvantages to using embryonic

stem cells for research.

Learning Outcomes

• Practise discussing and debating issues and expressing an opinion.

• Understand the arguments for and against the use of embryonic stem cells.

• Consider social, ethical and factual issues in an integrated way.

• Think about different points of view.

• Learn to back up opinions with facts.

The key players:

Additional characters:

1. Read your card in your pair/group. 2. One person will read out the first section of the card to the

class. 3. Class vote: for or against the statement. 4. Each group will then take it in turns to read out their fact

from their character card. 5. Class vote: has anyone‟s position changed? 6. Each group will then read the issue on their character card. 7. Class vote: any changes in the way people feel? 8. Class debate: A representative from each group will play

the character of their card, using the questions from the bottom of the card to carry out a debate with the other characters.

9. Final class vote about the use of embryonic stem cells for research and which position they agree with the most.

Johan

We all make mistakes – that’s how

we learn. Medical treatments like

this can give us a second chance.

That’s a good thing!

Christian

Science is there to make our lives

better. It’s great that Monika can

get a new liver so she can be free

to do what she wants.

Carla

It’s Monika’s own fault her liver is

getting damaged. She shouldn’t be

able to just get treated and then

keep drinking. She’s causing

problems for her family and

wasting her doctor’s time.

Hannah

Monika should watch out. All that

drinking will damage her heart and

her memory too. Soon she’ll need

more than a new liver.

www.eurostemcell.org

www.eurostemcell.org www.eurostemcell.org

www.eurostemcell.org

Maria

There must be a reason why the

treatment isn’t available here. If

Peter’s doctor is worried, he

should listen to him.

Stefan

Peter has the right to decide what

he wants to do. Only Peter knows

how bad he feels. If he wants to try

the treatment, no-one should stop

him.

Ben

I think Peter could still have a good

life so it’s not worth taking any

risks. If he had a different disease

and needed something to save his

life, it would be worth trying out a

new treatment even without proof

it would work.

Natalia

It must be awful to have a disease

and know there is no cure. But the

treatment might make Peter much

worse. He wants to get better so

much that he needs help to make

the right decision.

www.eurostemcell.org

www.eurostemcell.org www.eurostemcell.org

www.eurostemcell.org

Starter

• 50 Questions on cells, tissues and organs