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Cells and MRS GREN revision. The 7 signs of life. Animal and plant cells. Here is a picture of a plant cell and an animal cell. Cells are the smallest units of life. Some cells can exist on their own, whilst others are found in groups. - PowerPoint PPT Presentation
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Cells and MRS GREN revision
The 7 signs of life
Here is a picture of a plant cell and an animal cell. Cells are the smallest units of life.
Some cells can exist on their own, whilst others are found in groups.
Humans are a collection of many billions of cells, all working together.
Animal and plant cells
While some cells do look different, all cells have three basic features.
nucleus
cytoplasm
cell membrane
7A What is a cell?
The Cell - a living factory!
Role Check
Most cells have three basic parts.
nucleus cytoplasm cell membrane
But cells can be different shapes and sizes and also have different functions. This is because they are…
specialised
The shape of a cell is related to its function.
Where do you see this idea in sport? CLUE: World Cup!
7A Do all cells look the same?
Rugby players are different shapes and sizes because they do different jobs for the team.
Like rugby players, cells are different shapes and sizes because they perform different jobs.
Why are the players in a rugby union team different shapes and sizes?
7A Specialised rugby players
Whose cell is it anyway?
Plant cellsTherefore, if plants and animals are different shapes, they must be made of different shaped cells. Let’s have a look at the shape of a basic plant cell.
Apart from the shape, the cell looks very similar to an
animal cell.
However, here is how the plant cell differs from the
animal cell.
Cytoplasm
Cell Membrane
NucleusStarch Grains
Cell Wall
Vacuole (contains cell sap)
Chloroplast (contains
chlorophyll)
Animal, plant or both?
Now that we know what the basic structure of a plant and animal cell is, we can begin looking at the bigger picture.
Cells are not flat…..
…they are usually three-dimensional
The 3D shape of the cell will be determined by its location in the body and the job it does.
Cell shapes
You can make your own 3D cell using the following equipment.
• Plastic bag
• Cellulose paste
• Cardboard box
You will need to find some small objects to suspend in the cellulose
paste. These will represent the internal structures of the cell.
Try to make a model of both the plant and animal cell. Then label these and display them.
Bring it to life!
A great way to visualize how a cell functions, is to become one!
Make sure you have a cell membrane and a nucleus as a minimum. Then you can choose from the list and role-play cell activity.
• Cell Membrane• Nucleus• Cell Wall• Vacuole• Water
• Glucose• Starch• Chloroplast• Light• Waste Material
You can get people to stand in a circle, holding hands to represent a cell membrane.
Then, get other people to be the nucleus and so on. If you are feeling adventurous, you can even dress up to represent the job of that part of the cell.
Cell-play
As we know, all life is built of cells. The way we look is the result of the types of cell we are made of and the way those cells are organised.
For example, if we look at the cells of the plant and animal, it is no surprise that plants and animals look different…
Animal
From Cell to Organism
Plant
Animal and Plant Cells
How is the body organised?
To help us understand this, think of how a school is organised.
A school needs to be very organised. Every pupil in the school needs to know where they should be and what they are doing. However...
Not all pupils study the same subjects.
Not all pupils can work together efficiently.
There is not room for all the pupils to be in the same place.
Therefore, a school uses the following system.
One pupil
Registration groups
Subject classes
A year group
A school
How is the body organised?
This hierarchy of organisation is also found in living organisms.
Each specific cell
Is grouped with cells similar in structure and function.
We call this a tissue.
How is the body organised?
Examples of Tissues
Animal Tissues Plant Tissues
Muscle
Bone
Liver
Skin
Lung
Mesophyll
Phloem
Xylem
Can you think of any more types of tissue?
How is the body organised?
Together, they are known as an….
ORGAN
Different tissues link together to carry out a certain job.
TISSUECELL
Next, different organs are linked together by tubes/ vessels…..
Organ 1
Organ 2
Organ 3
Organ 4
To become..An organ system
How is the body organised?
The body is then made up of different organ systems working together to carry out all the functions of a living organism.
In summary...
Cell Pupil
Tissue Registration groups
Organ Subject Classes
Organ system Year
Organism School
How is the body organised?
Q. Can you think of a problem if one cell splits to produce two cells?
A. The two new cells would be smaller than the original cell.
Therefore, a cell needs to make new copies of the material inside itself as well as the membrane and nucleus.
Just before a cell divides, it will appear to grow slightly as it reproduces everything inside itself.
The nucleus must also divide into two equal halves.
This only occurs once the nucleus has doubled from its original size.
Where do cells come from?
Cell division occurs extremely quickly and can happen over and over again.
Grow quicklyThis is how it is possible for the body to ...Repair cuts and replace dead cells quickly.Produce an enormous number of reproductive
cells.
Where do cells come from?
Cell Division
Activity – animal cell
Activity – plant cell