1. 1.1 Introduction to Cells Understanding:
According to the cell theory, living organisms are composed of cells
Organisms consisting of only one cell carry out all functions of life in that cell
Surface area to volume ratio is important in the limitation of size
Multicellular organisms have properties that emerge from the interaction of their cellular components
Specialized tissues can develop by cell differentiation in multicellular organisms
Differentiation involves the expression of some genes and not others in a cells genome
The capacity of stem cells to divide and differentiate along different pathways is necessary in embryonic development. It also makes stem cells suitable for therapeutic uses
Applications:
Questioning the cell theory using atypical examples
Investigation of functions of life in Paramecium and one named photosynthetic unicellular organism
Use of stem cells to treat Stargardt’s disease and one other named condition
Ethics of the therapeutic use of stem cells
Nature of science:
Looking for trends and discrepancies: although most organisms conform to cell theory, there are exceptions
Ethical implication of research: research involving stem cells is growing in importance and raises ethical issues
Skills:
Use of a light microscope to investigate the structure of cells and tissues
Drawing cell structures as seen with the light microscope
Calculation of the magnification of drawings and the actual size of structures shown in drawings and micrographs

2. Cell theory principles
All organisms are made of one or more cells
Cells are the smallest units of life
One cell can perform all functions of life
Cells vary in shape and size but have some common features…
Unicellular = made of one cell
Multicellular = made of more than one cell
Understanding:
According to the cell theory, living organisms are composed of cells
Organisms consisting of only one cell carry out all functions of life in that cell

3. Collaboration between scientists Robert Hooke Zacharius Jansen
All played a role in the development of ‘Cell Theory’
Date of birth
Date of death
Where were they from?
What did they do?
How has their work contributed to science today?
Isaac Newton
Zacharius Jansen
Antonie Van Leeuwenhoek
Theodore Schwann
Matthias Schleiden
Robert Remak
Rudolf Virchow
Skills:
Use of a light microscope to investigate the structure of cells and tissues

4. Robert Hooke
Isaac Newton
Antonie Leeuwenhoek

5. Matthias Schleidon
Theodore Schwann
Rudolf Virchow

6. Robert Remak
Robert Remak
Robert Remak

7. Zacharius Jansen

8. Common cell features
Every living cell is surrounded by a membrane, separating the cell contents from everything else
Cells contain genetic material – storing all instructions for cell activities
Enzymes inside cells catalyze reactions
Cells create their own energy
Nothing smaller than a cell can survive on it’s own
Understanding:
According to the cell theory, living organisms are composed of cells
Organisms consisting of only one cell carry out all functions of life in that cell

9. More Cell Theory Principles
4. Cells come from pre-existing cells
5. Energy flow within cells
6. DNA passed from cell to cell
7. All cells have the same basic chemical composition
All cell theory principles lay the foundation for the study of life.
Understanding:
According to the cell theory, living organisms are composed of cells
Organisms consisting of only one cell carry out all functions of life in that cell

10. Draw a simple animal cell (like you would in Year 6)
Skills:
Drawing cell structures as seen with the light microscope

11. Correct or annotate onto your diagram:
Rules: Drawing
Correct or annotate onto your diagram:
Sharp pencil
Draw single lines not sketches
No shading
Label each structure with a straight line
Include a title
Include the magnification or scale
Studied microorganisms
Microscope ‘invented in 1590s’ still disputed
Monks cells = cells
Skills:
Drawing cell structures as seen with the light microscope

13. Nutrition Irreversible increase in size Metabolism
Ability to react to changes in the environment
Growth
Chemical reactions that happen inside the cell
Response
Obtain food to provide energy and materials needed for growth
Excretion
Keep conditions inside the organism within tolerable limits
Homeostasis
Produce offspring (sexually or asexually)
Reproduction
Get rid of waste products

14. Unicellular Organisms
Draw and label into your books. How do they carry out the functions of life?
Paramecium Chlorella
Applications:
Investigation of functions of life in Paramecium and one named photosynthetic unicellular organism

15. Function of life Paramecium Chlorella
Reproduction
Divides transversely
Metabolism
Metabolic pathways happen in cytoplasm
Homeostasis
Manages water content using vacuole
Growth
Ingests food, grows and divides
Response
Cilia moves in waves = movement
Nutrition
Cilia sweep food into cell ‘mouth’
Photosynthesis in cytoplasm provides food
Also ingests
Excretion
Expel water containing metabolic waste controlled by membrane
Oxygen waste controlled by plasma membrane
Also metabolic waste

16. Longitudinal division
Transverse division

17. Light Microscope

18. Microscope’s ability to separate objects that are close together so more detail can be seen
How clear an image is
Resolution
Low Magnification
Good Resolution
High Magnification
Poor Resolution

19. Magnification Quantified by a calculated number
Magnification is the process of enlarging something only in appearance, not in physical size.
Quantified by a calculated number
The ratio of the size of an image to the size of the object

20. What is the equation for the following?
Magnification
What is the equation for the following?
Image size
Actual size
Magnification um x um
Skills:
Calculation of the magnification of drawings and the actual size of structures shown in drawings and micrographs

21. Measurements are expressed in micrometers (um)
Magnification
Either:
Magnification = Apparent size of image
Real size of image
Or:
Calculated by multiplying the viewing lens magnification by that of the objective lens
E.g. you have a x10 eyepiece and x40 objective, the total magnification is x400
Measurements are expressed in micrometers (um)
1mm = 1000 um
Studied microorganisms
Microscope ‘invented in 1590s’ still disputed
Monks cells = cells
Skills:
Calculation of the magnification of drawings and the actual size of structures shown in drawings and micrographs

22. Magnification 30mm Green blobs always measure 0.01 mm
Magnification = Apparent size of image
Real size of image
30mm
Green blobs always measure 0.01 mm
Remember to convert into um first
1mm = 1000 um
Skills:
Calculation of the magnification of drawings and the actual size of structures shown in drawings and micrographs

23. Magnification 30mm Green blobs always measure 0.01 mm
Now work your way through the calculation sheet
30mm
0.01 mm x 1000 = 10 um
30 mm x 1000 = 30,000 um
Magnification = 30,000/10
Magnification = x3000

24. How are giant algae, fungi and striated muscle ‘misfits’?
Nutrition: Obtain food to provide energy and materials needed for growth
Metabolism: Chemical reactions inside the cell
Growth: Irreversible increase in size
Response: Ability to react to changes in the environment
Excretion: Getting rid of the waste products in the environment
Homeostasis: Keeping conditions inside the organism within tolerable limits
Reproduction: Producing offspring either sexually or asexually
Giant Algae: huge structure with only one nucleus (technically one cells)
Striated muscle and hyphae: Large structures with no divisions – many nuclei
Applications:
Questioning the cell theory using atypical examples
Nature of science:
Looking for trends and discrepancies: although most organisms conform to cell theory, there are exceptions

25. Prescribed Practical
Calculation of the magnification of drawings and the actual size of structures shown in drawings or micrographs
Use your practical books to complete the investigation:
Prepare onion cell slide
View under microscope
Draw onion cell (following drawing rules!)
Look at other specimens if time
Skills:
Drawing cell structures as seen with the light microscope
Use of a light microscope to investigate the structure of cells and tissues

26. Rules: Drawing Remember your rules Sharp pencil
Draw single lines not sketches
No shading
Label each structure with a straight line
Include a title
Studied microorganisms
Microscope ‘invented in 1590s’ still disputed
Monks cells = cells
Skills:
Drawing cell structures as seen with the light microscope

27. Smaller cells have a larger surface area compared to their volume.
Surface Area: Volume
Smaller cells have a larger surface area compared to their volume.
Whereas larger cells have smaller surface area compared to their volume
Understanding:
Surface area to volume ratio is important in the limitation of size

28. Who would freeze first? Husky Chihuahua Understanding:
Surface area to volume ratio is important in the limitation of size

29. Surface Area: Volume
Larger cells have less surface area to bring in the materials that the cell needs, and to get rid of waste.
Smaller cells have lots of surface area compared to their volume to do this.
This limits the size of cells
Reactions inside the cytoplasm would not work well otherwise
Understanding:
Surface area to volume ratio is important in the limitation of size

30. Cell Size
Larger animals do not just have just a few large cells in them, they have many small cells.
Understanding:
Surface area to volume ratio is important in the limitation of size

31. How do we get from…
This…
(A simple animal cell)
To this… (A human)

32. Cells
Many multicellular organisms start as a single cell, made from sexual reproduction.
This cell can reproduce at a rapid rate.
But then we are just a pile of the same cells…
Understanding:
Multicellular organisms have properties that emerge from the interaction of their cellular components

33. The possibilities are endless…

35. Differentiation Every cell has - An entire set of genes
Instructions to develop into any type of cell
Cells just use the genes they need for their pathway
Once on a pathway they are committed
Understanding:
Specialized tissues can develop by cell differentiation in multicellular organisms
Differentiation involves the expression of some genes and not others in a cells genome

36. Differentiation
Some cells have greatly reduced ability to reproduce after specializing
Nerve cells & muscle cells
However some can reproduce throughout their life
Skin cells
Understanding:
Specialized tissues can develop by cell differentiation in multicellular organisms
Differentiation involves the expression of some genes and not others in a cells genome

37. How does surface area to volume ratio limit the size of cells?
Practical
How does surface area to volume ratio limit the size of cells?
Use your practical books to complete the investigation
Understanding:
Surface area to volume ratio is important in the limitation of size

38. Retain their ability to divide and differentiate into various cell types.
What are stem cells
Give examples of how stem cells can be used (Stargardt’s disease and leukemia)
Describe the sources of stem cells (Embryonic, cord blood or adult)
Described how stem cell research has progressed – how may local, cultural and religious traditions impact stem cell research in different countries
Arguments for and against stem cell research
Your own thoughts/opinions on the matter
Stem Cells
Nature of science:
Ethical implication of research: research involving stem cells is growing in importance and raises ethical issues
Understanding:
The capacity of stem cells to divide and differentiate along different pathways is necessary in embryonic development. It also makes stem cells suitable for therapeutic uses
Applications:
Use of stem cells to treat Stargardt’s disease and one other named condition
Ethics of the therapeutic use of stem cells