This document provides information about cell structure and organization. It defines cells and their basic components, including the cell membrane, nucleus, cytoplasm, chloroplasts and mitochondria. Specific cell structures in plant and animal cells are described along with organelles and their functions. The structures of typical plant and animal cells are compared. Examples of specialized cell types and how their structures relate to their functions are provided. It explains how cells differentiate and work together to form tissues, organs and organ systems. Microscopes and their uses in studying cell structure are also outlined.

1. Cell Structure &
Organisation

2. Chapter Outline
(a) identify cell structures (including organelles) of typical
plant and animal cells from diagrams,
photomicrographs and as seen under the light
microscope using prepared slides and fresh material
treated with an appropriate temporary staining
technique:
• chloroplasts
• cell membrane
• cell wall
• cytoplasm
• cell vacuoles
• nucleus

3. Chapter Outline
(b) identify the following organelles from diagrams and
electronmicrographs:
• mitochondria
• ribosomes
(c) state the functions of the organelles identified
above
(d) compare the structure of typical animal and plant
cells

4. Chapter Outline
(e) state, in simple terms, the relationship between cell
function and cell structure for the following:
• absorption – root hair cells
• conduction and support – xylem vessels
• transport of oxygen – red blood cells
(f) differentiate cell, tissue, organ and organ system

5. What is a cell?
• From Latin cella, meaning "small room") is the basic
structural, functional and biological unit of all
known living organisms. Cells are the smallest unit of
life that can replicate independently, and are often
called the "building blocks of life". The study of cells
is called cell biology.
• Chemical reactions in the cell keeps us alive

6. Cells
Red Blood Cells White Blood Cells

7. Other Examples of Cells
Amoeba Proteus
Plant Stem
Red Blood Cell
Bacteria
Nerve Cell

8. Cells
What does a cell consists of?
Each living cell consists of living material called
protoplasm.
Protoplasm:
• Water makes up 70% of protoplasm
• Proteins
• Carbohydrates
• Fats

9. Protoplasm
1) Cell Surface Membrane
2) Cytoplasm
3) Nucleus

10. Cell Structures in Plant
and Animal Cells
• nucleus
• cytoplasm
• cell membrane
• cell wall
• cell vacuoles
• ribosomes
• mitochondria
• chloroplasts

11. Animal Cell

12. Animal Cell

13. Cell Surface Membrane
• Surrounds the cytoplasm of the cell
• Partially permeable membrane
– Allows some substances but not all to move in
and out of the cell

14. Nucleus
• Surrounded by a membrane
called the nuclear
envelope
• Contains one or more
nucleoli
• Contains chromatin
Functions of the nucleus:
1. Controls cell activities such as
cell growth and the repair of
worn-out parts
2. Essential for cell division
Nucleolus

15. Cytoplasm
• Between the cell surface membrane and the nucleus
• Contains enzymes and organelles

16. Organelles in the Cytoplasm
• Mitochondria
• Ribosomes
• Chloroplasts (only in plant cells)
• Cell vacuoles

17. Mitochondria
• Aerobic respiration occurs in the mitochondria
• Energy production
• Energy used to perform cell activities such as
growth and reproduction

18. Vacuoles in Animal Cells
• A vacuole is a fluid-filled space
enclosed by a membrane
• Animal cells have many small
vacuoles that contain water and food
substances such as proteins and
carbohydrates

19. Centrioles
• All animal cells have two small
organelles known as centrioles. The
centrioles help the cell to divide.
Centrioles are seen the process of
mitosis and meiosis. The centrioles
together are typically located near the
nucleus.

20. Plant Cell
Plant Cells:
http://lgfl.skoool.co.uk/keystage3.aspx?id=63

21. Plant Cell

22. Cell Wall
• Surrounds the cell surface
membrane
• Cell wall is made of
cellulose
• Protects the cell from injury
• Gives the plant cell a fixed
shape
• Cell wall is fully permeable

23. Chloroplasts
• Found only in plant
cells
• Chloroplasts contain a
green pigment called
chlorophyll
• Chlorophyll is essential
for photosynthesis, the
process by which plants
make food

24. Vacuoles in Plant Cells
• Plant cells usually have
a large central vacuole
which contains a liquid
called cell sap
• Cell sap contains
dissolved substances
such as sugars, mineral
salts and amino acids

25. Animal and Plant Cells
Animal Cell Plant Cell
Cell Structure and Function:
http://lgfl.skoool.co.uk/keystage3.aspx?id=63

26. Differences Between Animal
and Plant Cells
Animal Cells Plant Cells
Cell wall absent Cell wall present
Chloroplasts absent Chloroplasts present
Vacuoles are small,
temporary in animal cells
Vacuoles are large, sap-filled
in plant cells

28. Cell Differentiation
The process by which cells develop special
structures or lose certain structures to
enable them to carry out specific functions.
Hence, cells become differentiated to form
specialised cells.
The structure of each cell is adapted to
perform the specific functions of the cell.

29. Cell Differentiation

30. Specialised Cells
Red Blood Cell
Root Hair Cell
Nerve Cell
Sperm Cell
Egg Cell

31. How is cell structure
related to cell function?
1) Red Blood Cell
Cell Structure Adaptation to Function
Contains haemoglobin Haemoglobin transports
oxygen from the lungs to
all parts of the body.
No nucleus Carry more haemoglobin
which leads to increased
transport of oxygen.
Circular biconcave shape Increased surface area
to volume ratio of the
cell. Hence, increased
transport of oxygen.

32. How is cell structure
related to cell function?
Cell Structure Adaptation to Function
Long hollow tubes (no
protoplasm)
Enables water to move
easily through the lumen.
Lignified walls Lignin strengthens the
walls and prevents the
xylem vessels from
collapsing.
2) Xylem Vessel

34. How is cell structure
related to cell function?
Cell Structure Adaptation to Function
Long and narrow Increased surface area
to volume ratio of the cell
which leads to increased
absorption of water and
mineral salts from the
soil.
3) Root Hair Cell
Specialised Plant and Animal Cells:
http://lgfl.skoool.co.uk/keystage3.aspx?id=63

36. How is cell structure related to
cell function?
• These highly specialized nerve cells are responsible for communicating
information in both chemical and electrical forms.
• Neurons have a membrane that is designed to sends information to
other cells. The axon and dendrites are specialized structures designed
to transmit and receive information.
Cell Structure Adaptions and Functions
Neurons are long To communicate with distant
parts of the body
Have branched endings
called dendrites.
These connect with many
other neurones.

38. How do cells
work together in
a multi-cellular
organism?
Organisation in Living Things:
http://lgfl.skoool.co.uk/keystage3.aspx?id=63

39. Tissue
A tissue is a group of similar cells which work together
to perform a specific function.
Examples of tissues:
• Muscle, the lining of the intestine, the lining of the
lungs, phloem, root hair tissue
Connective
Tissue

40. Organ
Different tissues may be combined together to form
organs.
An organ is a structure made up of different tissues
working together to perform a specific function.
Examples of organs:
• Heart, lung, brain, leaf, root
Lungs

41. An organ is a structure made up of different
tissues working together to perform a
specific function.

42. Organ System
Organs work together to
form organ systems.
Various systems work
together to make up the
entire organism.
Examples of organ systems:
• Circulatory system,
respiratory system,
digestive system,
nervous system and
reproductive system
Circulatory System

43. Organ Systems

44. Organs work together to form organ
systems.
System Organs
Digestive Esophagus
Stomach
Small intestine
Large intestine
Respiratory Trachea
Lungs

45. Microscope
• A microscope (from the Ancient Greek: mikrós, "small" and skopeîn, "to
look" or "see") is an instrument used to see objects that are too small for the
naked eye. The science of investigating small objects using such an
instrument is called microscopy.
• Historians credit the invention of the compound microscope to the Dutch
spectacle maker, Zacharias Janssen, around the year 1590. The compound
microscope uses lenses and light to enlarge the image and is also called an
optical or light microscope. The simplest optical microscope is the
magnifying glass and is good to about ten times (10X)
magnification. The compound microscope has two systems of lenses for
greater magnification,
• 1) the ocular, or eyepiece lens that one looks into and
• 2) the objective lens, or the lens closest to the object.

46. PARTS OF A
MICROSCOPE:
Eyepiece Lens: the lens at the top that
you look through. They are usually 10X
or 15X power.
Tube: Connects the eyepiece to the
objective lenses
Arm: Supports the tube and connects it
to the base
Base: The bottom of the microscope,
used for support
Illuminator: A steady light source (110
volts) used in place of a mirror. If your
microscope has a mirror, it is used to
reflect light from an external light source
up through the bottom of the stage.
Stage: The flat platform where you
place your slides. Stage clips hold the
slides in place. If your microscope has a
mechanical stage, you will be able to
move the slide around by turning two
knobs. One moves it left and right, the
other moves it up and down.
Revolving Nosepiece or Turret: This is
the part that holds two or more objective
lenses and can be rotated to easily
change power.

47. • Objective Lenses: Usually you will find 3 or 4 objective lenses on a microscope. They almost
always consist of 4X, 10X, 40X and 100X powers. The shortest lens is the lowest power, the
longest one is the lens with the greatest power.
• Rack Stop: This is an adjustment that determines how close the objective lens can get to the
slide.
• Condenser Lens: The purpose of the condenser lens is to focus the light onto the
specimen. Condenser lenses are most useful at the highest powers (400X and above).
• Diaphragm or Iris: Many microscopes have a rotating disk under the stage. This diaphragm has
different sized holes and is used to vary the intensity and size of the cone of light that is projected
upward into the slide. There is no set rule regarding which setting to use for a particular
power. Rather, the setting is a function of the transparency of the specimen, the degree of
contrast you desire and the particular objective lens in use.
• Coarse Adjustment knob: large, round knob on the side of the microscope used for focusing the
specimen; it may move either the stage or the upper part of the microscope.
• Fine Adjustment Knob: small, round knob on the side of the microscope used to fine-tune the
focus of your specimen after using the coarse adjustment knob.
• Magnification Formula: size of Measured image /size of Actual image