1. Chpt. 8 Cell Diversity
Cells are not identical - they diversify their structure to suit their function!!!!!!!

2. Tissues
A Tissue is a group of similar cells that are modified to carry out the same function.

3. Tissue Types Animal Tissue:
Four main types of animal tissue (two of which we will study in more detail):
Epithelial – covers internal and external surfaces
of the body.
Connective
Muscular – capable of contraction found in
muscles and internal organs.
Nervous

4. Animal Tissue:
Connective Tissue:
Consists of a number of cells spread out in a matrix that is
produced by the connective cells.
Connective tissue joins and supports other body structures.

5. Animal Tissue:
Nervous Tissue:
Nervous tissue is composed of nerve cells called neurons.
Neurons are adapted to carry impulses to and from the brain and
spinal cord.

6. Tissue Types Plant Tissue:
Four main types of plant tissue (two of which we will study in more detail):
Dermal
Vascular
Ground
Meristematic

7. Plant Tissue:
Dermal tissue:
A single layer of cells that surrounds the different parts of a plant
e.g. one type of dermal tissue – epidermis
Location – epidermis found as a covering on leaves, stems and
roots.
Appearance – epidermis cells are living, rectangular cells.
Sometimes a layer called a cuticle is found on its outer surface.
Function – protect the plant.
- presence of a cuticle prevents water loss from the plant.

8. Plant Tissue:
Vascular Tissue:
Transports materials around a plant.
Consists of two types of cells:
- xylem
- phloem
Xylem: - transports water and minerals around the plant.
- provide support (woody plants)
Phloem: - transports food from the leaves to the other parts of the
plant.

9. Plant Tissue:

10. Plant Tissue:

11. Tissue Culture
Tissue culture is the growth of tissues in or on an artificial
medium outside an organism.
The tissue sample is removed from a plant or animal and grown
in glassware ( in vitro) or in a bioreactor under carefully
controlled conditions.
Sterile conditions are essential in tissue culture. This involves
the prevention of the growth of micro-organisms in the
bioreactor, such as bacteria and yeast, as these would produce
waste products which contaminate the container and often kill
the desired cells.
Growth is by mitosis and produces a cluster of identical
offspring - a clone.

12. Conditions necessary for Tissue growth
Oxygen
Nutrients
Growth factors and
hormones
Correct pH
Optimum temperature
Sterile conditions
Freedom from
competition

13. Applications of Tissue Culture Monoclonal Antibodies
Micropropagation
Monoclonal Antibodies

14. Micropropagation:
this is the growth of large numbers of plants from very small plant pieces.
Desirable plant cells obtained
Cells grown on controlled culture medium
Form callus (clump of similar cells)
Growing conditions changed to promote callus growth
Over time callus forms a plant embryo and then a young plant
Once large enough young plant can be planted out

16. Benefits of micropropagation:
Produces exact copies
Quickly produces mature plants
Doesn’t need pollinators or seeds
Producing plants that are disease resistant and virus free
Inexpensive method of producing large number of similar
plants.

17. Monoclonal Antibodies (MAB’s) and Cancer Research:
Antibodies are special proteins that react with one particular
chemical – called an antigen.
Cancer cells produce special antigens that are not produced by any
other normal body cells.
Tissue culture can be used to produce special antibodies, MAB’s,
that will react with the antigens on cancer cells

18. Benefits of monoclonal antibodies:
MAB’s will not join to normal cells.
May change colour on reacting with cancer antigens allowing the
presence of cancerous cells to be detected.

19. Organs
An organ is a structure composed of a number of tissues that work together to carry out one or more functions
Examples of Plant Organs:
Leaf – Dermal tissue, vascular tissue, ground tissue
- all of these tissues combine so that the leaf can carry out photosynthesis.
Root – anchorage and absorption
Stem – support and transport
Flower – reproduction
Seeds – reproduction

20. Organs Examples of animal organs:
Heart – muscular tissue, epithelial tissue, connective tissue, nervous tissue
- combined all of these tissues allow the heart to carry out its function i.e. pump blood
Stomach
Intestine
Liver
Lungs
Skin

21. Organ Systems
An organ system consists of a number of organs working together to carry out one or more functions.
Animal such as humans consist of ten organ systems:
epithelial
skeletal
muscular
digestive
circulatory
respiratory
urinary
nervous
endocrine
reproductive

22. Organ Systems All the organ systems combine to form the organism.
Animal organ systems:
Circulatory system: - consists of heart, blood vessels, blood, lymph vessels, lymph.
- function transport materials, fight infection
Digestive system: - consists of mouth, oesophagus, stomach, small intestine, large intestine and anus.
- function to take in, break down and transfer digested food into circulatory system.