Cells are characterized by both uniformity and diversity in structure and function. While all cells share some basic components like a plasma membrane, DNA, and ribosomes, cells also show specialization. For example, flight muscle cells have many mitochondria for energy production during locomotion, while pancreatic cells secrete digestive enzymes. The document then predicts how cells would be affected without certain organelles, such as not being able to carry out protein synthesis without a nucleus, conduct aerobic respiration without mitochondria, or secrete enzymes without a Golgi apparatus.

2. LEARNING OUTCOMES
• Predict the state of certain
cells without a particular
component.
• Illustrate that most cells are
specialised for the job that
they perform.

3. Appreciating the
Uniqueness of the
• Cell
A living cell is a basic unit of life.
• Cells are characterised by both uniformity &
diversity in terms of structure & function.
• Living cells resemble one another in fundamental
ways :
– All cells are surrounded by a selectively permeable
plasma membrane
– They have double-stranded DNA which carry genetic
information
– Ribosomes are present to function as sites for protein
synthesis.

4. • The diversity of cell structure & function
are due to cellular specialisation & division
of labour. For example,
– The flight muscle cells of the pigeon have
many well-developed, highly active
mitochondria to produce energy for
locomotion
– The human pancreatic cells are highly
specialised to secrete large amounts of
digestive enzymes & hormones. The cells
have many well-developed rough & smooth
endoplasmic reticulum, Golgi apparatus &
mitochondria.

5. THE SECRETION OF EXTRACELLULAR ENZYMES
IN AN ANIMAL CELL
1. DNA on chromosome in nucleus carries genetic
information.
2. Production of mRNA
3. Energy (ATP) generated by mitochondria
4. Proteins are synthesised at ribosomes
5. Proteins transported by RER.
6. Proteins depart from ER wrapped in transport vesicles
7. Transport vesicles fuse with Golgi apparatus which
modifies & packages the proteins.
8. Secretory vesicles contain inactive enzyme
(proenzyme).
9. Secretory vesicles fuse with the PM & enzymes are
secreted outside the cell.

7. STATE OF CELLS WITHOUT
PARTICULAR CELLULAR COMPONENT
MISSING ORGANELLE/ CONDITION OF THE CELL
CELLULAR COMPONET
NUCLEUS • No protein & enzyme synthesis
• Cellular activities cannot be
carried out.
•No cell division
•Cell dies
RIBOSOME • No protein synthesis Growth is
inhibited
•Enzymes, antibodies & some
hormones cannot be produced.

8. STATE OF CELLS WITHOUT
PARTICULAR CELLULAR COMPONENT
MISSING ORGANELLE/ CONDITION OF THE CELL
CELLULAR COMPONET
MITOCHONDRION • No aerobic respiration
•Energy not released for cellular
activities
ROUGH ENDOPLASMIC • Transportation of proteins
RETICULUM synthesised by ribosome does not
occur.

9. STATE OF CELLS WITHOUT
PARTICULAR CELLULAR COMPONENT
MISSING ORGANELLE/ CONDITION OF THE CELL
CELLULAR COMPONET
SMOOTH ENDOPLASMIC • synthesis & transport of lipids
RETICULUM cannot be carried
GOLGI APPARATUS • Cell cannot secrete digestive
enzymes, hormones & mucin.
•Lysosomes cannot be produced.

10. STATE OF CELLS WITHOUT
PARTICULAR CELLULAR COMPONENT
MISSING ORGANELLE/ CONDITION OF THE CELL
CELLULAR COMPONET
LYSOSOMES •No intracellular digestion of food,
worn out organelled, old or
damaged cells.
VACUOLES • Plant cell loses its shape &
turgidity
•No space to store soluble food &
waste products
CHLOROPLAST •No photosynthesis

11. STATE OF CELLS WITHOUT
PARTICULAR CELLULAR COMPONENT
MISSING ORGANELLE/ CONDITION OF THE CELL
CELLULAR COMPONET
•Plant cell lost its shape, absorb
CELL WALL water & burst.
PLASMA MEMBRANE •No regulation of substances