1. 2.3 Eukaryotic Cells
Topic 2 Cells

2. Eukaryotic Cells
2.3.1 Draw and label a diagram of the ultrastructure of a liver cell
as an example of an animal cell. The diagram should show free
ribosomes, rough endoplasmic reticulum (rER), lysosome, Golgi
apparatus, mitochondrion and nucleus.
2.3.2 Annotate the diagram from 2.3.1 with the functions of each
named structure.
2.3.3 Identify structures from 2.3.1 in electron micrographs of liver
cells.

3. Eukaryotic Cells
2.3.4 Compare prokaryotic and eukaryotic cells. Differences
should include:
• naked DNA versus DNA associated with proteins
• DNA in cytoplasm versus DNA enclosed in a nuclear envelope
• no mitochondria versus mitochondria
• 70S versus 80S ribosomes
• eukaryotic cells have internal membranes that compartmentalize
their functions.
2.3.5 State three differences between plant and animal cells.

4. Eukaryotic Cells
2.3.6 Outline two roles of extracellular components:
The plant cell wall maintains cell shape, prevents excessive water
uptake, and holds the whole plant up against the force of gravity.
Animal cells secrete glycoproteins that form the extracellular
matrix. This functions in support, adhesion and movement.

5. A Generalised Animal Cell

6. A Generalised Animal Cell
Ref: Advanced Biology, Roberts,Riess

7. Parts of a Generalised Animal Cell
You should know the function of the following parts:
– Ribosomes
• Site of protein synthesis
– Rough Endoplasmic Reticulum
• Transportation of proteins synthesised by the attached ribosomes
– Lysosome
• Small vesicles containing digestive enzymes
– Golgi Apparatus
• Packaging of proteins into vesicles
– Mitochondrion
• Site of aerobic respiration
– Nucleus
• Contains the chromosomes (genetic information) for the cell
• Controls the activities of the cell

8. Mitochondria
Double membrane:
– Outer membrane and
Inner membrane.
Inner membrane is
folded forming cristae
The interior contains
an organic matrix
containing chemical
compounds.

9. Rough Endoplasmic Reticulum and Ribosomes
A membrane system of flattened parallel cavities which are
interconnected and covered with ribosomes.
An intracellular transport system

10. Golgi Apparatus
Consists of a stack of
flattened cavities which
package substance
produced by the cell into
vesicles.
These vesicles can fuse
with the cell membrane
(exocytosis) or become
lysosomes (digestive
vesicles).

11. Golgi Apparatus
Ref: Advanced Biology Roberts etal.

12. Prokaryotic vs Eukaryotic
Feature Prokaryotic Cells Eukaryotic Cells
Type of Genetic
material
A naked loop of DNA Chromosomes consisting of strands of
DNA wrapped around associated
proteins (Histones)
Location of
genetic material
In the cytoplasm in a region
called the nucleoid
In the nucleus, inside a nuclear
membrane (nuclear envelope)
Mitochondria Not present
(mesosome used instead)
Always present
Ribosomes Smaller sized (70S) Larger sized (80S)
Organelles No membrane bound
organelles
Many are present
eg: ER, Golgi Apparatus, lysosome
S = svedburg units. A measure of the size of organelles

13. Plant vs Animal Cells

14. Plant vs Animal Cells
Plant and animal cells have many similarities because they are
both eukaryotic.
They also have some differences:
Feature Animal Plant
Cell Wall Not present Present (made of cellulose)
Chloroplasts Not present Present in plant cells that
photosynthesise
Carbohydrate
Storage
Glycogen Starch
Vacuole Not usually present. If
present they are small
Large and permanent

15. Plant Cell Walls
The main component of plant cell walls is cellulose.
Cellulose molecules are arranged in bundles called microfibrils.
The function of the plant cell wall is to provide strength and
support the plant.
The microfibrils are laid down in a criss-cross way across the
cytoplasm.
These give the cell great tensile strength
They also allow high pressure to be built up as a result of
Osmosis. This is called Turgor Pressure.

16. IBO guide:
2.3.1 Draw and label a diagram of the ultrastructure of a liver cell
as an example of an animal cell.
The diagram should show free ribosomes, rough endoplasmic
reticulum (rER), lysosome, Golgi apparatus, mitochondrion and
nucleus.
(The term Golgi apparatus will be used in place of Golgi body,
Golgi complex or dictyosome).
2.3.2 Annotate the diagram from 2.3.1 with the functions of each
named structure.

17. IBO guide:
2.3.3 Identify structures from 2.3.1 in electron micrographs of liver
cells.
2.3.4 Compare prokaryotic and eukaryotic cells. Differences
should include:
• naked DNA versus DNA associated with proteins
• DNA in cytoplasm versus DNA enclosed in a nuclear envelope
• no mitochondria versus mitochondria
• 70S versus 80S ribosomes
• eukaryotic cells have internal membranes that compartmentalize
their functions.

18. IBO guide:
2.3.5 State three differences between plant and animal cells.
2.3.6 Outline two roles of extracellular components:
The plant cell wall maintains cell shape, prevents excessive water
uptake, and holds the whole plant up against the force of gravity.
Animal cells secrete glycoproteins that form the extracellular
matrix. This functions in support, adhesion and movement.