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Topic 2.2: Prokaryotic Cells
2.2.1: Draw and label a diagram of the ultrastructure of Escheriscia Coli (E. Coli) as an example of a
prokaryote. Annotate the diagram with the functions of each named structure.
2.2.3: Identify structures from 2.2.1 in electron micrographs of E. Coli.
2.2.4: State that bacteria divide by binary fission
1. This is an electron micrograph of the bacterium Salmonella typhi.
a. What is the maximum length of the main body of the cell?
2 μm
b. What are the name and function of this structure?
Flagellum – responsible for propulsion and motility
c. S typhi and E. coli are examples of prokaryotes.
What does the term ‘prokaryote’ literally mean?
From the Greek pro – (before) and karyote – kernel/nut –
Means’before nucleus’
2. In the space below, draw and label (with names and functions), the structure of a
generalized prokaryote cell. Include cell wall, plasma membrane, pili, flagella, nucleoid
(naked DNA), ribosomes and a scale bar.
3. . In the table below, compare prokaryote and eukaryote cells.
Prokaryote

DNA in a ring form without protein attached

DNA free in cytoplasm (nucleoid region) and also
Eukaryote

DNA is combined with histone proteins as
chromatids/chromosomes
small fragments as plasmids

DNA enclosed within a nuclear envelope

No mitochondria

Mitochondria present

70 S ribosomes, primitive

80 S ribosomes

no internal compartmentalisations

internal endomembrane system and

< 10 μm
compartmentalization into organelles

> 10 μm
Eukaryotic Cell Structure
Syllabus States:
Eukaryotic Cells
2.3.1
2.3.2
Draw and label a diagram of the ultrastructure of a liver cell as an example of
an animal cell.
Annotate the diagram from 2.3.1 with the functions of each named structure
Cell Part & Picture
Description of Function
Is like…
Mitochondria are the organelles
A power plant
(organelle means “little organ) that
convert energy from one form to
another. It is enclosed by two
membranes (inner and outer). All of the
folds (called cristae) of the inner
membrane increase the surface area so
the mitochondria can make more ATP
(ATP is adenosine triphosphate –a form
of cellular energy). (Campbell et. al, 59)
Nucleus
Isolated region containing DNA.
Dark region called the nucleolus is the site
of ribosome synthesis, where molecules of
the ribosome are manufactured before
passing into the cytoplasm for assembly.
Endomembrane System
This is a communicating system of
membrane-bound structures within the
cell, consisting of:
The nuclear envelope
The ER
Lysosomes
Golgi apparatus
Vacuoles
Vesicles
Mitochondria and chloroplasts are Not
considered part of the endomembrane
system
Rough ER
Responsible for protein synthesis and
transport tin concert with ribosomes.
Located close to the nucleus
Control tower –
White House
Smooth ER
Extensive network of tubules and
channels, involved in transport of materials
throughout the internal region of the cell.
Smooth ER has unique enzymes
embedded in its surface, and is responsible
for:
 Synthesis of membrane lipids and
phospholipids
 Production of steroid hormones
 Detoxification of drugs in the liver
 Storage of calcium ions
 Transportation of lipid-based
compounds
 Assists the liver in release of glucose
into the circulation
Golgi Apparatus/Body
Consists of flattened sacs called cisternae;
packages, modifies and distributes
materials synthesized within the cell.
Particularly prevalent in glandular cells
with secretory function.
Lysosome
Membrane bound sacs containing up to 40
different hydrolytic enzymes, which break
down macromolecules and also digest old
or damaged organelles.
Also digest material internalized through
phagocytosis
Acidic interior environment
Vacuole (include both how it works in
plants and in protists)
Storage organelles synthesized by the
Golgi apparatus. Occupy a large space in
plant cells and can store numerous
susbstances, including potential food,
metabolic wastes and toxins, and water.
Vacuoles anable plant cells to maintain
high surface area to volume rations even at
large cell size, and allow plant cells to
maintain rigidity.
Chloroplast
Found only in algae and plant cells.
Contains a double membrane; same size as
a bacterial cell and contains its own DNA
(in ring form) and 70S ribosomes.
Interior contains grana, thylakoids and
stroma, responsible for photosynthesis
Cytoskeleton
Cilia & Flagella
4. . With the aid of labelled diagrams, compare the structures of plant and animal cells.
Include annotations on the functions of each organelle.
LInk here for hyperlinked versions of these images
5. Extracellular components are materials or structures which extend beyond the plasma
membrane. Outline the role of an extracellular component in a plant cell and an animal cell.
Plant: Cell Wall: composed of cellulose, maintinas cell shape, regulates water uptake and helps to
support the plant’s upright position.
Animal:
 Flagellae (rare in animal cels – sperm cells)
 Extracellular matrix – composed of collage fibres plus a combination of sgars and proteons called
glycoproteins, which form fibre-like structures which anchor the matrix to the plasma membrane
and help it to attach to adjacent cells. ECM has many important functions
o Cell-cell interaction
o Influences gene expression
o Co-ordinates co-ordinated cell action within tissue
o May direct stem cells to differentiate
o Influences cell migration and movement
23. State three differences between plant and animal cells.
PLANT
Celullose cell wall
Chloroplasts
Large central vacuole
Carbohydrates stored as starch
No centrioles within centrosome
Fixed, angular shape
ANIMAL
No cell wall, only cell membrane
No chloroplasts
vacuoles small or absent
Carbohydrates stored as glycogen
Contain centrioles within centrosome