Topic Outline
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Eukaryotic and Prokaryotic cells: structure
Role of the rough ER and Golgi apparatus in protein transport
Gamete structure and function (mammalian)
Gamete formation (meiosis) and fertilisation (flowering plants and mammals)
The cell cycle (mitosis): role in growth, asexual reproduction and the stages of mitosis
Totipotency: Cells are totipotent during the first couple of divisions after fertilisation
and can give rise to all other types of cells that make up the body
7. Stem cell research: These are an example of totipotent cells
8. The role of the nucleus in the control of development: differential gene expression (only
a small portion of the genome is expressed in each individual cell)
9. Development of specialised cells: How they develop. Why only red blood cells make
haemoglobin when all cells contain the gene for its production?
10. Cellular organisation (tissues, organs and organ systems)
11. Phenotypes and Genotypes (how phenotypes are affected by genotypes and the
environment but the level of which is difficult to determine)
3.2
Animal Cell
3.2
Plant Cell
3.2
Cell Organelles
• Organelle= “little organ”
• Found only inside
eukaryotic cells
• All the stuff in between
the organelles is cytosol
• Everything in a cell
except the nucleus is
cytoplasm
3.2
Cell Membrane
• Boundary of the cell
• Made of a phospholipid bilayer
Nucleus
• Control centre of the cell
• Contains DNA in the form of
chromatin
• Surrounded by a double
membrane: Nuclear
envelope
• Usually the easiest organelle
to see under a microscope
• Contains nuclear pores
3.2
Cytoskeleton
• Acts as skeleton and
muscle
• Provides shape and
structure
• Helps move organelles
around the cell
• Made of three types of
filaments
3.2
Endoplasmic Reticulum
• A.k.a. “ER”
• Connected to nuclear
membrane
• Highway of the cell
• Rough ER: studded with
ribosomes; it makes proteins
• Smooth ER: no ribosomes; it
makes lipids, hormones and
breaks down toxins
• Cisternae : folded spaces
3.2
Ribosome
3.2
• Site of protein synthesis
• Found attached to rough
ER or floating free in
cytosol
• Produced in a part of the
nucleus called the
nucleolus
That looks familiar…what is a
polypeptide?
Golgi Apparatus
• Looks like a stack of
plates
• Stores, modifies and
packages proteins
• Molecules transported
to and from the Golgi by
means of vesicles
3.2
3.3
How proteins
transported and
modified by the
RER and Golgi.
Your text here
Sample Qs:
3.5
Cells of the Eukaryote domain contain rough endoplasmic reticulum and
Golgi apparatus. Both the rough endoplasmic reticulum and the Golgi
apparatus are made up of membrane-bound sacs.
(i) Describe how you would recognise the Golgi apparatus as seen using
an electron microscope (Try first and then click for answer)
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Stacked structure
Cisternae present
Smooth membranes
Absence of ribosomes
Presence of vesicles
Lysosomes
3.2 & 3.3
• Garbage disposal of the
cell
• Contain digestive enzymes
that break down wastes
• Sperm cells contain
lysosome called acrosomes
that break through egg.
Which organelles do
lysosomes work with?
Enzymes of the lysosomes are synthesised in
the rough ER. The enzymes are released
from Golgi apparatus in small vesicles which
fuse with the membrane, thus becoming full
lysosomes
Mitochondria
3.2
• “Powerhouse of the cell”
• Cellular respiration occurs
here to release energy (ATP)
for the cell to use
• Bound by a double membrane
• Has its own strand of DNA
• Cristae: inner membrane
where ATP is made
• Its inner matrix is thicker than
cellular cytosol as it contains
less water
Cristae
Chloroplast
• Found only in plant cells
• Contains the green pigment
chlorophyll
• Site of food (glucose)
production
• Bound by a double membrane
• Thylakoid: Stacks of grana
(membranes) where
photosynthesis happens
3.2
Cell Wall
• Found in plant and
bacterial cells
• Rigid, protective barrier
• Located outside of the
cell membrane
• Made of cellulose (fibre)
3.2 & 3.5
Vacuoles
3.2 & 3.5
• Large central vacuole
usually in plant cells
• Many smaller vacuoles
in animal cells
• Storage container for
water, food, enzymes,
wastes, pigments, etc.
What type of microscope may have
been used to take this picture?
Centrioles
3.2
• Aids in cell division
• Usually found only in
animal cells
• Made of microtubules
Where else have we talked
about microtubules?
Quick Review:
Eukaryotes
• Which organelle is the control center of the cell?
Nucleus
• Which organelle holds the cell together?
Cell membrane
• Which organelles are not found in animal cells?
Cell wall, central vacuole, chloroplasts
• Which organelle helps plant cells make food?
Chloroplasts
• What does E.R. stand for?
Endoplasmic reticulum
3.2
Prokaryotic
Cells
• Commonly known
as bacteria
• 10-100 microns in
size
• Singlecelled(unicellular)
or
• Filamentous
(strings of single
cells)
3.4
Plasmids
3.4
Bacterial cells often contain several plasmids – small
continuous loops of DNA.
Plasmids are replicated independently of a bacterium’s
genophore (e.g. during bacterial conjugation), and may
confer an advantage, such as antibiotic resistance.
pilus draws
bacteria together
replication of plasmid
Plasmids are commonly used in genetic engineering to make
copies of genes or large quantities of proteins or hormones.
Endosymbiont theory in evolution:
3.1
• A prokaryote ancestor “eats” a smaller prokaryote
• The smaller prokaryote evolves a way to avoid being digested, and
lives inside its new “host” cell .
• The small prokaryotes that can do photosynthesis evolve into
chloroplasts, and “pay” their host with glucose.
• The smaller prokaryotes capable of aerobic respiration evolve into
mitochondria, and convert the glucose into energy the cell can
use.
• Both the host and the symbiont benefit from the relationship
• The host begins its journey to be a eukaryote