Most of this structure is only visible under the electron microscope
 To
look at the structure of the cell and to
consider the function of the parts.
 To discuss how a cell is organised and
relate this to the processes carried out
 By
the end of today I expect you to be
familiar with the parts of the cell
 By the end of the week I expect you to
know the functions of the main parts of
the cell.
 1. Cytoskeleton
 2. Nucleus
and ribosomes;
 3. The endomembrane system;
 4. Peroxisomes and vacuoles;
 5. Energy related organelles;
 Create
energy
 reproduce+
 Constitute tissues
 Die
 Protect us
 Move
 Produce/ secrete
 Consume/ absorb
 These
are called prokaryotes;
 Bacteria are prokaryotes;
 They are much smaller;
 They are much simpler – have much less
ultrastructure.
 Genetic
material not enveloped in
nucleus
 No internal membrane structure based
on nuclear envelope
 Cell not compartmentalised
 No plastids
 Cell membrane may be ensheathed in
cell wall.
 May have flagellae and thus moves
 Much smaller than eukaryote
 All
multicellular and most unicellular
organisms that you will learn about;
 Larger and more complex
 Compartmentalised with different parts of
the cell having different functions e.g. the
nucleus;
 Certain organelles such as mitochondria
and chloroplasts (plastids)may have
evolved from the inclusion of prokaryotic
cells in ancestral eukaryotes. They have own
DNA and function fairly independently.
Nucleus communicates with ribosomes
 Organelles of the membrane system
communicate with each other;
 Energy related organelles are self-sufficient;
 Each organelle has its own enzymes and makes
its own products;
 Products transported through cytoplasm in
transport vesicles (little membranous sacs that
keep them separate from the cytoplasm)
 Chemicals imported and exported across cell
membrane in different ways.

 600g
x 10 minutes = nuclei;
 15000g x 5 minutes = mitochondria and
lysosomes;
 100000g x 60minutes = ribosomes and
endoplasmic reticulum;
 What remains in the solution is the
soluble part of the cytoplasm
A
net of protein fibres that give structure to
the cell and help in the movement of
organelles:
 Protein fibres act as tracks for the transport
vesicles;
 Without it the cell could not function
because the chemicals could not be
transported to where they are needed.
 Includes the centrioles which have a role in
cell division.
 Nucleus
contains chromatin in a semiliquid called nucleoplasm;
 The chromatin is fibres of DNA that form
the chromosomes;
 Also contains RNA
 Ribosomes are made here.
 Different types of RNA and ribosomes
involved in the transfer of information
from DNA and protein synthesis
Surrounded by a double membrane called a nuclear
envelope which is full of nuclear pores through which
substances enter and leave the nucleus;
 Ribosomes are made of a unit of RNA and a unit of
protein
 They are where proteins are made.
 They can move around the cell and group together as
polyribosomes or attach to the rough endoplasmic
reticulum;
 The proteins they synthesise are coded for in the
DNA
 Enzyme producing cells such as those in the
pancreas contain many ribosomes because…….

 Consists
of:
 The nuclear envelope;
 Smooth and rough endoplasmic
reticulum (SER) and (RER);
 The Golgi apparatus’
 Several types of vesicles
 Job
is to synthesis and transport materials
around the cell;
 To secrete chemicals from the cell, e.g.
hormones;
 To recycle and destroy cellular
components;
 Cell death
The difference is whether they have ribosomes
attached.
 RER contains ribosomes
 SER does not
 As a result they make different things.
 RER is where proteins are synthesised by the
ribosomes
 SER is where lipids and steroids are synthesised,
e.g. in cells in the testes it is where testosterone
is made.
 Both form vesicles that transport materials to
other parts of the cell – especially the Golgi
body

 It
alters and synthesises new chemicals from
those delivered to it in vesicles from the RER
and SER.
 It receives chemicals in vesicles from the ER
on the inner face
 It packages chemicals into vesicles and
releases them from the outer face.
 These vesicles may either be lysosomes or
may deliver chemicals to the cell
membrane for secretion
 Membrane
bound vesicles produced by the
Golgi apparatus
 Have a low pH
 Contain powerful hydrolytic digestive
enzymes
 Recycle cell material
 Destroy non-functioning organelles
 In white blood cells help destroy engulfed
bacteria and viruses.
 Have a role in programmed cell death
Membranous sacs in the cell that have nothing to
do with the endomembrane system.
 Peroxisomes contain enzymes often involved in
the break down of materials such as lipids;
 Contain enzymes whose action result in the
production of hydrogen peroxide which must
then be broken down;
 Vacuoles store substances especially in plant
cells where they contain sap and pigments and
maintain plant structure by hydrostatic pressure;
 Collect excretory products of plants.
 In some organisms actively remove excess water.

 Self-sustained organelles (Plastids)
 Have their own DNA
 Mitochondria make ATP which stores
the
energy from aerobic respiration
 Chloroplasts contain pigment chlorophyll
 They are where photosynthesis occurs.
 The folded cristae of the mitochondria and
stacked thylakoids of the chloroplasts
increase the surface area for reactions.
 Evolutionary genesis is believed to be
through the inclusion of prokaryotic cells.
 Often called the power house of the cell.
 Have an inner membrane folded into cristae
and an outer membrane.
 Inner membrane encloses the matrix which
is full of mitochondrial DNA and ribosomes;
 Matrix is a highly concentrated mixture of
enzymes that break down carbohydrates
and other nutrients.
 Supplies energy that allows the synthesis of
ATP on the inner membrane.
 ATP is a chemical store of energy
 Bound
by a double membrane
 Contain their own DNA
 Reproduce themselves
 Double membrane encloses a space called
the stroma which contains discs made from
a third membrane called thylakoids;
 A Stack of thylakoids is called a granum;
 Chlorophyl in the thylakoid membrane traps
the sun’s energy which is used by enzymes
in the stroma to create carbohydrates.
 Chromoplasts
contain the colours in fruit,
flowers & vegetables such as carrots and
beetroot;
 Leucoplasts synthesise starches and oils
 Under the microscope it is possible to
see many leucoplasts in starch rich
vegetables such as potatoes.
Plasma membrane, Mitochondrion, Chloroplast;
Cytoplasm; Smooth endoplasmic reticulum;
Rough endoplasmic reticulum; Golgi body;
Ribosomes; Nucleus; Nucleolus; Nuclear Pore;
Nuclear envelope; Chromatin; Centrioles;
Lysosomes; Vacuoles; cristae in the mitochondria;
matrix in mitochondria;
 In the chloroplast: stroma, thylakoids, granum
and lumen
 Each person needs to find out the function of one
of these and help everyone add it to their list. I
will check.
 Quiz next week on the functions of the parts.

 http://www.cellsalive.com/cells/3dcell.htm
 http://www.sheppardsoftware.com/healt
h/anatomy/cell/index.htm
 http://www.williamsclass.com/SeventhSc
ienceWork/CellBrochure.htm
(homework)
 Next
lesson we are going to make a model
of the cell.
 You must bring what you need to make it
including scissors, tape and glue.
 It needs labeling
 Pictures of these are widely available on the
net.
 You must include all the organelles I named
 You may make separate models of some
parts to show detail
Marks
Model
Explanation
Innovation/presentati
on
2
Some effort
made
Unable to explain
Can’t tell what it is
4
A cell
completed
Explanation does not
use technical terms
Some organelles can
be identified
6
Most
organelles
shown
Some effort made to
correctly name
organelles
Mostly fairly clear
8
Up to 3
organelles
missing
Most organelles
correctly named
Model shows different
organelles clearly
10
All organelles
shown
2 or fewer organelles Model makes
not correctly named innovative use of
materials to
differentiate organelles
 Plasma
membrane, Mitochondrion,
Chloroplast; Cytoplasm; Smooth
endoplasmic reticulum; Rough endoplasmic
reticulum; Golgi body; Ribosomes; Nucleus;
Nucleolus; Nuclear Pore; Nuclear envelope;
Chromatin; Centrioles; Lysosomes; Vacuoles;
cristae in the mitochondria; matrix in
mitochondria;
 In the chloroplast: stroma, thylakoids,
granum and lumen
1
2
3
4
5
• Write article for Ezine on your organelle
• Include description of function and processes
• Include images
• Find a link to describe some science about it.
• Find a link to video or cartoon that describes its action
Marks
Description
processes
Article
1
Just identified Just identified Just a link
2
Some facts
Some aspects
correct
3
Description
mostly
correct
Description
mostly
correct
4
Description
complete
Description
complete
You´ve added
a caption
5
Description
of organelles
complete and
illustrated
Description
Brief clear
of processes explanation
complete and of content
illustrated
Caption
comprehensi
vely
describes in
brief what it´s
about
Brief
explanation
confused
Video
Just a link
A good
choice