CELLS: STRUCTURE & FUNCTION
Biology ATAR Unit 2
Text: Chapter 7
Pages 160-163; 175-177
Keywords
Organelles
 Cell membrane
 Cell wall
 Chloroplast
 Endoplasmic reticulum
 Golgi body
(apparatus)
 Lysosome
 Mitochondria
 Nucleus
 Plastid
 Ribosome
 Vacuole
Making connections
Every cell in an organism is
connected in some way
to every other cell.
Cells make up tissues,
tissues make up organs
and organs work together
as systems.
Cells are the basic unit of
life. They are extremely
complex machines with
many interdependent
parts.
Understanding how a cell
works is the first step to
understanding how
organisms function.
LEARNING OUTCOMES

Describe and explain the function of the different
organelles

Relate the structure of organelles to their function

Describe and understand the difference between
plant and animal cells
CELL THEORY
 Cells
are the
smallest living
units of
organisms
 All cells come
from pre-existing
cells.
 Each organism is
made of one or
more cells.
CELL STRUCTURE

Cells are made up of the following parts:
Cell membrane
 Cytosol
 Organelles
 Cytoskeleton


the skin
the fluid
the machines
the bones
Cytoplasm = cytosol + organelles
CELL STRUCTURE
Organelles are the internal
structure of cells.
Cells from all sorts of
organisms have at least
some, if not all, of these
structures.
Cell membrane
 Endoplasmic reticulum
 Golgi bodies (apparatus)
 Mitochondria
 Nucleus
 Ribosomes
ANIMAL CELLS
 Centrioles
 Lysosomes
PLANT CELLS
 Cell wall
 Chloroplasts
 Vacuoles

CELL MEMBRANE
Structure
 Is a bilayer of
phospholipids molecules
enclosing the cytoplasm
in all cells
Function
 It controls the movement
of substances into and
out of the cell
 It contains receptor
proteins that allow it to
communicate with other
cells
ENDOPLASMIC RETICULUM
Structure
 A network of intracellular
membranes that links with
the plasma membrane and
other membranous
organelles.
 Endoplasmic reticulum may
be rough (associated with
ribosomes) or smooth
(lacking ribosomes).
Function
 It is involved with the
production, processing,
transport and storage of
materials within the cell.
GOLGI BODIES (GOLGI APPARATUS)
Structure
 A stack of flat membrane sacs linked to the
endoplasmic reticulum.
Function
 The golgi bodies package proteins into membranebound vesicles before they are secreted from the
cell.
ANIMAL CELLS:
LYSOSOMES
Structure
 Membrane-bound
vesicles containing
powerful enzymes
Function
 The enzymes break
down debris and
foreign material
Structure
 The nucleus is a large organelle that is surrounded
by a porous membrane.
 The nucleus contains genetic material (DNA)
Function
 The nucleus controls all cellular activity
NUCLEUS
MITOCHONDRIA
Structure
 Mitochondria are
composed of many
folded layers of
membrane
Function
 The mitochondria are
involved in energy
production
RIBOSOMES
Structure
 Tiny organelles located
in the cytosol,
sometimes associated
with endoplasmic
reticulum.
Function
 They are sites of
production of proteins.
ANIMAL CELLS:
CENTRIOLES
Structure
 A pair of small
cylindrical structures
composed of
microtubules.
Function
 They are involved in
the separation of
chromosomes during
cell division in animal
cells and protists.
They are not found in
plant cells.
PLANT CELLS:
CELL WALL
Structure
 The cell wall is found in
plant cells
 It is made of cellulose and
surrounds the cell
membrane
 Lignin is present in the cell
wall of the xylem of woody
plants to give them further
support
Function
 provides support
 prevents expansion of the
cell
 allows water and dissolved
substances to pass freely
through it
PLANT CELLS:
CHLOROPLASTS
Structure
 Found mostly in plant
leaf cells
 Contains chlorophyll – a
green pigment that
absorbs light energy
Function
 photosynthesis
PLANT CELLS:
VACUOLE
Structure
 A vacuole is found in
most plant cells
 They may contain
food, enzymes and
waste products
Function
 Vacuoles are filled
with fluid and provide
physical support
SUMMARY: CELL STRUCTURES
Structure
Function
Cell
membrane
•Border patrol: controls movement of substances
in and out of the cell
•Enables chemical communication between cells
Centrioles
•Separate chromosomes during cell division
(protista and animalia only)
Endoplasmic •Processing and transport centre
reticulum
•Rough (+ribosomes) or smooth (-ribosomes)
Golgi bodies
•Packaging & export centre – vesicles
Lysosomes
•Recycling & waste disposal centre (animalia only)
Mitochondria •Power supply centre
SUMMARY: CELL STRUCTURES
Structure
Function
Nucleus
•DNA – blueprint for building specifications
Ribosomes
•Assembly line – manufacture of proteins
Vacuoles
•Storage centre – food or enzymes
•Support – fluid (plantae)
Contractile
vacuole
•Osmoregulation (maintaining fluid balance)
•Protists and unicellular algae
PLANT CELLS ALSO CONTAIN:
Cell wall
•Structure and support
Chloroplasts
•Food manufacturing centre - photosynthesis
Plastids
Class of organelles which include:
•Chloroplasts
•Amyloplasts (starch storage)
•Chromoplasts (pigmentation organelles)
CONTRACTILE VACUOLE