Cells
=the basic unit of life
Cell Theory



All living organisms are made up of one or
more cells and their products
The cell is the simplest unit that carries out all
life processes
All cells come from other living cells (first cell
~ 4 billion years ago)
The activity of an organism depends on the
activity of all of its cells!
Classification of Cells
Organism
Prokaryote
Eukaryote
• No nucleus
•Nucleus present
Multicellular
organism
Plants
Animals
Single-celled
organism
Cell Structure




Cells have specific purposes within the
organism
Each cell is made up of many structures to
enable it to achieve its function
Structures are called ORGANELLES
Each organelle has a specific function
ORGANELLES


*http://www.youtube.com/watch?v=aczbMlS
Mr8U
*https://www.khanacademy.org/science/biolog
y/cell-division/v/parts-of-a-cell
Cytoplasm




Fluid that suspends all the organelles
Contains nutrients
Medium for chemical reactions
Changes in viscosity from jelly to liquid
Cell Membrane



Flexible double layer
Semi-permeable – allows some molecules to pass
through while preventing others
Provides support and structure
Nucleus





Spherical
Contains chromosomes
Chromosomes are one form of DNA (coded
instructions for all cell activities)
Surrounded by the nuclear membrane
Contains the nucleolus (contains RNA- important
for making protein)
Mitochondria





Oblong (sausage-like) structure with finger like
projections throughout
Produces all energy for the cell
Contain enzymes to convert stored energy into
easy to use form (cellular respiration)
Cells that require more energy contain more
mitochondria
Contain their own DNA
Mitochondrion
Checkpoint

Write the word and chemical equation for
cellular respiration
C6H12O6
+
6O2

6CO2
+
6H2O
+ Energy
Endoplasmic Reticulum (E.R.)





3D network of tubing throughout the cell
Connects cell membrane to nuclear membrane
Functions as transport system
Parts of the E.R. have ribosomes attached to them
and are called rough E.R.
Smooth ER is the area where fats or lipids are
made
Endoplasmic Reticulum
Ribosomes




Small bodies that receive instructions from the
nucleus to make proteins.
They are found throughout the cytoplasm or attached
to rough E.R.
Proteins are widely used in cells to serve diverse
functions. Some proteins provide the structural
support for cells while others act as enzymes to
catalyze biochemical reactions.
There are a lot of rough E.R. in cells that secrete
digestive enzymes (cells lining stomach).
Ribosome
What protein do you want
me to make?
Golgi Bodies (aka Golgi Apparatus)





They are tube-like membranes that have many sacs
at the end- appear like a stack of pancakes
Modifies and packages proteins from ribosomes
http://www.johnkyrk.com/golgiAlone.html
G.B also make and secrete mucus (e.g. cells lining
intestine)
Active cells contain more G.B. than less active
cells
Golgi Apparatus
Vacuoles


Fluid filled sac enclosed by membrane
Variety of functions




Store substances for use (water, food, minerals & waste)
Remove unwanted substances from cell
Bring substances into cell
Maintain internal pressure in plant cells which is why
they have large vacuoles compared to animal cells
Organelles Specific to Plants

Cell wall



Just outside of the cell membrane
Rigid but porous
Provides support and protection to cell
Organelles Specific to Plants cont’d

Chloroplasts


Contain chlorophyll giving leaves their green
colour
Chloroplasts absorb light energy used in
photosynthesis
Note: There are other pigment containing organelles
in plants e.g. chromoplasts
Checkpoint

Write the word and chemical equation for
photosynthesis
6CO2
+
6H2O
+ Energy (sunlight)  C6H12O6 + 6O2
Organelles Specific to Plants cont’d

Vacuoles


While not specific to plants, in plants there is
usually only one large vacuole
Helps maintain a plant’s turgor pressure
Organelles Specific to Animals

Centriole
Barrel shaped tube
 Consists of 9 triplets of microtubules
 Involved in organization of
miotic spindle (for
Mitosis)

Organelles Specific to Animals cont’d

Lysosomes (rare in plants)




Break down large molecules and cell parts within
the cytoplasm by releasing digestive enzymes
Also an important component of the human body’s
defense mechanism (immune system)
White bloods cells contain many lysosomes since
they engulf invading bacteria
Lysosomes ensure infected cells are destroyed
“suicide sacs”
Animal vs Plant Cells
Checkpoint


Draw a Venn Diagram for plants and animals
containing all the organelles
Copy this into your notes