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Unit B – Section 2.0
BIOLOGY
Structures and Function of Cell Organelles
Structure
Cell Membrane
Nucleus
Cytoplasm
Vacuoles
Endoplasmic Reticulum
Ribosomes
Lysosomes
Golgi apparatus
Mitochondria
Chloroplasts
Cell Wall
Function
-
Selectively Permeable
Keeps contents
Most obvious organelle in any eukaryotic cell
Surrounded by a double membrane
Control Center of Cell
Contains DNA
Surrounds Nucleolus, which produces ribosomes
Aka cytosol
Jelly like substance that surrounds and holds other organelles in place
Consists of mostly water, and many proteins responsible for cell metabolism
-
Continuation of the outer nuclear membrane
2 types
Rough ER – has ribosomes on outside – synthesizes proteins
Smooth ER – synthesizes lipids and membrane proteins
Synthsize Protein
Membrane bound structure (single membrane)
Stack of Vesicles that package molecules for transport elsewhere in the cell
‘Mighty Mouse’ Power House of the Cell
Provides
Similarities and Differences between
plant and animal cells
Plant Cell
Cell Wall (composed of cellulose)
and Cell Membrane
Chloroplasts producing chlorophyll
Large Vacuole
Undergo Photosynthesis and
Cellular Respiration
No Centrioles
Animal Cell
Cell Membrane only (No Cell Wall)
No Chloroplasts
Small Vacuoles & Vesicles
Only Cellular Respiration
Centrioles
Cell Composition
 Elements: C, H, O, N
 Lipids (fats and oils)
 Carbohydrates (sugars and starches)
 Proteins (muscles fibres and enzymes)
 Nucleic Acids (DNA, RNA)
Cell Equilibrium
 The cell membrane is sometimes referred to as the
plasma membrane.
 The plasma membrane is made up of a
phospholipid bilayer and some proteins

2 layers

Hydrophobic Tails and hydrophilic heads
2.2 – Transport through cell –
Particle Theory of Matter
 All matter is made up of particles. Different
substances will have different size and composition
of particles
 Particles are constantly moving. Solids least, Gases,
most. Change in energy to substance will change
movement.
 Particles are attracted to each other and may form
bonds
 Particles have spaces between them (least in solids,
most in gases) Exception: Ice.
Vocabulary
 Selectively Permable – Controls what enters
and exits cells (aka semi-permeable)
 Diffusion – materials go from high concentration
to low concentration. Perfume spreading through
a room.

Rate of Diffusion – Can be increased by adding energy
and increasing molecular movement
More Vocab.
 Concentration Gradient – Determines direction
of water or solution will move.
 Osmosis – water going from high concentration to
low across a semi-permeable membrane (selectively
permeable).
More Vocab!
 Dialysis – solutes going from high concentration to
low across a semi-permeable membrane.
 Facilitated diffusion- molecules transported
across the semi-permeable membrane with the use
of channel or carrier proteins.
All of the above go with the
concentration gradient (high to low)
 All of the above don’t require energy

Even more Vocab!
 Active transport – carries
molecules across the semipermeable membrane
against the concentration
gradient (low to high). This
requires energy and carrier
molecules. The energy that a
cell uses is ATP (adenosine
triphosphate)
Types of Solutions
 Solutions that cells are placed in are categorized into
3 types depending on the concentration of solute the
solution has to the cell.



Hypertonic
Hypotonic
Isotonic
Isotonic – Same Concentration
Hypotonic – Less Solute
Hypertonic – More Solute
Cells can also bring in large objects:
•
Endocytosis – Cell pinches
off small chunks of material
 Exocytosis – Cell dumps
out small chunk
2.3 Medical Applications
 Liposomes - create an artificial membrane that
can house medicines and carry them throughout the
cell.
 Insulin – (naturally made) glucose controls cells in
the pancreas to release insulin by exocytosis. Insulin
increases the intake of glucose into cells
 Peritoneal dialysis – filtering the blood by
diffusion
 Desalination – reverse osmosis – force water out
of a membrane so that it goes against the osmotic
gradient.
Cell Size
 Why cells are roughly the same size no matter
what they do or are located?
 Cells are roughly cube like in shape and as the cell grows
in size the Surface Area :Volume ratio gets smaller. This
is bad for the cell.



Surface area determines how much material can come in and how
much can leave. Materials come in via diffusion across the
membrane. You want lots of this.
Volume represents how much stuff is needed (food and necessary
gases) and how much must be gotten rid of (wastes solids and gases).
Materials come in via diffusion across the membrane.
The cell also responds to slowly to its environment if it gets too large
Calculating Surface Area to Volume Ratio
 Before we calculate the ratio of surface area to
volume…we need to review how to calculate Surface
Area and volume independently…
Calculating Surface Area
You should recall from math:
Surface Area = Sum of the AREAS of each side.
For example:
This rectangle has 6 sides.
Short sides = 3cm each, Long side = 5cm
1. So calculate the area of each side :
 Short = 3cm x 3cm = 9cm2
 Long = 3cm x 5cm = 15cm2
2. Multiply each by the number of sides:
 Short = 2 sides x 9cm2 = 18cm2
 Long = 4 sides x 15cm2 = 60cm2
3. Add them together:
 18cm2 + 60cm2 = 78cm2
Calculating Volume
 Again…recall from math
 Volume = length x width x height
Which for the same rectangle:
5cm x 3cm x 3cm = 45 cm3
**Note –> 1 cm3 = 1 mL
Now we can show the ratio of surface area to
volume
 Back to the same rectangle:
 We always show the ratio as:
surface area: volume
SO = 78cm2 : 45 cm3
Reduced to = 78:45
AND IT MUST BE IN THAT ORDER!!
Your notes show:
This is an example
calculation that will
only work for cubes
that are the same
size on each side.
Example #1
 Calculate the surface area:volume ratio
 Side length: 1.0 cm
Area of each side: 1.0 cm x 1.0 cm = 1.0 cm2
 Surface Area: 1.0cm2 x 6 sides = 6.0cm2
 Volume: 1.0cm x 1.0cm x 1.0cm = 1.0cm3
 Answer: 6.: 1
Example #2
 Surface Area: Volume for a cube:
 Each side is 2.5 cm
 Area: 2.5cm x 2.5cm = 6.25cm2
 6 sides x 6.25cm2 = 37.5cm2
 Volume: 2.5cm x 2.5cm x 2.5cm = 15.63cm3
 Answer = 38 : 16
reduce it = 19: 8
Example #3
 Surface Area: Volume for a cube:
 Each side is 4.0 cm
 Area: 4.0cm x 4.0cm = 16cm2
 6 sides x 16cm2 = 96cm2
 Volume: 4.0cm x 4.0cm x 4.0cm = 64cm3
 Answer = 96 : 64
reduce it = 3 : 2
Homework:
 Practice problems in Text pg 289 #1-3
 Check and Reflect p294 – even #’s
 Section 2.0 quiz on Tuesday!!