Transcript cell organelles and membranes powerpoint

By the end of today: Name a function of each organelle
The nucleus
 Contains genetic
information
 Has a double membrane
with pore complexes
 Contains nucleolus – a
structure where rRNA is
synthesized
 Fun fact: your red blood
cells do not have nucleii
(anucleated)
Endoplasmic reticulum
 Smooth ER
 Synthesis of lipids,
metabolism of
carbohydrates and
detoxification of drugs
and poisons
 Fun fact – cells that
synthesize hormones
(steroids which are lipids)
, such as testes and ovaries
are rich in smooth ER
 Another fun fact - Also
proliferation of smooth ER
in response to drugs and
alcohol
 Rough ER
 Proteins are synthesized
using ribosomes and then
in the rough ER they are
folded and carbohydrates
are added to make a
glycoprotein
 The membrane buds off to
form a transport vesicle
which takes the protein to
another area in the cell
Golgi
 Products of the ER are
modified, stored and sent to
other destinations in the
golgi
 Golgi can also manufacture
macromolecules, such as
polysaccharides
 Strucutre
 Trans face – shipping side
 Cis face – near the rough ER
 Fun fact – molecular
identification tags are added
to golgi products that aid in
their placement within the
cell
Lysosomes – Digests
macromolecules using enzymes
Phagocytosis – Eating or
digestion of products
Autophagy – Breaks down
damaged organelles
Lysosomal lipase is missing
Vacuoles
 Different functions in
different cells
 Ex. Food vacuoles,
contractile vacuoles
(pump excess water out of
the cell), and in plant cells
central vacuole
 Plant cells central vacuole
has many functions such
as organic compound
reserve, disposal site,
pigment storage, poison
storage, etc.
Mitochondria
 The site of cellular
respiration (creates
energy from food)
 Has two membranes
 Has DNA
 Fun fact – there are lots
of mitochondria in your
muscle cells and you can
increase the amount
with exercise
Chloroplasts
 The site of photosynthesis
 Creates organic molecules that can be broken down in
the mitochondria
 They are not found in animal cells
Cytoskeleton
 Function
 Support
 Motility
 Regulation
 Types
 Microtubules
 Microfilaments
 Intermediate Filaments
Microtubules
 Structure
 Hollow rods
constructed from
tubulin dimers (protein
with two subunits)
 Function
 Aid in shape, support
and form tracks which
organelles move along
 Examples : Centrosomes
and cilia and flagella
How a cilia or flagellum works
 D:\Chapter_06\C_Anim
ation_and_Video_Files\0
6_Animations\06_24Cili
aFlagella_A.swf
Microfilaments
 Structure
 Solid rods built from
twisted actin chains
(smallest)
 Function
 Bears tension


helps support the cell’s
shape
Movement


Contraction of muscle cells
Amoeboid movement
Microfilaments – muscle
contraction
Microfilaments – amoeboid
movement
 Amoeba moving
Intermediate Filaments
 Structure
 Proteins coiled into
thicker cables
 Bigger than
microfilaments but
smaller than
microtubules
 Function
 Tension bearing

Permanent fixtures of cells
(do not move)
Check for understanding
 Cell parts checklist
 Contrast cell types
 As you are doing the worksheet, review the function of
each organelle with your group
Diffusion
 The movement of molecules from an area of higher
concentration to an area of lower concentration
What determines whether a
substance will enter or leave a
cell?
Diffusion Lab
 Will substances move through the membrane?
 What determines which substances will move?
Check for understanding
 Define diffusion
 What types of molecules could move freely through a
cell membrane?
Demo with potatoe
Membranes
 Know the parts of the cell membrane and what the
function is
Membranes
 Function
 Acts as a barrier that
separates the inside and
outside of the cell
 Regulates the “traffic” of
molecules into and out
of the cell
Membranes
 Structure
 Lipids and proteins
 Amphipathic
(hydrophilic and
hydrophobic regions)
 Fluid mosaic model
For the following that are circled: Give
the name and at least three facts,
including the function
Two types of movement
through the membrane
Passive transport – Does
not need energy to
transport
Active transport – Uses
energy to transport
Something to ponder…
 Most fish are not able to move between salt water and
fresh water. Why do you think this is?
Osmosis lab
 Be able to define osmosis
 Determine which way water will move given certain
solute concentrations
Osmosis
 The diffusion of water across
a selectively permeable
membrane.
 Ex. Lettuce and salad
dressing
 Or wilted lettuce in water
Water balance in cells
Check for understanding
 Draw a representation of the concept of osmosis.
(Hint: You may want to draw solutes to one side of
a membrane and show which way the water is
moving)
Water Potential
 Read exercise 1C in lab notebook
 Water potential is the potential for water to do work,
or move out of the cell
 Ψ = Ψp + Ψs
 Water potential equals the pressure potential plus the
solute potential.
 Increasing the pressure increases water potential (+)
 Increasing solutes decreases water potential (-)
Check for understanding
 If a plant cell has a lower water potential than its
surrounding environment and if pressure is equal to
zero, is the cell hypertonic (in terms of solute
concentration) or hypotonic to its environment? Will
the cell gain water or lose water?