Cell Organelles and their
Function
Cell
Membrane
Cytoplasm
•Semi-permeable
•Regulates
movement in & out
•All the material
from the nucleus to
the cell membrane
More on the cell
membrane to come…
Nucleus
Nucleolus
Chromosomes
Nuclear Envelope
•Control center of the cell
•Located inside the nucleus
•Ribosomes are made here
•DNA material seen in the
nucleus
•Made up of Chromatin
(DNA and proteins)
•Encloses the nucleus
See next slide for
chromatin
Chromatin
DNA wrapped around proteins
A protein
Chromatin
condenses to form
the chromosomes
Endoplasmic Reticulum
Golgi Apparatus
Vesicle
•Synthesizes and transports proteins
(Rough ER)
•Synthesizes lipids and steroids (Smooth
ER)
•Collects, modifies, sorts, and secretes
cell products
•Picks up molecules from golgi apparatus
and transports in cell or to other cells
Ribosomes
–Synthesize proteins
during translation
Free – in cytoplasm
Bound – on rough ER
Lysosome
Peroxisome
•Break down cellular waste
products and debris
•Rid cells of hydrogen peroxide
and other toxins
Mitochondria
•Creates energy through
cellular respiration
Centrosome
In animal cells only
•Play a role in cell division
•Help to organize cytoskeleton
•Animal cells have Centrioles which are paired
structures within the centrosome
•Located near the nucleus
Vacuoles
• Central Vacuole
(in plant cells only)
• Food vacuoles
• Contractile vacuoles
•Holds food, water and minerals
•Formed when particles are taken into
the cell
•Pump water out of cells
In Plant Cells Only
Plastids – A double membrane bound organelle
involved in the synthesis and storage of food, and is
commonly found within the cells of photosynthetic
organisms, like plants.
Chloroplast
(example of plastid)
Cell Wall
Site of photosynthesis in
plants only
•Thick outer covering
outside the cell
membrane
•Protects and
supports a plant cell
Cytoskeleton
• A network of protein filaments that organizes
structures and activities in the cell.
• All help to maintain the cell shape and other
specific functions
– See next slides
Components of the Cytoskeleton
• Microtubules
– Hollow tubes made of proteins known as
tubulins
– Main Functions
• Cell motility (cilia and flagella)
• Chromosome movements in cell division
• Organelle movements
Components of the Cytoskeleton
• Microfilaments
– Two intertwined strands of actin (a protein)
– Main Functions
•
•
•
•
Changes in cell shape
Cytoplasmic streaming
Cell motility (pseudopodia)
Cell division (cleavage furrow formation)
Components of the Cytoskeleton
• Intermediate Filaments
– Fibrous proteins supercoiled into thicker cables
– Main Functions
• Anchorage of nucleus and other organelles
• Formation of nuclear lamina
•
The Endomembrane System
A cell's endomembrane system consists of the
rough and smooth endoplasmic reticulum,
Golgi apparatus, vesicles and plasma
membrane, all working together to transport
cellular materials.
http://study.com/academy/lesson/the-endomembrane-system-functions-components.html
Cell Membrane
• Allows materials to move in and out of the
cell.
• The “fluid-mosaic model” Of an Animal Cell
• Made of a phospholipid bilayer
– Two layers of lipids (they can move. They need to be
fluid to work properly). Allow certain materials to pass
through
– dotted with proteins
• Proteins aide in certain molecules moving through
the membrane
Gen bio. Lipids and
proteins only. Copy of this
slide
Phospholipid bilayer of Cell Membrane
Water loving
•
The arrangement of the
phospholipid bilayer allows only
certain molecules to pass through
the cell membrane.
• Some large molecules, like sugar
Cannot “fit” through this layer
• Small molecules generally move through easily
• Also if the molecule is soluble in the “tail” region it
will go through faster.
Water fearing
“head region” – likes water
“tail region” - does not like
water
Cell Membrane of an Animal Cell
ECM – extracellular
matrix (cells attach to this
•
and send signals to one
another. Made of protein
fibers)
Carbohydrate chains –
assist in cell signaling
Proteins-aid certain
molecules moving
through the membrane
Cholesterol- keeps
membrane fluid, from not
freezing or becoming too
liquid
Regeneration of cells – regrowing finger
https://www.youtube.com/watch?v=ITxx2sOLW2Y
Phospholipid bilayer –
allow certain materials to
pass through
How do substances move in and
out of cells?
How Do Substances Move In and
Out of Cells?
1. Diffusion – movement of molecules
from greater concentration to lesser
concentration.
No Energy Required by the cell
Passive Transport
DIFFUSION – A type of Passive Transport
How do substances move in and
out of cells?
2. Osmosis – movement of water across a
membrane from greater to lesser
concentration.
–
–
Examples – water into plant cell, salt on
slugs, preserving meats
Also passive transport (no energy needed)
Review of terms
• Solute – what is being dissolved
• Solvent – What is doing the dissolving
• Solution – solute + solvent
Types of Solutions
• Hypertonic - higher concentration of solute
• Hypotonic - lower concentration of solute
• Isotonic - equal concentration of solute
Less solute / More water
More solute/less water
Hand out
Hand out answer
In a solution with higher
concentration of solute
In a solution with
equal concentration of
solute and solvent
In a solution with lower
concentration of solute
(more water)
•
Osmosis and animal cells
“Special Cell Processes” Examples
Salt on slug
E.coli
http://www.youtube.com/watch?v=9QCxTf0QfTo&feature=related
Osmosis on lettuce
https://www.youtube.com/watch?v=SrON0nEEWmo
Egg osmosis
Facilitated Diffusion
Passive Transport No Energy required
-Molecules move from Higher concentration to Lower
concentration.
-Molecules are being “helped” through by proteins
The molecules “glide”
through, like a boat going
through a channel
Active Transport -Requires Energy
Molecules are now moving the opposite way we have discussed.
• Molecules move from a lower concentration to a higher
concentration.
• Uses a transport protein
• Energy comes from ATP
Lower
concentration
https://www.youtube.com/watch?v=ovHYKlHYpyA
Review of diffusion and osmosis
Higher concentration
Active Transport-example
• The Sodium (Na), Potassium (K) pump
High Na
Low K
High K
Low Na
Yahoo search sodium potassium pump
- animation
Bulk Transport across the cell membrane
require energy
• Endocytosis
– Taking materials into the cell
Bulk Transport across the cell membrane
require energy
• Exocytosis
– Secreting materials
(moving materials from inside the cell to outside the cell)
• Usually moving products