Transcript Prokaryotic vs Eukaryotic Cells

Prokaryotic vs Eukaryotic Cells
Cellular Hierarchy
• Some organisms are unicellular (single celled);
the cell carries out all life functions. Unicellular
organisms are prokaryotic.
• Multicellular organisms have many cells that
work together to carry out life processes.
• Tissues are groups of cells that perform the
same function. Organs are several types of
tissue working together to perform specific
functions.
Cell>Tissue>Organ>Organ System
• An organ system is a group of organs
working together for a particular function.
For example, your digestive system
breaks down food and puts it in the blood.
Your circulatory system moves blood
throughout your body. Your respiratory
system puts O2 into your blood to be used
by cells for respiration, and removes H20
and CO2.
Organelles in unicellular organisms…
• Work like the organ
systems of
multicellular
organisms.
• Each organelle has a
specific function that
helps keep the onecelled organism alive.
Cell Membranes
• Are found in ALL cells.
• Help cell to maintain homeostasis
(keeping a balance of solutes within a
cell).
• Are selectively permeable, meaning that
only certain substances can go through in
either direction.
• Made of phospholipid bilayer.
Passive Transport
• Does NOT require energy.
• Molecules move through the cell
membrane from areas of higher
concentration to areas of lower
concentration.
• There are 3 types of passive transport –
diffusion, facilitated diffusion, and osmosis.
Diffusion & Facilitated Diffusion
• Diffusion is the process by which
substances move directly through the cell
membrane.
• Facilitated diffusion involves the help of
a carrier protein to move a substance from
one side of the cell wall to the other.
Osmosis
• The movement of water from an area of
high water concentration to an area of low
water concentration through a semipermeable membrane.
• Hypotonic has a lower concentration of
solute (higher of water).
• Hypertonic has a higher concentration of
solute (lower of water).
• Isotonic means the solute concentration
is the same inside and outside the cell.
Osmosis ALWAYS occurs from
hypotonic to hypertonic…
Active Transport
• A process of moving material across the
cell membrane from an area of low
concentration to an area of high
concentration
• Requires energy to happen.
• Exocytosis removes materials from a cell.
• Endocytosis brings materials into a cell.
The membrane “absorbs” the material.
Factors Affecting Cellular Activity
• Volume – cells with large internal volume
cannot efficiently transport materials to the
organelles that need them.
• Surface Area – the greater the surface
area, the more efficient the cell.
• Environmental Factors – most cells
function best within a specific range of
temperature, light, and pH. (ex – plants)
Fluid Pressure in Cells
• Fluids are liquids and gases. Pressure is
a force (push or pull) applied uniformly
over an area.
• Blood Pressure – pressure exerted by
blood on the walls of blood vessels.
• Turgor Pressure – pressure that plant
cells put on each other when full of water;
allows plants to stand up and move water
up the stem or trunk to the top of the plant.
Review
• Unicellular organisms have one cell; multicellular have
many.
• Cells make tissues, which make organs, which make
organ systems.
• Organelles act as organs in a cell.
• Passive transport (diffusion/osmosis) does not require
energy. Active transport does.
• Volume, surface area, and environmental factors
(temperature, light, pH) affect cellular activity.
• The amount of fluid pressure in a cell affects its
efficiency.