Transcript The Cell - Flow in Sports

The Cell
Biology 314
Mr. Doron
The Cell
• The cell is the structural and
functional unit of all living organism
and is sometimes called the "building
block of life.
• Some organisms, such as bacteria are
unicellular consisting of a single cell.
Another example is the ameba.
• Other organisms, such as humans are
multi-cellular (humans have an
estimated 100 trillion cells).
The Animal Cell - Picture
Plant Cell Picture
The Cell
• It is the smallest structural unit of an
organism that is capable of independent
functioning
• All living things are composed of cells.
These cells come from preexisting cells
• Consists of one or more nuclei,
cytoplasm, and various organelles, all
surrounded by a semi-permeable cell
membrane.
Properties of a cell
• Each cell is at least somewhat selfcontained and self-maintaining:
• a cell can take in nutrients
• convert these nutrients into energy
• carry out specialized functions and
reproduce as necessary.
• Each cell stores its own set of instructions
for carrying out each of these activities.
Components of a cell
• A cell has three basic components
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1) The cell or cytoplasmic membrane
2) the cytoplasm
3) the nucleus
The cell membrane:
this is the outside part of the cell
separates its interior from its environment
regulates what moves in and out (selectively
permeable)
– maintains the electric potential of the cell.
How do Cells Stay Alive?
– Cells needs nutrients, oxygen and water.
– Taken from the environment
– Excretes waste products into
environment
Exchanges Between Cell
and its Environment
• Occurs in three ways
– 1) diffusion
– 2) osmosis
– 3) endocytosis
Diffusion
• Movement of particles from an area
with high concentration to an area of
low concentration
• Click the play button to see the video
Osmosis
• Passage of a solvent (i.e. water)
across a semi-permeable membrane
• Click the image for a video
Endocytosis
• Whereby the cell ingests whole solid
or liquid particles
• 2 examples of endocytosis are
phagocytosis and pinocytosis
• Phagocytosis - capacity of the cell
membrane to invaginate or form a
pocket which engulfs solid
substances and draws them into the
cytoplasm to be digested
Pinocytosis
• Capacity of the cell membrane to
invaginate and engulf liquid
substances and draws them into the
cytoplasm to be digested.
• Active transport: the cell uses
energy to move molecules against
their concentration gradient (low 
high)
Nucleus
• The nucleus is a membrane-enclosed
organelle
• The main function of the cell nucleus is to
control gene expression and mediate the
replication of DNA during the cell cycle.
• Chromosomes are responsible for passing
hereditary characteristics such as eye
colour, hair texture, blood type etc.
Cytoplasm
• Cytoplasm is a jelly-like material that fills
cells.
• The cytoplasm is inside the cell. It ensures
the transport of the different substances
that enter or leave the cell.
• Carries particles that are suspended called
organelles.
• Each organelle has at least one definite
job or function and has a definite form.
Organelles
• An organelle is a discrete structure
of a cell having a specialized
functions.
• An organelle is to the cell what an
organ is to the body.
Golgi Apparatus
• integral in modifying, sorting, and
packaging proteins.
• In this respect it can be thought of
as similar to a post office; it
packages and labels "items" and then
sends them to different parts of the
cell.
Lysosome
• They are organelles that contain digestive
enzymes
They digest excess or worn out organelles,
food particles, and engulfed viruses or
bacteria. The membrane surrounding a
lysosome prevents the digestive enzymes
inside from destroying the cell.
Mitochondrion
• Responsible for energy production
Vacuole
• storage & homeostasis
Endoplasmic Reticulum
• modification and folding of new
proteins and lipids