Download CELLS-Chapter 2 - St. Thomas the Apostle School

CELLS-Chapter 2
Common cell traits
Cell membrane- a cells outer
covering
And
Cytoplasm- gelatinlike substance
-
CELL TYPES1. Membrane bound structures-Prokaryotic
2. NO membrane-bound structure- Eukaryotic
CELL ORGANIZATION
Cell wall-a tough rigid outer covering that protects
the cell and gives it shape
Plant cell- cellulose-long threadlike fibers
Cell membrane- Protective layer around all cells
a. For cells with cell walls, the cell membrane is
inside the cell wall.
b. B. a cell membrane allows food and oxygen into
the cell and waste products out of the cell
Cytoplasm- gelatinlike substance found in
the cell membrane. Many chemical reactions
occur within the cytoplasm
a. Cytoskeleton- scaffolding like structure in
cytoplasm which helps cell keeps its shape.
b. In the cytoplasm, eukaryotic cells have
organelles which help with life processes.
NUCLEUSContains instructions for everything cell does;
includes DNA, powerhouse of the cell. The
nucleus directs all cell activities.
Energy processing organelles help cells do their
work
• Green organelles in plant cells contain
CHLOROPHYLL to make food
• Organelles which release energy from food are
called MITOCHONDRIA
MANUFACTURING ORGANELLES
-RIBOSOMES make protiens for all cell activities
-some ribosomes attach to the rough part of the
ENDOPLASMIC RETICULUM- moves material
around in a cell
Transporting and Storing Organelles
• Golgi bodies- move substances out of a cell to other parts of
a cell
• Vacuoles- Membrane bound temporary storage spaces
• Endoplasmic reticulum- materials are processed and moved
around inside the cell; Folded memebranes
ENERGY PROCESSING ORGANELLES
-In plant cells- chloroplasts which contain chlorophyll trap
sunlight to give the plant light energy and chemical
energy
-Mitochondria-release energy that is needed by the cell
from food.
Manufacturing organelles
Ribosomes- small structures that make their own
proteins
Recycling Organelles
- Lysosomes break down food molecules and cell
wastes
FROM CELL TO ORGANISM
1. Tissue- group of similar cells working together on
one job
2. Different types of tissues working together make up
an organ
3. A group of organs working together on a paticular
function form an organ system
Animal cell
Plant Cell
Viewing cells
Magnifying cellsearly microscopes- lenses made images larger but
not always clear
Modern microscopes- use lenses to bend light
- A simple microscope has one lense while a
compond microscope has two sets of lenses.
- A Stereomicroscope, which has two eyepieces,
creates a three dimensional image.
- Powers of the eyepiece multiplied by the
objective lenses determine total magnification.
Electron Microscope- More powerful than other
microscopes.
-Uses a magnetic field in a vacuum to bend
electronic beams.
- Images must be photographed or produced
electronically
Development of the cell theory
1. The cell theory resulted from many scientists
observations and conclusions
2. The basic unit of organization is the cell
3. All organisms are composed of one or more
cells.
4. New cells come from old cells through cell
division
VIRUSES
• A non –living strand of hereditary material surrounded
by a protien coating
Virus multiplication- viruses can make copies of
themselves only inside a living host cell
1. Active virus- make the host cell produce new viruses ,
which kill the host cell
2. Latent virus- hide in the host cell without destroying
it.
- Virus hereditary material becomes part of the
host cell’s hereditary material.
- latent viruses can become active and the destroy
the host cell.
VIRUS EFFECTS ON ORGANISMS
- Most viruses infect only specific types of cells
- Viruses are often carried to the host through
the air.
- The virus and host cell must fit together
exactly to begin a viral infection.
- Bacteriophages attach to the bacteria and
inject their hereditary material.
FIGHTING VIRUSES
Vaccines- weakened virus particles which allow the
host to fight some diseases
Treating a viral disease-antibiotics are NOT effective treatments for viral
infections.
-infected cells sometimes produce interferons,
which are proteins that can protect non-infected
cells.
- Antiviral drugs often have adverse side effects,
limiting their use
- - Public health message can prevent or slow
disease spread.