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Cells. The Basic Units of Life. Cell Structures. Cell Membrane. Look: a thin line that surrounds the whole cell - PowerPoint PPT Presentation
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CellsThe Basic Units of Life
Cell Structures
Cell MembraneO Look: a thin line that surrounds
the whole cell
O Function: - barrier between inside/outside and what comes in/out - helps with shape/form
Cell WallO Look: a rigid, frame-like covering
that surrounds the cells
O Function: - helps regulate pressure in the cell (too much water in or out) - also protects the cell
- only in plant cells
CytoplasmO Look: a liquid inside the cell, grainy
look
O Function: - the “kitchen” of the cell - contains nutrients cell needs to maintain life processes
NucleusO Look: a fairly large, dark, circular structure usually near the center of the cell
O Function: - a “command center” - directs all cellular activity (i.e.: growth, movement)
VacuolesO Look: clear, liquid-filled space in various
places within the cytoplasm
O Function: - a “storage room” for nutrients, waste, etc…
- many in animal cells, plant cells 1 big one P.C
.
A.C.
ChloroplastsO Look: medium sized, green circular shaped
structures, typically around edges of cell
O Function: - solar panel of the cell & found on green parts (i.e.: leaves)
- perform photosynthesis & only plant cells
Animal Cell
Plant Cell
Organelles O Most cellular life cannot be seen with a
light microscope O Problem solved with electron microscope
OrganellesO Organelles: specialized structures
that carry out specific functions
O Cells work just like mini factories in that they have specialized areas to accomplish specific tasks
OrganellesO Mitochondria: - “powerhouse” of
the cell - chemical reactions occur here converting energy cell receives to form it can use
Uni vs. Multi CellularO Smallest known organism is the
mycoplasma which is magnified 18000x to be viewed
O This is a single cellorganism (as are mostbacteria)
Uni vs. Multi CellularO Largest known animal is the blue
whale, it can be 30m long
O It is a multi-cellularorganism
(as most plants/ animals are)
UniCellularO Not all unicellular organisms are simple O See: Diatoms
AmoebaO Common unicellular organism O Lives in waterO Moves using tiny foot-like projections
(pseudopods) O Uses them to eat too
- engulfs food creating a vacuole then digests it into cytoplasm
ParameciumO Another Common unicellular
organism O This has tiny hairs all around it
O Called ciliaO They use it to move (like tiny oars)
and to eat (sweeps food down into oral grooves where eaten)
Substance Movement O Every second of every day your cells are
moving things (waste, energy, nutrient, etc…)
O This is vital for survival O Cells have a structure that permits vital
exchange of substances cell membrane
O Process is typically via diffusion
Diffusion & OsmosisO Diffusion is key for plant roots
O Moving and distributing evenly from areas of higher concentrations to lower concentration
DiffusionO So what is it?
O High Concentration to Low ConcentrationO An “evening out” processO Occurs until concentrations are the same everywhere
O How?O Selectively permeable membrane O That is to say it allows certain things in (i.e.: oxygen)
while holding what it needs in (i.e.: no cytoplasm leaking out)
O For example: mitochondria need oxygen to function and diffuses into the cells as needed because the concentration is higher outside of the cell compared to inside
OsmosisO Is essentially the same as diffusion but speaking
specifically about water in cells
O Diffusion of water particles through a selectively permeable membrane O Water from higher concentration to lower
concentration
O Why?O Water in cells need to stay relatively consistent for
proper cell health and function
Cells ReproduceO Unicellular organisms grow and
develop O Differences?
O When they reach their max they divide into two identical organisms
O This is how your cells reproduce as well O It is how your body replaces the
roughly 50000 skin cells it loses each day or repairs skin when you get scraped or cut
Specialized CellsO Our bodies are made up of trillions of
cells … many are specializedO Example:
O Red blood cells carry oxygen, lose nucleus so they cannot self-reproduce when they mature and are pliable to fit small spaces
O To reproduce they need other organs/tissues in the body
O This case blood needs marrow (found in most bones) to make new cells
Cell Categories
Connective Tissue
Nervous Tissue
Epithelial Tissue
Muscle Tissue
Plant Cell CategoriesO Plants are similar in that they have 3 cell
categoriesO 1) Photosynthesis/StorageO 2) Protective O 3) Transport
O No organ systems exist in plants though however they need the substances produces/provided by the other cell categories to survive
O Good way to identify them? Look at leaf, stem and root cells
So ..! O Here is a question to see if you were
paying attention!
O Is a red blood cell more specialized than an amoeba or is it the other way around?
O Discuss…
Goodbye Topic 2