Cells

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