Cells
Unit 3CellsAtoms- smallest unit of matter
Molecules/compoundsMacromolecules (lipids, etc.)Organelles
(nucleus, etc.) Cells
The Discovery of the CellRobert Hooke- corkVan Leeuwenhoek- pond
waterPlay videoCell TheoryAll living things are composed of
cells.Cells are the basic unit of structure and function in all
living organisms.All cells come from pre-existing cells.Play
videoProkaryotes and EukaryotesProkaryotesEukaryotesNo
nucleusNucleusNo membrane-bound organellesMany organelles1-10 um in
size2-1000 um in sizeEvolved 3.5 billion years agoEvolved 1.5
billion years agoOnly bacteriaAll other cells (plants , animals,
complex single-celled organisms)Very basicMore complex*um =
micrometers (smaller than a millimeter)
Prokaryotes
DNA/genetic materialrrrrrrrrrrhhhhhhFlagellum
cytoplasm/
(filler)lllllllllllllllllllllllllllllllllllllllllllllllllllnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnCell
wallCell membraneMost cells have 3 basic identifiable
organelles:Cell membrane: outer boundary of the cellNucleus:
control center; contains the DNACytoplasm: jelly-like filler
material that bathes the organelles and transports materials within
the cell from one area of the cell to another.Play videoC ell
MembraneGives cells structure and formsemi-permeableRegulates what
enters and leaves the cellMade up of the lipid by-layerProteins may
be embedded in the by-layer to further regulate the movement of
molecules into and out of the cell
Play videoCell Wall (plants only)1. Found only in plants, algae,
and some bacteriaSurrounds the cell membranePorous in design;
allows water, oxygen, and carbon dioxide in and out3 layers:
primary layer contains pectin, secondary layer contains cellulose,
and tertiary layer contains lignin (these fibrous materials are
indigestible by humans).
NucleusLarge dark structure in the cellCenter of
informationWhere DNA is found; chromosomes are the protein-based
structures of genetic information.Is surrounded by the nuclear
envelope/membrane.The nucleolus is inside the nucleus; Ribosomes
are made there.The DNA inside the nucleus directs the cells growth
and development.
Play videoCytoplasmBathes organellesProvides movement and
transport within the cellCytoplasmic Streaming moves material from
one area of the cell to another.
VacuolesStorage area for water, salts, proteins and
carbohydrates.They are the most prominent in plant cells; take up
to 60% of the cell.The pressure of the central vacuole makes it
possible for plants support heavy structures such as leaves and
flowers.
LysosomesSmall organelles filled with enzymesDigest/break down
foreign material and old, worn out organelles.ChloroplastsRound,
green structures found in plant cells only; contain
chlorophyll.Absorb light energy for photosynthesisPlant cells make
their own chemical energy (ATP) from light energy.
RibosomesOne of the most important jobs of cells is to make
proteins.Proteins are assembled on ribosomes.they produce proteins
by following the instructions found in the DNA in the
nucleus.Smallest organelles
Endoplasmic Reticulum (ER)Eukaryotes contain an internal
membrane system called ER.Site where lipid components of the cell
membrane, proteins, and other cell materials are assembled.Smooth
ER (no ribosomes), stores enzymes.Rough ER (studded with ribosomes)
for protein modification.
Golgi ApparatusProteins produced in the rough ER move to the
golgi apparatus.Looks like a stack of membranesFunction is to
modify, sort, and package proteins and other materials from the ER
for storage in the cell or secretion outside the cell wall.
MitochondrionBreaks down ingested food into chemical energy
(ATP)Often called the powerhouse of the cell.Enclosed by 2
membranes: outer and inner.
CytoskeletonThe framework for the cellmicrotubules-1. gives cell
shape2. forms centrioles (animal cell division)microfilaments1.
movement or support structures2. allow for cytoplasmic
streaming
Plant cells vs. Animal CellsPlant cells have the
following:chloroplasts/chlorophyll for photosynthesiscell
wallenlarged vacuolesgeometric/blocky shape (like solar panels that
fit together to eliminate wasted space)Play videoQuiz: Match the
Organelle with the Number. Use the list provided.
Microtubules/cytoskeletonNucleusNucleolusVacuolesGolgi
apparatusMitochondriaRibosomesMembraneCytoplasmChromosomesEndoplasmic
reticulum
Quiz: Match the Organelle with the Number. Use the list
provided.
12.13.14.15.ChloroplastsNucleusVacuoleCell wall
Cell Boundariescell membrane regulates what enters and leaves
the cell.The membrane and cell wall are boundaries that separate
the cell from its surroundings.
Cell BoundaryDiffusionEvery cell lives in a liquid environment,
even if you cant really see it.Inside the cell is cytoplasm, which
contains many substances dissolved in water (solution).In a
solution, particles spread out randomly as they continuously
collide with each other.As a result, particles move from an area of
high concentration to an area of low concentration = diffusion.When
the concentration of solute in the solution is the same throughout
a system, then the solution reaches equilibrium.Diffusion does not
need energy from the cell to occur.
Diffusion
Play videoOsmosisWater will tend to move across the cell
membrane until equilibrium is reached = solutions on either side of
the membrane are isotonic.Hypertonic = above strength
(undiluted).Hypotonic = below strength (diluted).
OsmosisOsmosis is the diffusion of water across the cell
membrane.
Play videoOsmotic PressureOrganisms have to have a way to
balance the intake of water.Because a cell is filled with salts,
sugars, and proteins and other molecules, it is hypertonic to fresh
water.This will cause water to fill the cell until it is filled.
Wont always burst becauseBody cells are in isotonic
fluids.Single-cell organisms have a protective cell
wall.Facilitated DiffusionDoes not require energy from the
cell.Membrane allows material across the membrane driven by
diffusion.Protein channels are tunnels that allow material to be
passed through.
Play video
Active TransportProtein pumps actively move material across the
cell membrane; requires energy from the cell.Endocytosis: cell
takes in material by enfolding itself around it.Phagocytosis:
extensions of cytoplasm surround a particle and package it within a
food vacuole.Pinocytosis: like endocytosis, but with
liquid.Exocytosis: removal of water/materials from cell using a
contractile vacuole.Play videoLevels of OrganizationAtoms
Molecules/compounds organelles Cells Tissues Organs Organ Systems
organism
Cells begin as blank slates (unspecialized- STEM CELLS) and then
become specialized; they get specific jobs.
