Transcript Welcome to Mrs. Gomez-Buckley General Biology Class (Room 615)

A tour of the Cell
Chapter 7
http://www.youtube.com/watch?v=o1GQyciJaTA&feature=related
http://www.ibiblio.org/virtualcell/textbook/chapter3/chapter3.htm
http://vcell.ndsu.edu/animations/
Cell theory
 All
living things are composed of
cells
 Cells are the basic unit of function
and structure in living things
 All cells come from pre-existing cells
Eukaryotic vs. prokaryotic
cells
Contains nucleus
 Many organelles
present
 10-100 micrometers
 Appeared later in the
fossil record

Lacks a nucleus
 Lacks organelles

1-10 micrometers
 Appeared earlier
in the fossil
record

Two Basic types
Cell membrane
cytoplasm
Prokaryote
Cell membrane
cytoplasm
nucleus
Eukaryote
Cell organelles
Compare and Contrast
Prokaryotes
Cell membrane
Ribosomes
Eukaryotes
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Page 206
Compare/contrast plant and
animal cells
Plant cell
Cell wall
Large vacuole
chloroplast
ribosomes
mitochondria
Golgi apparatus
Endoplasmic reticulum
Cell membrane
nucleus
Animal cell
Centrioles
flagellum
Cell Membrane
 Composed
of proteins and a type
of lipid called phospholipid
 The structure that makes the
plasma membrane is called the
phospholipid bilayer
http://www.wisc-online.com/Objects/construction-of-the-cell-membrane/
Phospholipid molecule of Plasma
Membrane
Plasma Membrane Structure
Ways cells get molecules in
and out of cell
No cell energy used
Diffusion
Facilitated diffusion
Cell energy used
Active transport
http://www.wisc-online.com/Objects/construction-of-the-cell-membrane/
Diffusion
 The
net movement of particles of a
substance from where they are
more concentrated to where they
are less concentrated
Diffusion


The random movement of molecules
from a high concentration to a low
concentration
If system is left alone the molecules
will eventually spread themselves
equally every where – the molecules
do not stop moving through
Types of Transport through
plasma membrane

Passive transport
– Diffusion: some molecules cross the
plasma membrane with no expenditure of
energy or help from transport proteins

Osmosis: diffusion of water through a
membrane
– Facilitated diffusion: Transport proteins
provide a pathway for certain molecules
to pass

Active transport
Water moves from high concentration to low concentration
What happens to a red blood cell when it is
placed in water with different concentrations of
salt?
Results of water movement
on cells – Osmotic Pressure
Types of Transport
through plasma
membrane

Passive transport
– Diffusion

Osmosis
– Facilitated diffusion

Active transport: A transport protein
pumps a solute across a membrane in
the opposite direction to the way it
travels with diffusion. It requires
chemical energy.
Bulk Transport
For larger molecules and solid clumps of
material the cell uses
 Endocytosis – cell takes in materials in
by infoldings in the membrane




Phagocytosis
Exocytosis – cell releases materials
through membrane
http://www.ibiblio.org/virtualcell/textbook/chapter3/cmf4a.htm
http://www.youtube.com/watch?v=aWItglvTiLc
Main cell parts and
functions
Cytoplasm: holds organelles
- transport medium
Nucleus: Control center –
contains the DNA (genetic
material)
Ribosomes: make
proteins
Ribosome
RER: modify and
transport proteins
SER: Production of lipids
(fats)
Golgi apparatus: Process and
package proteins and lipids
Chloroplast: Where
photosynthesis occurs
Mitochondria: Release
energy usable by the cell
Lysosome: Breaks down
macromolecules into
particles the cell can use
Homeostasis
(homeo_=same
_stasis=standing still)
Unicellular organisms as well as cells in
multicellular organisms must maintain
homeostasis, or that is to say, relatively
constant physical or chemical conditions.
 Unicellular organisms
 Multicellular organisms
To maintain Homeostasis

Unicellular organisms
– Grow
– Respond to environment
– reproduce

Multicellular organisms
– Have specialized cells that communicate
with each other
Examples of Homeostasis in humans


Thermoregulation
Glucose regulation
Cell Specialization

In multicellular organisms there is a
division of labor among the specialized
cells
Levels of Organization
cell
tissue
organ
organism
organ system
Homeostatic loops
http://www.youtube.com/watch?v=jkioZCDHT_E&list=PL7A750281106C
D067&index=38
Examples of Homeostasis in humans