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

A tour of the Cell
Chapter 6
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
Main cell components
 Plasma
membrane
 Cytoplasm
 Nucleus
 Organelles
 Cell wall (only in plant 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

Pages 112-113
Plasma membrane
 Composed
of proteins and a type
of lipid called phospholipid
 The structure that makes the
plasma membrane is called the
phospholipid bilayer
Phospholipid molecule of Plasma
Membrane
Plasma Membrane Structure
Ways cells get molecules in
and out of cell
No cell energy used
diffusion
passive transport (facilitated diffusion)
Cell energy used
Active transport
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 though
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: difusion of water through a
membrane
– Facilitated diffusion: Transport molecules
provide a pathway for certain molecules
to pass

Active transport
Higher Concentration
of Water
Lower Concentration
of Water
Water molecules
Sugar molecules
Water moves from high concentration to low concentration
Results of water
movement
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.
Facilitated diffusion or
Passive transport
Glucose
molecules
High
Concentration
Cell
Membrane
Low
Concentration
Protein
channel
Protein
channel
Used when the cell wants to make sure
it has lots of the molecule
Molecules moved from
LOW concentration to HIGH
concentration
Molecule to
be carried
Low
Concentration
Cell
Membrane
High
Concentration
Molecule
being carried
Low
Concentration
Energy from the cell is
used
Cell
Membrane
High
Concentration
Energy
Energy
Main cell parts and
functions
Cytoplasm: holds organelles
- transport medium
Nucleus: Control center –
contains the DNA
Ribosomes: make
proteins
RER: modify and
transport proteins
SED: Production of lipids
(fats)
Golgi apparatus: Process and
package proteins and lipids
Chloroplast: Where
photosynthesis occurs
Mitochondria: Releases
energy usable by the cell