Download Ch 7: A View of the Cell

Ch 7: A View of the Cell
7.1 - The Discovery of Cells
Section 7.1
Inside This Section...
The History of the Cell Theory
The Cell Theory
2 Types of Microscopes
2 Basic Cell Types
Section 7.1
The History of the Cell Theory
The microscope was invented by
Anton van Leeuwenhoek
Dutch Scientist
First Microbiologist
Section 7.1
The History of the Cell Theory
Section 7.1
The History of the Cell Theory
The first person to see a cell (in cork)
was Robert Hooke.
Observed cells in Cork
Section 7.1
The History of the Cell Theory
Matthias Scleiden Concluded that all
plants have Cells
German Botanist
Section 7.1
The History of the Cell Theory
Theodore Schwann observed that
animals were also composed of cells
Section 7.1
The Cell Theory
3 main ideas:
All living things are composed of
one or more cells
The Cell is the basic unit of
organization of organisms
All cells come from preexisting cells
Section 7.1
The Light Microscope
Uses light and lenses
The Simple light Microscope
used one lens and natural light
(Leeuwenhoek)
The Compound light microscope:
Uses multiple lenses
Magnifies up to 1500 times
Section 7.1
The Electron Microscope
Invented in the 1940s
Uses a beam of electrons
Magnifies up to 500,000 times
Two Kinds:
Scanning electron microscope (SEM):
Scans the surface of cells.
Transmission electron microscope
(TEM): Allows for study of structures
inside cells.
Section 7.1
Microscope COmparison
TEM
SEM
Section 7.1
Two Basic Cell Types
Prokaryotes: Cells lacking internal membrane-bound
structures
Eukaryotes: Cells containing internal membrane-bound
structures. The membrane-bound structures are called
organelles. Contains a nucleus: organelle that manages
cellular function. First observed by Robert Brown. Rudolf
Virchow concluded that it was responsible for cell division.
Section 7.1
Two Basic Cell Types
Section 7.1
In Review...
The History of the Cell Theory
The Cell Theory
2 Types of Microscopes
2 Basic Cell Types
Section 7.1
Animal Cell Structure
Section 7.1
Plant Cell Structure
Ch 7: A View of the Cell
7.2 - The Plasma Membrane
Section 7.2
Inside This Section...
Maintaining a Balance
The Plasma Membrane
The Structure of the Plasma Membrane
Section 7.2
Maintaining a Balance
The Plasma membrane is the
boundary between the cell and it’s
environment
Needs to let the good stuff (e.g.
nutrients) in and the bad stuff (waste)
out
The plasma membrane maintains
homeostasis.
Section 7.2
Maintaining a Balance
Section 7.2
The Plasma Membrane
Maintains Homeostasis: regulates internal environment
[Good in (but not too much), Bad Out]
Selective permeability: Allows some molecules into the cell
and keeps some out.
Some molecules can cross the plasma membrane (i.e.
water). Others must go through channels (i.e. Na, Ca, etc)
Section 7.2
Plasma Membrane Structure
Composed of a phospholipid bilayer.
A Lipid with a phosphate group
attached
Has only 2 fatty acid tails
Forms a sandwich
The phosphate group forms the polar
head
The fatty acid tails form the nonpolar
tail
Section 7.2
The Fluid Mosaic Model
The membrane is fluid: It is flexible and phospholipids can move
in the membrane like water in a lake.
The membrane is mosaic: There are proteins embedded in the
membrane that also move (like boats in the lake)
Section 7.2
Other Components
Cholesterol: Helps stabilize the plasma membrane, and prevents
the phospholipids from sticking together.
Transport Proteins: Proteins that span the entire membrane and
form channels for specific molecules to enter and leave (like a
door).
Other Proteins and carbohydrates on the external surface: Helps
with identification.
Proteins on internal surface: Provides flexibility by attaching the
plasma membrane to the cell’s internal structure.
Section 7.2
Section 7.2
In Review...
Maintaining a Balance
The Plasma Membrane
The Structure of the Plasma Membrane
Ch 7: A View of the Cell
7.3 Eukaryotic Cell
Structure
Section 7.3
Inside This Section...
Cellular Boundaries
The Organelles
Support And Locomotion
Section 7.3
Cellular Boundaries
Plasma membrane surrounds the cell
In plants, fungi, most bacteria and
some protists, the cell wall surrounds
the plasma membrane
Section 7.3
Cellular Boundaries
Cell Wall
Fairly rigid
Provides support and protection
Made up of the carbohydrate
cellulose
Has pores to allow molecules
through
Section 7.3
The Nucleus and Cell Control
The Nucleus is the leader of the
cell
Gives directions for the making of
proteins
The master set of directions is in
chromatin
During cell division, chromatin
condenses to form chromosomes.
Section 7.3
The Nucleus and Cell Control
Inside the nucleus there is also the
nucleolus
Makes ribosomes
Ribosomes are sites where
proteins and other enzymes are
made, according to instructions
from DNA
Section 7.3
The Nucleus and Cell Control
The Nuclear envelope is a double
membrane that surrounds the
nucleus.
Made up of 2 phospholipid
bilayers
Contains small nuclear pores
Section 7.3
The Cytoplasm
• The Fluid
inside the
Cell
Section 7.3
Assembly and Transport
The endoplasmic reticulum: A
series of highly folded
membranes
Where cellular chemical
reactions take place
Like a large workspace
Section 7.3
Assembly and Transport
Some parts have ribosomes
attached (rough endoplasmic
reticulum - RER)
Others don’t (smooth
endoplasmic reticulum –
SER)
Section 7.3
Assembly and Transport
RER: Proteins made in the
RER may:
form part of the plasma
membrane
be released from the cell
transported to other
organelles
Section 7.3
Assembly and Transport
SER: involved in production
and storage of lipids.
Section 7.3
Assembly and Transport
The Golgi apparatus: flattened
system of tubular membranes and
vesicles
Modifies proteins
Sorts and packages proteins
It’s kind of like the post office:
Sorts the mail and sends it to the
right place
Section 7.3
Vacuoles
A vacuole is a sac surrounded by membrane
Used for temporary storage of
Food
Enzymes
Waste
Plant cells usually have one large vacuole, animal cells have
many smaller ones
Section 7.3
Vacuoles
Section 7.3
Lysosomes and Recycling
Lysosomes are organelles that contain digestive enzymes
They digest food particles, organelles and engulfed viruses or
bacteria
Can fuse with vacuoles and digest the contents.
Can also digest cells that contain them.
i.e. tadpole’s tail
Section 7.3
Energy Transformers
For all the cellular processes to happen, energy is
needed
Two organelles provide that energy:
Choloroplasts (in plants)
Mitochondria (in animals and plants)
Section 7.3
Chloroplasts
Chloroplasts are organelles that
captures light energy and produces
food to store for later
Has a double membrane (like the
nucleus)
The inner membrane folds in to form
stacks of membranous sacs called
grana/thylakoids.
Section 7.3
Chloroplasts
In the thylakoid membrane there is
the green pigment called
Chlorophyll
Traps light energy
Gives leaves and stems their green
color
Section 7.3
Mitochondria
Mitochondria produces
energy in a form that can be
used by the cell when
necessary.
Has an outer membrane and
a highly folded inner
membrane.
Provides large surface area.
Section 7.3
Support and Locomotion
Cytoskeleton: forms the framework
of the cell
Maintains shape
Composed of:
Microtubules: thin hollow
cylinders made of protein
Microfilaments: thin, solid protein
fibers
Section 7.3
Support and Locomotion
Cilia and flagella : Structures that aid in
locomotion and feeding.
Composed of pairs of microtubules, with
a central pair surrounded by 9 additional
pairs.
Cilia are short, numerous, hair-like
projections that move in a wavelike
motion
Flagella are longer projections, move in
a whip-like motion.
Section 7.3
In Review...
Cellular Boundaries
The Organelles
Support And Locomotion