Transcript Tour Of The Cell - BronxPrepAPBiology

Tour Of The Cell
Microscopy
• What is the difference between
magnification and resolving power?
• Magnification is how much larger the
object can now appear.
• Resolving power is the ability to
distinguish between two points, it is
limited by the wavelength of visible light.
The different microscopes:
• Light microscope - resolving power is
limited by the wavelengths of light.
• Specimen should be stained, but can be
alive
– Compound microscope
– stereomicroscope
• Electron microscope - resolving power is
greater since wavelengths of electrons is
smaller than those of light.
– SEM - 3D image
– TEM - flat image
• electron microscopes cannot use live specimens
How did scientists first discover
the different cell parts?
As Organisms Get Larger,
Why do They Become
Multicellular?
It’s all
about
the
surface
area to
volume
ratio!
Prokaryotic vs. Eukaryotic Cells
Prokaytotic cells:
• monerans
• genetic material not in
a nucleus
• no membrane bound
organelles
Eukaryotic cells:
• Protists, Plants, Fungi
and Animals
• true nucleus with
genetic material
• has membrane boun
organelles
The Prokaryotic Cell:
The Plasma Membrane:
General Eukaryotic Cells:
Two Areas of the Eukaryotic
Cell:
• What is the space between the cell
membrane and the nucleus called?
• The cytoplasm. This includes the
organelles and the cytosol.
• The cytosol is the fluid medium found in
the cytoplasm
The
nucleus
Nuclear Components:
• Envelope =
Nuclear Components:
• Envelope = double layered membrane
that has pores for molecular transport.
• Chromatin =
Nuclear Components:
• Envelope = double layered membrane
that has pores for molecular transport.
• Chromatin = DNA + protein complex of
threadlike fibers that make up the
eukaryotic chromosome.
• Chromosome =
Nuclear Components:
• Envelope = double layered membrane
that has pores for molecular transport.
• Chromatin = DNA + protein complex of
threadlike fibers that make up the
eukaryotic chromosome.
• Chromosome = Chromatin fibers
condense into visible chromosomes
during cell division.
Ribosomes:
• Prokaryotic ribosomes differ from eukaryotic ribosomes
• Function =
Ribosomes:
• Prokaryotic ribosomes differ from eukaryotic ribosomes
• Function = Site of Protein synthesis
The Endomembrane system:
• Related through direct continuity or by
transfer on membrane segments
through vesicles.
• Structure of membranes is not identical
• Includes:
• Nuclear envelope --> Endoplasmic
reticulum --> Golgi apparatus -->
lysosomes --> vacuoles -->plasma
membrane
Transport vessicle
from ER
New vessicle
forming
Transport vessicle
from golgi
Function of Golgi:
• Modifies stores and routes products of
ER
• Alters membrane phsopholipids
• Targets products for parts of the cell
Vacuoles
• Larger than vessicles
• food vacuoles =
Vacuoles
• Larger than vessicles
• food vacuoles = formed by phagocytosis
• contractile vacuole =
Vacuoles
• Larger than vessicles
• food vacuoles = formed by phagocytosis
• contractile vacuole = found in fresh
water protozoans, keep water balance
• central vacuole =
Vacuoles
• Larger than vessicles
• food vacuoles = formed by phagocytosis
• contractile vacuole = found in fresh
water protozoans, keep water balance
• central vacuole = found in most plant cells
stores organic compounds, has enzymes
to break macromolecules, has poisonous
and unpalatable compounds,etc...
Mitochondria and Chloroplasts
• Not part of endomembrane system
• their membrane proteinsare made by
free ribosomes and their own ribosomes
• Both have small amount of DNA
• Grow and reproduce on their own within
the cell
• Involved in Energy transformation
Plastids
• Amyplasts - store starch, in roots and
tubers
• chromoplasts - non-chlorophyll
pigments responsible for non-green
colors.
• Chloroplasts - chlorophyll containing
plastids
Peroxisome
• Contains enzymes that transfer hydrogen
from substrates to oxygen, producing
hydrogen peroxide.
• Some use oxygen to fuel the breakdown of
fatty acids to smaller molecules that can be
used in the mitochondrion.
• In liver they detoxify alcohol and other
poisons, by transferring hydrogen from
poison to oxygen
• Hydrogen peroxide is toxic, what enzyme
can be used to break this down?
Cytoskeleton
• Provides
structural
support
• Functions in
motility and
motion
Microtubules
• Cellular support
• provides tracks for movement within the
cell: e.g. transport vessicles
• Composes cilia and flagella, locomotive
appendages of certain cells.
• separation of chromosomes during cell
division (spindle fiber)
• composes centrioles in animal cells
Microfilaments
•
•
•
•
Smaller than microtublues
participates in muscle contraction
support
localized cell contractions
The Cell Surface
• Cell Walls in plant cells
• membrane linked channel plasmodesmata that connects
cytoplasm between cells
Animal Cell Surfaces
• Glycocalyx - strengthens cell surface,
helps glue animal cells together
• tight junctions - holds cells together to
block transport
• desmosomes - rivets cells together into
strong sheets but permits transport
• gap junctions - analogous to
plasmodesmata in plant cells
Let’s Review:
Name the cell structure and its
function.
Be able to tell if this structure is
found in prokaryote, eukaryote,
plant and/or animal cells
Take a
closer
look!