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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.
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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
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 Prokaryotic vs. 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
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 • Amyloplasts - 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