microscopes & cells
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Microscopes & Cells
Microscopes and Cells: History• In 1663, __________
coined the term “cells”• 10 years later,
_________________ observed bacteria and protozoa
• In 1833, __________ observed and coined the term “nucleus”
Robert Hooke
Anton van Leeuwenhoek
Robert Browne
Don’t copy down this slide – just listen
Cell Theory: History
• In 1838 (and 1839) German scientists, ________________ & ________________ independently came up with the “Cell Theory”
Matthias Schleiden
Theodore Schwann
Guten Tag, Dr. Shwann
Guten Tag, Dr. Schleiden
It appears we have come up with a very similar
theory…What shall we call this
theory?
Cell Theory
1. All living things are composed of one or more cells.
2. Cells are organisms' basic units of structure and function.
3. Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation).
• In 1855, German physician Rudolph Virchow discovered that…
all cells must come from pre-existing
cells.
Please add the above as point #4 to the cell theory
How big are cells?• Eukaryotic cells include
_______ & _______ cells.• Most eukaryotic cells are
between __ and ___ m.• What is the limit of the
light microscope? • Why?
• What is used to see smaller objects? __________________
plant animal
10 100
Electron Microscopes
0.2 mIt is limited to the
visible light spectrum
Electron Microscopy
• ___________ Electron Microscopes (TEM) emit light through a thin piece of heavy metal ion stained tissue
• ________ Electron Microscopes (SEM) reflect light off of a piece of heavy metal ion stained tissue
Transmission
Scanning
Prokaryotic Cells (cells without a nucleus) for ex. bacteria
DNA (Nucleoid)
Ribosomes
Plasma Membrane
FlagellumFlagella
Cytoplasm
TEM of a bacterium
CiliumCilia
Label this diagram in your handout
Eukaryotic Cells (cells with a nucleus)
Eukaryotic cells include both plants and animal cells
Plant cell
Animal cell
Differences and similarities between Prokaryotes and Eukaryotes
DifferencesProkaryotes lack:1.True nucleus2.Membrane bound organellesProkaryotes are much smaller than eukaryotes (prokaryotes are ~1 – 10 m and eukaryotes are 10 – 100 m )
SimilaritiesBoth have:1. DNA2. Cytoplasm3. Ribosomes4. Plasma Membrane
The Plasma Membrane(in all cells)
• It is a semi-permeable barrier that allows for the passage of some things based upon ______, _______, and _____________.size charges
solubility in fat
• Fingerlike-projections from the cell’s membrane that increase the surface area.
Plasma Membrane’s Microvilli
Cell Wall(in plant cells and prokaryotic cells)
• Surrounding the , this 1. provides support2. protectsplant cells and prokaryotes
cell membrane
Cytoplasm(in all cells)
• The jelly-like fluid that holds all organelles within the cell
• Hair-like projections that aide in movement
• Cilia are shorter, more numerous and move back & forth
• Flagella are longer & move in a snake-like motion.
Cilia and Flagella (in all cells)
Nucleus and nucleolus(in eukaryotic cells)
• _________make ribosomes here:
• Nucleus holdsDNA wrappedaround proteins that form ________
• ____________, allow things to pass into and out of the nucleus
SEM of a freeze-fractured nuclear membrane
TEM of nuclear pores
Nucleolus
chromatinNuclear pores
Ribosomes: (in all cells)
Function in
TEM of ribosomes
Free ribosomes
Attached ribosomes(on ER)
protein synthesis (formation)
Ribosome unit
1.Proteins made by free ribosomes stay in the cell
2.Proteins made by attached ribosomes are shipped out of the cell or sent to the membrane
Endoplasmic Reticulum(in eukaryotic cells)
There are two types:1. ER has
ribosomes attached.• Modifies & transports
proteins2. ER does not
have ribosomes on it.• Makes • Breaks down carbohydrates• Detoxifies drugs & poisons
Rough
Smooth
lipids (fat)
Vesicles (in eukaryotic cells)
Organelles that transport proteins from the ER to the golgi and eventually to the plasma membrane
Golgi Apparatus (in eukaryotic cells)
_______ carrying protein from the ER move here.It sorts, packages, and ships these proteins outside the cell or to the membrane.
Vesicles
Mitochondria (in eukaryotic cells)
takes place here.It is the “____________” of the cell because it creates
energy using oxygen.
Cellular Respirationpowerhouse
Chloroplasts (in plant cells)
• This changes energy from the sun into chemical energy (sugar)
in a process is calledphotosynthesis
The Cytoskeleton (in all cells)
3 types: microtubules, microfilaments, and intermediate filaments
2. Moves the organelles within the cell and helps move flagella/cilia
Organelle
The Cytoskeleton (in all cells)
1. Provides shape and support (skeletal)
Centrosome (in eukaryotic cells) and Centrioles (in animal cells only)
• Centrosomes make microtubules (cytoskeleton).• In animal cells, a pair of structures called
(made of microtubules) help in cell division.centrioles
centrioles
Centrosome(halo)
Lysosomes (in animal cells)
• Special vacuole in animal cells with _________ enzymes that help clean-up the cell
digestive Lysosome engulfing a worn-out organelle
Vacuoles (in eukaryotic cells)
• Large, central organelle in plants
• Stores water and waste products
• In animals, it stores food and is small in size compared to plant vacuoles
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