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

Differences

Prokaryotes lack:

1.True nucleus

2.Membrane bound organelles

Prokaryotes are much smaller than eukaryotes (prokaryotes are ~1 – 10 m and eukaryotes are 10 – 100 m )

Similarities

Both have:

1. DNA

2. Cytoplasm

3. Ribosomes

4. 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

proteins

2. 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