Part 1

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

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…

I do believe that all cells must come from pre-

existing cells.

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 m

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

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)

Similarities

Both have:

1. DNA

2. Cytoplasm

3. Ribosomes

4. Plasma Membrane

Part 2

Eukaryotic Cells (cells with a nucleus)

Comparing and Contrasting

Organelles in Eukaryotic Cells

The Plasma Membrane

TEM of a red blood cell

Hydrophilic Region

Hydrophilic Region

Hydrophobic Region

Phospholipid

Proteins

Carbohydrate side chains

The Plasma Membrane

• It is a semi-permeable barrier that allows for the passage of certain things based upon ______, _______, and _____________.

• What are the forms of transport across a cell membrane?

H2O used by cell for Respiration

size chargessolubility in fat

• Fingerlike-projections from the cell’s surface that increase the surface area.

Microvilli

Intermediate Filaments

Microfilaments

Plasma Membrane’s Microvilli

Cell Wall• Surrounding the , this

feature does the following for plant cells:1. Provides Support

2. Provides Protection

cell membrane

Cytoplasm

• The jelly-like fluid that holds all organelles within the cell

Nucleus and nucleolus

• Ribosomes are made here:

• DNA andproteins

are found in the nucleus• Openings in the

nuclear membrane

SEM of a freeze-fractured nuclear membrane

TEM of nuclear pores

nucleolus

chromatin

Nuclear pores

Ribosomes: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

There are two types:1. ER has

ribosomes attached.• Modifies & transports

proteins

2. ER does not have ribosomes on it.

• Synthesizes • Breaks down carbohydrates• Detoxifies drugs & poisons

Rough

Smooth

lipids

Golgi ApparatusER products move here in

It is the center of Warehousing, Sorting and Shipping of Proteins

vesicles

Vesicles

Membrane-bound organelles that transports materials from the ER to the golgi

Mitochondria

takes place in this organelle.

It is often called the “ “ of the cell.

Cellular Respirationpowerhouse

Chloroplasts

• An organelle that converts energy from the sun into chemical energy

The process is called:Photosynthesis

The Cytoskeleton

• A network of fibers that extend throughout the cytoplasm

• Three types:

Microtubules

Microfilaments

Intermediate

Filaments

Cytoskeleton: Functions

1. Provides shape and support

2. Moves the cell and organelles

3. Regulates biochemical activities in cell

Organelle

Centrosome

• Microtubules grow out of this structure• In animal cells, a pair of structures called

(made of microtubules) help in celldivision.

centrioles

centrioles

centrosome

Cilia and Flagella

• Cellular projections that aide in movement

• Flagella are longer & move in a snake-like motion.

• Cilia are shorter, more numerous and move back & forth

Lysosomes

• Membrane-bound organelle that contains

enzymesdigestive

Lysosome engulfing a peroxisome and a

mitochondria

Vacuoles

• Large, central organelle in plants

• Stores water and waste products

• In animals, it stores food and is small compared plant vacuoles

• Protists have a Contractile Vacuole