Do Now

• What are cells?

• Why do we need them?

• List different types of cells that you know of…

Objective

• Describe how cells were discovered and named.

• Identify the scientists that discovered and observed cells.

• List the 3 parts of the cell theory.

LETS CELLEBRATE!

Chapter 1

What are Cells?

a) Basic structural and functional unit of all living organisms!

b) They come in all shapes and sizes

Lets take a look…

How were they discovered?

a) The light microscope led to the discovery of cells.

Who discovered cells?

i. Observed dead cork cells.

ii. Said boxes looked like tiny rooms or cells, that is where they get their name.

iii. Used a microscope at 30x magnification

Who discovered cells?

i. Observed pond water.

ii. 1st to observe living cells.

iii. Used a microscope at 300x magnification

But WHERE do they come from????

Hmmmm…

What happens when you leave meat out?

Fransisco Redi Experiment

He placed meat in both an open container, and a closed container to see what happened…

Redi’s Conclusion…

-Maggots come from FLIES, not meat.

-Life must come from life, not spontaneous generation right?

-Nobody believed him!

Where do cells come from?

i. Discovered that cells must come from other cells.

ii. He disproved the theory of “spontaneous generation”- theory that life can just appear out of nowhere.

Pasteur’s Experiment

Pasteur’s Experiment

• Control group-

• Experimental group-

Pasteur’s Results

• flask that was exposed to the air contained bacteria in it from the air. Flask that wasn’t exposed did not contain anything. The cells must come from living things in the air!!

Pasteurization

*Pasteur came up with the idea of Pasteurization after discovering bacteria could contaminate milk from the air. This process kills the bacteria so that it does not harm us!

Cell Theory!

Cells come only from other living cells. Every living

thing is made of 1 or more cells. Cells carry out

the functions needed to support life.

Do Now

• When you drew your slides in lab, were they in 3D?

• What would be the benefit of seeing something in 3D?

• Could you see through the specimens that you were looking at?

• Why might this be beneficial?

Objective

• Compare and contrast a scanning electron microscope vs. a transmission electron microscope.

• Describe prokaryotic and eukaryotic cells.

Section 1.2 - MICROSCOPES

• How small are cells?– We use micrometers

(μm )= 1 millionth of a meter!

– Range from 1 μm to 1000 μm

Types of Microscopes

A) Compound Light Microscrope (LM)

B) Scanning electron microscope (SEM)

C) Transmission electron microscope (TEM)

Compound Light Microscope

i. Uses lightii. Thin specimeniii. Total

magnification = 40x-100x

iv. Used to see cells, but not organelles inside

Scanning Electron Microscope(SEM)

i. Uses electrons that bounce off the specimen

ii. 3-D image, must be dead

iii. Specimen is coated in metal

iv. Total magnification= 100,000x

v. See details of OUTSIDE of cell, cell membrane and cilia.

Transmission Electron Microscope (TEM)

i. Uses electrons to deflect through specimen

ii. Thin specimen

iii. Total magnification= 300,000x

iv. Allows us to see organelles INSIDE cell.

Prokaryotes vs. Eukaryotes

What do you notice that is different between these 2 cells?

Prokaryotic Cells

i. Have circular DNA

ii. NO nucleus

iii. Doesn’t have membrane-bound organelles

iv. Most unicellular organisms are prokaryotes

Example: Bacteria

Eukaryotic Cells

i. Have linear DNA that is in a double helix shape.

ii. Has a nucleus.

iii. Have membrane-bound organelles.

iv. Mostly multicellular although there are some unicellular eukaryotes

Multicellular Eukaryote

Unicellular Eukaryote

Where did these cells come from?

Scientist: Lynn Margulis

Theory: organelles in eukaryotic cells were once

prokaryotes that were engulfed!

Theory= EVIDENCE!!

i. Mitochondria have circular DNA like bacteria

ii. Replicates (reproduces) like bacteria separate from the host cell

iii. Mitochondria make their own proteinsiv. Mitochondria have two membranes

(one from the host cell and one from their own cell membrane)