do now what are cells? why do we need them? list different types of cells that you know of…
TRANSCRIPT
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)