Download Chapter 1- CELLS

Chapter 1- CELLS!
Section 1.1
A. What are cells?
a. Basic structural and functional unit of life.
b. Come in all shapes and sizes.
B.How did we discover cells?
a. The microscope led to the discovery of cells.
C.Who discovered cells?
a. Scientist: Robert Hooke
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
b. Scientist: Anton van Leeuwenhoek
i. 1st to observe living cells.
ii. Looked at pond water
iii. Used a microscope at 300x magnification
D.Where do cells come from?
a. Scientist: Fransisco Redi
i. Experiment:
1. Control group- flask with meat uncovered
2. Experimental group- flask with meat with stopper on top
ii. Results- flask that did NOT have the stopper on top produced larva
because flies laid their eggs on the meat. Flask with stopper
contained no maggots.
b. Scientist: Louis Pasteur
i. Discovered- cells must come from other cells.
ii. Disproved theory of “spontaneous generation”
iii. Spontaneous generation: theory that life can just appear out of
nowhere.
iv. Experiment:
1. Control group- flask that was not exposed to air
2. Experimental group- flask exposed to air
3. Results- flask that was exposed to the air contained bacteria
in it from the air. Flask that wasn’t exposed did not contain
anything.
4. Pasteur came up with the idea of ____________________
after discovering bacteria could contaminate milk from the air.
This process kills the bacteria so that it does not harm us!
E. Cell Theory
a. Cells come only from other living cells.
b. Every living thing is made of 1 or more cells.
c. Cells carry out the functions needed to support life.
Chapter 1- CELLS!
Section 1.2A. How small are cells?
a. We use micrometers (μm )= 1 millionth of a meter!
b. Range from 1 μm to 1000 μm
B. Different Types of Microscopes
a. Compound Light Microscope (LM)
i. Uses light
ii. Thin specimen
iii. Total magnification = 40x-100x
iv. Used to see cells, but not organelles inside
b. Scanning Electron Microscrope (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.
c. Transmission Electron Miscroscope (TEM)
i. Uses electrons to deflect through specimen
ii. Thin specimen
iii. Total magnification= 300,000x
iv. Allows us to see organelles INSIDE cell.
C. Prokaryote vs. Eukaryote??
a. Prokaryotes:
i. Have circular DNA
ii. NO nucleus
iii. Doesn’t have membrane-bound organelles
iv. Most unicellular organisms are prokaryotes
1. Example: Bacteria
b. Eukaryotes:
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 (ex:Yeast)
c. Endosymbiont theory
i. Scientist: Lynn Margulis
ii. Theory- eukaryotes came from prokaryotes, Cell
“engulfed” other cells.
iii. Evidence of theory1. Mitochondria have circular DNA like bacteria
2. Replicates (reproduces) like bacteria separate from
the host cell
3. Mitochondria make their own proteins
4. Mitochondria have two membranes (one from the
host cell and one from their own cell membrane)