THE CELL
Chapter 1
DO NOW
1.1. Do we have eukaryotic
or prokaryotic cells?
Chapter Objectives
•
Differentiate unicellular and multicellular organisms.
•
List the characteristics of life/living things.
•
Identify the scientists that observed and discovered cells.
•
List the 3 parts of the cell theory.
•
Compare light, SEM, and TEM microscopes.
•
Compare prokaryotic vs. eukaryotic cells AND plant vs. animal cells.
•
Explain the term specialization and compare to our bodies.
DO NOW …
• What are cells?
• Name different types of cells you know
of...
• What is a difference between living and
non-living things?
What is a cell?
• Basic structural and
functional unit of all
living organisms!
• They come in different
shapes + sizes
How were cells discovered?
The light
microscope
helped
discover cells!
Who discovered the cell?
ROBERT HOOKE
• Observed dead cork cells
• Said boxes looked like tiny
rooms or jail “cells”.
• Used a microscope at 30x
magnification
Who else discovered the cell?
ANTON VAN LEEUWENHOEK
• Observed pond water
• 1st to observe “living” cells
• Used a microscope at 300x magnification
← Cork cells!
*Cork is from tree bark
(dead cells)
Animalcules ➔
Do you have these recipes at
home?
People thought organisms grew from non-living materials!
Fransisco Redi Experiment
• Placed meat in both an open container and a closed container
to see what happened.
Redi’s Conclusion
•
Maggots come from flies, NOT the meat!
•
Life must come from life, which proved
that spontaneous generation is not
real!
•
People still did not believe him but he
was right.
Louis Pasteur Experiment
•
Showed that bacteria are present in air and do not appear
spontaneously.
Louis Pasteur Conclusions
•
Discovered that cells MUST come from
other cells
•
Disproved “Spontaneous Generation”
and said life cannot just appear out of
no where.
•
Helped verify Redi’s research!
DO NOW
1. Give an example of a multicellular
organism and unicellular organism.
2. What type of cells did Robert Hooke
observe?
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!
•
Used in milk, cheese, yogurt, etc.
• Cell Theory =
• Every living thing is made of one or more
cells
• Cells carry out the functions needed to
support life
• Cells come only from other living cells
Unicellular vs. Multicellular
• Unicellular – a single cell
• Multicellular – made up of many cells
Characteristics of Life
1. Organization
2. The ability to develop and grow
3. The ability to respond to the environment
4. The ability to reproduce
Section 1.2 - Microscopes
How small are cells?
• Unit used =
micrometer (um)
One millionth of a meter
• Most cells range
from 1 um to 1000
um.
Types of Microscopes
1. Light Microscope
2. SEM Microscope
3. TEM Microscope
Light Microscope
• Uses thin light
• Looks at thin specimen
• Total Magnification =
40x-1000x
• Use to see cells, but not
detailed organelles
SEM vs. TEM
SEM
•
•
“Scanning electron
microscope”
TEM
• “Transmission electron
microscope”
Beams of electrons bounce of
• Electrons pass through the
the surface of the coated cell.
think section.
•
Images appear 3D
•
Total Magnification =
100,000x
•
Must be dead ☹. Specimen
coated in metal
• Images appear 2D
• Total Magnification = 300,000x
• Allows us to see organelles
inside the cell
SEM
TEM
Prokaryotic vs. Eukaryotic
cells
What are the differences you can see?
Prokaryotic Cells
• Have circular DNA
• NO nucleus
• Does not have
membrane bound
organelles ex: snow
globe
• Most unicellular
organisms are
prokaryotes
Example: Bacteria
Eukaryotic Cells
• Have linear DNA –
double helix shape
• Has nucleus
• Have membrane bound
organelles
• Most multicellular
organisms are
eukaryotic cells. Some
are unicellular though.
Example: You!
Section 1.3 – cell functions
• 3 domains of life:
• Eukarya – Have a nucleus. Plants, animals, and
fungi.
• Bacteria – prokaryotics.
• Archaea – “ancient”. Genetically different from
bacteria.
Specialization
•Specific cells perform
specific functions.
Ex: Blood cells can only
be blood cells. Muscle
cells cannot be turned into
blood cells.
Tissue and organs
•
Tissue – group of similar cells that are organized to do a
specific job.
•
Organ – different tissues working together to perform a
particular function.
Stem Cells to determine
specialization
•
https://www.youtube.com/watch?v=evH0I7Coc54
DNA
• Rosalind Franklin – used x-rays to produce images of
DNA
• Watson and Crick – put together a 3D model of DNA
and present it to the world in 1953