class warm-up what do you already know about cells?
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Class Warm-Up
WHAT DO YOU ALREADY KNOW ABOUT CELLS?
Chapter 7.1 Life is Cellular
Cell Structure and Function
The Discovery of the CellRobert Hooke
1665EnglishmanLooked at a slice of cork (plant material) under an early microscope
Found the cork was made up of thousands of small chambers
He called these chambers “cells”
The Discovery of the CellAnton von Leeuwenhoek
1674 Holland, The NetherlandsConsidered to be the “Father of
Microbiology”First to observe living microorganisms using a microscope
BacteriaProtists
Microscopes Over the Ages
Co-Founders of The Cell Theory
Matthias Schleiden, Botanist, 1837All plants are made of cells.
Theodor Schwann, Physiologist, 1838All animals are made of cells
Rudolf Virchow, 1858All cells are made from the division of existing cells
The Discovery of the Cell
The Cell Theory1. All living things are made up of cells.2. Cells are the basic units of structure
and function in living things.3. New cells are produced from existing
cells.
Cells – the basic unit of life
Class Warm-Up
"an unbelievably great company of living animalcules, a-swimming more nimbly than any I had ever seen up to this time. The biggest sort. . . bent their body into curves in going forwards. . . Moreover, the other animalcules were in such enormous numbers, that all the water. . . seemed to be alive."
Which scientist that we discussed yesterday would have said this? How do you know?
CLASS WARM UpWhich Cells are prokaryotic and
which are Eukaryotic? How do you Know?
‘
Cheek Cells
(Bacteria)
Elodea Cells
Onion Cells
400x
400x
400x
Eukaryotic Prokaryotic(Plant & Animal)
Compound Light MicroscopeUse lenses to magnify the
image of an object by focusing light
Cell structures as small as 1 millionth of a meter
Magnification up to 2,000xClassroom microscopes go up
to 400x
How Big? Animation
Exploring the CellWhy are chemical stains/dyes used in
microscopy?Most living cells are nearly transparent Stains allow the cells to be seen under the
microscopeSome reveal only certain compounds and
structures within the cellFluorescent dyes
Different colors attached to different moleculesAllows scientists to observe how materials move throughout the cell
Dissecting MicroscopeAlso referred to as the stereo
microscope designed for low magnification
observation of a sample, typically using light reflected from the surface of an object rather than transmitted through it.
3D imagesused to study the surfaces of solid
specimens or to carry out close work such as dissection, microsurgery, watch-making, and circuit board manufacture or inspection
Electron Microscopes2 types: Transmission (TEM) and
Scanning (SEM)Used for viewing NON-LIVING cells and
organisms onlySends an electron beam through a
vacuum to illuminate a specimen and produce a magnified image
Smaller cell structures as small as 1 billionth of a meterDNAProtein moleculesViruses
SEM vs. TEMSEM (Scanning Electron Microscope)3D imagesup to 200,000x magnifiedfocuses the electron beam to a very small point on the sample and scans over the sample to produce an image
TEM (Transmission Electron Microscope)sends an electron beam through a thin sample, projecting an image on a fluorescent screenCannot view the surface of specimensUp to 50 million times magnified
Cool Electron Microscope Images
Types of CellsProkaryotic Cells
– cells that do not contain a nucleus
Eukaryotic Cells – cells that contain a nucleus
Nucleus – a large membrane-bound structure that contains genetic material (DNA) and controls many of the cell’s activities
A B
Prokaryotes Eukaryotes Both
•No nucleus
•Smaller and simpler cells
•No membrane bound organelles
•Most primitive form of life on Earth
Example: Bacteria
•Nucleus
•Larger and more complex cells
•Have membrane bound organelles
Examples:•Plants•Animals•Fungi•Protists – single celled (unicellular) organisms
•Cell membrane
•DNA
•Ribosomes
•Cytoplasm
•Cytoskeleton
WOW!!! One cell has 2 meters of DNA.If all the DNA in your body was put end
to end, it would reach to the sun and back over 600 times!
Your body has about 75-100 trillion cells!90% of those cells are bacteria cells!!They can live as short as a day to as long as a
year!
Formative AssessmentLearning GoalsExplain the 3 parts of the cell theory.
Describe the differences, similarities and evolutionary links between prokaryotic and eukaryotic cells.
Which of the following statements are true?
1 2 3 4
4%
96%
0%0%
1. All living things are made up of cells
2. Cells are the basic unit of structure and function
3. New cells are produced from existing cells
4. All of the above
What is a membrane bound structure that contains genetic material and controls many of the cell’s activities?
1 2 3 4
0%
16%
76%
8%
1. Prokaryote2. Eukaryote3. Nucleus4. Cell membrane
Which of the following cells do not contain a nucleus?
1 2 3
0%
84%
16%
1. Animal cell2. Plant cell3. Bacterial cell
Both prokaryotes and eukaryotes
1 2 3 4
4%0%
16%
80%1. have a nucleus2. have DNA3. have membrane
bound organelles
4. are the same size
True or false? Eukaryotes are cells that do not have a nucleus.
1 2
100%
0%
1. True2. False
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