Download Biology I 10/18/12

Biology I
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10/18/12
HW: Cell Theory – Write & Restate
Take out 7.1 Reading Guide
CHAPTER 7
CELL STRUCTURE & FUNCTION
Objectives
Explain what the cell theory is.
 Describe how researchers explore the living
cell.
 Distinguish between eukaryotes and
prokaryotes.
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7.1 Life is Cellular
Cells are the basic structural and functional
units of life.
 They differ in structure and complexity
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This idea is relatively new
 Microscopes
were first used around mid-1600’s
 The invention of microscopes made the discovery of the
cell possible
Robert Hooke
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In 1665, Robert Hooke used
an early compound
microscope to look at cork
Observed that cork was
made up of 1000’s of
hollow chambers
Dubbed them cells since they
looked like the monastery’s
tiny rooms called “cellula”.
Anton van Leeuwenhoek
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Late 1600’s- Dutch textile
salesman
Created different types of
microscopes
Observed pondwater and
found living organisms
Discovered over 5,000 types
of microscopic life
Lenses were able to magnify
up to 300X
The Cell Theory
A fundamental concept: a summary of confirmed
discoveries
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Cells are the most basic unit and structure of life
All living things are made up of cells
New cells are produced from existing cells
More Discoveries
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1839 – German biologists Matthias Schleidan &
Theodor Schwann
 proposed
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that all organisms are made of cells.
1855 – German physician Rudolf Virchow
 Proposed
that all cells produce more cells through time
Exploring The Cell
Three major types of microscopes
1. Light Microscope
 Magnifies 40-1,000 times
 Used to magnify objects that
light can pass through
 Uses slides
2. Electron Microscopes - Uses electrons to illuminate objects
 Magnifies from 30,000 to 9 million times
 Two types
 Transmission –
Beam of e- pass through thin slice
 Images are 2-D
 Useful to study internal cell structures, large proteins
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 Scanning
– beam of e- scan over surface
3-D images
 Useful to study external structure
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Can only be used to look at dead specimens
3. Scanning Probe
Microscopes
 Traces surface of
sample with a probe
 View single atoms,
DNA, protein
molecules
 Can view living things
Cells
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Cells come in a variety of shapes
Range in size from microscopic bacteria to giant
amoeba
Mycoplasma
pneumoniae
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Chaos carolinensis –
Giant amoeba,
approximately 1mm in
length
All cells have a cell membrane – outer flexible
barrier
All cells have (or had) DNA
Cells
Cell
membrane
Nucleuscontaining
DNA
2 Main categories of cells
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Eukaryotes- have cells that enclose their DNA in a nucleus
Prokaryotes- cells that do not enclose their DNA in a nucleus
Nucleus: large,
membrane-bound
structure that
contains the cell’s
genetic material in
the form of DNA
Prokaryotes
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Are generally smaller than eukaryotic cells
Have no nucleus
Carry out all of life’s processes
Ex: bacteria
Bacillus anthracis
Eukaryotes
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Are generally larger and more
complex than prokaryotes
Contain dozens of membrane
bound structures that are
specialized
Nucleus separates DNA from rest
of cell
Come in a variety of shapes and sizes
Ex: protists, fungi, plant, and animal cells
HW: Cell Theory: Write & Restate
1.
2.
3.
4.
Write the 1st part of
the cell theory
Restate the sentence
in your own words
Draw a picture to
describe the
statement
Repeat steps 1-3 for
2nd and 3rd sentences.
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Example:
Write: Each day the
temperature is below
32 degrees.
Restate: It’s freezing
everyday!
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SunDraw:
Mon Tue
Wed Thur Fri
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