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Unit One
Matter and Energy for Life
Historical Development Cell Theory
• Biology is “the study of life”.
• Living things are composed of individual units
called cells.
Cell
• the basic unit of structure and function
•
smallest unit capable of displaying
characteristics of life
•
the human body is made up of trillions of cells
and every one carries out the same life
processes as a single-celled organism.
Cell biologists
• early cell biologists paved the way for cell
study
• they each built on previous knowledge,
modified techniques and changed the way
science viewed the origins of life
• i.e. a paradigm shift occurred
• a paradigm shift is a rare but significant
change in how we view the world
• often controversial when first proposed but
becomes accepted as a major advance in
scientific knowledge/understanding.
• have discovered the cell theory
Obj. 1 Cell Theory
Four hypotheses include:
• All living things are composed of one or more
cells.
• Cells are the basic units of structure and function
in all organisms.
• All cells are derived from pre-existing cells.
• In a multicellular organism, the activity of the
entire organism depends on the total activity of
its independent cells.
Obj 2
• The idea that life arises from life is called
biogenesis.
• Prior to the cell theory, (late 19th century), many
people believed that small living organisms could
arise suddenly from non-living or once-living
things.
• This idea was known as spontaneous generation,
later renamed abiogenesis by Thomas Huxley.
Objective 3, 5, & 6
Scientist contributions:
• Read: Chapter 1, p 7-10 and handout.
• (Significant Events in Biological history, related
to the Cell Theory)
• Activity – Jigsaw for Obj. 3
Aristotle
• 384-322 B.C.E.
• Greek philosopher and scholar
• Answers through observations,
not experiments
• 2 kingdoms – plants and
animals
• Organisms arise spontaneously
from non-living matter ** supported abiogenesis
Francesco Redi
• Mid 1600’s
• Used decaying meat to disprove abiogenesis
• When meat was left in open containers, maggots would form
on the meat.
• Redi hypothesized that the maggots came from eggs laid by
flies
• When meat was put in closed containers, no maggots formed
– it was argued it needed air
• When meat containers were covered with gauze, maggots
appeared on gauze where flies were.
• People weren’t convinced.
Needham
• John Needham (English) - supports
abiogenesis
• 1745 - boiled flasks of chicken, lamb and
corn broth for a few minutes and then
sealed container
• after several days observed many micro
organisms reinforcing the idea of
spontaneous generation
Spallanzani
• Lorenzo Spallanzi (Italy) supports biogenesis
• 1765 - Claimed Needham
did not boil broth for long
enough, so boiled it much
longer to kill all micro
organisms
• argument was that he
boiled it too long, thus
destroying "vital principle"
contained in the air.
Pasteur
• Louis Pasteur (France)
• 1860 - Disproved Spontaneous generation by
bending the neck of flask into an S shape and
put nutrient broth in them and boiled them
• Fresh air could reach broth, but organisms and
their spores were trapped in the long necks
Obj. 6
Explain the contributions of :
•
Hooke - had illustrations of lining of dead tree bark viewed under compound
microscope; named the ‘cell’
•
Leeuwenhoek - Created the best compound microscope at the time (~1666) with
his exceptional lens making ability (6X stronger); examined plaque from his teeth
(and his family’s), marking the discovery of bacteria.
•
Schleiden – 1838 – “all plants are made of cells”
•
Schwan – 1839 – “all animals are made of cells”
•
Virchow - states that cells compose all other components of the body (tissues,
organs, systems, etc), and that cells came from previous cells. P. 10
•
Brown - observed that cells have a darker region (nucleus) near the centre
•
Braun ( 1805 – 1872) wrote “The cell is the basic unit of life”
Obj. 8
The Microscope: (Pg 12-22)
• The microscope permitted scientists to discover
the existence of cells in that:
• it was a tool with such a great resolving power
(the ability to distinguish between small objects
close together) that it allowed people to view
things that had been too small to see,
• lenses had distorted images (color aberrations
and blurry images); improvements in glass
making and lens grinding removed the distortion
effects.
Obj. 10
Microscopes (Two types:)
1. Light - light energy is passed through the
specimen to allow the image to be viewed
• glass lenses are used to magnify the image
• resolution is commonly -> 1000x
• two kinds of light microscopes are:
• (a) simple -> one lens eg. magnifying glass
• (b) compound -> two or more lenses
(commonly used in labs)
Handout – label light microscope & handout – using the microscope, prelab exercise
Obj. 10
2. Electron
• a flow of electrons are used (instead of light)
• magnetic lenses are used to focus the
electrons
• resolution is commonly -> 50 000x
• (new model can magnify image 500 000x
showing molecular structure!)
Obj. 10
Two types of electron microscopes:
(a) scanning electron microscopes, (SEM)
• scan the surface of a specimen showing details
of the outside (ex. picture of an orange)
(b) transmission electron microscope, (TEM)
• take slices of the specimen to show the inner
structures (ex. orange slice)
• Light microscopes are good for most
microscope work and are less expensive.
• electron microscopes are sometimes chosen
over the light microscope because objects can
be seen more clearly (better resolution), and
magnification is greater.
Which is which?
Transmission electron microscope
Scanning electron microscope
Videos showing “How to Use” a
microscope:
Microscope part 1/3
• http://www.youtube.com/watch?v=oUsJfttUZ_w&feature=related&
safety_mode=true&persist_safety_mode=1&safe=active
Microscope part 2/3
• http://www.youtube.com/watch?v=AEzzTCRRlEE&NR=1&safety_m
ode=true&persist_safety_mode=1&safe=active
Microscope part 3/3
• http://www.youtube.com/watch?v=btjyDha4II0&feature=related&s
afety_mode=true&persist_safety_mode=1&safe=active
Field of View
Low power: measure using ruler
Medium power FOV =
low power FOV X
Magnification of low-power objective
Magnification of medium power obj.
Example: If low power field of view is 3mm, calculate medium and
high power field of views.
Medium power FOV = 3mm X
4
10
= 3mm X 0.4
= 1.2mm
high power FOV =
low power FOV X Magnification of low-power objective
Magnification of high power objective
= 3mm X
4
40
= 3mm X 0.1
= 0.3 mm
Convert field of view from mm to
micrometres (µm)
• 1mm = 1000µm
• 1um = 0.001 mm
So…..
• Low power FOV in µm
= 3 * 1000 = 3000µm
• Medium power FOV in µm = 1.2 *1000 = 1200µm
• High Power FOV in µm
= 0.3 *1000 = 300µm
Cells may be classified as either:
Prokaryotes
Eukaryotes
eg. bacteria, *archaea
eg. plants, animals, fungi, protists
smaller in size
larger in size
less complex structures
more complex structures
no nucleus
- has a concentrated area called
nucleoid
has a nucleus and contains membrane-bound
*organelles
a
* archaea - live in extreme environments (extreme heat in volcanoes, acid, salt, eg.
in Dead Sea)
* organelles - highly specialized structures that have certain functions (jobs) to do.
- work together as a team to carry out cell processes and the work tasks of the cell.
eg. making proteins, packaging, transport, etc.
Cell Organelles and Their Functions.
• - Referring to pages 25-30 in your text,
complete the table of the cell organelles
(handout).
Plant vs. Animal Cell Characteristics
• Most of the organelles found in animal cells
are also found in plant cells ( eg.
mitochondria, ribosomes, nucleus, etc.), but
there are some differences
Animal Cells
Only
1. centrioles
2. lysosomes
Plant Cells Only
1. Cell wall
- in addition to the cell membrane, a thick outer cell wall gives
strength and support to cells. eg. it allows a blade of grass to stand tall.
2. Plastids
- double membrane sacs that may be:
(a) chloroplasts
- contain green coloring pigment, chlorophyl, that traps solar energy
in photosynthesis to make food.
3. Large central vacuole
Note:
Animal cells have small vacuoles and a variety of shapes.
Plant cells have large vacuoles and shapes tend to be
geometrical
eg. rectangular (onion skin - later in the lab!)
Interactive Websites to Teach Cell
Organelles and Functions:
1)
Drag the name of the cell to the part in the diagram (Excellent for recognizing
parts of cell in diagram)
http://www.mrphome.net/mrp/CellPartsDragandDropres/frame.htm
2)
Interactive cell structure game:
http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_struct
ure/cell_structure.htm
3)
Eucaryotic Cell Organelle Identification (pretty neat) http://www.wisconline.com/Objects/ViewObject.aspx?ID=ap11604
4)
Drag and Drop cell organelles (Names) to match their function (good activity)
http://www.execulink.com/~ekimmel/drag_gr11/organell.htm
5)
Inside a Cell: http://learn.genetics.utah.edu/content/begin/cells/insideacell/
video clips on parts of the cell
Cell Videos
https://www.youtube.com/watch?v=1Z9pqST72is – Mr.
Anderson – A tour of the cell (15 mins)
https://www.youtube.com/watch?v=URUJD5NEXC8
• Sites for Biology 2201 Microscope
Preparation: Lab #2
• How to prepare a wet mount Slide:
• https://vimeo.com/28981480 (3:30)
• Preparing wet mount slides and staining:
http://vimeo.com/11687298 (4:38)
Rules for Drawing Biological Sketches
(pg. 17 & 18)
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Give a title (at bottom of page).
Use 1/4 - 1/3 of the page to draw two or three cells.
Indicator lines are to be drawn to the right of the sketch.
All indicator lines end parallel to each other and in the
same vertical plane.
Label in capital letters and PRINT!
Use pencil.
No shading! For texture or depth, stipple only ( use pencil
to make dots).
Give magnification (at bottom of sketch). eg. Mag. 400x
Give estimated size (when required), ie. Length x width
Label fully.
Practice drawing a cell properly
Retained much?
Biology 2201 Lab #2 - Animal and
Plant Cell Lab
Here are the web sites for the lab.
• The first part is done in the lab (making wet mount) then the drawing of human blood,
frog blood, cheek cells, etc... can be put up on the smartboard and done as a class.
Animal Cells:
• Red Blood Cell:
http://www.mc.vanderbilt.edu/histology/labmanual2002/labsection2/Blood_hematop
oiesis03_files/image002.jpg
• Frog Blood Cell: http://phs.psdr3.org/science/forensics/images/blood/frogblood.jpg
• Human Cheek Cell:
http://schoolworkhelper.net/wp_content/uploads/2011/02/cheekcell.jpg
Note:
• Only draw 3 or 4 cells for the human blood cell, frog blood and the cheek in the field of
view. Don’t forget to label them.
.
Biology 2201 Lab #2 - Animal and
Plant Cell Lab
Plant Cell:
• Onion Cell for #8 - Proper Biological Drawing
http://faculty.ntcc.edu/mhearron/onionep1.jpg
• Lettuce Cells:
http://www.bing.com/images/search?q=lettuce+cells+under+micro
scope&view=detail&id=3E0C7440616EA237FBC0745B5B2AF796724
C5547&FORM=IDFRIR&adlt=strict
Note:
• For your proper biological drawing of the onion, you are only
drawing one onion cell lengthwise on a blank sheet of paper. Follow
the guidelines you were given on your handout
Lab #2
• Complete questions 1 & 2 before the lab
• Read the lab worksheet so you will know the
things you will be doing in tomorrow’s lab
• Bring your ‘prepare a wet mount’ handout
with you
• Highlight any areas that you have questions
about
Lab #2
• Your first two questions should be answered
before entering the lab
• You need ‘prepare a wet mount’ and ‘make a
drawing’ sheets
• You have to make your onion and lettuce
slides, and do those sketches TODAY
• If time, continue on after those are done with
the rest of the lab
Onion Cell
Lettuce cells
Human Red Blood Cells
Frog Blood Cells
Cheek Epithelial Cells
Cell Analogy
• Compare the cell and 8 organelles to the
running of a school.
• i.e., cytoplasm – the inner air space of the
school.
Cell analogy C slot
• Cell membrane – school walls – allows things in
and out of the building
• Nucleus – office – responsible for containing
information used by the cell/building.
• Vacuole – lockers – store items used in the
cell/building
• Mitochondria – panel box – energy used by the
cell/building
• Nuclear pore – office door – allows things in and
out of nucleus/office
Cell analogy – C slot
• ER – classroom – where things/ideas are put together
• Lysosome – janitor - breaks down worn out/ used parts
of the cell/school
• Chromatin – records/transcripts – contains important
information for the cell/students
• Chloroplasts – cafeteria workers – make food used by
the cell/students
• Cytoskeleton – inside walls of school – supports
structure of cell/building
• Nucleolus – Kearley’s office – section of the
nucleus/office responsible for proteins/decisions on
structure of the building
Cell analogy – D slot
• Cell membrane- exterior walls/doors/windows of
building that allows things in and out of the
cell/building
• Cytoskeleton – interior walls – keeps the
structure/shape of the cell/building
• Vesicles – book bag – allows stored substances to
be moved throughout the cell/school
• Nucleus – office – main control centre for the
cell/building
• Cell wall – parking lot – allows things on and off
the premises without needing permission.
Cell analogy – D slot
• Cafeteria - Golgi – putting together ingredients
used by cell/students
• Nuclear pore – office door – allows things in and
out of the nucleus/office
• Lysosome – janitors – takes care of anything the
cell/school no longer needs
• Mitochondria – panel box – generates the energy
for the cell/school
• Chromatin – files/documents - pertaining to
students in the school
Careers in Biological Sciences
• Using your mobile device (or pair up with
someone who has one) Google three
professions in the Biological Sciences (jobs
related to Biology)
• If you do not have a device (and no partner),
brainstorm a couple of examples that you
know off-hand
Careers – C slot
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Neurologist
Biotechnology
Microbiologist
Biochemist
Marine biologist
Oncology
Biology teacher
Vet
Pharmacologist
Research
•Clinical director
•Soil scientist
•DNA Analyst
•Doctor
•Health professional
•Plant physiologist
•Orthodontist
•Botanist
•Anesthesiologist
Professions
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Health Care
Education
Research
Museums/Zoos/Nature Parks
Biotechnology
Forensic Science
http://carleton.ca/biology/prospectivestudents/undergraduate/biology-careers/