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Unit 1
Introduction to Biology
What does a
Biologist study???
Biologists study living
and once-living things.
Is it Alive??!!
What does it
mean to be
ALIVE???
http://movieclips.co
m/KzE5Lfrankensteinmovie-its-alive/
Activity – Is it Alive???
• Directions – Part 1
–With a partner, brainstorm to come
up with a list of things that make
something living vs. non-living.
–Record these on your worksheets.
Activity – Is it Alive???
Directions - Part 2:
With a partner, decide if the following items
are:
• Living
• Non-Living
• Or Once-Living
Activity - Items
1. Hard-Boiled Egg
2. Seeds
3. Rocks
4. Mushrooms
5. Leaves
6. Virus
7. Lichen (moss+fungi)
8. Bacteria
9. Water
10.Hair, feathers
What is it?!
What is it?!
Seawater!!!
Magnified 15 times!!!
What makes something living?
1. Made up of 1 or more cells
a. cell = basic unit of life
b. Levels of organization:
cell tissueorgansorgan systems
whole organism
What makes something living?
2. Respond to changes in the environment
(stimuli):
–Examples:
• Shivering when cold
• Pupils changing size based on
amount of light
What makes something living?
3. Groups of organisms change over time
(evolve)
– Based on favorable adaptations (traits that aid in
an organism’s ability to survive and reproduce in
current environment).
– Example:
– Camouflage of frogs to blend in with
environment and avoid predators.
What Makes Something Living?
• 4. Maintain homeostasis
– Homeostasis – ability of an organism to maintain
internal stability
– Example: Sweating during exercise to reduce body
temperature.
What Makes Something Living?
• Involves regulation of body systems
through cellular communication.
–Endocrine System
–Nervous System
Homeostasis
Pushing Human Limits:
Disrupting Homeostasis!!!
Homeostasis
Homeostasis
Homeostasis
What Makes Something Living?
• 5. Have a common genetic code:
– The code is found in the DNA of each organism,
which is found in the form of chromosomes in the
nucleus.
– The DNA is a code for proteins!!!
What Makes Something Living?
• 6. Are able to reproduce:
– 1. Asexual Reproduction: 1 parent cell divides and
results in 2 new identical cells.
– 2. Sexual Reproduction: 2 cells combine to create
a new offspring.
– Note: Reproduction is NOT necessary for survival
of an individual organism but is for survival of a
species.
What Makes Something Living?
• 7. Able to grow
–Increase in cell size and number of
cells.
–Results from the assimilation of
materials and synthesis of new
materials.
–Materials come from nutrients (you are
what you eat!)
What Makes Something Living?
• 8. Carry out metabolic reactions:
– Metabolism = All the chemical reactions that
occur in living things to maintain life.
– Metabolic reactions include the following life
functions:
What Makes Something Living?
– A. Nutrition: Ability to obtain and process
food.
• Autotrophic – Use energy from sunlight to
make glucose (food) – ex: green plants
• Heterotrophic – Organisms need to ingest
(take-in food).
Life Functions
Nutrition (continued)
– Reactions
• Enzymes – molecules needed for every
chemical reaction to occur.
• Hydrolysis – water is added to break a
larger molecule into smaller pieces
• Dehydration Synthesis – water is taken
away to build a bigger molecule from
smaller ones
What Makes Something Living?
• B. Respiration – Process of changing glucose
into energy (ATP).
– Aerobic –
• Occurs in mitochondria
• Requires oxygen
• Produces more ATP (36)
– Anaerobic –
• Occurs in cytoplasm
• No oxygen needed
• Produces less ATP (2)
What Makes Something Living?
• C. Transport – Movement of materials
throughout an organism.
What Makes Something Living?
• D. Excretion – Removal of cellular wastes
(wastes of metabolism) from an organism.
(End of notes for quiz 1)
Scientific Method
Notes: Scientific Method
• Series of steps scientists use to answer a
question.
Scientific Method
1. Define the problem
- Conduct thorough research on the topic
Scientific Method
2. Formulate a hypothesis
a. An educated guess
b. State the relationship between the
variables.
c. Example: If light intensity is increased,
then the rate of plant growth will
increase.
Scientific Method
Writing Hypotheses: Examples
1. If brine shrimp are placed in water with high
levels of salt, then the shrimp will have a higher
hatching rate.
2. If people are exposed to high levels of UV light,
.
then they will have a higher frequency of skin
cancer.
Scientific Method
3. Design and conduct a controlled experiment
1. Have a control set-up in which no changes
are made
2. Independent variable – one you purposely
change
3. Dependent variable – one you have no
control over (what you are testing)
Scientific Method
4. Record and analyze data
a. Organize data in a table
b. Graph data
c. Look for relationships between the variables
- Example: As the temperature
increases, the heart rate increases.
Scientific Method
5. Write a conclusion
a. State whether or not the hypothesis was
supported
b. States possible reasons for differences
between the hypothesis and experimental
results
c. Suggests ideas for further research
6. Repeat the experiment
Scientific Method
•
Ways to make your experiment and/or results
more reliable and valid:
1. Increase the sample size
2. Repeat the experiment to show similar
results each time
Tables
• When given a list of experimental data,
organize the information:
– The independent variable should be listed in
increasing amounts
– List the corresponding values for the
dependent variable next to them
Tables
Example:
• Given (plant height vs. time):
• 3 days – 10cm; 2 days – 8 cm; 5 days – 15
cm; 7 days – 20cm
Time (days)
Plant Height (cm)
2
8
3
10
5
15
7
20
Graphing
– Determine which data set goes on which
axis.
• Independent Variable: x-axis; factor that
you can CONTROL
• Dependent Variable: y-axis; factor you
have no control over (what you are testing)
Graphing
–You must choose values that are
EQUAL increments to label the
axes.
–In the chart above, do not label
the x axis: 2, 3, 5, 7.
–Instead, choose equal
increments: 2, 4, 6, 8
Graphing
– Be sure to label both axes (with units) and
give a title if required.
• The Effect of __(x)____ on __(y)___
• Example: The Effect of Time on Growth in
Plants
– Connect only the points you have plotted.
• Do NOT draw the line to “0” if you have not
plotted a point there.
• Example of a graph
Tools of Biologists
Notes: Tools of Biologists
– Used by scientists to study living and onceliving things.
Tools of Biologists
Compound Light Microscope:
• Used to study living and non-living cells.
• Can be used for viewing large cell organelles
(nuclei, chloroplasts)
Tools of Biologists
Part
Function
1. Body Tube
Connects eyepiece to rest of
microscope
2. Nose Piece
Holds the objective lenses
3. Scanning Power Lens
Magnifies image (40x total)
4. Low Power Lens
Magnifies image (100x total)
5. High Power Lens
Magnifies image (400x total)
6. Stage Clips
Holds slide in place
7. Diaphragm
Turns to adjust light
Tools of Biologists
Part
Function
8. Light Source
Illuminates specimen
9. Eyepiece (Ocular)
10. Arm
Piece you look through –
magnifies
Part you hold to carry
11. Stage
Holds slide
12. Coarse Adjustment Knob Used to find specimen
(moves stage up and down)
13. Fine Adjustment Knob
Used to fine-tune specimen
14. Base
Other part you hold to carry
DEMO – How to Use a
Microscope!!!
Microscope Measurement
• Total Magnification
– Multiply eyepiece x objective lens in use
– Example:
• Low Power: 10 x 10 = 100X
• High Power: 10 x 40 = 400X
Microscope Measurement
• Under the microscope, the object appears:
upside down and backwards
– So, if the specimen appears too far to the top and
right of the field of view, you would move the slide
up and to the right.
Microscope Measurement
• When switching from low to high power, the
field of view gets smaller and darker.
Low Power
High Power
Microscope Measurment
Measurement using a microscope
• Micrometers (µm) - measure very small
structures.
1 mm = 1000µm
See microscope measurement
worksheet
Microscope Measurement
• You can place a clear ruler on the stage of a
microscope to figure out the diameter of the
field of view (not for high power).
• Determine how many mm wide the diameter is.
– Example: 1.3 mm under 100X
Microscope Measurement
• Use this number to figure out the diameter in
um.
– Example: 1.3 mm x 1000 = 1300 um
– You can then figure out the diameter under high
power!
• Example: For 400X
– 1300 um x ¼ = 325 um
Tools of Biologists
Electron Microscope
• Can produce magnification greater than
200,000X.
• Specimens are not living.
• Used to study small structures, such as
mitochondria and chromosomes.
Tools of Biologists
A ‘Water Bear’
Tools of Biologists
What is it?!
Tools of Biologists
Tools of Biologists
What is it?!
Tools of Biologists
Tools of Biologists
Dissecting Microscope:
• For viewing larger animals and plants
• 3D image
• Less magnification than compound microscope
DEMO!!!
Tools of Biologists
Centrifuge:
• Separates cell parts by density
• Spins materials very fast.
• Most dense at bottom – least dense on top.
DEMO!!!
Tools of Biologists
Chromatography:
• Separate out different substances from one
another by their chemical or physical properties.
DEMO!
Tools of Biologists
End of Notes for Quiz 2
• These lab tools, specifically the microscope,
have allowed scientists to make discoveries
about cells!!!
• Question to answer on a sheet of paper:
• What do you know about cells??!!
– What do they look like, how do they function, what
parts do they have?
Cells
History: Key Players in Early Cell Biology
1. Robert Hooke:
•
•
1655 - Examined slices of cork through
primitive compound microscope.
Found substances were made of structures he
called cells (he saw dead cells)
Cells
–Define:
Cell – the basic unit of life.
– Unicellular vs. multicellular???
Cells
Primitive Microscope
Cork viewed
under microscope
Cells
Anton van Leeuwenhoek:
• Late 1600’s - Used single-lens
microscope with better power.
• Looked at drops of pond water
– saw living things – onecelled organisms.
• Also looked at human blood
cells
Cells
3. Schleiden and Schwann:
•
In 1838 – proposed the cell theory
Cells
The Cell Theory:
1. All living things are made up of one or more
cells.
2. All cells carry on life functions.
3. All cells come from other cells.
Cells
Exceptions / Questions Regarding the Cell
Theory:
• Since all cells came from pre-existing cells,
what produced the 1st cell?
• Viruses are not considered to be a cell, yet
they contain genetic material that takes
over the activities of the host cell.
Cells
Cell Parts
• Define:
Organelle – Specialized cellular structures that
perform certain functions.
Videos on Server
• Cells overview.wmv (1:36)
• Cell organelles.wmv (1:20)
Cells
1. Cell Wall
•Gives plant cells shape
and protection (rigid).
•Made of cellulose
Cells
2. Cytoplasm
•Jelly-like material
within cell membrane.
•Contains cellular
organelles.
Cells
3. Cell Membrane
•Fluid-Mosaic Model: Made of
proteins, lipids, and carbohydrates.
•Selectively permeable – controls
movement of materials into and out
of cell.
•Receptor molecules- cellular
communication.
Video on Server- Cell
Membrane Function
(0.38)
Cell Membrane: Continued
• Receptor Molecules
Cells
4. Nucleus
•Control center for cell.
•Contains heredity
information
(chromosomes).
Nucleus: Continued
• Contains chromosomes
– Genetic Information
– Each gene is a code to make a protein
– ‘Machinery of Life’
Cells
5. Nucleolus
•Makes ribosomes – in
nucleus
Cells
6. Endoplasmic
•Transports materials
Reticulum
throughout cell.
(Smooth and Rough)
•Smooth ER – no
ribosomes.
•Rough ER – has
ribosomes.
Cells
7. Ribosomes
•Where proteins are
made.
Ribosomes: Continued
• Ribosomes get the code
to make proteins from
DNA in nucleus.
• Each gene on the
chromosomes codes to
make one protein
Cells
8. Mitochondria
•Where energy (ATP) is
produced from glucose
(called cellular respiration)
Cells
9. Golgi Body
•Package and store
proteins and lipids the cell
will eventually send out
Cells
10. Vacuole
•Storage sites for materials
and wastes.
•Plant cells have large
vacuoles for storing water
• Unicellular organisms –
contractile vacuoles help
remove excess water.
Cells
11. Lysosome
•Contain strong digestive
(hydrolytic) enzymes.
Cells
12. Centrioles
•Only in animal cells.
Plant cells do NOT
have!
•Involved in cell division.
Cells
13. Chloroplast
•Only in plant cells.
•Site of photosynthesis –
where food (sugar) is made
•Contain chlorophyll – green
pigment.
Cilia and Flagella
• Used for locomotion!!!
Smooth ER
Vacuole
Rough ER
Ribosomes
Mitochondria
Nuclear Pores
Nucleolus
Cell Membrane
Cytoplasm
Nucleus
Lysosome
Golgi Body
Centrioles
Nuclear Membrane
Ribosomes
Rough ER
Vacuole
Nucleolus
Golgi Body
Nucleus
Cell Wall
Cell Membrane
Nuclear Membrane
Mitochondria
Chloroplasts
Cells
• How are plant and animal cells different???
• Different:
– Plant cells have a cell wall and chloroplasts and
animal cells do not
– Animal cells have centrioles
– Plant cells have a large central vacuole
– Plant cells are connected to one another and have
a boxier shape
• All of these organelles need to work together to
maintain homeostasis.
– Select 2 organelles and explain how they work
together to maintain homeostasis.
• Nucleus and ribosome
• Chloroplast and cell membrane
– End of notes for quiz 3
• The nucleus instructs the ribosomes on which
proteins to synthesize.
• The cell membrane allows carbon dioxide and
water into the cell which the chloroplast needs
to make glucose.
Websites
• http://www.cellsalive.com/cells/3dcell.htm
• Video on Server: Cell organelles.mov (8:09)
Golden Ticket
• Select 2 cell parts and explain how they work
together to maintain homeostasis.