Chapter 2 –Biology as a Science
and Tools of the trade
The Nature of Matter
• Pg 40-52
• Story of the discovery of oxygen
Brief summaries you should be writing down as you
read:
early Greek beliefs
phlogiston theory
Pierre Bayen experiment
Joseph Priestley experiment
Lavoisier experiment
Who then discovered oxygen?
Spontaneous Generation vs. Biogenesis
• Pgs 52-60
• Living vs. non-living experiments
summaries to write down while you are reading
spontaneous generation theory components
biogenesis theory components
John Needham’s experiment
Lazarro Spallanzani experiment
Louis Pasteur’s classic experiment
I. Characteristics of Living Things
• We can state with some confidence that
all living things
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Are made up of one or more units called cells
Reproduce
Grow and develop
Obtain and use energy
Respond to their environment
Living things are made up of cells
• Cell- basic unit of structure and function
in living things
• Organisms are of two types
– Unicellular-an organisms consisting of a
single cell- bacteria, protists, some fungi
– Multicellular- an organism consisting of many
cells, some of which are typically specialized
for particular functions
Living things reproduce
• Reproduction- producing new organisms
of the same type
• Two different types of reproduction:
– Asexual – a single organism produces new organisms
genetically identical to itself – bacteria, protists,
fungus, plants, some animals
– Sexual reproduction- a process in which two cells,
normally from different organisms unite to produce
the first cell of a genetically different organism.bacteria (simple), protists, fungus, plants, animals
Living things grow and develop
• Growth can be accomplished in two ways:
– Increase in cell size
– Increase in cell number (at least for multi-cellular
organisms)
• Development involves maturation
• A butterfly goes through a metamorphosis to change from
egg, to larva, to pupa to butterfly
• Female egg cells mature during menstruation
– Organisms have some type of life cycle that takes
them from birth to death- some are more
complicated than others but all living things have
them
Living Things Obtain and Use Energy
• Real science terms:
• Autotroph- organism that makes it’s own
food (consumer)
– Photosynthetic autoroph- uses sunlight as its
energy source to make food
– Chemotrophic autotroph- uses the energy
from chemical reactions as its source of
energy to make food
• Heterotroph- organisms that get their
food from an outside source – cannot
make it themselves
- Chemotrophic heterotroph- organisms that
can obtain energy by taking in organic
molecules and then breaking them down
- Phototrophic heterotroph- organisms that is
able to use sunlight for energy but also
requires organic compounds for nutrition
Terms that are important here
• Metabolism- the sum total of all the
chemical reactions in the body – the
balance of anabolism and catabolism
– Anabolism- any process in a living thing that
involves putting together , or synthesizing,
complex substances from simpler substances
– Catabolism- the final breakdown of complex
substances into simpler ones, usually resulting
in the release of energy
Living things Respond to their
environment
• Responses can be rapid or slow
• Stimulus- anything in the environment
that causes an organism to react
• Irritability- no, not grumpiness-it’s the
ability of an organism to respond to
stimuli
• Homeostasis- an organism’s ability to
maintain constant or stable conditions
that are necessary for life- sweating
Biology: The Study of Life
• Biologist- anyone who uses the scientific
method to study life
• Branches of biology
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Zoology- study of animals
Botany- study of plants
Microbiology- study of small microscopic organisms
Paleontology- study of extinct organisms
Ethology- study of animal behavior
Cytology- study of cells
Levels of Organization
• Look at pgs 58-59
Tools of a biologist
• Compound light microscope
– Lab on its parts and use
– Limitations: as magnification increases,
resolution decreases; the limit of resolution is
the point at which the specimen is too blurry
to see
– Uses light and two mirrors to reflect through
a thin specimen
– Must stain many specimens to see
Electron microscopes
• Electromagnets used to bend streams of
electrons like lenses bend light
• Much more powerful- can magnify
millions of times without loss of
resolution
• Several different types: TEM, SEM,
scanning probe
Types of electron microscopes
• Transmission electron microscope (TEM)
– Thin specimens in vacuum –must be dead
– 2D view (like compound light only more
magnification)
• Scanning electron microscope (SEM)
– Beam of electrons around specimen – in a vacuum –
dead
– 3D can see outside surfaces
• Probe microscopes- scanning probe
microscopes
– can be alive- probes the outside- 3D
Biology lab techniques
• Staining- for visibility
• Centrifugation-separates particles by
mass- spins at high speed moving heavy
particles to bottom of the test tube
• Micromanipulation- using a microscope to
do microdissection or insertion of
material into a cell
Chapter 3 intro atoms and
molecules
II. Matter
• All things around us are made up of
matter
• Matter- anything that has mass and takes
up space (volume)
Properties of Matter
• Physical properties- a property that can be
observed and measured without permanently
changing the identity of the matter
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Color
Texture
Odor
State its in- solid, liquid, gas- and the points at which
it changes- boiling point, freezing point, etc.
– Density
– Hardness
• Chemical properties- a substance’s ability
to change into another substance as a
result of a chemical change
– Burning coal, wood
– Digesting food
– Tarnishing silver
Composition of Matter
• Atom- the basic unit of matter
– 115 + types of elements- 92 are naturally
occurring
– Human body contains about 20.
• Most notable: carbon, nitrogen, oxygen,
hydrogen, sodium, phosphorus, fluorine, silicon,
sulfur, magnesium, potassium
Atomic Structure
• All atoms are made up of a central nucleus
that contains positively charged protons,
and neutral neutrons.
• Orbiting the nucleus in energy levels are
negatively charged electrons.
Chemical Compounds
• When atoms combine they form
substances known as compounds.
• These compounds are made up of two or
more elements that chemically join to
form new substances that no longer
possess the properties they once had, but
now have new properties.
Interaction of Matter
• Matter forms compounds in two ways:
– Ionic bonds
• bonds formed when two or more elements gain
or lose electrons becoming charged particles
(ions)
• These ions are then held together by their
opposite charges (ionic bonds)
– Covalent bonds
• Bonds formed when two or more atoms share
electrons
III. The Chemical Basis of Life
• Mixtures- two or more substances that
mix together but are not chemically
bound.
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can be separated by physical means
Retain the properties of the components
Can form solutions, suspensions or colloids
Solutions are the most important and water is
usually the solvent in living organism
solutions
Solutions
• A homogeneous mixture in which one
substance is dissolved in another with the
particles evenly distributing themselves
throughout the mixture.
– Ex salt and sugar can form solutions with
water, pepper cannot.
Suspensions & Colloids
• Suspension & colloids- mixtures
containing non-dissolved particles
distributed within a solid, liquid or gas