The Science of Biology 
Chapter 1

Are viruses organisms(living things)?

Living things:

Are made up of cells

Most reproduce

Are based on a Genetic Code

Grow

Use energy

Respond to a stimuli (changes in the environment)

Maintain a stable internal environment

Change over time

II. Definition of Life

A. Scientists have been unable to agree upon a single definition of life. This syllabus characterizes life by the functions (fxn’s) that living organisms perform.

B. LIFE FUNCTIONS (processes) [in class students discussed examples of each processes]

1. Nutrition includes the activities of an organism by which it obtains materials from its environment and processes them for its use.

a. heterotrophic nutrition- can NOT make own food, consumes other organisms

b. autotrophic nutrition- organisms that have the ability make their own organic food from inorganic material

2. Transport involves the absorption & distribution (circulation) of materials within an organism.

a. Transport in Heterotrophs

b. Transport in Autotrophs

3. Respiration includes the exchange of gases AND those processes which provide the energy necessary for the maintenance of life functions.

a. aerobic- releases energy while using oxygen

b. anaerobic- releases energy without using oxygen

4. Excretion involves the removal of cellular (metabolic) waste products.

5. Synthesis involves those chemical activities by which large molecules are built from smaller ones. ex) assimilation- taking this material and combining it into your body-ATP.

6. Regulation involves the control coordination of the various activities of an organism.

7. Growth involves an increase in cell size and/or cell numbers. The process utilizes the products of synthesis.

8. Reproduction involves the production of new individuals. Species survival is dependent upon this life fxn.

a. sexual- involves 2 parents, offspring contains different genetic material

b. asexual- only 1 parent, offspring is a clone of parent

C. METABOLISM is the sum of all the life activities required to sustain life.

1. anabolism-building process

2. catabolism-breaking down process

D. HOMEOSTASIS in order for an organism’s metabolism to work properly, it must maintain a stable internal environment. This maintenance is known as homeostasis.

Life Function Interactive Quizzes

{tape}

{toolman}

Tools for a Biologist

{hammer}

{vice}

III. Metric System

A. In science, measurements are expressed in units of the metric system or the International System of Units (Systeme Internationale d'Unites), abbreviated SI.
B. The metric system is a decimal system of weights and measurements. The units of the system are related by factors of ten. Prefixes in the names of the units denote the size of the units.

Prefix	Meaning	Example
Kilo-	One thousand times (103)	1 kilometer = 1,000 meters (103)
Hecto-	One hundred times (102)	1 hectometer = 100 meters (102)
Deka-	One ten times (101)	1 dekameter = 10 meters (101)
	Liter, Meter, Grams	1 meter = (100)
Deci-	One-tenth (10-1)	1 decimeter = 0.1 meter (10-1 m)
Centi-	One-hundredth (10-2)	1 centimeter = 0.01 meter (10-2 m)
Milli-	One-thousandth (10-3)	1 millimeter = 0.001 meter (10-3 m)
Micro-	One-millionth (10-6)	1 micrometer = 0.000001 meter (10-6 m)
Nano-	One-billionth (10-9)	1 nanometer = 0.000000001 meter (10-9 m)

1. BASE UNITS

Meter (m) = length
Liter (L) = volume
Kilogram (Kg) = mass

Volume Equivalents: 1 ml = 1 cm³ (cc)
                             1 L = 1 dm³

2. TEMPERATURE

a. Celsius (0⁰C) based on freezing point of H2O = 0⁰C

                                & boiling point of H2O = 100⁰C

3. FACTOR-LABEL METHOD uses a ratio which is a factor equal to 1 that converts a quantity expressed in one unit to one expressed in another unit.

examples of conversion factors: 1 km = 1000 m; 1 mg = .001 g; 1 lb. = 16 oz

Sample Problem: Nitrogen gas is the major component of air.  A sample of nitrogen gas in a glass bulb weighed 243 mg. What is this mass in SI base units of mass (kilograms)?

Solution: So the conversion in two steps. First convert milligrams to grams; then convert grams to kilograms. To obtain the conversion factor from milligrams to grams, note that the prefix milli- means 10-3. Therefore,
1 mg = 10-3 g

243 mg x 10-3 g/ 1 mg = 2.43 x 10-1 g

Then, because the prefix kilo- means 103, we write
1 kg = 103 g
and

2.43 x 10-1 g x 1 kg/103 g = 2.43 x 10-4 kg

Note, however, that we can do the two conversions in on step, as follows:
243 mg x 10-3 g/ 1 mg x 1 kg/ 103 g = 2.43 x 10-4 kg

 

4. SHORT CUT for FACTOR LABEL METHOD

King

Henry’s

Daughter

Makes

delicious

corn

muffins

_

_

(m)monday

_

_

night

kilo-

hecta-

deka-

unit

deci-

centi-

milli-

micro-

nano-

RULE: when you are given a prefix and would like to convert to another unit, start at that prefix given, count the number of prefixes away from the desired prefix and move the decimal that many places in the same direction

Sample Problem) 14.5 mm = ? mm

Solution) Micro(m) is three places away from milli. Move the decimal three places to the left to get the answer.
0.0145 mm

 

What do scientists use to study cells?

IV. TYPES of MICROSCOPES

What does a cell look like?

The CELL THEORY states:

1. Cells are the basic units of structure and function of living things.
2. Cells come from preexisting cells.
3. Cells carry out life functions.

EXCEPTIONS to the CELL THEORY:

1. If all cells must arise from previously existing cells, there is a question as to the origin of the first cell. Where did it come from? Biologists are still searching for the complete answer.
2. Viruses contain simple genetic material and carry out a type of reproduction, but are not true cells. There is some question as to the status of viruses as "living" organisms, since they apparently do not carry on life functions other than synthesis. Viruses do NOT contain organelles.
3. Certain cell organelles behave like cells in some respects. Both mitochondria & chloroplasts are known to contain genetic material and to produce new organelles like themselves under certain circumstances.

A. Simple Microscope- a magnifying glass or hand lens

B. Compound Microscope- produces magnification of 40x (scanning objective), 100x (low power objective) & 430x (high power objective)

STEPS for FOCUSING the Compound Microscope
1. Position the specimen under scanning.
2. Adjust the diaphragm.
3. Focus using the coarse adjustment.
4. Center specimen.
5. Switch to low power, position specimen and repeat steps 2-4 in order.
6. Switch to high power, position specimen, & adjust the diaphragm.
7. Focus using the fine adjustment.

RESOLUTION- is the quality of the compound microscope that makes it possible to see the separatation between objects that are very close together in a microscope field

STAIN- allows normally invisible cell parts to be viewed under the microscope
examples: iodine & methylene blue

C. Phase-Contrast Microscope- this microscope can details of cells without staining

D. Stereo Microscope (DISSECTING Microscope)- low power microscope that gives the viewer a three dimensional image for purposes of gross dissection.

E. Electron Microscopes-

1. Transmission Electron Microscope (TEM)- has extremely high magnification, used to view cell structures (organelles), has resolving power of 0.5 nm
2. Scanning Electron Microscope (SEM)- produces three-dimensional image, has resolving power of 500 nm

IV. OTHER TOOLS SCIENTISTS USE for EXPERIMENTS

A. Graduated Cylinder- measures volume, the experimenter must read the meniscus which is the bottom of the curve within the graduated cylinder

B. Centrifuge- is use to separate substances

C. Ultracentrifuge- a tool used to separate cell parts according to their densities

D. Video Cameras- used to view objects in motion

E. Tissue Cultures- placing living organisms on a medium (containing nutrients & other factors so the organism can survive) outside the body

F. Electrophoresis- technique for separating substances made of particles that have an electrical charge. Used to separate DNA.

G. Micro-dissection Apparatus- is a small instrument used to operate on cell organelles

return to Mr. Via's syllabus