BIO 151---LAB PRACTICAL

Parts of the scientific method

1. Making observations 2. Formulating a hypothesis 3. Testing the hypothesis 4. Coming to a conclusion 5. Developing a scientific theory

Water boils

212 degrees F and 100 degrees C

Water freezes

32 degrees F and 0 degrees C

How many segments and pairs of walking legs are in the thorax of a pillbug?

7

What is a scientific theory?

A scientific theory is a conclusion based on many conclusions in the same field.

Lens system below the stage used to focus the beam of light passing through the condenser

Diaphragm or diaphragm control lever

refers to the use of two sets of lenses: the ocular lenses located near the eyes and the objective lenses located near the object

compound

Does the stereomicroscope or compound light microscope resolve the greater amount of detail?

compound light

used for examining small or thinly sliced sections of objects under higher magnification than that of the stereomicroscope.

compound light microscope

What step in the scientific method follows experiments and observations?

conclusion/results

What do you call a sample that goes through all the steps of an experiment and does not contain the factor being tested?

control

a crosswise cut through any type of specimen

cross section

What do you call the information scientists collect when doing experiments and making observations?

data

the results of experiments

data

the area from top to bottom that comes into focus while slowly focusing up and down with the microscope's fine-adjustment knob

depth of field

the length of the field from one edge to the other

diameter of field

can cause fats to disperse in water; contains molecules with both polar and nonpolar ends

emulsifier

proteins that speed chemical reactions

enzymes

ocular lenses

eyepieces

the circle visible through the lenses

field of view

only has one sugar unit, is a monosaccharide

glucose

Two metric units of weight

gram (g), milligram (mg)

Why does the scientific method begin with observations?

help scientists begin their study of a particular topic

low power or high power: Which has a smaller field but magnifies to a greater extent?

high power

based on observations, scientists come to a tentative decision

Formulating a hypothesis

What is a tentative explanation of observed phenomena?

hypothesis

Two metric units of volume

liter (l), milliliter (ml)

A lengthwise cut through any type of specimen

longitudinal section

Does low power or high power have a larger field of view?

low power

Low or high power: To locate small objects on a slide, first find them under -; then place them in the center of the field before rotating to -.

low; high

help scientists begin their study of a particular topic

making observations

has two sugar units, a disaccharide

maltose

Metric units of length measurement include

meter (m), centimeter (cm), millimeter (mm), micrometer (um), nanometer (nm)

the standard system of measurement in the sciences, including biology, chemistry, and physics.

metric system

a sample or event that is not exposed to the testing procedure

negative control

Can data prove a hypothesis true? (yes or no)

no

Is starch a protein?

no

they have no charged groups of atoms

nonpolar

revolving device that holds objectives

nosepiece

objective lenses

objectives

When an experiment or observations support a theory

Scientific Theory

How is a scientific theory different from a conclusion?

Scientific Theory is based on many experiments and takes many years to be accepted, while a conclusion is a result of one.

Why is it important to use one substance at a time when testing a pillbug's reaction?

So the pillbug is still not showing a reaction from the last Pillbug. There should always be a clean environment while working in a lab.

clips that hold a slide in place on the stage

Stage clips

scientists make further observations or perform experiments

Testing the hypothesis

A chain of two or more amino acids

peptide

the bond between the amino acids

peptide bond

have the same structure as fats, except that in place of the third fatty acid there is a phosphate group

phospholipids

A virus is 50 nm in size. Which type of microscope should be used to view it? Why?

The scanning electron because it can see the dimensions of the virus and magnify it to greater detail.

Which two types of microscopes view the surface of an object?

Transmission electron, scanning electron microscope

All living things consist of basic units of matter called

atoms

include sugars and molecules that are chains of sugars.

carbohydrates

molecules that have charged groups or atoms

polar

a very long chain of amino acids

polypeptide

goes through all the steps of the experiment and does contain the substance being tested. Therefore, positive results are expected

positive control

Enzymes are composed of what type of organic molecule?

proteins

analogous to the dissecting light microscope. It gives an image of the surface and dimensions of an object

scanning electron microscope

Are pipettes customarily used to measure large or small volumes?

small volumes

platform that holds and supports microscope slides

stage

designed to study entire objects in three dimensions at low magnification

stereomicroscope (dissecting microscope)

Which two types of microscopes view objects that have been sliced and treated to improve contrasts?

stereomicroscope and compound lights

Why do experimental procedures include control samples?

to compare results

Now you know what you will actually do. What is the benefit of formulating a hypothesis?

to help scientists decide how an experiment will be conducted

A scientist never says that a hypothesis has been proven true because, after all, some future knowledge might have a hearing on the experiment. What is the purpose of the conclusion?

to summarize the outcome of the experiment

analogous to the compound light microscope. The object is ultra-thinly sliced and treated with heavy metal salts to improve contrast.

transmission electron microscope

holds the ocular lenses

viewing head

when a specimen is prepared for observation, the object should always be viewed as a ----------

wet mount

Does a pillbug have the ability to move directly forward?

yes

Hypothesis, conclusion, or theory: The data show that vaccines protect people from disease.

Conclusion

whether or not the data supports or does not support the hypothesis

Coming to a conclusion

milli

(10^-3)

micro

(10^-6)

nano

(10^-9)

Hypothesis, conclusion, or theory: Pillbugs that back away from a substance are (attracted to/repelled by) the substance.

Conclusion

contains a strong solution of sodium or potassium hydroxide and a small amount of dilute copper sulfate solution.

Biuret solution

knob used to bring object into apprx. focus; used only with low-power objective

Coarse-adjustment knob

What advantages does the metric system provide over English units of measure?

Easier to convert because it is all in 10s.

Two temperature scales?

Fahrenheit (F) and Celsius (C)

knob used to bring object into final focus

Fine-adjustment knob

HPD equation

HPD=LPM/HPM

If your microscope has three objective lenses, this lens will be the longest. It is used to view an object in even greater detail.

High-power objective

Hypothesis, conclusion, or theory: How many body divisions does a pillbug have?

Hypothesis

Hypothesis, conclusion, or theory: If a pillbug travels 5 mm in 60 sec, what is its rate of speed?

Hypothesis

Hypothesis, conclusion, or theory: What can be concluded if a pillbug curls into a ball?

Hypothesis

are compounds that are insoluble in water and soluble in solvents, such as alcohol and ether.

Lipids

This lens is longer than the scanning objective lens and is used to view objects in greater detail.

Low-power objective

two knobs that control forward/reverse movement and right/left movement, respectively

Mechanical stage control knobs

goes through all the steps of the experiment except it does not contain the substance being tested. Therefore, negative results are tested.

Negative Control

the remainder group is also called?

R group

the minimum distance between two objects at which they can still be seen, or resolved, as two separate objects.

Resolution

Which objective (scanning, low power, or high power) allows you to observe the greatest number of cells within the field of view? Explain.

Scanning because it creates a bigger viewing window to view the most cells.

this is the shortest of the objective lenses and is used to scan the whole slide. The magnification is stamped on the housing of the lens. It is a number followed by an x.

Scanning objective

Why is locating an object more difficult if you start with the high-power objective rather than the low-power objective?

The higher power is harder because it is harder to locate the object. Starting with low helps to find it and then the high helps look into it.

Hypothesis, conclusion, or theory: All living things are made of cells

Theory

Why must a scientist keep a complete record of an experiment?

accuracy

proteins are made up of what that are joined together?

amino acids

supports upper parts and provides carrying handle

arm

How can you recognize the end of a pillbug?

the antennae

Which is more comprehensive, a conclusion or a theory?

theory

an encompassing conclusion based on many individual conclusions in the same field

theory