Unit 1a Labs

In a controlled experiment, all variables are ____ ________ except the one being tested.

held constant

The individual slender filamentous structures typical of molds are called _____.

hyphae

Why is the image blurred when the 100x objective is used?

immersion oil has not been added to the slide

How does a pillbug react when confronted with a noxious (unpleasant) substance?

it moves away

What indicates a positive response from the pillbug?

it moves toward a substance

What are flagella?

long appendages used for motility, usually singular or few in number

Microscopes make microorganisms appear larger than they are. This apparent increase in size is known as ____.

magnification

What do you do in the analysis phase?

make calculations based on the raw measurements graph the results

Protozoa are traditionally classified into several groups based on their _______.

means of motility

Which metric unit is most appropriate for expressing the size of bacterial cells?

micrometer

Which of the following approaches to the study of microorganisms enables direct viewing of microbial cells? -genetic -macroscopic -biochemical -microscopic

microscopic

The total magnification of an image is determined by _____ the magnification power of the ocular lens and the magnification power of the objective lens used

multiplying

The lens on the microscope that is primarily responsible for the magnification of the specimen is the ___ lens.

objective

The _____ lenses further magnify the image produced by the objective lens.

ocular

When preparing your experiment for this lab exercise, how many substances or conditions should you test at a time?

one (1)

Suppose you have the speed on the x-axis and braking distance on the y-axis. Which graph would confirm the hypothesis "braking distance is proportional to speed"?

points on a straight line through (0,0) progressing upward and to the right

An organism moves by beating its short appendages called cilia. This organism is a(n)... -yeast -algae -protozoan

protozoan

the ability to distinguish fine detail or discriminate between two closely spaced objects

resolution

Which of the following is a defense mechanism of pillbug's against predation?

rolling up in a ball

What is the last and final step in operation of the bright-field microscope?

rotate the nosepiece to change objective lens in order to increase magnification

If leaving an objective lens over the stage when storing the microscope, which objective lens should be placed over the stage?

scanning (4X)

Where can you perform the experiment phase of the scientific method?

scientific experimentation can occur anywhere, depending upon the problem being examined

What do you do in the report phase of the scientific method?

share your results and compose a report

What are cilia?

short appendages used for motility, usually very numerous.

How do pillbugs detect the presence of food?

smell

The hypothesis is: "The braking distance grows linearly with speed." What is commonly graphed on the x-axis on the graph?

speed

In order to enhance the contrast of a slide preparation, the physician could have _______ the specimen before viewing

stained

Scientific tests are ___ and ___.

systematic and reproducible

In order to be of scientific value, it is important that a hypothesis should be ____.

testable

When you formulate your hypothesis, it is important to be sure that it is an idea that can be ______.

tested by scientific experimentation

Suppose two groups of people are participating in the testing of a new drug. One group is given the drug, the other is given a placebo like a sugar pill. What is the role of the placebo in the group?

the control group

What is true about the independent variable of an experiment?

the independent variable remains the independent variable throughout the experiment.

The total magnification of an image is determined by ___ and ___.

the magnification of the objective lens used the magnification of the ocular lens

What is the stage clip used for on a microscope?

to hole the slide being viewed in place

What is the first step in operation of the bright-field microscope?

turn the light knob to adjust the contrast of the spcimen

What is the third step in operation of the bright-field microscope?

use the coarse focusing ring and the fine adjustment knob to focus on the specimen and use the stage adjustment knobs to navigate on the specimen to find microscopic structures of interest

After viewing a slide under oil immersion, what could happen if you rotated the nose piece in the wrong direction before removing the slide?

you could drag the 40x objective lens through the oil, making it dirty

List the steps to add immersion oil to a slide.

1. identify the region of interest using the 40x objective 2. rotate the nosepiece halfway towards the 100x lens 3. apply ONE drop of immersion oil directly to the slide 4. rotate the 100x lens over the slide and into the drop

List the steps to remove immersion oil from a slide.

1. rotate the 100x objective away from the oil drop 2. use lens paper to remove immersion oil from the microscope slide 3. use lens paper to remove immersion oil from the 100x lens

If a specimen was being viewed using a 100x objective and 10x oculars, what would be the total magnification?

1000x

Which lens(es) require the use of immersion oil when viewing a specimen on a slide?

100x

Which of the following are defining characteristics of fungi? -they lack tissue differentiation -they propagate by spores -they are prokaryotic -fungal cell walls are composed of chitin -they are heterotrophic

ALL, except they are prokaryotic

T/F: It is okay for immersion oil to tough the 40x objective lens when trying remove immersion oil, since you are not looking through it

FALSE, the 40x objective should NEVER touch the oil drop

T/F: Prokaryotic cells are generally larger than eukaryotic cells.

False

T/F: Due to their small size, all prokaryotes must be visualized using electron microscopy.

False, most prokaryotes can be visualized using bright-field microscopy by enhancing their contrast through staining techniques

T/F: low power and high power lenses can withstand exposure to immersion oil.

False. only high power lenses can

T/F: immersion oil is required for viewing when using high powered lenses.

True

A good scientific experiment is reproducible. What does this mean?

anyone can conduct the same experiment in another lab and expect the same results

Which of these domains include prokaryotic microorganisms? -archaea -bacteria -eukarya

archaea and bacteria

Which of the following is the role of the control in an experiment? A. To make statistical analysis of data possible B. To compare a treated or exposed group with an untreated group C. To prove or disprove multiple hypothesis D. There is no set role

b

Which of the following is true of the control group? A. It is exposed to the experimental factor, while the other group is not B. It is treated exactly the same as the experimental group, but without being exposed to the factor being tested C. It is not really a part of the experiment D. No data is collected from the control group

b

Why is it important to perform an experiment with a control? A. Because in that way you assure that the substances in the experiment are not harmful to lab personal B. Without a control, negative test result could have been explained causing a false negative C. Without a control, negative test result could have been explained causing a false positive

b and c

What would be natural to do in the experiment phase if your hypothesis is: "The braking distance grows linearly with speed?" a. write a conclusion b. accelerate the car to different speeds in multiple trials c. measure the distance covered while braking d. record the braking distance at different speeds

b, c, and d

Which of these topics belong in a scientific paper: a. dedication and prologue b. methods (procedures) c. introduction d. results

b, c, and d

Which of the following is not a microorganism? a. algae b. ticks c. yeast d. protozoa

b. ticks

Why is a good experimental design more important than a true hypothesis?

because a good experiment yields information even when the hypothesis is disproved because we do not set out with bias to specifically prove or disprove the hypothesis is true or false

According to convention, in the example where the hypothesis is: "The braking distance grows linearly with the speed," what usually will be graphed on the y-axis?

braking distance

Suppose your hypothesis is: "Braking distance grows linearly with speed." What is the dependent variable?

braking distance

Protozoa, fungi, algae as well as most bacteria can be viewed using a(n) _______ microscope, whereas smaller objects such as viruses and molecules require more powerful microscopes.

bright-field

When using the higher magnification lenses (40X and 100X), only the ______ focus adjustment knob should be used.

fine

The major approaches to characterizing organisms include:

genetic, biochemical, microscopic, and macroscopic

What are the four phases of the scientific method?

1. hypothesis phase 2. experiment phase 3. analysis phase 4. report phase

T/F: When using the high power and oil immersion objective lenses, only the fine focus adjustment knob should be used.

TRUE. Coarse adjustment could break the slide

Which of the following groups are categorized as microscopic organisms? -bacteria -insects -protozoa -algae -fungi

-bacteria -protozoa -algae -fungi

What are the three most important factors that determine the quality and clarity of a microscopic image?

-resolving power -magnification -contrast

What might be observed microscopically in the wet prep that would indicate an infection?

-white blood cells -microorganisms

Select statements that correctly describe the process of bringing an object into focus with the 100X objective lens. - The intensity of light may need to be adjusted to optimize illumination - A drop of immersion oil must be placed between the specimen on the slide and the 100x lens -The immersion oil should not touch the 100x lens - The object should be first focused under low power, the high power prior to using the 100X objective lens

1, 2, and 4

Rank the following in terms of size, from smallest to largest. -Staphylococcus (bacteria) -Amobea -Candida albicans

1. Staphylococcus (bacteria) 2. Candida albicans 3. Amobea

Which type of appendage if used by the pillbug to collect sensory information about its environment?

Antennae

The cell walls of most fungi are made up of _____.

Chitin

What do you do in the LabSmart's hypothesis phase?

Formulate a tentative explanation to your question or observation

How do fungi obtain their energy and nutrients?

Fungi absorb their nutrients

What is lens paper used for?

It is used to remove oil from the lens after viewing under oil immersion.

Which of the following are phases in LearnSmart Labs' 4-phase model of the scientific method? a. experiment b. hypothesis c. discussion d. science

a and b

What is required of a scientific result? (select all that apply) a. it has been tested using the scientific method b. it must have been made at a university by a professional researcher c. it must be open to revision in the light of new data d. it has to be true

a and c

Why is the testing strategy important in the design of an experiment?

a good strategy will produce accurate results

Which of the following are most often included as part of a pillbug's diet? a. rotting wood b. leaf litter c. live insects d. plant materials

a, b, and d

Which items must be placed into a hard-sided sharps container rather than a biohazard bag or regular trash can? a. Pasteur pipettes (glass) b. used scalpel blades c. discarded animal tissue d. disposable agar plates e. needles/syringes f. used glass slides

a, b, e, and f

Which of the following items can be correctly discarded into biohazard bags or a biohazard bin? a. plastic agar plate with bacterial culture b. long plastic serological pipettes c. glass bacterial culture tubes d. glass slides e. discarded dissection tissue f. old lab notes g. gloves used to work with infectious materials

a, b, e, and g

Which of the following are used by protozoa for motility? a. cilia b. fimbriae c. cytoplasmic extensions called pseudopods d. flagella

a, c, and d

Which of the following should you do when using a choice chamber to observe pillbug behavior? a. Have a control substance on one side of a choice chamber b. Have test substances on both sides of the chamber c. Place only one test substance in the chamber d. Place at least two substances in the test side of the chamber e. Have a test substance on one side of choice chamber f. Insure pillbug is able to roll up defensively

a, c, and e

Which of these items should be placed in the sink after completing the lab activity? a. used glass beaker b. used plastic pipettes c. tools used in preserved specimen dissection d. glass bacterial culture tubes e. tray used in preserved specimen dissection

a, c, and e

When pillbugs are placed in a choice chamber which of the following behaviors indicates a preference for the test substance? a. Pillbug spends more time in chamber with test substance b. Pillbug moves back and forth between two chambers c. Pillbug moves away from chamber with test substance d. Pillbug rolls up to defensive position

a. pillbug spends more time in chamber with test substance

In designing an experiment, the researchers must first determine the characteristics of the population that will be involved in the study. For example, a study may be designed to examine the effects of ingested pesticides on young children under the age of 12 years. How should a subject, who fits the age range of the study, be chosen to be a part of a control group or an experimental group? A. Selection should be based on age B. Selection is always based on size C. Selection should be random D. Selection should be based on the sex of the individual

c

You decide to test your pillbugs preference for moisture. On one side of the chamber you place filter paper moistened with water. What is appropriate to place on the other side to test this variable? a. Sand b. Baking soda c. Dry filter paper d. Filter paper moistened with vinegar

c. dry filter paper

Which best describes the pillbug's organ of respiration? a. skin b. nostrils c. gills d. true lungs with air sacs

c. gills

What do you do in the experiment phase of the scientific method?

carry out the strategy and collect measurements

What do you do in the LabSmart experiment phase?

carry out the strategy chosen in the hypothesis phase collect measurements in the notebook

Which of the following would NOT be found in protozoa? -mitochondria -nucleus -chloroplast -cytoplasm

chloroplast

What is enhanced when a stain is used to make a sample or parts of a sample, darker than the background in a slide?

contrast

In an experiment where two groups are compared, one group has a treatment applied and called the experimental group; the other group is identical to the experimental group, but has not treatment applied. The second group with no treatment applied is called the ______ group.

control

What do you do in the hypothesis phase of the scientific method?

create a strategy and formulate a hypothesis

The goal of microscopy is to

create an enlarged clear image of objects to small to be seen without magnification

In an experiment to test a new drug, one group is given the drug in pill form while another is given a sugar pill. What is the reasoning behind giving some people a sugar pill rather than nothing at all? A. Sugar pills provide energy B. Sugar pills give the test subjects a treat C. The sugar pill might actually cure the disease being studied D. The sugar pill stimulates the same timing, sensation, and psychological stimulation as taking a drug in pill form

d

As you view a specimen on higher magnification, the amount of the slide seen in the field of view_____.

decreases

What do you do in the analysis phase of the scientific method?

draw graphs, evaluate results, and evaluate the hypothesis

What is the second step in operation of the bright-field microscope?

ensure that the ocular lenses are aligned with our own eyes