Test 1 Study Guide

Question 1

Know the difference between prokaryotes and eukaryotes.

Answer 1

Prokaryotes are microscopic, unicellular organisms, lack
nuclei and membrane-bound organelles.

Eukaryotes are unicellular (microscopic) and multicellular,
nucleus and membrane-bound organelles

Question 2

Know the contributions of early microbiologists to the field of microbiology

Answer 2

Louis Pasteur and Robert Koch disproved spontaneous generation and proved the Theory of Biogenesis.

Anton van Leeuwenhoek discovered the microscope, protozoa, and bacteria.

Carl von Linne created the taxonomy system.

John Tyndall and Ferdinand Cohn each demonstrated the presence of heat resistant forms of some microbes.

Development of aseptic techniques was done by Dr. Oliver Wendell Holmes, Dr. Ignaz Semmelweis, and Joseph Lister.

Question 3

Know the significance of the different fields of microbiology

Answer 3

There are many different fields of microbiology including medical microbiology, public health microbiology, epidemiology, biotechnology, genetic engineering, industrial microbiology, immunology, agricultural microbiology, and food microbiologists.

Question 4

Know the difference between pathogens and non-pathogens

Answer 4

Organisms that cause disease are called pathogens, while organisms that do not cause diseases are called non-pathogens.

Question 5

Know the steps of the scientific process

Answer 5

1) defining the problem
2) making observations
3) forming a hypothesis,
4) conducting an experiment and
5) drawing conclusions.

Question 6

Know the difference between autotrophs, heterotrophs and decomposers

Answer 6

Autotrophs are the primary producers and are placed first in the food chain.

Heterotrophs include herbivores that feed on plants (autotrophs), carnivores that feed on other animals, and omnivores that feed on both plants and animals.

Decomposers are heterotrophs that break down dead organic material and wastes.

Question 7

Know the different levels of taxonomic classification

Answer 7

Domain, Kingdom, Phylum/division, Class, Order, Family, Genus, Species

Question 8

Know the difference between taxonomy, evolution and phylogeny

Answer 8

Taxonomy is the science of classification and naming living things.

Phylogeny is the science of evolutionary relationships between organisms.

Evolution is the science of how different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.

Question 9

Know the difference between Protista, fungi, plantae and animalia

Answer 9

Animalia do not have a cell wall.

Fungi and animalia do not have chloroplast.

Protista do not have tissue or multicellularity.

Protista and plantae are autotrophic.

Animalia and fungi are heterotrophic.

Question 10

Know the difference between genetic engineering and biotechnology

Answer 10

Genetic engineering is the modification of genome of an organism to yield a desired outcome.

Biotechnology is the use of a biological system, product, derivative, or organism in a technological aspect to benefit financially.

Question 11

Know the difference between free-living and parasitic microbes

Answer 11

Free living organisms are not directly dependent on another organism for survival whereas parasitic organisms are directly dependent on other organisms for their survival.

Question 12

Know how to properly write a scientific name

Answer 12

The binomial name consists of a genus name and species, and are italicized. The genus name is always capitalized and is written first; the species follows the genus name and is not capitalized.

Question 13

Know The Six I’s of studying microorganisms

Answer 13

Inoculation: The sample is placed into a container of medium to support its growth.

Incubation: Inoculated media are placed in a controlled environment to promote growth.

Isolation: Microbes are separated to create isolated colonies that each contain a single type of microbe.

Inspection: Cultures are observed for the macroscopic appearance of growth characteristics.

Information gathering: Additional tests to provide specific information unique to a certain microbe.

Identification: Using keys, charts, and computer programs that analyze data and attach a name or identify the microbe.

Question 14

Know the difference between general purpose, selective, differential and enriched media

Answer 14

Selective media: contains One or more agents that inhibit growth of some microbes and encourage growth of the desired microbes

Differential media: allows growth of several types of microbes and displays visible differences among those microbes

General purpose media: grows a broad range of microbes, usually nonsynthetic

Enriched media: contains complex organic substances such as blood, serum, hemoglobin, or special growth factors required by fastidious microbes

Question 15

Know the examples of general purpose, selective, differential and enriched media

Answer 15

Selective: MacConkey Agar
Differential: CHROM agar
General: Tryptic Soy Agar (TSA)
Enriched: Chocolate Agar

Question 16

Know the names of different types of microscopes

Answer 16

Bright-field: specimen is darker than surrounding field

Dark-field: specimen is lighter that surrounding field.

Phase-contrast: transforms subtle changes in light waves passing through the specimen into differences in light intensity.

Fluorescence: ultraviolet radiation source and filter.

Scanning confocal: uses a laser bean of light to scan the specimen.

Electron microscopy: Forms an image with a beam of electrons that can be made to travel in wavelike patterns when accelerated to high speeds.

Question 17

Know how to determine the total magnification

Answer 17

Multiply the magnification power of the ocular lens by the power of the objective lens. For instance, a 10x ocular and a 40x objective would have a 400x total magnification.

Question 18

Know the difference between synthetic and complex media

Answer 18

A chemically-defined (synthetic) medium is one in which the exact chemical composition is known.

A complex (undefined) medium is one in which the exact chemical constitution of the medium is not known.

Question 19

Know the difference between pure and mixed colonies

Answer 19

A pure culture contains only one single type; a mixed culture contains two or more different bacteria.

Question 20

Know the structure and the functions of the different parts of a microscope

Answer 20

Ocular lens, revolving nosepieces, mechanical stage, lamp voltage control, objective lens, condenser, diaphragm, light source, coarse focus, and fine focus.

Question 21

Know the difference between objective and ocular lenses

Answer 21

While an objective is on the side of the observed object, the ocular lens is on the side of the observing eye. It may contain a single optical lens or some combination of lenses and is normally placed in a cylindrical housing (barrel).

Question 22

Know the different types of bacterial appendages and their functions

Answer 22

Two major groups of appendages:

Motility – flagella and axial filaments (periplasmic flagella)

Attachment or channels – fimbriae and pili

Question 23

Know the difference between simple and Gram’s Stain

Answer 23

A simple stain uses one dye and reveals shape, size and arrangement.

A differential stain use a primary stain and a counterstain to distinguish cell types or parts.

Question 24

Know the difference endospore and acid-fast stain

Answer 24

The endospore stain is a differential stain that is widely used to distinguish between vegetative cells and endospores.

The acid-fast stain is a laboratory test to use to determine if a sample of sputum, skin tissue, blood, urine, stool, or bone marrow is infected with Mycobacterium.

Question 25

Know the difference between wet mount and fixed smear

Answer 25

Wet mounts allow examination of characteristics of live cells, such as size, motility, shape and arrangement.

Fixed mounts are made by drying and heating a film of specimen. The smear is stained using dyes to permit visualization of cells or cell parts.

Question 26

Know the correct sequence of Gram’s stain and other differential staining techniques

Answer 26

First cells are stained with crystal violet, followed by the addition of a setting agent for the stain (iodine).

Then alcohol is applied, which selectively removes the stain from only the Gram negative cells.

Finally, a secondary stain, safranin, is added, which counterstains the decolorized cells pink.

Question 27

Know the difference between a Gram positive and negative cell wall

Answer 27

Gram positive bacteria have a thick peptidoglycan layer, one periplasmic space, and no outer lipid membrane.

Gram negative bacteria have a thin peptidoglycan layer, two periplasmic spaces and have an outer lipid membrane.

Question 28

Know the difference between bacteria, fungi and plant cell wall

Answer 28

Bacterial cell walls are made up of peptidoglycan, a material made from 2 different polysaccharides (N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG)).

Cell walls of fungi are composed of chitin, which made up of many N-acetylglucosamines (NAG).

A plant cell wall is composed of cellulose, a complex sugar.

Question 29

Know the four structures that found in all cells

Answer 29

The four structures found in all cells are DNA, ribosomes, cytoplasm, and cell (plasma) membrane.

Question 30

Know the structures that are unique to prokaryotes

Answer 30

Prokaryotes are unicellular organisms that lack membrane-bound structures, the most noteworthy of which is the nucleus. Prokaryotic cells tend to be small, simple cells, measuring around 0.1-5 μm in diameter.

Question 31

Know the differences between the different types of flagella

Answer 31

Monotrichous – single flagellum at one end

Lophotrichous – small bunches emerging from the same site

Amphitrichous – flagella at both ends of cell

Peritrichous – flagella dispersed over surface of cell

Question 32

Know the parts of a viral particle

Answer 32

The simplest virions consist of two basic components: nucleic acid (single- or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.

Question 33

Know the difference between the theories of spontaneous generation and the germ theory of disease

Answer 33

Spontaneous generation states that living organisms can arise from inanimate, nonliving matter.

The germ theory of disease states that living organisms can only arise from other living organisms.

Question 34

Know the different types of isolation techniques

Answer 34

Streak plate technique: a four-part or quadrant streak.

Pour plate technique: Molten agar cooled to 45°C, is poured into a Petri dish containing a specified amount of the diluted sample. Following the addition of the molten-then cooled agar, the cover is replaced, and the plates gently rotated in a circular motion to achieve uniform distribution of microorganisms.

Spread plate technique: a technique to plate a liquid sample containing bacteria so that the bacteria are easy to count and isolate

Question 35

Know the difference between a liquid, semisolid and solid media

Answer 35

Solid medium contains 1.5 to 2.0% solidification agent (like agar)

Semi-solid medium is soft, and it doesn’t solidify completely as solid media. Contains 0.2 to 0.5% solidifying agent.

Liquid media are sometimes referred as “broths” (e.g nutrient broth), and have no solidifying agent.

Question 36

Know the difference between phototaxis and chemotaxis

Answer 36

Chemotaxis is the movement of a cell or an organism in response to a chemical stimulant while phototaxis is the movement of an organism either towards or away from a source of light.

Question 37

Know the structures and functions (anatomy and physiology) of prokaryotes

Answer 37

Nucleoid: A central region of the cell that contains its DNA.

Ribosome: Ribosomes are responsible for protein synthesis.

Cell wall: The cell wall provides structure and protection from the outside environment. Most bacteria have a rigid cell wall made from carbohydrates and proteins called peptidoglycans.

Cell membrane: Every prokaryote has a cell membrane, also known as the plasma membrane, that separates the cell from the outside environment.

Capsule: Some bacteria have a layer of carbohydrates that surrounds the cell wall called the capsule. The capsule helps the bacterium attach to surfaces.

Fimbriae: Fimbriae are thin, hair-like structures that help with cellular attachment.

Pili: Pili are rod-shaped structures involved in multiple roles, including attachment and DNA transfer.

Flagella: Flagella are thin, tail-like structures that assist in movement.

Question 38

Know the characteristics of living organisms

Answer 38

All living things have certain traits in common: Cellular organization, the ability to reproduce, growth & development, energy use, homeostasis, response to their environment, and the ability to adapt.