micro lecture midterm Flashcards

1
Q

1) What is a virus, pathogen, infection, microbe, bacterium.

A

Virus: A small infectious agent that can only replicate inside the living cells of an organism. Pathogen: An organism or substance capable of causing disease. Infection: The invasion and multiplication of microorganisms in body tissues, causing disease. Microbe: A microscopic organism, which may be a single cell or multicellular organism. Bacterium: A type of microorganism that has a simple single-celled structure without a distinct nucleus.

PATHOGEN

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2
Q

2) The formal system for classifying and naming organisms

A

Known as binomial nomenclature, it was developed by Carl Linnaeus. It uses two Latin name parts, genus followed by species, to create a unique name for each species.

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3
Q

3) What is a domain name, kingdom, genus, specie, family name.

A

These are taxonomic ranks in biological classification. “Domain” is the highest, followed by “Kingdom,” “Family,” “Genus,” and “Species.”

SPECIES

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4
Q

4) Characteristics of a prokaryotic cell.

A

Prokaryotic cells do not have a nucleus or other membrane-bound organelles. Their DNA is circular and located in a nucleoid region. They may have cell walls, ribosomes, and sometimes structures like flagella or pili.

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5
Q

5) Can you recognize cell morphologies?

A

Common bacterial cell shapes include cocci (spherical), bacilli (rod-shaped), spirilla (spiral), and vibrios (comma-shaped).

STAPH

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6
Q

6) Protozoan motility is related to what structures?

A

The microbes commonly known as ___ are single-celled eukaryotes that are generally motile.
Protozoa

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7
Q

7) Difference between Archaea and Bacteria.

A

The cytoplasmic membranes of ___ may contain branched hydrocarbons.
ANS: Archaeal Cells

Some ____ use group translocation are a means of transport.
ANS: Bacteria

____ may have pili.
ANS: Bacteria

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8
Q

8) Who is credited with first observing microorganisms?

A

Antoni Van Leeuwenhoek

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9
Q

9) Who provided evidence of microbes causing diseases?

A

Robert Koch

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10
Q

10) The contributions of Edward Jenner?

A

He developed the first successful smallpox vaccine using material from cowpox lesions, thus founding the field of immunology.
ANS: True

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11
Q

11) Penicillin was discovered by?

A

Alexander Fleming

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12
Q

12) Recombinant DNA refers to?

A

DNA that has been formed artificially by combining constituents from different organisms

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13
Q

13) Molecular biology refers to?

A

The branch of biology that deals with the structure and function of the macromolecules (proteins and nucleic acids) essential to life.

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14
Q

14) Differences between Eukaryotes and Prokaryotes through a microscope.

A

Eukaryotes have a nucleus and membrane-bound organelles; prokaryotes do not.

TRUE

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15
Q

15) What type of samples did Anton van Leeuwenhoek examine and report?

A

Pond water, blood, sperm, and bacteria from his mouth.

Which of the following types of microbes was NOT observed by Leeuwenhoek?
ANS: Virus

TRUE

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16
Q

16) What cell have cell wall.

A

Plant cells, fungi, bacteria, and archaea.

Which of the following NEVER have cell walls?
ANS: Animal cells.

FALSE

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17
Q

17) Typical characteristic of cellular plasma membranes?

A

Semi-permeable, composed of a phospholipid bilayer with embedded proteins.

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18
Q

18) What is true about spores?

A

Highly resistant to environmental stress and used for survival and reproduction in certain bacteria and fungi.
Typically resistant to heat, desiccation, and chemicals and can be produced by various organisms, including bacteria and fungi.

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19
Q

Figure 4.1

A

e

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20
Q

20) Functions of the glycocalyx.

A

Protection, adhesion to surfaces, and evasion of host immune responses.

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21
Q

21) Bacterial cell structure and phagocytosis.

A

The cell wall can protect against phagocytosis; the capsule (part of the glycocalyx) can also inhibit phagocytosis.

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22
Q

22) Bacterial photosynthetic pigments.

A

Include chlorophylls, bacteriochlorophylls, carotenoids, and phycobiliproteins.

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23
Q

23) DNA characteristics in Eukaryotes and Prokaryotes.

A

Eukaryotic DNA is linear and contained within a nucleus.
Prokaryotic DNA is circular and not contained within a nucleus.

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24
Q

24) DNA composition.

A

Deoxyribonucleic acid, composed of a phosphate group, a sugar group (deoxyribose), and 4 nitrogenous bases (adenine, thymine, cytosine, and guanine).

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25
Q

25) Genetics and Genome.

A

Genetics is the study of genes and heredity.
Genome is the complete set of genetic material in an organism.

ALL OF THE ABOVE

26
Q

26) Table 8.2. Given a codon on mRNA and corresponding amino acid, can you identify the corresponding bases in a short sequence of DNA?

A

5 AGAGCTTTGAAT

27
Q

27) What are cells mutations and their function?

A

Mutations are changes in the DNA sequence, they can lead to new traits or diseases. Their functions include:
Neutral mutations: have no significant impact.
Beneficial Mutations: Can enhance survival and adaptation.
Harmful Mutations: May cause diseases or negatively affect the organisms.
Cancer Mutations: Contribute

TRUE

28
Q

28) What are base substitution and frameshift mutations?

A

Base substitution is the replacement of one nucleotide with another. Frameshift mutation is the insertion or deletion of a nucleotide in the DNA sequence that shifts the reading frame of the genetic message.

TRUE

29
Q

29) What is a genus as a classification group?

A

A genus is a rank in the biological classifications system that is above species and below family, grouping together species that are structurally similar of phylogenetically related.

Which of the following is NOT a characteristic of a genus name?
ANS: It is usually an adjective.

30
Q

30) Difference between a bacterial species and a species of a eukaryotic organism.

A

Bacterial species are often defined based on genetic homogeneity, while eukaryotic species are defined based on reproductive isolation.

31
Q

31) Characteristics of a unicellular organism based on the size of the ribosome.

A

Eukaryotes have 80S ribosomes, while prokaryotes have 70S ribosomes.

32
Q

32) What can be the product of transcription?

A

mRNA (messenger RNA)

Which of the following statements concerning transcription in bacteria is FALSE?
ANS: Different RNA polymerases are required for synthesis of mRNA, rRNA, and tRNA.

33
Q

33) What is transformation?

A

The genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings through the cell membrane.

34
Q

34) Differences between virus and bacteria?

A

Viruses are acellular, require a host cell to replicate, and do not perform metabolism.
Bacteria are cells that can live independently, perform metabolism, and replicate on their own.

35
Q

35) An infectious protein.

A

Prion

36
Q

36) Primary components of cell plasma membranes.

A

Phospholipids, proteins, and cholesterol.

37
Q

37) What are genes?

A

Genes are segments of DNA that contain the instructions for building and maintaining an organism.

38
Q

38) Structures of a compound microscope and their function

A

Eyepiece (Ocular): Magnifies the image, typically 10x.
Objective Lenses: Further magnify the specimen, usually 4x, 10x, 40x, and 100x.
Stage: Supports the specimen being observed.
Light Source: Illuminates the specimen.
Condenser: Focuses light onto the specimen.
Diaphragm: Controls the amount of light entering the condenser.
Coarse and Fine Adjustment Knobs: Adjust focus.
Base: Supports the microscope.

39
Q

39) Characteristics of bacterial dyes and stains.

A

Used to increase contrast between bacteria and the background.
Basic dyes (positive charge) bind to negatively charged bacterial structures.
Acidic dyes (negative charge) are repelled by cell structures.

Basic Dyes: Positively charged, bind to negatively charged bacterial structures.
Ex: Crystal violet, methylene blue.
Acidic Dyes: Negatively charged, used for negatively charged bacterial structures.
Ex: Eosin, Acid Fuchsin.
Simple Stains: Use of a single dye to color the entire bacterial cell.
Differential Stains: Use multiple dyes to distinguish different bacterial structures or types.
Ex: Gram stain, acid-fast stain.

40
Q

40) Characteristics of bacterial dyes and stains.

A

Used to increase contrast between bacteria and the background.
Basic dyes (positive charge) bind to negatively charged cell structures.
Acidic dyes (negative charge) are repelled by cell structures.

41
Q

41) What is a mordant and its function?

A

A substance used to fix or intensify stains in microscopy.
A substance that is used to enhance the binding of a dye or stain to a specimen, especially in microscopy. The function of a mordant is to fix the dye to the specimen, making it more resistant to washing out and increasing the intensity of the staining. Mordants often form complexes with the dye molecules, promoting their attachment to the specimen.

A ____ is a substance that binds to a dye and makes it less soluble.
ANS: Mordant

The function of a mordant in staining procedures is to:
ANS: Decrease the solubility of dye molecules.

42
Q

42) What is a negative?

A

Negative stain technique – where the background is stained instead of the cell, enhancing contrast. This results in a bright specimen against a dark background, making it easier to observe certain structures.

43
Q

43) Simple staining and the use of the microscope.

A

Simple staining involves applying a single dye to a sample to highlight the organism for observation under a microscope.

Use of the microscope: after simple staining, the stained bacterial specimen can be observed under a microscope. The microscope allows for the magnification and visualization of the stained cell. Adjustments to the objective lenses and focus knobs are made to achieve a clear and detailed view of the stained specimen.

44
Q

44) Different types of microscopes and their use

A

Light microscope – Uses visible light to magnify and resolve specimens. Common in general laboratory use.
Electron microscope (TEM, SEM) – Uses electron beams for a higher magnification and resolution. Transmission electron microscopes (TEM) and Scanning Electron Microscope (SEM) are two types.
Fluorescent Microscope – Uses fluorescence to visualize specific structures within cells.
Confocal Microscope – Provides optical sectioning and three-dimensional imaging of specimens.
Phase Contrast microscope – for live cells

In a transmission electron microscope, the “lenses” are
ANS: Magnets

The microscope preferred for viewing living specimens is the ____ microscope.
ANS: Phase-Contrast

All of the following are types of light microscopes except:
ANS: Scanning tunneling

45
Q

45) Microscopes, magnification, and resolution.

A

Magnification enlarges the image; Resolution is the ability to distinguish two points as separate entities.

Which of the following is the best definition of “empty magnification”?
ANS: An image is magnified so much resolution and contrast are lost.

The resolution of a microscope is a function of the ___ of the lenses and the _____ of the light.
ANS: Numerical Aperture; Wavelength

Which of the following phenomena produces magnification?
ANS: The refraction of radiation as it passes through a lens.

46
Q

46) Microscopy unit conversion.

A

0.1

47
Q

47) The path of light in the compound microscope.

A

Light source – Condenser Lens – Sample – Objective Lens – Eyepiece Lens

48
Q

48) Microscope that use UV light.

A

Fluorescence Microscope

49
Q

49) Sequence in the Gram Stain1.

A

Purple

50
Q

50) Sequence in the Gram Stain2.

A

Purple

51
Q

51) Sequence in the Gram Stain3

A

Colorless

52
Q

52) Role of the Gram Stain in Clinical Medicine.

A

Classifying bacteria into two major groups (gram-positive and gram negative) in clinical samples.
Guides treatment.
Decisions, as gram-positive and gram-negative bacteria often respond differently to antibiotics.
Provides initial information about the bacterial structure, influencing further diagnostic steps.
Aids in identifying potential pathogens and determining appropriate therapeutic strategies.

The gram stain works because of differences in the ____ of bacteria.
ANS: Cell walls

53
Q

53) How to calculate the magnification in a microscope.

A

450x

54
Q

54) Relation between Bacillus and the stain malachite green.

A

Bacillus, forms endospores that are resistant to heat and chemicals while malachite green is used in staining the endospores, allowing them to be visually distinguished from the rest of the cell and the background.

The _____ stain makes use of malachite green.
ANS: Endospore

55
Q

55) Critical step in the Gram stain.

A

Decolorization step, this differentiates between gram-positive and gram-negative bacteria based on the thickness and permeability of their cell walls.

56
Q

56) Sequence in the Gram Stain4.

A

Safranin (Counterstain) – Stains the decolorized cells.

57
Q

57) Bacterial smears

A

Preparing a sample on a slide by spreading and fixing bacteria for staining.

Identification of bacteria in the laboratory usually begins with the ____ for placement in one of two large groups of bacteria.
ANS: Gram Stain

You are examining a bacterial smear on a light microscope. You observe a pinkish-red bacilli and blue cells of various shapes. You are probably looking at a smear prepared with the ____ stain.
ANS: Ziehl-Neelsen Acid Fast

58
Q

58) Resolution of a microscope1.

A

The ability to distinguish two points as separate.

59
Q

59) Resolution of a microscope2.

A

Enhance the resolution beyond limited by the wavelength of light and numerical aperture of the lens.

60
Q

60) What bacterial structures can be observed in the gram stain?

A

FALSE

61
Q

YOU ARE

A

AWESOME