Microbial Cell Structure and Function

Question 1

How can microbes be identified through?

Answer 1

microscopic appearance, characterization of cellular metabolism, genetic and immunologic characteristics

Question 2

What are the three domains to life?

Answer 2

eukarya- eukaryotes
archaea- prokaryotes
bacteria- prokaryotes

Question 3

What are the six kingdoms of living forms?

Answer 3

plant, animal, fungi, moneran, Protista, archaea

Question 4

Classify the kingdoms into eukaryote and prokaryote

Answer 4

Eukaryote: fungi, protista
Prokaryote: archaea, moneran

Question 5

What is classified under fungi?

Answer 5

mold and yeast

Question 6

What is classified as Protista?

Answer 6

algae- photosynthetic
protozoan- not photosynthetic
(includes water molds, slime mold, brown algae)

Question 7

What is classified as archaea?

Answer 7

Archaebacteria
Ex: Methanogenic, Thermophilic

Question 8

What is classified as moneran?

Answer 8

Eubacteria
Ex: bacteria, mycoplasma (No cell wall), chlamydia (intracellular parasite), cyanobacteria (photosynthetic)

Question 9

Differentiate algae, fungi, protozoa, and helminths

Answer 9

Algae- phototrophic
Fungi- non photosynthetic that contain a rigid cell wall
Protozoa- unicellular eukaryotes that lack a cell wall
Helminths- flatworms and roundworms

Question 10

Why are viruses not considered cells?

Answer 10

no metabolic abilities of their own
infect all types of cells
rely completely on biosynthetic machinery of infected cell

Question 11

What structures differentiate eukaryotes from prokaryotes?

Answer 11

prokaryotic cells are smaller and do NOT have membrane containing organelles

Question 12

What are the cons of using a bright field microscope?

Answer 12

prokaryotes lack contrast with surrounding media, have to stain bacteria to use this scope

Question 13

How does a fluorescent microscope operate?

Answer 13

uses UV light and special dyes

Question 14

How does a phase contrast microscope operate?

Answer 14

increases the contrast between the cell and the media.
main advantage is in studying living cells

Question 15

How does a dark field microscope operate?

Answer 15

greatest contrast, only the outlines of the organisms are seen

Question 16

What are the types of light microscopy?

Answer 16

Bright field, fluorescent, phase contrast, dark field

Question 17

What is magnification, resolution, working distance, and depth of field?

Answer 17

magnification- amount of enlargement
resolution- ability to separate 2 points
working distance- space between specimen and lens
depth of field- distance between nearest and farthest object that are in focus

Question 18

List the shapes of bacteria and an example of each

Answer 18

Coccus- Staphylcoccus aureus
Rod- Bacillus subtilis
Spirillum- Spirillum volutans
Spirochete- Treponema palidum
Hydra/Stalk- Caulobacter sp.
Filamentous- Leptothrix sp.

Question 19

What is the Gram Stain and what color does each result appear?

Answer 19

Gram positive bacteria is purple and gram negative bacteria is red after staining

Question 20

What does acid-fast stain do and what color does each result appear?

Answer 20

Acid-fast bacteria is hot pink and non-acid-fast bacteria is blue

Question 21

What microbe can be detected with an acid-fast stain?

Answer 21

Mycobacterium tuberculosis

Question 22

What does an endospore stain do?

Answer 22

Distinguishes between spore cells (red) and vegetative cells (blue)

Question 23

What microbe can be detected with an endospore stain?

Answer 23

Identifies gram-positive, spore forming members of Bacillus and Clostridium

Question 24

What does capsule staining do?

Answer 24

can observe the microbial capsule of a microbe

Question 25

What does flagellar staining do?

Answer 25

can observe the filaments used by bacteria for locomotion

Question 26

What are types of electron microscopy?

Answer 26

Transmission electron microscopy, Scanning electron microscopy

Question 27

What are 4 methods that a transmission electron microscope can do?

Answer 27

thin sectioning- shows internal structure shadow casting- shows shadows negative staining- stains background Freeze etching

Question 28

What can a scanning electron microscope do?

Answer 28

shows surface structure

Question 29

What is the difference between electron and light microscopy?

Answer 29

Electron microscopy uses electrons instead of light and requires special techniques

Question 30

What is taxonomy?

Answer 30

the science of identification, classification, and nomenclature categorizes on traits

Question 31

What is systematics?

Answer 31

study of diversity of organisms and their evolutionary relationships uses rRNA sequencing with taxonomy

Question 32

What is Phylogeny?

Answer 32

evolutionary history of a group of organisms, inferred indirectly from nucleotide sequence data

Question 33

What are molecular clocks/chronometers?

Answer 33

certain genes and proteins that are measures of evolutionary change assumes that changes occur constantly, generally neutral, and random

Question 34

Which is Archaea more closely related to?

Answer 34

Eukarya

Question 35

What are the 4 structures that are found in all prokaryotic cells?

Answer 35

plasma membrane, cytoplasm, ribosomes, and DNA (circular)

Question 36

What are additional structures that can be found in prokaryotes?

Answer 36

cell wall, pili, flagellum

Question 37

What is the cell membrane made out of and its function?

Answer 37

semi-permeable lipoprotein structure that is a permeability barrier

Question 38

Where are integral membrane proteins located?

Answer 38

embedded in the membrane

Question 39

Where are the peripheral membrane proteins located?

Answer 39

one portion anchored in the membrane

Question 40

What is the composition and purpose of the cytoplasm?

Answer 40

complex mixture of sugars, amino acids, and salts serves as a pool for building blocks for cell synthesis or sources of energy

Question 41

What is the composition and purpose of the nucleoid?

Answer 41

holds hereditary material with 1 chromosome of supercoiled DNA in a circle contains Ca 2+ and Mg 2+

Question 42

What are the composition and purpose of ribosomes?

Answer 42

made of rRNA and proteins, site of protein synthesis

Question 43

What are the sizes of the small, large, and combined subunits?

Answer 43

Small subunit: 30S Large subunit: 50S Combined: 70S Archaeal ribosome: 70S Eukaryotic ribosome: 80S

Question 44

What is the purpose of peptidoglycan?

Answer 44

provides protection from osmotic lysis, determines the cell shape

Question 45

How can a gram stain determine the size of the peptidoglycan?

Answer 45

gram positive- thick cell wall (800A) gram negative- thin cell wall (50A)

Question 46

What are characteristics of a gram positive cell wall?

Answer 46

thick cell wall (800A) lack LPS layer have teichoic acids on outside of the cell treatment with lysozyme yields protoplasts

Question 47

What are characteristics of a gram negative cell wall?

Answer 47

thin cell wall (50A) Has 2 layers, outer layer is lipid, LPS, and proteins in order to keep enzymes from leaving periplasmic space inner later is made of peptidoglycan treatment with lysozyme yields spheroplasts

Question 48

What is the difference between protoplasts and spheroplasts?

Answer 48

Protoplasts have the cell wall fully removed, where spheroplasts have only part of the cell wall removed

Question 49

What are some prokaryotes that lack cell walls?

Answer 49

Mycoplasmas- group of pathogenic bacteria Thermoplasma- species of archaea

Question 50

What is the S layer?

Answer 50

single layer of thousands of copies of a single protein linked together like chain mail

Question 51

When is the S layer produced?

Answer 51

when bacteria are in a hostile environment

Question 52

What is the glycocalyx?

Answer 52

contains the capsule and slime layer, helps microbes resist phagocytosis and bacteriophages

Question 53

What microbe produce glycocalyx?

Answer 53

Klebsiella pnumoniae