1.01 Cell Structure and Classification of Bacteria Flashcards
(88 cards)
1
Q
The study of microscopic organisms including a large and diverse group/classes of: ▪ Bacteria ▪ Viruses ▪ Archaea ▪ Fungi ▪ Protozoa
A
Microbiology
2
Q
Microorganisms are responsible for cycling which of the chemical elements that are essential for life?
A
▪ Carbon ▪ Nitrogen ▪ Sulfur ▪ Hydrogen ▪ Oxygen
3
Q
These microorganisms lack many attributes of cells including the ability to replicate.
A
Viruses
4
Q
How does a virus reproduce?
A
When it infects a cell
5
Q
These are viruses that infect other viruses
A
Virophage
6
Q
Viral particles are generally small and consist of a ____ ____ molecule either ___ or ___
A
Viral particles are generally small and consist of a nucleic acid molecule either DNA or RNA
7
Q
A DNA virus infecting Acanthamoeba (a free-living soil amoeba)
A
Mimivirus
8
Q
A larger marine virus that resembles bacteria because of their size when observed
A
Megavirus
9
Q
Small, single-stranded, covalently closed circular RNA molecules existing as highly base-paired rodlike structures
A
Viroids
10
Q
True or False. Viroids are totally dependent on host functions for its replication
A
True
11
Q
True or False. Viroid RNA is replicated by the RNA-dependent RNA polymerase of the host
A
False. Viroid RNA is replicated by the “DNA- dependent” RNA polymerase of the host
12
Q
Prions are a type of protein that can trigger normal proteins in the brain to ____ _______?
A
Fold abnormally
13
Q
Prion diseases of importance?
A
- Kuru, Creutzfeldt-Jakob disease (CJD) - Most common
- Gerstmann-Straussler-Scheinker Disease
- Fatal Familial Insomnia
- Bovine Spongiform Encephalopathy
14
Q
What are the four major groups of protists?
A
- Algae - produce O2 as a product of photosynthesis
- Protozoa - Unicellular non photosynthetic protists
- Fungi - Unicellular non-photosynthetic protist
- Slime molds - characterized by the presence of an ameboid multinucleated mass of cytoplasm called Plasmodium
15
Q
One of the distinguishing features of protists.
A
True nucleus
16
Q
Agents of motility of protists.
A
Flagella or cilia
17
Q
Contains the cell’s genome
A
Nucleus
18
Q
A structure often visible within the nucleus, it is rich in RNA that is the site of ribosomal RNA synthesis
A
Nucleolus
19
Q
Major producer of glycoproteins.
A
Rough ER
20
Q
Participates in synthesis of lipids.
A
Smooth ER
21
Q
Site of ATP production
A
Mitochondria
22
Q
converts sunlight energy into chemical energy through photosynthesis
A
Chloroplasts
23
Q
Membrane-enclosed sacs that contain various digestive enzymes to digest macromolecules.
A
Lysosomes
24
Q
Membrane-enclosed structure that produce H2O2 from the reduction of O2
A
Peroxisome
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Cytoskeleton fills the cytoplasm and is composed of? (3)
1. Microfilaments
2. Intermediate filaments
3. Microtubules
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True or False. Most plant cells have no other surface layers. However, animal cells have an outer cell wall
False. Most animal cells have no other surface layers however plant cells have an outer cell wall composed of cellulose
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Organelle that move with a wavelike motion to propel the cell through water
Motility organelles
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Motility organelle that emanate from the polar region of the cell
Flagella
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Shorter than flagella, surrounds the cell
Cilia
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Average bacteria cell size
0.5-2.0 um diameter
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Surface area
12 um ^2
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Volume
4 um
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Surface Area to volume
3:1
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Typical eukaryotic cell surface area/Volume
0: 3:1
| * Eukaryotic cell is jam- packed with more elements that is why it has a smaller SA compared to bacteria
35
Essential bacterial cell components.
| (NCCRGP)
1. Nucleoid
2. Cytoplasm
3. Cell wall
4. Ribosomes
5. Granule Vesicles and Vacuoles
6. Periplasmic Space
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Non-essential bacterial cell components. (PCFPE)
| *not seen in all bacteria
1. Plasmids
2. Capsule and Glycocalyx
3. Flagella
4. Pili
5. Endospores
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- Gel-like matrix of water, enzymes, nutrients, wastes, and gases & contains cell structures like numerous ribosomes and polysomes
- Location of growth, metabolism, and replication
Cytoplasm
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Internal mobilities? (3)
1. Cytoplasmic streaming
2. Amoeboid movement and formation
3. Disappearance of vacuoles
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Bacteria’s way of storing nutrients
Granules or inclusions
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Example of bacteria staining that aids in identification?
Metachromatic Granules of Corynebacterium diphtheriae
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− Small electron dense particles
| − Involved in protein synthesis
Ribosomes
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Size of ribosome
70S (with subunits of 30s +50 s)
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3 types of RNA
1. rRNA
2. tRNA
3. mRNA
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Functions of the plasma membrane. (5)
1. Semipermeable membrane
2. Housing enzymes
3. Generation of ATP
4. Cell motility
5. Mediation of chromosomal segregation
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With the exception of _______, bacterial
| cytoplasmic membrane lacks sterol.
Mycoplasma
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The cell wall is composed of?
Peptidoglycan polymer (amino acids + sugars)
*Provides rigid support while freely permeable to solutes
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Backbone of peptidoglycan molecule is composed of which 2 derivatives of glucose?
1. N-acetylglucosamine (NAG)
| 2. N-acetylmuramic acid (NAM)
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NAG/NAM strands are are connected by?
Inter-peptide bridges
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True or False. D form of amino acids are used because it is harder to breakdown compared to the L form.
True
50
The two major classes of bacteria.
1. Gram Positive
| 2. Gram negative
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Why are these differences in cell wall structure so important?
Because there are some antibiotics that specifically target the cell wall thus making it permeable to the effects of the antibiotics, facilitating the killing of the organism (I.e. Penicillin)
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a) A major component of the cell wall of a Gram (+) bacterium only.
b) Functions?
a. Teichoic acids
b. 1. attachment for phages
2. Important role in Antigenic determination
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What are its compositions?
1. Glycerol
2. Phosphates
3. Ribitol
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a. Only seen in Gram (-) bacteria
b. Functions?
c. Structures?
a. Lipopolysaccharides
b. Functions as an Endotoxin or Pyrogen -- responsible for causing fever
c. 1. Lipid
2. Polysaccharide - corresponds to the antigen O of E. coli and Salmonella
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Forms a slime layer causes bacteria to adhere to solid surfaces and helps prevent the cell from drying out.
Glycoproteins loosely associated w/
| the cell wall
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The slime layer of Gram (+) _______ _____ allows it to accumulate on tooth enamel (one of the causes of cavities). This causes the other bacteria in the mouth become trapped in the slime and form a biofilm and eventually a buildup of plaque.
Streptococcus mutans
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Capsules adheres to solid surfaces and to nutrients in the environment.
Polysaccharides firmly attached to the cell wall
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Which bacteria have the type of capsule that protects bacteria from being phagocytized by cells of the hosts immune system?
Streptococcus pneumoniae
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Flagella arrangement which consist of 1 flagellum
Monotrichous
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Flagella forms a TUFT at 1 end
Lophotrichous
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Flagella at BOTH ENDS
Amphitrichous
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Flagella is all AROUND bacteria
Peritrichous
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Wind around bacteria causing movement in waves
Endoflagella
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Short protein appendages (smaller than flagella) that adhere bacteria to surfaces
Pili
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E. coli types of pili. (3)
K88
K99
F41
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Used in conjugation and exchange of genetic information
F-pilus
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It allows bacteria to survive in extreme temperature/environment
Endospores
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Location of the spores
1. Central
2. Subterminal
3. Terminal
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Spores used for quality control of heat sterilization equipment
Bacillus stearothermophilus spores
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Used for biological warfare
Bacillus anthracis spores
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One of the most important bacteriologic techniques within the microbiology laboratory because it is used in microscopic examination
Gram Stain
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Who discovered the Gram Stain in 19th century?
Hans Christian Gram
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```
Purpose of gram staining that:
- Distinguishes between the two most
common chemical cellular structures of
bacteria
- Easy visualization of the morphology and
cellular arrangement of the organism
```
Differential Stain
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Enumerate the Gram Stain Procedures. (5)
1. Fixation
2. Primary Stain
3. Mordant
4. Decolorization
5. Counterstain/Secondary Stain
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Methods of Fixation
1. Heating
| 2. Use of methanol
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What is the Stain used in primary staining?
Crystal violet
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The mordant applied after the crystal violet to chemically bond the alkaline dye to the bacterial cell wall
Gram's Iodine
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They retain crystal violet after decolorization.
Gram positive (+)
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Addition of the counterstain SAFRANIN will stain the clear gram-negative bacteria ____ or ____.
pink, red
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Highly CROSS-LINKED thick layer of peptidoglycan of Gram ____ bacteria will retain the primary dye, crystal violet.
Positive
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Spherical, and resemble tiny balls. Give an example
Coccus/Cocci
Streptococcus
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Rod shaped, and resemble a pill, some bacilli have rounded ends while others have squared ends.
Bacillus/Bacilli
Bacillus anthracis - anthrax
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a. Twisted or helical morphology that resembles little cork screws.
b. They appear as curved rods
a. Spiral
| b. Vibrios
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They have pliant bodies
Spirilla or spirochetes
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What causes gastritis and what is the shape of this bacterium?
Helicobacter pylori, spiral
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Arrangement that are found in pairs attached to each other
Diplococci
or
Diplobacilli
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These bacteria form long chains and remain attached to each other
Streptococcus
or
Streptobacilli
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These coccus bacteria are arranged irregularly in clusters like grapes
Staphylococcus
