Chapter 4 & 6.1- Bacteria, Archaea and Functional Anatomy of Prokaryotic Cells and Viruses

Question 1

What is the glycocalyx?

Answer 1

Outermost part of a bacterial cell (some DONT have one)

• Viscous, usually made of polysaccharides or polypeptides or both
• 2 types: capsule:firmly attached to cell and slime:loosely attached to cell

Question 2

How many strains of Streptococcus are there? What are they?

Answer 2

Rough (R. strain) and smooth (S. strain)
R=non-virulent
S=virulent

Question 3

What are the characteristics of the Streptococcus S. strain?

Answer 3

• Cannot be found by phagocytes: enables the bacteria to avoid being consumed by WBC’s
• Attaches to objects
• Can act as nutrients/energy when a normal food source is not available

Question 4

What is a cell wall?

Answer 4

Surrounds plasma membrane of many cells, including bacteria
Made of Peptidoglycan
Repeating units of NAG/NAM linked with a tetrapeptide
Provides structural support

Question 5

What is a tetrapeptide?

Answer 5

4 amino acids

Question 6

What are gram-positive bacteria?

Answer 6

Multiple layers of peptidoglycan that make up cell wall almost exclusively
Thicker wall with no outer membrane
Techoic acid present in cell wall attaches to lipid heads

Question 7

What are gram-negative bacteria?

Answer 7

Single layer of peptidoglycan forming a thin cell wall
Also has an outer membrane
No techoic acid in cell wall
Slightly more susceptible to lysis

Question 8

What is peptidoglycan?

Answer 8

Cross-linked chains of polysaccharides that form the rigid part of bacterial cell walls (strong but flexible)
Glycan chains and peptide fragments

Question 9

What is techoic acid?

Answer 9

Polymers containing glycerol that appear in the walls of gram-positive bacteria. Attaches to lipid heads.

Question 10

What are mycoplasmas?

Answer 10

Type of bacteria that lacks a cell wall but has a stabilized cytoplasmic membrane to prevent the cell from bursting and is resistant to lysis
Mycoplasmic pneumoniae= walking pneumonia

Question 11

What is the plasma membrane?

Answer 11

A selectively permeable layer that separates the inside of the cell from the outside.

• Small molecules
• Water
• Non-polar molecules
• Non-ionic molecules

Question 12

What is the plasma membrane composed of?

Answer 12

Phospholipid bilayer
Hydrophilic phosphate heads and hydrophobic fatty acid tails
Integral and peripheral proteins scattered around bilayer creating a mosaic appearance

Question 13

What are integral proteins?

Answer 13

Contact the hydrophobic core of the phospholipid bilayer

Question 14

What are peripheral proteins?

Answer 14

Do not reach or contact the hydrophobic region of the phospholipid bilayer

Question 15

What is a nucleoid?

Answer 15

Found in prokaryotic cells as they have no nucleus. Contains a single circular chromosome that attaches to inside of plasma membrane
Controls the cell and its proliferation

Question 16

What is a plasmid?

Answer 16

double stranded, circular chromosome that contains genes involved in resistance/fertility
F+ cells have plasmid
F- cells have no plasmid

Question 17

How does an F- cell become an F+ cell?

Answer 17

F+ cells will attach to F- cells and transfer a copy of its plasmid through the conjugal bridge turning an F- to an F+. An F- may also just absorb a plasmid from its surroundings.

Question 18

How does an F+ cell become an F- cell?

Answer 18

During starvation, a bacterial cell may expel its plasmid to save on energy

Question 19

What is fertility?

Answer 19

Getting an F- cell attracted to an F+ cell so it can receive a plasmid

Question 20

What is resistance?

Answer 20

Cells may be resistant to certain antibiotics so there may be a gene w/ resistance to penicillin or others.
If a cell has a resistance gene, the antibiotic cannot kill the cell

Question 21

What is the difference between nucleoid and plasmid?

Answer 21

The nucleoid is present in ALL bacteria, plasmid is not.
Nucleoid controls all genetics of the cell and codes for proteins, plasmid only contains genes for fertility and resistance

Question 22

What is cytoplasm?

Answer 22

Water based solution that fills the cell, contains cytosol and organelles

Question 23

What are ribosomes?

Answer 23

Organelle that performs protein synthesis.
2 subunits (large/small)- large sits atop small in the functional ribosome, each is made of protein and RNA

Question 24

Centrifugation

Answer 24

Length of time it takes for substance in a mixture to settle out of solution

Question 25

Svedberg Unit (S)

Answer 25

Sedimentation constant (10^-13seconds)

Question 26

Svedberg Units of ribosomes in prokaryotic and eukaryotic cells

Answer 26

Type of RNA in each type of cell is different. Eukaryotes are heavier
In Prokaryotes, whole ribosomes of bacteria and archaea are equal at 70S. Bacterial small subunits are 30S, lare are 50S.
In eukaryotes, whole ribosomes are 80S, large subunit 60S, small subunit 40S

Question 27

What are the 3 parts of flagellum? What is their purpose?

Answer 27

Propel the cell in movement
Fillament- part you can see that moves the cell
Hook- connects fillament to basal body
Basal Body-“motor” that spins in response to ATP

Question 28

Bacteria are classified by # and location of flagella

What are the 5 classification?

Answer 28

Atrichous- no external flagella- sessile
Monotrichous- One flagella
Amphitrichous- One at each end
Lophotrichous- Tuft at one end
Peritrichous- All over

Question 29

What is an axial filament?

Answer 29

Internal flagella that wraps around cell wall of GRAM NEGATIVE bacteria in spirochetes, then covered with an outer sheath

Question 30

What are two examples of spirochetes with axial filaments?

Answer 30

Treponema pallidum- Syphilis

Borrelia burgdorferi- Lyme disease

Question 31

What do sex pili do?

Answer 31

Attaches an F+ cell to an F- bacterial cell to transfer DNA

Question 32

What are fimbrae and what do they do?

Answer 32

Attach a cell to an object like a rockBristles on the cell surface that help w/ adhesion to other objects, cells, surfaces

Question 33

What are the inclusions of bacterial cells?

Answer 33

Stored lipids, pigments, gases, metals etc.

Question 34

What type of cells are capable of endospore formation?

Answer 34

Vegetative cells

Question 35

What are vegetative cells?

Answer 35

bacterial cells that acquire energy for growth and reproduction from feeding on other living things
They are considered “harmful”

Question 36

What are some things that may kill a vegetative cell?

Answer 36

Absence of O2, too much heat, chemicals, starvation

Question 37

How are endospores released? How do they survive?

Answer 37

Released when vegetative cells are disrupted.
Can last indefinitely without energy or nutrients
All about survival of species, not reproduction

Question 38

What are the characteristics of viruses?

Answer 38

Acellular
Can only reproduce in host
Inert- Inactive outside host cell
Capsid surrounds nucleic acid core
Nucleic acid core contains RNA OR DNA
Extremely small
Geometrically shaped
Classified based on shape, host and type of nucleic acid

Question 39

What is the cytoplasmic membrane of a bacterial cell?

Answer 39

Thin layer of proteins and lipids that surround the cytoplasm and controls the flow of materials in and out of the cell

Question 40

What is the S layer?

Answer 40

Single layer of protein used for protection/attachment

Question 41

What is the outer membrane?

Answer 41

Extra layer of protection, controls the flow of materials and can be toxic to mammals when released

Question 42

What is the actin cytoskeleton?

Answer 42

Long protein fibers that are found just outside the cytoplasmic membrane, contribute to shape of the cell

Question 43

What is the capsule?

Answer 43

Coating of molecules outside the cell wall.
Protective, adhesive, receptor of functions
AKA Glycocalyx

Question 44

What are inclusions/granules?

Answer 44

Dense crystals of fat, phosphate or glycogen, stored until needed

Question 45

What are bacterial microcompartments?

Answer 45

Protein-coated packets used to localize enzymes and other proteins in cytoplasm

Question 46

What are endospores?

Answer 46

Dormant body found within some bacteria that allows for their survival in adverse conditions

Question 47

What are nano wires/nano tubules?

Answer 47

Membrane extensions that allow bacteria to transmit electrons or nutrients to other bacteria onto environmental surfaces