Ch. 3 Exam Study Guide

Question 1

Pleomorphic

Answer 1

Bacterial characteristic meaning a bacteria can take on different forms.

Question 2

Diffusion

Answer 2

The movement of molecules from an area of higher concentration to an area of lower concentration without an energy investment.

Question 3

Bacilli

Answer 3

Rod or cylindrical shaped

Question 4

Cocci

Answer 4

Spherical shape

Question 5

Vibrio

Answer 5

Banana shaped

Question 6

Stella

Answer 6

Star shaped

Question 7

Coccobacilli

Answer 7

Oviod shaped

Question 8

Spirochettes

Answer 8

Spiral shaped bacteria

Question 9

Staph

Answer 9

Grape like clusters

Question 10

Filamentous

Answer 10

Long hairlike strands

Question 11

Define Binary Fission

What are the steps?

Answer 11

The way most prokaryotes reproduce (asexual).

1) Cell makes copy of its chromosome
2) Cell elongates
3) A septum (new cell wall) begins to form at the midpoint of the elongated cell.
4) Walling off is complete and two daughter cells are separated, though still attached.
5) The two cells may separate.

Question 12

How are bacteria and archaea similar?

Answer 12

Both prokaryotic
non-membrane bound nucleus
unicellular
lack membrane bound organelles

Question 13

Define: Step

Answer 13

Chain like formation

Question 14

Define: Palisades

Answer 14

A combination of bacillus ( rod shaped cells) that looks like fence slats that have been attached together at odd angles instead of perfectly vertical.

Question 15

How do prokaryotes divide?

Answer 15

Binary fission- the chromosome copies itself, then the cell elongates till a septum forms that divides the two chromosomes. That septum becomes the cell wall, and then the cells split apart completely, or sometimes they stay connected forming one of the previously discussed cell combination formations.

Question 16

What are two other names for the plasma membrane?

Answer 16

Cell membrane and cytoplasmic membrane

Question 17

What is the structure of the lipid bilayer?

Answer 17

Built like a sandwich. The bread is made up of hydrophilic phosphates. The filling is hydrophobic fatty acids. It is possible that proteins make up as much as half of the plasma membranes mass.
Phospholipids (main component of plasma membrane) are made of glycerol, phosphate, and two fatty acids.

Question 18

What is the function of the lipid bilayer?

Answer 18

It separates the cell from its external environment, functions as the cells main platform for interaction with the environment, and is the site of metabolic reactions that prokaryotes use to create ATP.

Question 19

What functions do the proteins have in the plasma membrane?

Answer 19

They serve as transporters, anchors, receptors, and enzymes.

Question 20

What do glycoproteins do?

Answer 20

They help with cellular identification… Helps cells recognize each other. The body can use these to help cells identify themselves as part of the body, that way phagocytes don’t attack them.

Question 21

What do membrane proteins do?

Answer 21

They are both different types of integral proteins. There are channel proteins and carrier proteins. The channel proteins allow for diffusion of small substances through the cell wall. Carrier proteins use energy to bring substances through the cell wall against the concentration gradient.

Question 22

Describe the structure of a gram negative walls. Describe clinical implications of its gram negative status.

Answer 22

Outer membrane with porins and lipopolysaccharides in it. - This outer membrane guards agains lysosomes, antibacterial enzymes, some drugs, and some detergents and disinfectants. Lipopolysaccharides are poisonous to most animals.

Between the outer membrane and the peptidoglycan layer there is a periplasmic space.

Following the outer membrane, there is a peptidoglygan layer.
Then we progress inward to the plasma membrane, which is much more selective than the outer membrane. - This allows amino acids, vitamins, and proteins to pass through the membrane. It stops large molecules and some drugs
Clinically- gram negative cells are more resistant to penicillin because penicillin targets the peptidoglycan layer which is protected in gram negative cells by the outer membrane.

Question 23

Describe the structure of gram positive cell walls.

Describe the clinical clinical implications of the gram positive cell wall status.

Answer 23

Gram positive cell walls are made completely of peptidoglycan, but the layer is much thicker than the peptidoglycan layer of gram negative cell walls. Thus they appear purple when gram stained. This all means the it is less susceptible to dry environments as it can retain more water in the peptidoglycan layer.

Peptidoglycan layer contains teichoic acids which stabilize the cell wall, help maintain shape, transport cations into the cell, and aid regulation of cell division.
These also aid bacteria in causing disease by increasing cellular adhesion to host tissue and protecting them from various antimicrobial compounds. Specifically this can cause Staphylococcus aureus- which is a skin infection.

Question 24

What are the five main structures inside of a bacteria? What do they do?

Answer 24

Plasmid- extra chromosome ring that gives cell “superpowers” specific instructions on how to resist drugs etc…
Ribosome- Made up of proteins and RNA. Helps the cell make proteins.
Nucleoid- where the cell DNA material resides.
Chromosomes- the DNA of the cell.
Inclusion body- stores stuff for cells- gasses, nutrients…

Question 25

What is the structure of the acid fast bacterial cell wall?

Answer 25

1) Mycolic Acid layer
2) Peptidoglycan layer
3) Plasma membrane layer

Question 26

What kind of acid is on the outside of acid fast bacterial cell walls?

Answer 26

Mycolic Acid

Question 27

What are the clinical implications of finding a acid fast bacteria?

Answer 27

It’s possible that the bacteria could be Mycobacterium leprae which causes leporasy or Mycobacterium tuberculosis which causes tuberculosis.
Nocardia is another strain of bacteria with a acid fast cell wall. It’s found in soil and causes skin infection and lung infection in immunocompromised patients.
Drawn out, multi-drug therapies are usually required to treat patients infected with acid fast bacteria. You can’t treat it with drugs like penicillin as they target the peptidoglycan in call walls. Acid fast bacteria protect their peptidoglycan layer with the waxy mycolic acid, and so are less susceptible to such drugs.

Question 28

Do mycoplasma have a cell wall?

Answer 28

No, they have a sterol enriched plasma membrane.

Question 29

How does lack of a cell wall effect how we treat mycoplasma?

Answer 29

Mycoplasma pneumoniae can be caused by this. It doesn’t kill an initially healthy host, but it takes a month to heal from without the use of antibiotics.

Question 30

What does L-from mean in reference to cells?

Clinically, what could the presence of L-form bacteria mean?

Answer 30

It refers to cells that had a cell wall and lost it.

Normal sterilization procedures may not be sufficient to kill off L-form cells.

Question 31

What does L-from mean in reference to cells?

Clinically, what could the presence of L-form bacteria mean?

Answer 31

It refers to cells that had a cell wall and lost it.

Normal sterilization procedures may not be sufficient to kill off L-form cells.

Question 32

What are the four things that cells need to do to survive?

Answer 32

Obtain nutrients, maintain water balance, exchange gases, and dispose of waste products.

Question 33

Explain diffusion.

Answer 33

Diffusion is the movement of molecules with a concentration gradient so that there is an equal distribution of of molecules of a given type on both sides of a membrane.

Question 34

Define simple diffusion.

Answer 34

Simple diffusion occupes when diffusion is occurring without transporter proteins. No energy is required for this to occur. Noncharged molecules, gases, and lipid-soluble substances move through the lipid bilayer this way.

Question 35

Define facilitated diffusion.

Answer 35

Diffusion that requires transport proteins. No energy is required for this to occur. Uses one or more membrane proteins. This kind of diffusion is done by proteins that are designed to transport only one specific type of substance. These proteins take the form of channels that move substances though the cell wall, or by proteins that can flip flop inside and outside the cell wall.

Question 36

Describe osmosis.

Answer 36

Water is attracted to solute, so it moves from areas of low concentration to areas of high concentration. In order for this to be defined a osmosis, the water must pass through a selective membrane. This is a passive process. Osmosis stops when the concentration os solute on both sides of the membrane is the same. However, water molecule movement doesn’t stop, there use just equal numbers of molecules moving through the membrane in both directions.

Question 37

Describe active transport

Answer 37

The movement of specific substances through specific channels agains the concentration gradient. There are three classes of active transport that are defined by how they are fueled.

Question 38

Describe Primary active transport

Answer 38

Fueled by ATP. Used to build ion gradients and transport a variety of nutrients across cell membranes.

Question 39

Describe Secondary active transport. What are other names for this form of transport?

Answer 39

This is also called coupled transport or co-transport. This relies on ion gradient to drive transport. Helps move amino acids across cell membranes. The energy released from the movement of a substance from an area of high to low concentration fuels the movement of an unrelated (target)substance from a low to high concentration.

Question 40

Define symport

Answer 40

When ions flow in the same direction as the target substance during secondary transport.

Question 41

Define antiport

Answer 41

When ions flow the opposite direction as the target substance during secondary active transport.

Question 42

Define phosphotransferase. What is another name for this?

Answer 42

Also called group translocation. These systems “transfer” a high-energy phosphate from a molecule other than ATP onto the substance being transported. Phosphoenol pyruvate is often the source of the phosphate. Often used to import sugars into the cells and shuttle them directly into metabolic pathways.

Question 43

Define the structure and function of Flagella

Answer 43

A filament-like extracellular structure that is used for motility. Built from a protein called flagellin. Works like a rotary propellor which spins from a rod and ring (basal body) structure embedded in the bacterial cell wall. Two rings used in gram positive and two rings used in gram negative.

Question 44

Define chemotaxis

Answer 44

Movement in response to a chemical stimulus.

Question 45

Define phototaxis

Answer 45

Movement in repose to light.

Question 46

Define aerotaxis

Answer 46

Movement in response to oxygen levels.

Question 47

What are the different arrangements of flagella?

Answer 47

Monotrichous- single flagella
Lophotrichous- cluster of flagella at one end of the cell
Amphitricous- a flagella on each end of a cell
Peritrichous- when a cell has flagella all over it

Question 48

What kind of flagella are located in the periplasmic space between the plasm membrane and cell wall?

Answer 48

Periplasmic flagella

Question 49

Define fimbriae’s structure and function.

Answer 49

Short bristle like structures that protrude from a cell’s surface. Made of protein. Used to adhere to each other for making biofilms, and to other surfaces for invading a host. Common in gram negative, occasionally found in archaea and gram positive.

Question 50

Define pill’s structure and function.

Answer 50

Long, rigid structures. they are used to adhere to surfaces, move, and transfer genes through conjugation.

Question 51

Define capsule structure and function.

Answer 51

Well organized glycocalyx tightly associated with the cell wall. This promotes adhesion to the cell wall and interferes with phagocytosis. Capsules also encourage adhesion for biofilms, protects cells from drying out, and offers seem protection against antibiotics and typical disinfection measures.

Question 52

Define slime layer

Answer 52

Unorganized and loosely associated glycocalyx

Question 53

Capsule

Answer 53

A well organized, tightly associated glycocalyx

Question 54

What are the medically relevant types of endospores?

Answer 54

Clostridium tetani- Tetanus
Clostridium botulinum- botulism
Clostridium perfringens- gas gangrene 
Clostridium difficile- C-diff (bad diarrhea!)
Bacillus antracis- anthrax

Question 55

What are the steps of sporulation?

Answer 55

Copying DNA
Packaging DNA, ribosomes, and enzymes into the spore core.
Surround spore core with several heat and chemically resistant layers
Release