Bacterial Structure and Function

Question 1

What is a bacteria

Answer 1

A bacteria is a single celled organism that contains both RNA and DNA. It has cytoplasm with no nucleus and can reproduce via binary fission. They colonize your skin, hair, mouth, gut, and genital tract (everywhere)

Question 2

What are some ways we classify bacteria?

Answer 2

Using the gram stain and the shape of the bacteria.

Question 3

What would you classify a round purple gram stained bacteria?

Answer 3

A cocci that is gram positive

Question 4

What are the 4 various types of bacteria shapes?

Answer 4

Cocci (round)
Bacilli (sticks)
Curved (curvy)
Spiral (spiral)

Question 5

The gram stain colours are what?

Answer 5

Purple for gram positive and pink for gram negative.

Question 6

Why do we use a gram stains

Answer 6

It is cheap, has great resolution to use for bacteria characterization

Question 7

How does the gram stain work?

Answer 7

It uses a dye that stains the peptidoglycolic layer

Question 8

What would you classify this bacteria as? Stick like and pink

Answer 8

Gram negative bacilli

Question 9

What is the rule for naming bacteria?

Answer 9

Kingdom, Phylum, Class, Order, Family Genus, Species (KPCOGS) King’s play chess on fancy green squares, always capitalize the Genus name and italicize the whole name

Question 10

What are 2 groupings of bacteria called?

Answer 10

Clusters (staufoccocus) and chains (streptococcus)

Question 11

What is important about the bacterial membrane?

Answer 11

Gram positive bacteria has a very thick peptidoglycan layer
Gram negatives can have an outer membrane
In between the peptidoglycan layer and the cell membrane is the peri-plasmic space

Question 12

What is the outer membrane of the bacteria composed of?

Answer 12

Lipopolysaccharides endotoxin (only in gram negatives)

Question 13

What is in the gram positive bacteria?

Answer 13

A thick cell well (peptidoglycan layer) that is cross-linked between N-acetyl Glutamine (NAG) and N-acetyl Muramic acid (NAM)

Question 14

What is the main difference between gram positives and gram negatives?

Answer 14

The gram positives have a thick peptidoglycan layer and the gram negatives have a thin peptidoglycan layer

Question 15

Why is the cell membrane important?

Answer 15

It is involved in energy production, nutrient processing, the transport of nutrients and waste, the selective transport of molecules, it is a site for secretion of toxins and enzymes and it is essential for the somatic barrier

Question 16

What is one exception to the gram stain? (Acid fast)

Answer 16

Mycobacterium spp. can’t be stained and identified by a gram stain because it has a very thick and impermeable membrane capsule and mycelia cell wall. They are often known as acid fast bacteria, and a stain called Zeihl-Neilson can be used to visualize this bacteria. An example of this is mycobacterium tuberculosis and mycobacterium leprae (leprosy)

Question 17

What is another exception to the gram stain rule/usage?

Answer 17

Mycoplasma is the simplest of bacteria and does not have a peptidoglycan layer to stain at all (only has a lipoprotein layer)

Question 18

What are the 3 medically relevant gram positive cocci (GPC)

Answer 18

Staphylococci (cluster), streptococci (chained), and single cocci
They are found on skin but can be possibly pathogenic

Question 19

What are the 2 major groups of staphylococcus?

Answer 19

Coagulase positive Staphylococcus (S. aureus)
Coagulase negative staphylococcus (ALL non S. aureus)

Question 20

Why is Staphylococcus aureus medically relevant?

Answer 20

It can cause infections but is also part of normal flora of various parts of the body. MRSA is a super bug from this-hand washing can prevent it

Question 21

What are some coagulase-negative staphylococcus spp.?

Answer 21

S. epidermidis and S. capitus and S. hominus
They are skin flora, not as medically important as the others
Typically opportunistic infections

Question 22

What is the streptococci hemolytic patterns?

Answer 22

Alpha hemolysis (partial lysis of blood cells)
Beta hemolysis (complete breakdown of blood)
Gamma hemolysis (not actually breaking anything)

Question 23

Streptococcus classification

Answer 23

Group A-strep throat (strep pyogenes)
Group B-pregnant women (causes neonatal sepsis) typically in normal oral flora
Group C-Enteroccoci (multi drug resistant organism)

Question 24

What are some major gram positive bacilli?

Answer 24

Bacillis-bacteria that is resistant to reheating food (heat kills other bacteria, and plies B serious)
Listeria-deli meat and soft cheeses (thrives in fridge temp), spontaneous abortion
Clostridium-antibiotic diarrhea
Proprioni-ACNE, lead to joint infections

Question 25

What are some gram negative bacilli?

Answer 25

E. coli
Klebsiella pneumonia
Proteus mirabilis
(These all are major because they are antibiotic resistant)
These are found in water and gastrointestinal tract

Question 26

What are some gram negative cocci?

Answer 26

Neisseria gonorrhoea (lead to pelvic inflammatory disease) STI
Neisseria meningitides