Structure of bacterial cells

Question 1

What are the two classifications of microbe?

Answer 1

Prokaryotic

Eukaryotic

Question 2

What microbes class as prokaryotes?

Answer 2

Bacteria

Archaea

Question 3

What microbes class as eukaryotes?

Answer 3

Yeast
Algae
Protozoa

Question 4

What do prokaryotic microbes express?

Answer 4

Cell wall
Flagella
Cytoplasmic membrane
Ribosomes

Question 5

What do eukaryotic microbes express?

Answer 5

Nucleus
Chromosomes
Mitochondria
Chloroplasts

Question 6

Describe the cell structure of a prokaryote

Answer 6

Cell wall
Cytoplasm
Nucleoid
Ribosomes
Cytoplasmic membrane

Question 7

What is the capsule?

Answer 7

Present in some bacteria species
Polysaccharide gel surrounding the cell wall
Protects against adverse conditions to increase chance of survival

Question 8

What is the capsule made of?

Answer 8

Polysaccharides
Single sugar polymerised e.g. glucose to glucan
Or
Repeat units of two or more derivatives e.g. glucosamine and glucuronic acid

Question 9

What is the glycocalyx?

Answer 9

Loose meshwork of fibrils extending outwards from the cell

Helps adherence to surfaces

Question 10

What is a gram stain?

Answer 10

Bacteria are either gram negative or gram positive

Based on retention of crystal violet/iodine

Question 11

What will a gram stain look like?

Answer 11

If it is positive, will appear purple

If it is negative, will appear pink

Question 12

What does coccus mean?

Answer 12

Round in shape

Question 13

What does bacillus mean?

Answer 13

Rod shaped

Question 14

What is a gram positive cell wall like?

Answer 14

Thick layer of peptidoglycan outside the cell membrane

Question 15

What is peptidoglycan?

Answer 15

N-acetyl glucosamine

N-acetylmuramic acid

Question 16

What is a gram negative cell wall like?

Answer 16

Membrane and outer membrane
In the middle is periplasm
Periplasm contains peptidoglycan

Question 17

What is the difference in gram negative and gram positive peptidoglycan?

Answer 17

Gram positive has glycine linkages

Gram negative has linkages between different amino acids

Question 18

What is present in a gram positive cell wall?

Answer 18

Peptidoglycan layer contains:
Lipoteichoic acid
Teichoic acid
Wall-associate protein

Question 19

What is present in a gram negative cell wall?

Answer 19

Outer membrane contains:
Lipoprotein (extending inward into periplasm)
Proteins
Porins
Lipopolysaccharides

Question 20

What are fimbriae?

Answer 20

Involved in adherence to surfaces

Question 21

What is a type I fimbriae?

Answer 21

Expressed by gram negative bacteria
Highly inflammatory
Bind to macrophages, neutrophils, mast cells and lymphocytes

Question 22

What are flagella?

Answer 22

Long thin appendages
Polar, appear at one end
Very thin
Chemotaxis

Question 23

What is the name given to flagella located all over the cell?

Answer 23

Peritichous

Question 24

What is the structure of flagella?

Answer 24

Helically shaped
Made of flagellin
Hook structure for base
Mot proteins drive movement 
Fli proteins act as switch to reverse motor
Energy from protonmotive force

Question 25

What is a spore?

Answer 25

A resting cell

Highly resistant to desiccation, heat and chemical agents

Question 26

What is the bacterial chromosome?

Answer 26

Found in the nucleotide

Contains a single long continuous circular double stranded DNA molecule

Question 27

What are plasmids?

Answer 27

Extra chromosomal elements