L1b. Bacterial Anatomy

Question 1

Bacillus

Answer 1

usually straight rods

Question 2

Cocci

Answer 2

Usually spherical but can be oval or elongated.

When they divide, the cells can remain attached to one another

Question 3

Diplococci

Answer 3

cocci that remain attached in pairs

Question 4

Streptococci

Answer 4

Cocci that remain attached in chains

Question 5

Tetrads

Answer 5

Cocci that remian attached in groups of four

Question 6

Sarcinae

Answer 6

Cocci that remain attached in groups of eight

Question 7

Staphylococci

Answer 7

Cocci that are in clusters

Question 8

Coccobacilli

Answer 8

Bacilli that have curved ends and closely resemble cocci

Question 9

Vibrios

Answer 9

Bacilli that have one curve or twist. They are usually coma shaped

Question 10

Helicobacter

Answer 10

long rods with a few twists.

Question 11

Spiral

Answer 11

these are rods shaped with multiple twists.

Question 12

Cell envelope

Answer 12

cytoplasmic membrane and cell wall.
inner membrane, thin layer that encloses the cytoplasm of the cell.
composed primarily of phospholipids and proteins.
Bacterial cytoplasmic membranes do not contain sterols like cholesterol.

Question 13

Cell Wall

Answer 13

is outside the cytoplasmic membrane and protects the interior of the cell from adverse changes in the outside environment.
Complex, semi-rigid structure responsible for shape.
Determines the gram reaction (+ or -)
Contributes to the ability of some species to cause disease, site of action of some antibiotics.
Composed of Peptidoglycan

Question 14

Peptidoglycan

Answer 14

“murein”
consists of repeating disaccharide attached to a polypeptide to form a lattice. The disaccharide portion is made up of nomosaccharides called N-acetylclucosamine (NAG) and N-acetylmuramic acid (NAM) linked by B-1,4 glycosidic linkage.
Adjacent rows are linked by a tetrapeptide (4 amino acids)

Question 15

Cell walls of Gram Positive Bacteria

Answer 15

cell wamm consists of a thick peptidoglycan (20-80nm) with multiple layers. This makes the cell envelope a two layered structure.

Question 16

Cell walls of Gram Negative Bacteria

Answer 16

cell wall consits of a thin peptidoglycan layer. usually one or a few (2-4nm). Also have an Outer Membrane

Question 17

Lipoteichonic Acid

Answer 17

Macromolecule in the cell wall of Gram Positve Bacteria. Spans the peptidoglycan layer and is linked to the cytoplasmic membrane.

Question 18

Cell wall teichoic acid

Answer 18

linked ot ehe peptidoglycan.

Question 19

Outer Membrane

Answer 19

consists of proteins, phospholipids, and lipopolysaccharides. Provides structural rigidity in place of a thicker peptidoglycan layer.
Attached to the peptidoglycan via lipoprotiens.

Question 20

Lipopolysaccharide

Answer 20

Toxicity to mammalian cells, (endotoxin)

Question 21

Cytoplasm

Answer 21

substance of the cell enclosed within the cytoplasmic membrane.
80% water, and is composed primarily of proteins, carbohydrates, lipids, inorganic ions, and low molecular weight compounds.
Thick, aqueous, semitransparent, and elastic.

Major structures:
nuclear material, 
ribosomes
mesosomes
inclusions
spores

Question 22

Nuclear Material

Answer 22

is called nucleoid
contains a single, long, tightly coilded, circular double stranded DNA.
Does NOT include histones, and are NOT surrounded by a nuclear membrane.
May contain small circular double stranded DNA molecules called Plasmids

Question 23

Ribosomes

Answer 23

appear as granules that give the cytoplasm a granular appearance. Function as the site of protein synthesis
Composed of two subunits, each subunit contains a protein and a type of RNA. Bacterial Ribosomes are called 70s ribosemes.
Several antibiotics exert their actions on riboseome to inhibit protein synthesis.

Question 24

Mesosomes

Answer 24

NOT observed in Gram Negative bacteria. Folds of cell memebrane, they function in cell division. They are the point of attachement for DNA to begin duplicaiton, and play a role in septum formation during cell division

Question 25

Inclusions (Storage Granules)

Answer 25

Reserve deposits, where the cell stores certain nutrients whey they are plentiful and use them when needed.

Question 26

Spores (Endospores)

Answer 26

Cytoplasmic structures in Gram Positive bacteria that are dehydrated, highly durable, resistant, and dormant. When released into the environment they can survive for a long time and resist extreme heat, lack of water, chemicals, radiation, etc.

Gram Negative species also form spore like structures that resist heat and chemicals.

Question 27

Sporulation (Sporogenesis)

Answer 27

the process of spore formation within a cell. The process begins whenever the key nutrient is depleted or deficient.

Question 28

Germination

Answer 28

the process of spores becoming vegetative cells.

Question 29

Biofilms

Answer 29

Groups of cells become embedded in a common matirix composed fo polysaccharides. Bacterial cells within biofilms are physiologically different from their corresponding free counterparts. Function in a coordinated matter as consortia (may mimic behavior of multicellular organisms)
Formation occurs in 4 distinct stages:
initiation, maturation, maintenance, dissolution

Question 30

Flagella

Answer 30

long (15-20 micrometers) filamentous appendages attached inside the cytoplasmic membrane and free at the other end. Confer motility to organisms
Composed of a protein called Flagellin (flagellar antigen is H)

Question 31

Fimbriae/Pili

Answer 31

Hair-like appendages that are shorter, thinner and straighter than flagella. Used for attachment. Composed of Pilin.

Can have a Sex Pilus, is used to join two bacteria cells and transfer DNA.