Chapter 4

Question 1

Prokaryote:

-___ circular chromosome, not in a membrane (nucleoid)

• no histones
• no organelles

-_______: peptidoglycan cell walls

-_______: pseudomurein cell walls

• divides by _____ ______

Answer 1

One
bacteria
archaea
binary fission

Question 2

Eukaryotes:

-_____ chromosomes, in nuclear membrane
-histones (to help bind DNA)

• organelles encompassed by membranes (Golgi, ER, mitochondria, lysosomes- imp. to immune system)
• _____________ cell walls (chitin in fungi)
• divides by ______
• meiosis for making sperms/eggs

Answer 2

paired
polysaccharides
mitosis

Question 3

What can identify if a bacteria is an enemy?

Answer 3

shape

Question 4

Bacterial Cells:

• average size : ______
• most bacteria are monomorphic (single shape)
• a few are pleomorphic (many shapes)
• bacillus (rod-shaped) and coccus (spherical-shaped)

spiral 3 shapes?

Answer 4

0.2 to 2.0 micrometers
diameter x 2 to 8 um length

spiral: vibrio, spirillum, spirochete

Question 5

The Arrangement of Bacterial Cells:

• Pairs: _____cocci/bacilli
• Clusters: ______cocci
• Chains: _______cocci/bacilli
• Groups of four: _______
• Cubelike groups of eight: ________

Answer 5

diplo;
staphylo;
strepto;
tetrads;
sarcinae

Question 6

glycolcalyx

Answer 6

Polysaccharide components lying outside the outer membrane of gram-negative cells or the peptidoglycan layer of gram-positive cells

external to cell wall

• viscous and gelatinous
• made of polysaccharide (sugar coat) and/or polypeptide
• Two types:
  1. capsule: easily to be seen, what can resist the stain
  2. slime layer: easily deforms, loose, unorganized
• contribute to virulence: capsules prevent phagocytosis; extracellular polymeric substance helps form biofilms

Question 7

phagocytosis

Answer 7

Your immune cells take up (eat) a bacterium.

After the bacterium is phagocytosed, immune cells use lysosomes containing digestive enzymes to kill the bacterium

Question 8

Flagella:

• Filamentous appendages external of the cell
• Propel bacteria; provide ______
• 3 parts?

Answer 8

motility

• Filament: outermost region
• Hook: attaches to the filament
• Basal body: consists of rod and pairs of rings; anchors flagellum to the cell wall and membrane

Question 9

How many basal bodies does a gram negative bacteria have vs a gram positive bacteria?

Answer 9

gram + : 4 because of 2 layers
gram - : 2 because of 2 layers

Question 10

arrangements of bacterial flagella

Answer 10

• Amphitrichous
• Peritrichous
• Monotrichous
• Lophotrichous

Question 11

run forward: ____
tumble: ______

Answer 11

counter-clockwise
clockwise

Question 12

Flagella proteins are _ _____ and distinguish among ______

name a dangerous strain of E. coli?

Answer 12

H antigens
serovars

Escherichia coli O157; H7

Question 13

E. coli O157:H7:
what is H7? what problem/disease does it cause?

Answer 13

H7 = flagella component

-produces toxins that cause infection

Question 14

Axial filaments:

• also called _______ (under flagella’s membrane)
• embedded underneath outer membrane
• found in spirochetes (spiral shape)
• anchored at one end of a cell
• rotation causes cell to move like a corkscrew

Answer 14

endoflagella

Question 15

How does the movement provided by axial filament help the bacterium?

Answer 15

helps bacterium penetrate mucus layers

*rotation + movement

Question 16

Fimbriae and Pili:

-structures _______ bacteria

-fimbriae= hairlike appendages (made by proteins) that allow for attachment; biofilm formation; attach to epithelial cells of hosts in E. coli O157:H7
^why is it bad?

-pili: (similar to flagella) nano-machine consists of multiple proteins, involved in motility (gliding and twitching), ________ pili involved in ___ _____ from one bacteria cell to another (can spread antibiotic resistance)

Answer 16

outside

it’s bad because E. coli O157:H7 has fimbriae that helps attach to other healthy bacteria -> infects healthy cells

conjugation; DNA transfer

Question 17

Cell Wall in Bacteria:

-prevents osmotic _____ and protects the cell membrane

-made of ________ and other macromolecules in bacteria

-contributes to pathogenicity (the ability to cause disease)

Answer 17

lysis
peptidoglycan

Question 18

peptidoglycan:
-made of?
-rows are linked by?

Answer 18

protein and sugar
polypeptides (amino acids)

*maintains shape