Chapter 7 - Prokaryotes

Question 1

coccus, cocci

Answer 1

Spherical

Question 2

bacillus, bacilli

Answer 2

Rodlike

Question 3

vibrio

Answer 3

comma shaped

Question 4

spirillum, spirilla

Answer 4

Rigid, wavy-shaped

Question 5

spirochete

Answer 5

Corkscrew-shaped

Question 6

Basic arrangements

Answer 6

Single
Diplo (two)
Strep (chain)
Tetrad (four in a square)
Sarcinae (8 in a cube)
Staph (big group)

Question 7

Limiting structures:

Answer 7

Plasma membrane/cell membrane

Question 8

Plasma membrane/cell membrane

Answer 8

fluid mosaic model, regulated movement of materials in/out of cell. Dynamic. Responsible for: synthesizing cell wall components, secreting proteins, assisting with DNA replication, carrying respiration, and capturing energy in the form of ATP

Question 9

Internal structures

Answer 9

cytoplasm, ribosomes, nuclear region, chromatophores, granules, vesicles

Question 10

Cytoplasm

Answer 10

semifluid substance (⅘ water), bigger portion than in eukaryotes, more semifluid available compared to eukaryotes

Question 11

Ribosomes

Answer 11

provide sites for protein synthesis, abundant in cytoplasm. Group in chains of polyribosomes.

Question 12

Polyribosomes

Answer 12

sedimentation rate of 70S, subunit 50s and 30s

Question 13

Nuclear region

Answer 13

centrally located, mainly DNA, but it has RNA and protein associated with it. One or several chromosomes. Linear or circular. Could contain plasmids. Plasmids: not essential DNA. Useful DNA, information complements.
DNA
RNA

Question 14

Chromatophores

Answer 14

found in photosynthetic and cyanobacteria. Membrane of chromatophores contains a pigment that captures light for energy

Question 15

Granules

Answer 15

no membrane bound. Contain densely compacted substances. Each granule consists of a specific substance: glycogen, metachromatic granule

Question 16

Vesicles

Answer 16

membrane bound structure. Some organisms have rigid gas-filled vacuoles. Regulate the depth at which they float by amount of gas inside the vacuole.

Question 17

External structures

Answer 17

glycocalyx, capsule, Slime layer, Flagella, axial filaments, pili, endospores, cell wall

Question 18

Glycocalyx

Answer 18

refers to all polysaccharides-containing substances found external to the cell wall

Question 19

Capsule

Answer 19

thickest layer of glycocalyx. Protective structure. Secreted by the cell wall. If a capsule producing bacterium loses its capsule, it’s less likely to cause disease.

Question 20

Slime layer

Answer 20

thinnest layer, protective layer against drying. Traps nutrients near the cell, adheres to objects.

Question 21

Flagella

Answer 21

½ of the known bacterial species are motile. Long thin helical appendages. There can be more than one flagella.
Rotate like a twirling L shaped hook
Counterclockwise: run in a straight line
Clockwise: tumble
Chemotaxis: move toward/away from substance
Phototaxis: move toward or away from a light source.

Question 22

Axial filaments

Answer 22

spirochetes, each filament is attached at one of its ends to an end of the cytoplasmic cylinder. Motility like a corkscrew.

Question 23

Pili

Answer 23

use for attachment, two kinds (conjugation and attachment)

Question 24

Conjugation pili -

Answer 24

sex pili, attaches to cells to allow the transfer of the genetic material. Antibiotic resistance transferred from partner.

Question 25

Attachment pili (or fimbriae)

Answer 25

help bacteria adhere to surfaces, contribute to pathogenicity.

Question 26

Endospores

Answer 26

resting state versus vegetative state (metabolizing nutrients). Medically significant genera
Sometimes called spores
Contain very little amount of water
Confer resistance to heat, drying, bases, disinfectants, and even radiation.
When conditions become favorable endospores germinate.

Question 27

Cell Wall

Answer 27

lies outside the cell membrane, semi rigid. It maintains the characteristic shape of the cell (spherical) and prevents the cell from bursting when fluids flow into the cell by osmosis.

Question 28

Gram-Positive

Answer 28

as many as 40 layers of peptidoglycan. Teichoic acid (used by viruses). Thick peptidoglycan (60-90% of cell wall). Retain crystal violet dye, purple/blue. If the cells are old they could stain pink like a gram neg

Question 29

Gram-Negative

Answer 29

less layers of peptidoglycan, liposaccharide A, also called endotoxin, Lipid A is responsible for the toxic properties of the bacterium. Antibiotics given late in an infection may cause a worsening of symptoms or death. Does not retain crystal violet dye, counter stained with safranin. Thinner wall, but more complex. Outer cell membrane. LPS components.

Question 30

Acid Fast

Answer 30

less peptidoglycan because 60% lipids. Protects cells from acids and alkalis. Stains gram positive, purple/blue. Organisms grow slower because: acid fast cell wall impedes the entry of nutrients. energy requirement of making lipids.

Question 31

Cell wall components:

Answer 31

Peptidoglycan - most important component of the bacterial cell wall, very large polymer.
Periplasmic space - gap between cell membrane and cell wall, active area of metabolism, rarely observed in gram positive. Wide periplasmic space between peptidoglycan and cell membrane. Digestive enzymes, and protein pumps within.
Lipids