Chapter 3 lecture notes

Question 1

All prokaryotes don’t have?

Answer 1

Cytoskeleton.

Question 2

A prokaryotes shell is made of?

Answer 2

Sugar and protein. The rigid structure works as exoskeleton to keep shape & cell from bursting

Question 3

The pili on prokaryotes adhere to?

Answer 3

Substrates & glue to each other using capsules

Question 4

Sperical round shape

Answer 4

Coccus

Question 5

Rod shape

Answer 5

Bacillus

Question 6

Short round rod

Answer 6

Coccobacillus

Question 7

Curved rod

Answer 7

Vibrio

Question 8

Spiral shape

Answer 8

Spirillus. Fiber in cell wall allows to curve on itself

Question 9

Helical shape, tight coiling

Answer 9

Spirochete

Question 10

Vary in shape

Answer 10

Pleomorphic. Can assume different forms

Question 11

Diplobacilli=

Answer 11

2 bacilli

Question 12

Streptobacilli=

Answer 12

String

Question 13

Prokaryotic cells may form groupings

Answer 13

After cell division. Cells adhere together after cell division for characteristic arrangements. Arrangements depends on plan of division

Question 14

Division along two or three perpendicular planes form

Answer 14

Cubical packets

Question 15

Division along several random planes form

Answer 15

Clusters

Question 16

General function of capsules and slime layer of glycocalyces

Answer 16

Protection and attachment.
Protection: Protects bacteria from host defenses
Attachment: Enables bacteria to adhere

Question 17

Organized layer of sugar=

Disorganized layer of sugar=

Answer 17

Organized= capsule
Disorganized= slime layer

Question 18

Distinct gelatinous layer

Answer 18

Capsule

Question 19

Irregular diffuse layer

Answer 19

Slime layer

Question 20

Chemical composition of capsules & slime layers varies depending on bacterial species. Most are made of?

Answer 20

Polysaccharides

Question 21

Glyco=

Calyx=

Answer 21

Glyco= Sugar
Calyx= Shell

Question 22

Cell wall of bacteria 6 main points

Answer 22

1) Rigid structure
2) Surrounds cytoplasmic membrane
3) Determines shape of bacteria
4) Holds cell together
5) Prevents cell from bursting
6) Unique chemical structure (distinguishes Gram + from -)

Question 23

The rigidity of the bacterial cell wall is due to?

Answer 23

Peptidoglycan (PTG)

Question 24

The basic structure of peptidoglycan

Answer 24

Peptido=protein
Glycan=sugar
Alternating series of two subunits; N-acetylclucosamine (NAG) and N-aceetylmuramic acid (NAM). Joined subunits form glycan chain and the chains are held together by string of four amino acids (tetrapeptide chain)

Question 25

What are the sugars in peptidoglycan

Answer 25

N-acetylglucosamine (NAG) | N-acetylmuramic acid (NAM)

Question 26

Gram-positive cell wall

Answer 26

1) Relatively thick layer of peptidoglycan (PTG) 2) As many as 30 layers of PTG chains 3) Teichoic acid component of PTG 4) Gives cells a negative charge

Question 27

Main points about prokaryotes

Answer 27

1) Lack nucleus 2) Lack various internal structures bound with phospholipid membranes 3) Small ( ~ 1.0 micrometers in diameter) 4) Simple structure 5) Include bacteria & archaea 6) Do not have cytoskeleton 7) Shell is made out of sugar & protein 8) Capsules are important infector in disease 9) Flagellum responsible for motility, different than eukaryotic cells 10) Pili adheres to substrates & glue to each other using capsules

Question 28

Gram-negative cell wall main points (4)

Answer 28

1) More complex than Gram + 2) Only contains thin layer of peptigoglycan (3-10) 3) PTG sandwiched between outer membrane and cytoplasmic membrane 4) Region between outer membrane and cytoplasmic membrane is called periplasm ( most secreted proteins are contained here, proteins of ABC transport system are located here)

Question 29

Cytoplasmic membrane main points

Answer 29

1) Selectively permeable 2) Molecules pass through membrane via simple diffusion or transport mechanisms that may require carrier proteins & energy

Question 30

Simple diffusion

Answer 30

Molecules move freely across the cytoplasmic membrane like H20, some gases & small hydrophobic molecules pass via simple diffusion

Question 31

Facilitated diffusion main points (3)

Answer 31

1) Moves compounds in the direction of the concentration gradient (from greater concentration to lesser) 2) Molecules diffuse until equilibrium is reached (system can only eliminate concentration gradient; it cannot create one) 3) No energy required * Example movement of glycerol into the cell

Question 32

Some bacteria have protein appendages which are not essential for life. They aid in survival in certain environments. They include?

Answer 32

1) Flagella | 2) Pili

Question 33

Flagella are

Answer 33

Long protein structure that is responsible for motility. * Use propeller-like movements to push bacteria * Can rotate more than 100,000 revolutions/minute (Equivalent to a 6 ft man running 82 mile/hour) * Some important in bacterial pathogenesis (H. pylori penetration through mucous coat)

Question 34

3 basic parts of flagella

Answer 34

1) Filament- Extends to exterior. Made of proteins called flagellin 2) Hook- connects filament to cell 3) Basal body- anchors flagellum into cell wall

Question 35

Bacteria use flagella for

Answer 35

Motility. Motile through sensing chemicals (chemotaxis) if the chemical compound is a nutrient it acts as attractant. If the compound is toxic it acts as repellent

Question 36

Bacteria can have flagella and pili, the pili are?

Answer 36

Considerably shorter and thinner than flagella. They have a similar structure (protein subunits). They function to attach, which are called fimbriae, movement, and conjugation, mechanisms of DNA transfer.

Question 37

Differences in cell wall account for differences in staining characteristics

Answer 37

Gram-positive bacterium retain crystal violet- iodine complex of Gram stain-purple Gram-negative bacterium lose crystal violet-iodine complex-pink

Question 38

Some bacteria lack cell wall

Answer 38

Called Mycoplasma. - Causes mild pneumonia - Sterols in membrane account for strength of membrane

Question 39

If a bacteria doesn't have a cell wall then what can happen?

Answer 39

Antimicrobial drugs directed against cell wall are ineffective

Question 40

Bacteriain Domain Archaea

Answer 40

Have a wide variety of cell wall types | – None contain peptidoglycan but rather pseudopeptidoglycan in some

Question 41

Cytoplasmic membrane proteins

Answer 41

Membrane is embedded with numerous proteins – More than 200 different proteins – Proteins function as receptors and transport gates – Provides mechanism to sense surroundings – Harvest light energy in photosynthetic bacteria – Proteins are not stationary. Constantly changing position. Called fluid mosaic model

Question 42

Osmosis is

Answer 42

Simple diffusion of H2O – H2O flows freely across the cytoplasmic membrane – H2O flows to equalize solute concentrations inside and outside the cell – Inflow of H2O exerts osmotic pressure on membrane (Membrane rupture prevented by cell wall)

Question 43

Two primary forms of energy

Answer 43

ATP & Proton motive force

Question 44

3 mechanisms for active transport

Answer 44

– Uniport – Antiport – Coupled Transport (Uniport & Symport)

Question 45

Alters the molecule

Answer 45

Group translocation

Question 46

Movement of many molecules directed by

Answer 46

Transport systems: – Transport systems employ highly selective proteins – Transport proteins include permeases, channels, or ports – These proteins span membrane * Single carrier transports a specific molecule * Most transport proteins are produced in response to need Transport systems include: Facilitated diffusion Active transport Group translocation

Question 47

Storage granules / Inclusions is

Answer 47

Accumulation of polymers - Synthesized from excess nutrients Example is glycogen-excess glucose in cell is stored in glycogen granules

Question 48

Gas vesicles main points

Answer 48

1) Small protein compartments 2) Provides buoyancy to cell 3) Allows organism to reach ideal position in environment

Question 49

Endospores main points

Answer 49

1) Dormant cell types - Produced through sporulation - Theoretically remain dormant for 100 yrs 2) Resistant to damaging conditions - Heat, desiccation, chemicals and UV light 3) Vegetative cell produced through germination - Germination occurs after exposure to heat or chemicals - Germination not a source of reproduction 4) Not affected by crenation

Question 50

Essential for translation (proteins)

Answer 50

Ribosome

Question 51

Site of protein synthesis, composed of large and small subunits, units make of riboprotein and ribosomal RNA

Answer 51

Ribosome

Question 52

Prokaryotic ribosomal subunits Large= Small= Total=

Answer 52

Large=50S Small=30S Total=70S

Question 53

Eukaryotic ribosomal subunits Large= Small= Total=

Answer 53

Large=60S Small=40S Total=80S

Question 54

The difference in ribosomal subunits of prokaryotic and eukaryotic cells is often used as?

Answer 54

A target for antimicrobials

Question 55

In a prokaryotic cell division along two or three perpendicular planes form?

Answer 55

Cubical packets, example Sarcina genus

Question 56

In a prokaryotic cell, division along a single plane may result in?

Answer 56

Pairs or chains of cells - Pairs= diplococci, example Neisseria gonorrhoeae - Chains= streptococci, example species of Streptococcus