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Flashcards in Chapter 3 lecture notes Deck (56):
1

All prokaryotes don't have?

Cytoskeleton.

2

A prokaryotes shell is made of?

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

3

The pili on prokaryotes adhere to?

Substrates & glue to each other using capsules

4

Sperical round shape

Coccus

5

Rod shape

Bacillus

6

Short round rod

Coccobacillus

7

Curved rod

Vibrio

8

Spiral shape

Spirillus. Fiber in cell wall allows to curve on itself

9

Helical shape, tight coiling

Spirochete

10

Vary in shape

Pleomorphic. Can assume different forms

11

Diplobacilli=

2 bacilli

12

Streptobacilli=

String

13

Prokaryotic cells may form groupings

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

14

Division along two or three perpendicular planes form

Cubical packets

15

Division along several random planes form

Clusters

16

General function of capsules and slime layer of glycocalyces

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

17

Organized layer of sugar=
Disorganized layer of sugar=

Organized= capsule
Disorganized= slime layer

18

Distinct gelatinous layer

Capsule

19

Irregular diffuse layer

Slime layer

20

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

Polysaccharides

21

Glyco=
Calyx=

Glyco= Sugar
Calyx= Shell

22

Cell wall of bacteria 6 main points

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 -)

23

The rigidity of the bacterial cell wall is due to?

Peptidoglycan (PTG)

24

The basic structure of peptidoglycan

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)

25

What are the sugars in peptidoglycan

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

26

Gram-positive cell wall

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

27

Main points about prokaryotes

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

28

Gram-negative cell wall main points (4)

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)

29

Cytoplasmic membrane main points

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

30

Simple diffusion

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

31

Facilitated diffusion main points (3)

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

32

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

1) Flagella
2) Pili

33

Flagella are

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)

34

3 basic parts of flagella

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

35

Bacteria use flagella for

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

36

Bacteria can have flagella and pili, the pili are?

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.

37

Differences in cell wall account for differences in staining characteristics

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

38

Some bacteria lack cell wall

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

39

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

Antimicrobial drugs directed against cell wall are ineffective

40

Bacteriain Domain Archaea

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

41

Cytoplasmic membrane proteins

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

42

Osmosis is

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)

43

Two primary forms of energy

ATP & Proton motive force

44

3 mechanisms for active transport

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

45

Alters the molecule

Group translocation

46

Movement of many molecules directed by

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

47

Storage granules / Inclusions is

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

48

Gas vesicles main points

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

49

Endospores main points

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

50

Essential for translation (proteins)

Ribosome

51

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

Ribosome

52

Prokaryotic ribosomal subunits
Large=
Small=
Total=

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

53

Eukaryotic ribosomal subunits
Large=
Small=
Total=

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

54

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

A target for antimicrobials

55

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

Cubical packets, example Sarcina genus

56

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

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