Microbiology Block E- Lecture 1

Front 1

What is the size range for prokaryotes

Back 1

0.2 to >700 um

Front 2

Examples of very large prokaryotes

Back 2

Epulopiscium fishelsoni

Thiomargarita namibiensis

Front 3

Size range of eukaryotic cells

Back 3

10 to >200 um

Front 4

What is the advantage to a small cell

Back 4

Have more surface area relative to cell volume than large cells

Front 5

What advantages do small cells have

Back 5

Support greater nutrient exchange per unit cell volume

Tend to grow faster than large cells

Faster grow= more mutations

Front 6

What is morphology

Back 6

The study of cell shapes

Front 7

What are the major cell morphologies

Back 7

Coccus

Rod

Spirillum

Front 8

What is coccus shape

Back 8

Spherical or ovoid

Front 9

What is rod shape

Back 9

Cylindrical shape

Front 10

What is spirillum shape

Back 10

Spiral shape

Front 11

What cells have unusual shapes

Back 11

Spirochetes, appendages bacteria, and filamentous bacteria

Front 12

What does cell morphology not typically predict

Back 12

Physiology

Ecology

Phylogeny

Of prokaryotic cells

Front 13

What are the selective forces involved in setting the morphology

Back 13

Optimisation for nutrient uptake

Swimming motility in viscous environments or near surfaces

Gliding motility

Particulate environment

Front 14

What is the cytoplasmic membrane

Back 14

Thin structure that surrounds the cell

It is a vital barrier that separates cytoplasm from environment

Front 15

What does a highly selective permeable barrier mean

Back 15

Enables concentration of specific metabolites and excretion of waste products

Front 16

What is the general structure of a cytoplasmic membrane

Back 16

Phospholipid bilayer

Front 17

What two component does a cytoplasmic membrane

Back 17

Hydrophobic and hydrophilic

Front 18

What way do fatty acids face and what do they form

Back 18

They form the hydrophobic environment

Hydrophilic portions remain exposed to external environment or the cytoplasm

Front 19

How wide is the cytoplasmic membrane

Back 19

8-10nm wide

Front 20

What is embedded into the cytoplasmic membrane

Back 20

Proteins

Front 21

How is the cytoplasmic membrane stabilised

Back 21

Stabilised by hydrogen bonds and hydrophobic interactions

Front 22

How do Mg2+ and Ca2+ help stabilise the membrane

Back 22

It forms ionic bonds with negative charges in the phospholipid

Front 23

Is the cytoplasmic membrane fluid

Back 23

Somewhat

Front 24

What is a proton anchor

Back 24

Holds transport proteins in place

Front 25

What are the two different species of bacteria

Back 25

Gram positive and gram negative

Front 26

What does the gram negative cell wall contain

Back 26

Two layers- LPS and peptidoglycan

Two membranes

Front 27

What does the gram positive cell wall have

Back 27

One layer of peptidoglycan

One membrane

Front 28

What prokaryotes lack cell walls

Back 28

Mycoplasmas

Thermoplasma

Front 29

What are mycoplasmas

Back 29

Group of pathogenic bacteria

Front 30

What are thermoplasma

Back 30

Species of archaea

Front 31

What percentage of peptidoglycan do gram positive cells walls contain

Back 31

Up to 90%

Front 32

What are teichoic acids

Back 32

Acidic substances embedded in their cell wall

Front 33

What are lipoteicgoic acids

Back 33

Teichoic Acids covalently bound to membrane lipids

Front 34

What is the periplasm

Back 34

Space located between cytoplasmic and outer membranes

Front 35

What are porins

Back 35

Channels for movement of hydrophilic low molecular weight substances

Front 36

What percentage of total cell wall of a gram negative bacteria contains peptidoglycan

Back 36

Around 10%

Front 37

What does LPS stand for

Back 37

Lipopolysaccharide

Front 38

What does the old consist of

Back 38

Core polysaccharide and O-polysaccharide

Front 39

What does LPS replace most of

Back 39

Phospholipid in outer half of outer membrane

Front 40

What is an endotoxin

Back 40

The toxic component of LPS

Front 41

What are polysaccharides composed of

Back 41

N-acetylglucosamine and N-acetylmuramic acid

Amino acids

Lysine or DAP

Cross linked differently in gram negative bacteria and gram positive bacteria

Front 42

What is bactoprenol

Back 42

Carrier molecule that plays a major role in insertion of peptidoglycan precursor

Front 43

What does bactoprenol bond to

Back 43

N-acetylglucosamine/ N-acetylmuramic acid/ pentapeptide peptidoglycan precursors

Front 44

What are glycolyses

Back 44

Enzymes that interact with bactoprenol insert cell wall precursors into growing points of cell wall

Front 45

What do glycolyses catalyse

Back 45

Glycosidic bond formation

Front 46

What is transpeptidation

Back 46

Final step in cell wall synthesis

Front 47

What does transpeptidation form

Back 47

Forms the peptide cross links between murmaic acid residues in adjacent glycan chains

Front 48

What inhibits transpeptidation

Back 48

Penicillin

Front 49

What are autolysins

Back 49

Small openings in the wall

Front 50

What is added across the openings created by autolysins

Back 50

New cell wall material

Front 51

What is a wall band

Back 51

Junction between new and old peptidoglycan

Front 52

What way does the cell walls grow in cocci

Back 52

Grow in opposite directions outward from the FtsZ ring

Front 53

What way does the cell wall grow in, in rod shaped cells

Back 53

Growth occurs at several points along length of the cell

Front 54

What way does the cell wall grow in steptomyces

Back 54

Incorporated at hyphal tip

Front 55

What is the MerB

Back 55

Major snap determine factor in prokaryotes

Front 56

What is crescentin

Back 56

Shape determining protein produced by vibrio shaped cells of caulobacter crescentus

Front 57

What does the crescentin protein organise

Back 57

Organises into filaments around 10nm wife that localise on the concave face of the curved cells