Bacteriology W7

Question 1

What is the study of fungi

Answer 1

Mycology

Question 2

What are fungi

Answer 2

Heterotrophs - cant make own food

Principle decomposers in every ecosystem

Question 3

Fungi structure

Answer 3

• fungi are composed of filaments called hyphae (singular: hypha).
• fungi have cell walls (like plants) but the cell walls are composed of chitin
• fungi do not have flagella at any phase of their life cycle

Question 4

Other fungi characteristics

Answer 4

• store ‘food’ in the form of glycogen (as do animals)
• generally the cells are haploid (1 set of chromosomes)
• produce secondary metabolites
• grow as hyphae or yeasts, the hyphae exhibit apical growth
• produce spores by means of sexual and asexual reproduction

Question 5

Cell membrane contains …

Answer 5

Ergosterol (animal have cholesterol and plants have sitosterol)

Question 6

Human infections

Answer 6

Due t similarity of human and fungal cells, fungal infections are difficult to treat

Athletes foot, ringworm and thrush

Question 7

Plant infections

Answer 7

Fungi cause major crop diseases

The great bengal famine 1943

Question 8

Chemical production

Answer 8

the diverse nature of fungal metabolic pathways generates many commercial products:
• ethanol
• organic acids (citric acid)
• enzymes (amylase, pectinase, protease)
• antibiotics (penicillin G)

Question 9

Protozoa

Answer 9

No cell wall

Heterotrophic

Motile

Specialised vacuole function for food digestion a nd water elimination

Asexual reproduction - mitosis - but can be sexual during some parts of their life cycle

Question 10

Bacteria

Answer 10

• cell wall is composed of peptidoglycan
• bacteria can have an outer membrane consisting of lippolysaccharides and proteins
• cytoplasm consists of cytosol
• ribosomes are granular inclusions that coordinate synthesis of proteins
• thylakoids are flattened discs with light-sensitive pigment molecules

DNA in nucleiods with no surrounding membrane

Question 11

Prokaryote vs eukaryote : size

Answer 11

Prokaryote : 0.5-2 um
eukaryote : 2-200 um

Question 12

Prokaryote vs eukaryote : nucleus membrane

Answer 12

Prokaryote : no
eukaryote : yes

Question 13

Prokaryote vs eukaryote : chromosomes

Answer 13

Prokaryote : 1, circular
eukaryote : >1

Question 14

Prokaryote vs eukaryote : division

Answer 14

Prokaryote : binary fisison
eukaryote : mitotic division

Question 15

Prokaryote vs eukaryote : mitochondria

Answer 15

Prokaryote : no
eukaryote : yes

Question 16

Prokaryote vs eukaryote : chloroplasts

Answer 16

Prokaryote : no
eukaryote : yes

Question 17

Prokaryote vs eukaryote : internal membranes

Answer 17

Prokaryote : relatively simple
eukaryote : complex (ER, golgi)

Question 18

Prokaryote vs eukaryote : ribosomes

Answer 18

Prokaryote : 70S ribosomes
eukaryote : 80S ribosomes

Question 19

Aerobe

Answer 19

Need O2

Question 20

Anaerobe

Answer 20

Cannot tolerate O2

Question 21

Psychrophile

Answer 21

-5 to +15 degrees

Question 22

Mesophile

Answer 22

+10 to +45 degrees

Question 23

Thermophile

Answer 23

+30 to +85 degrees

Question 24

Acidophile

Answer 24

Grow under acidic conditions

Question 25

Neutrophile

Answer 25

Need pH around 7

Question 26

Alkaliphile

Answer 26

Need high pH

Question 27

Not halophile

Answer 27

Up to 2.5% salt

Question 28

Halotolerant

Answer 28

Up to 6.5% salt

Question 29

Halophile

Answer 29

Yo to 20-25% salt

Question 30

Bacterial conjugation

Answer 30

Have a f-(female) and f+(male) bacteria Come together and there id a conjugation of cells and copy of th F factor transferred into the f- cell F- then becomes f+ and both cells synthesise a complementary DNA strand Both cells now f+ and seperate

Question 31

Transformation

Answer 31

occurs when a bacterium picks up fragments of DNA released by dead bacteria or secreted by live bacteria

Question 32

Transduction

Answer 32

is when bacteriophages (viruses) carry portions of bacterial DNA from one cell to another

Question 33

Mutation

Answer 33

is a major source of variation in prokaryotes

Question 34

How can antibiotic resistance transfer between bacteria’s

Answer 34

By plasmid transfer

Question 35

Endospores

Answer 35

Not all bacteria produce • endospores are a method of survival, not reproduction • some bacteria form endospores when environmental conditions become unfavourable • spores can endure for hundreds of years • endospores are DNA and a portion of cytoplasm encased in a tough cell wall; they are resistant to extremes in temperature, drying, and harsh chemicals

Question 36

Gram negative

Answer 36

have a cell wall, low amount of peptidoglykan, are not sensitive against penicillin or lysozyme, are sensitive against mechanical pressure (E.coli, Pseudomonas aeruginosa)

Question 37

Gram positive

Answer 37

have a cell wall, high amount of peptidoglykan, are sensitive against penicillin, lysozyme, are not sensitive against mechanical pressure (Bacillus anthracis, Streptococcus mutans)

Question 38

Gram - vs + structure

Answer 38

Gram positive bacteria have a thick peptidoglycan layer and no outer lipid membrane Gram negative bacteria have a thin peptidoglycan layer and have an outer lipid membrane.

Question 39

Endotoxins from gram negative bacteria

Answer 39

are the most common cause of toxic reactions resulting from contamination of pharmaceutical products with pyrogens • their pyrogenic activity is much higher than that of most other pyrogenic substances • these endotoxins are lipopolysaccharides (LPS)

Question 40

Physiological effects of pyrogens

Answer 40

• dependant upon route of administration • effects are dose dependant • effects are dependant on the general state of health of the patient • low doses induce an asymptomatic inflammatory response • moderate doses induce fever and changes in plasma composition • high doses result in shock, multiple organ failure and death

Question 41

BP test for pyrogens

Answer 41

• product is administered initially to 3 rabbits at a dose of no greater than 10ml/kg • rabbits are housed in carefully controlled conditions and their temperature is monitored before the test product is given • temperatures are taken (rectally) at 30 minute intervals for 3 hours post administration

Question 42

BP Test for Bacterial Endotoxins

Answer 42

• LAL Test – Limulus Amoebocyte Lysate Test based on the endotoxin induced coagulation of the blood of the Horseshoe crab Limulus Polyphemus • test is based on observation that horseshoe crab blood forms clots when exposed to endotoxins • Amoebocyte extract from horseshoe crab blood is mixed with a sample suspected of endotoxin contamination, and a reaction is observed if endotoxins are present • about 1000 x more sensitive than the Test for Pyrogens