Intro - Lecture 1

Question 1

Describe the characteristics of a living organism (6 qualities that must be there)

Answer 1

1) Organization - cellular or molecular level
2) Metabolism - use energy to carry out functions
3) Growth - replication and enlargement
4) Adaptation - evolution of traits that increase fitness
5) Response to stimulus - evolution of traits that increase fitness and/or maintain homeostasis
6) reproduction

Question 2

Are bacteria prokaryotic or Eukaryotic?

Multicellular or unicellular?

Answer 2

Prokaryotic

Unicellular

Question 3

How are bacteria classified?

Answer 3

Classified by biochemical and morphological characteristics

Question 4

Are parasites prokaryotic or Eukaryotic?

Multicellular or unicellular?

Answer 4

Eukaryotic

Unicellular and multicellular

Question 5

How are parasites classified?

Answer 5

Classified based on life cycle and structure

Question 6

Most human parasite pathogens affect what part of the body?

Give some example pathogens

Answer 6

Most human pathogens affect the GI tract and the blood

• malaria
• helminths and worms
• amoeba

Question 7

Are fungi prokaryotic or Eukaryotic?

Multicellular or unicellular?

Answer 7

Eukaryotic

unicellular and multicellular

Question 8

How are fungi classified?

Answer 8

Classified by location of infection

Question 9

Where do most fungal infections occur?

Where else do fungal infections exist?

Answer 9

Mostly occur superficial or cutaneous

Also exist subcutaneously and systemically

Question 10

Give some examples of fungal infections.

Answer 10

Candidiasis - yeast infection, thrush
Dandruff
Athlete’s foot

Question 11

Give some characteristics of prions

and some examples

Answer 11

Non-living
Acellular, made up of protein
Transmissible, misfolded protein
-Bovine spongiform encephalopathy
-Kreutzfeld-Jakob disease
-Kuru

Question 12

Give five characteristics of prokaryotes

Answer 12

Unicellular
One cellular membrane
No organelles
Replicate by binary fission
Bear a haploid genome (one copy)

Question 13

Give five characteristics of eukaryotes

Answer 13

Unicellular and multicellular
Multiple membranes
Multiple membrane-bound structures (nucleus, mitochondria, ER, golgi, lysosomes etc.)
Replicate by mitosis
Bear a haploid or diploid genome (one or two copies)

Question 14

What are six things bacteria cells need to stay alive?

Answer 14

1) Genetic material
- Nucleoid DNA
- Plasmid DNA
2) Replication machinery
- DNA-dependent DNA polymerase
3) Gene expression
- Trascription: DNA-dependent RNA polymerase
- Translation: Ribosomes
4) Structural integrity
- Cell wall (some exceptions)
5) Motility
- Flagella, cilia, pili
6) Friends
- Genetic diversity
- Biofilms

Question 15

How do bacteria replicate?

Answer 15

Binary fission

Question 16

How are bacteria classified?

Answer 16

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Strain
Serotype/Serovar

Question 17

What is the difference between bacteria of different species?

Answer 17

They bear major genetic differences

Question 18

What is the difference between bacteria of different strains?

Answer 18

They are genetically distinct

Question 19

What is the difference between bacteria of different serotype/serovar?

Answer 19

The are serologically different (H__:N__)

Question 20

What are four major different morphologies of bacteria?

Name a few more

Answer 20

Cocci - round
Bacilli - rod-shaped
Sphirochetes - spiral
Vibria - curved rod
Helical, filamentous etc.

Question 21

What does a gram stain detect and what are the two dies used?

Answer 21

Detects peptidoglycan
Crystal violet is the primary stain
Safranin is the counterstain

Question 22

What colour are the gram positive bacteria?

Answer 22

Violet

Question 23

What colour are the gram negative bacteria?

Answer 23

Pink

Question 24

What are the 6 classis gram positive bacteria?

Answer 24

Streptococcus
Staphylococcus
Bacillus
Clostridium
Corynebacterium
Listeria

Question 25

What is the diplococcus gram negative bacteria?

Answer 25

Neisseria

Question 26

What are some examples of gram negative bacteria?

Answer 26

Neisseria
Enterobacteria (E. coli)
Pseudomonas
Salmoonella

Question 27

What are the three exceptions to gram stain bacteria?

Answer 27

1) Acid-fast bacteria - Mycobacteria
- These are weakly gram-positive but stain better with the acid-fast stain
- Include organisms that cause TB and leporsy

2) Spirochetes
- These have a gram negative cell wall, but do not stain/are too small to be seen under light microscopy
- Visulaized with darkfeild microscope

3) Bacteria lacking cell walls - Mycoplasm, ureoplasma

Question 28

What are three enzymes bacteria might have to break down oxygen products?

Answer 28

1) Catalase - breaks down hydrogen peroxide to water and oxygen
2) Peroxidase - breaks down hydrogen peroxide
3) Superoxide dismutase - breaks down the superoxide radical to hydrogen peroxide and oxygen

Question 29

Describe obligate aerobic bacteria

Answer 29

Require oxygen for growth

Possess all three enzymes

Question 30

Describe facultative anaerobes

Answer 30

Can grow in the absence of oxygen - use fermentation
But prefer oxygen
Possess Catalase and superoxidase dismutase

Question 31

Describe microaerophilic bacteria (aerotolerant anaerobes)

Answer 31

Use fermentation
But can tolerate low amounts of oxygen

Possess superoxide dismutase

Question 32

Describe obligate anaerobe bacteria

Answer 32

Hate oxygen

Posses no enzymes to defend against oxygen

Question 33

What can culturing bacteria in different media reveal?

Answer 33

1) Colony morphology - distinguish between specias
2) Colony growth
3) Enzymatic activity

Question 34

What does Bloor agar detect when culturing bacteria?

Answer 34

Haemolysis

Question 35

What does Lactose-containing agar detect when culturing?

Answer 35

Detects lactose fermentation

Question 36

Where do thermophile bacteria thrive?

Give an example

Answer 36

Thrive in hot environments

Thermus aquaticus

Question 37

Where do acidophile bacteria thrive?

Give an example

Answer 37

Thrive at low pH

Acetobacter aceti

Question 38

How does bacteria gain genetic diversity if they replicate via binary fission?

Answer 38

1) Mutation
2) DNA rearrangements (transposition, recombination)
3) Horizontal gene transfer (conjugation, transformation, transduction)

Question 39

What are the six major bacterial groups?

Answer 39

1) Gram-positive cocci and rods
2) Gram-negative bacteria
3) Enteric bacteria (mostly gram-negative)
4) Acid-fast bacteria (ie. Mycobacteria)
5) Mycoplasma and ureaplasma
6) intracellular bacteria