Lectures 4-7

Question 1

True or False: A large number of pathogens are bacteria

Answer 1

False

Question 2

True or False: Bacteria can be photosynthetic and non-photosynthetic

Answer 2

True - Cyanobacteria are photosynthetic

Question 3

What is a “Coccus” bacterium shape?

Answer 3

A spherical, round or ovoid shape that is 200 nm

Question 4

What is a “Bacillus” bacteria shape?

Answer 4

Rod-shaped

Question 5

What is a “Vibrio” bacteria shape?

Answer 5

A curved-rod or comma shape

Question 6

What is a “Coccobacillus” bacteria shape?

Answer 6

A very short rod-shape (longer than coccus, shorter than bacillus) - 2 nm in length

Question 7

What is a “Spirillum” bacteria shape?

Answer 7

A spiral or gently-curved shape

Question 8

What is a “Spirochete” bacteria shape?

Answer 8

A tightly-coiled spiral shape that is roughly 500 nm

Question 9

What are the cell walls of archaea made of?

Answer 9

Pseudopeptidoglycan

Question 10

What is the Domain of eukaryotes?

Answer 10

Eukarya

Question 11

What organisms are in Eukarya?

Answer 11

1) Protists
2) Fungi
3) Plants
4) Animals

Question 12

What are the different protists?

Answer 12

Algae and Protozoa

Question 13

What is one of the most defining characteristics of fungi outside of their chitin cell wall?

Answer 13

They are heterotrophic

Question 14

What are the four characteristics of viruses?

Answer 14

1) Acellular
2) Consist of proteins and genetic material (DNA or RNA)
3) They need a host in order to survive
4) They can infect all types of cells

Question 15

What is Light Microscopy?

Answer 15

A type of microscopy that resolves images according to the absorption of light

Question 16

What are the four types of Light Microscopy?

Answer 16

1) Bright Field Microscopy - Specimens appear as a dark silhouette against a light background through direct light transmissions
2) Dark Field Microscopy - Technique where an angled light is used to create a bright image of specimens against a dark background
3) Phase-Contrast Microscopy - Enhances the contrast of transparent specimens and organelles to the background/cytoplasm
4) Fluorescence Microscopy - The specimen absorbs light of a defined wavelength and emits light of lower energy, causing species fluoresces

Question 17

What is Electron Microscopy?

Answer 17

A type of microscopy that uses beams of electrons to resolve smaller (than visible light) details

Question 18

What is the difference between a Scanning Electron Microscope (SEM) and a Transmission Electron Microscope (TEM)

Answer 18

A Scanning Electron Microscope (SEM) creates a 3D image by detecting reflecting electrons.
A Transmission Electron Microscope (TEM) uses electrons that are passing through thin sections of the sample to create a 2D image

Question 19

What is a Simple Stain?

Answer 19

A simple stain adds a dark colour specifically to cells, but not the external medium or surrounding tissue
ex.) Methylene Blue

Question 20

What is a Differential Stain

Answer 20

A differential stain stains one kind of cell, but not another
ex.) Gram stain

Question 21

What does Gram staining differentiate?

Answer 21

Gram staining differentiates two types of bacteria:
1) Gram-positive bacteria retain the stain due to a thicker cell wall and appear purple
2) Gram-negative bacteria do not retain the stain and appear and pinkish-reddish colour

Question 22

What is an Acid-Fast Stain?

Answer 22

An acid-fast stain differentiates gram-positive cells with mycolic acids in their cell walls, and gram-positive cells that do not.