Chapter 1

Question 1

Virus

Answer 1

Acellular entities that must invade a host to replicate

Question 2

Viroids

Answer 2

Are infectious agents composed only of RNA. They cause numerous plant diseases

Question 3

Satellites

Answer 3

They co-infect cells with a virus. They are also called helper virus

Question 4

Prions

Answer 4

Infections agents composed only of protein and are responsible for causing neurological diseases such as mad cows disease

Question 5

Walter Gilbert

Answer 5

Coined the term RNA world

Question 6

Robert Koch (“coke”)

Answer 6

First direct demonstration that bacteria cause disease.

He used mice and Guinea pigs to show that mycobacterium terbculosis caused tuberculosis (TB) which was the lead leading cause of death at the time.

The relationship between a bacteria and its disease is now called a Koch postulate

Question 7

Louis pasture

Answer 7

Disproved “spontaneous generation”

Created pasteurization

Created vaccine for rabies

Developed theory for “germ theory”

Question 8

Bright field microscope

Answer 8

Ones you see in highschool labs. They shine light from the bottom

Question 9

Resolution

Answer 9

Ability to distinguish 2 points

Question 10

Contrast

Answer 10

White sheep on white hill
Or
White sheep on dark hill

Question 11

Dark field (light-microscopy)

Answer 11

Light shines from top down

Question 12

Phase-contrast microscope (light-micro)

Answer 12

2 beams shine and cancel each other out

There’s lots of contrast between points

Question 13

Differential interference contrast (DIC) (light-micro)

Answer 13

Similar to phase-contrast but it appears more 3D

Question 14

Fluorescent Microscope (light-micro)

Answer 14

Can use dyes or tags to see things glow

Question 15

Confocal microscope (light-micro)

Answer 15

Creates very sharp 3D images using a scanning laser beam

Question 16

Basic dyes

Answer 16

Positivity charged groups that bind to negatively charged molecules

Ex: Safranin

Question 17

Acidic dyes

Answer 17

Have negatively charged groups that bind to positive charged cell structures

Ex: eosin

Question 18

Steps to stain bacteria

Answer 18

Step 1: stain with crystal violet (primary stain). Rinse after 1 min
—> all cells will stain purple

Step 2: iodine wash (mordant) Rinse after 1 min
—> all cells will remain purple

Step 3: alcohol (decolorizer). Rinse after 30sec
—> gram positive remain purple
—> gram negative are colourless

Step 4: Safranin (counterstain). Rinse after 30sec
—> gram positive remain purple
—> gram negative become pink/red

Question 19

Transmission Electron microscope

Answer 19

Shoots beams of electrons through the specimen

Question 20

Scanning Electron microscope

Answer 20

Shoots and electrons at specimen and reads the reflected electrons (only good for SA)

Question 21

Scanning probe microscope

Answer 21

Most sensitive form. Uses a small probe to scan along the surface of a specimen. The probe moves up or down in response to the contours. Can measure at the single atom level (doesn’t require dehydration or a high vacuum like electron micro does)