Lecture 4

Question 1

(isoelectric point) pI=

Answer 1

(pK1+pK2)/2

Question 2

triprotic amino acids

Answer 2

can buffer at 3 pH’s, still only one pI

Question 3

Amino acid charge changes as….

Answer 3

pH changed

Question 4

7 amino acids that are triprotic due to their R group

Answer 4

-aspartic acid, glutamic acid, histidine, cysteine, tyrosine, lysine, arginine

Question 5

Some solutions are unstable so….

Answer 5

• make fresh
• store aliquots (smaller increments)
• prevent exposure to light

Question 6

solutions that are food for microorganisms must be…

Answer 6

kept sterile

Question 7

The effectiveness of heat killing is altered by…

Answer 7

temperature, time, conductance (if one is increased, another can be decreased to get same killing effects

Question 8

conductance example

Answer 8

opening the oven vs. dipping hand in hot oil of same temperature

Question 9

autoclave

Answer 9

pressure cooker; high pressure and temp.

Question 10

How to filter solutions which can’t be heated…

Answer 10

pass through filter with holes too small for bacteria

Question 11

basic microscopy

Answer 11

-2 lenses in combination

Question 12

quality of image is dependent on:

Answer 12

• thickness of section
• lighting
• quality/cleanlines of lenses
• staining

Question 13

how to focus a microscope

Answer 13

-light
-diaphragm
-condenser
-lowest objective lens
-slide
-raise stage
-position slide
-eyepiece
-focus
-next lens
…

Question 14

empty magnification

Answer 14

a bigger image is useless without more detail

Question 15

resolution

Answer 15

to increase the amount of detail in an image;smallesy resolvable distance between 2 objects

Question 16

R (resolution) =

Answer 16

0.61(wavelength)/NA

Question 17

NA

Answer 17

numerical aperture of lens

Question 18

NA=

Answer 18

nsin(theta)

Question 19

n=

Answer 19

the refractive index of material the light travels through from subject to lens

Question 20

theta

Answer 20

1/2 the angle that light can enter the lens

Question 21

To use immersion oil you must have a lens that….

Answer 21

• is close enough to make a continuous slide-oil-lens connection
• does not react with oil