Lab Exam 1

Question 1

magnify definition

Answer 1

appear larger or smaller

Question 2

resolution

Answer 2

the ability to distinguish 2 objects that are close together as being 2 separate objects, rather than just 1

Question 3

contrast

Answer 3

happens when different parts of an object absorb or transmit different amounts of light
* some parts appear darker or lighter than others

Question 4

What sizes are compound microscopes good for?

Answer 4

1/10 of a micrometer to a few mm

Question 5

Eyepiece

Answer 5

can be moved apart or together
The right eyepiece has a pointer
Have a diopter ring to adjust the sharpness of the image
Eyepiece magnification is 10x

Question 6

Nosepiece

Answer 6

has 4 objective lenses
Can be rotated to change objectives with different magnification (4x, 10x, 40x, and 100x)

Question 7

How do you calculate total magnification?

Answer 7

eyepiece magnification x objective lens magnification

Question 8

Mechanical stage

Answer 8

• Has a caliper that holds a slide in place
• Can move with stage controls
• Lower knob moves slide left to right
• Upper knob moves toward or away from you

Question 9

Condenser

Answer 9

• Contains an iris diaphragm: can be opened to permit more light to illuminate the slide
• High magnification objectives - The diaphragm allows enough light to see objects clearly
• Contrast can be increased by closing down the diaphragm through a lever at the front of the condenser
• contrast

Question 10

2 focusing knobs

Answer 10

• Coarse focus knob moves stage up or down
• Outer ring
• Fine focus knob moves stage up or down — - - only a SMALL distance
• 40x and 100x
• resolution

Question 11

What is the size order and what magnifications were used?

Answer 11

Bacillus: 0.005 to 0.01 mm: 400x
Amoeba: 0.025-0.05 mm: 100x
33 hr chick embryo: 4.5 mm: 40x

Question 12

What was the independent and dependent variable for lab 2 (Electrophoresis)

Answer 12

Independent variable: pH
Dependent variable: net electrical charge

Question 13

Electrophoresis

Answer 13

a way to separate and identify proteins

Question 14

What are the 3 categories of R-groups?

Answer 14

Non-polar
Polar
Ionic *matters for this lab

Question 15

What are the 5 amino acids with an ionic R-group?

Answer 15

Aspartic acid
Glutamic acid
Lysine
Arginine
Histidine

Question 15

Electrophoretic separation

Answer 15

• depends on net electrical charge of proteins
• If a protein has a net negative charge, it will go toward the positive pole of the field
• If it has a net negative charge, it will go toward the negative pole
• No net charge, will not move

Question 15

Which acids have COOH in their R-groups? How do they act in low and high pH?

Answer 15

• aspartic acid and glutamic acid
• At low PH, they are not charged; their COOH groups are protonated
• At high pH, their COOH groups lose protons and acquire a negative charge (COOH +OH- → COO- + H2O)

Question 16

Which acids have an amino (NH2) group in their R-groups? How do they act in low and high pH?

Answer 16

• lysine and arginine
• At low pH, they are positively charged; their NH2 groups are protonated (NH2 + H+ → NH3+)
• At high pH, their NH3+ groups lose protons and lose their charge (NH3+ + OH- → NH2 + H2O)

Question 17

Describe a low-pH environment

Answer 17

• protons (H+) are abundant
• neutral atoms may gain a proton
• lower the pH, more positively charged a protein is

Question 18

What does histidine have and how does it behave?

Answer 18

• imino group
• behaves similarly to lysine and arginine

Question 19

Describe a high pH environment

Answer 19

• Hydroxide ions may react with positively charged amino acids, giving them a net charge of 0
• higher the pH, more negatively charged a protein is

Question 20

isoelectric point

Answer 20

protein has no charge

Question 21

How does a protein behave when it is in a solution above and below the isoelectric point?

Answer 21

• Protein in solution where pH below isoelectric point will be net positive charge (b/c lots of H+)
• Protein in solution where pH above isoelectric point will be net negative charge

Question 22

Synapomorphy

Answer 22

a character or trait that is shared

ex. feathers in birds, hair on mammals

Question 23

What is the difference between eukaryotes and prokaryotes?

Answer 23

Eukaryotes have a nuclear membrane and prokaryotes don’t

Question 24

What are the 2 types of prokaryotes?

Answer 24

1. archaea
2. eubacteria

Question 25

archaea

Answer 25

live in very salty, hot, or acidic environments

Question 26

Permeable definition

Answer 26

makes it through phospholipid bilayer

Question 26

eubacteria (3 types)

Answer 26

• Have peptidoglycan cell walls which keep them from bursting when water diffuses in
• Cocci - spherical
• Bacilli - rodshaped
• Spirilla - helical

Question 27

What are the 2 types of eukaryotes?

Answer 27

1. protists
2. fungi

Question 27

Lyse

Answer 27

cell bursts if too much water goes in

Question 28

Hemolysis

Answer 28

lyse for red blood cells

Question 29

What happens with a not-so-permeable cell?

Answer 29

• solute enters slowly
• lysis takes longer to occur (takes longer to become transparent)

Question 30

What happens with a highly permeable cell?

Answer 30

• solute quickly diffuses in
• cell swells w/ water
• cell bursts

Question 31

Which molecules pass through cell membranes easily and why?

Answer 31

lipid-soluble molecules (ones with CH3, CH2, CH groups) pass through cell membranes easily b/c they can dissolve in the lipids of the cell membrane

Question 32

What are the independent (3) and dependent variables for lab 4 (membrane permeability)

Answer 32

Independent variables
Size of solute molecule
Net charge of solute particle
Lipid solubility of solute molecule

Dependent variable
Cell membrane permeability

Question 33

What effect does the net electrical charge on a molecule (or atom) have on membrane
permeability? How do you know

Answer 33

• electrically charged particles cannot cross
  the membrane
• We know b/c NaCl did not lyse the cells which means they didn’t enter the cell

Question 34

What is the relationship between CHn/OH and lipid solubility?

Answer 34

CHn/OH ratio is directly related to lipid solubility