Lab Exam 1 Flashcards
Labs 1-4
magnify definition
appear larger or smaller
resolution
the ability to distinguish 2 objects that are close together as being 2 separate objects, rather than just 1
contrast
happens when different parts of an object absorb or transmit different amounts of light
* some parts appear darker or lighter than others
What sizes are compound microscopes good for?
1/10 of a micrometer to a few mm
Eyepiece
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
Nosepiece
has 4 objective lenses
Can be rotated to change objectives with different magnification (4x, 10x, 40x, and 100x)
How do you calculate total magnification?
eyepiece magnification x objective lens magnification
Mechanical stage
- 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
Condenser
- 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
2 focusing knobs
- 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
What is the size order and what magnifications were used?
Bacillus: 0.005 to 0.01 mm: 400x
Amoeba: 0.025-0.05 mm: 100x
33 hr chick embryo: 4.5 mm: 40x
What was the independent and dependent variable for lab 2 (Electrophoresis)
Independent variable: pH
Dependent variable: net electrical charge
Electrophoresis
a way to separate and identify proteins
What are the 3 categories of R-groups?
Non-polar
Polar
Ionic *matters for this lab
What are the 5 amino acids with an ionic R-group?
Aspartic acid
Glutamic acid
Lysine
Arginine
Histidine
Electrophoretic separation
- 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
Which acids have COOH in their R-groups? How do they act in low and high pH?
- 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)
Which acids have an amino (NH2) group in their R-groups? How do they act in low and high pH?
- 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)
Describe a low-pH environment
- protons (H+) are abundant
- neutral atoms may gain a proton
- lower the pH, more positively charged a protein is
What does histidine have and how does it behave?
- imino group
- behaves similarly to lysine and arginine
Describe a high pH environment
- 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
isoelectric point
protein has no charge
How does a protein behave when it is in a solution above and below the isoelectric point?
- 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
Synapomorphy
a character or trait that is shared
ex. feathers in birds, hair on mammals
