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BSC2085 Lab > Midterm > Flashcards

Midterm Flashcards

1
Q

What are the five steps of the scientific method? (OHPEC)

A

Observation, hypothesis, prediction, experiment, conclusion

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2
Q

What is a hypothesis?

A

A proposed explanation for a phenomena

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3
Q

Why must a hypothesis be falsifiable?

A

You must be able to prove that it is false because if you can’t prove it false, you can’t prove it right.
Meaning that it can be tested in a way that can lead to evidence that does not support the hypothesis.

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4
Q

What is a beaker?

A

A beaker is used to hold large amount of liquid, but does not accurately measure volume

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5
Q

What is a graduated cylinder?

A

A graduated cylinder is used to measure smaller amounts of liquid, more accurate than beakers

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6
Q

Pipettes accurately measure small volumes of liquid, usually between __-__ml

A

0-10ml

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7
Q

Micropipettes measure volume in ____________

A

microliters

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8
Q

Mohr pipettes have…

A

graduation marks that stop before the end of the tip

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9
Q

Serological pipettes have…

A

graduation marks that continue to the tip

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10
Q

Volumetric pipettes…

A

Precisely and accurately measures one volume.

Wide at the middle of the pipette; dispenses a single volume

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11
Q

Always hold the pipette upright and view the meniscus at ____ ______

A

Eye level

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12
Q

How do you calculate % error?

A

(Measured vol -theoretical vol)/

(theoretical vol)x100

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13
Q

What is a spectrophotometer?

A

The spectrophotometer is an instrument used to measure the amount of light that is absorbed by (scale of 0-2) or transmitted through (percentile scale 0-100%) a sample at a particular wavelength of light.

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14
Q

Absorbance of a solution is directly proportional to the concentration of molecules in the solution according to _____-_________ law.

A

Beer-Lambert Law

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15
Q

You will use the spectrophotometer to obtain an __________ __________ and a ___________ _______ for a blue dye called ___________ ______

A

Absorption spectrum and a standard curve, bromophenol blue

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16
Q

What is an absorption spectrum?

A

A pattern of light absorption over a range of wavelengths for a particular substance

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17
Q

What can one determine from an absorption spectrum?

A

One can determine the wavelength of max (peak) absorbance by the substance

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18
Q

What is a standard curve?

A

A plot of known concentrations of a series of samples against absorbance.

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19
Q

How can the standard curve be used to find the concentration of an unknown substance?

A

Find the absorbance of the unknown sample, and then plug it into your standard curve, and you can 1) estimate the concentration by eye, or 2) plug in the absorbance of the unknown sample to the equation of the line

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20
Q

What is the control?

A

The single variable of interest that is being tested. The control is used as a standard of comparison when assessing the results of an experiment

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21
Q

What is the independent variable?

A

The variable that is being changed or controlled

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22
Q

What is the dependent variable?

A

The variable that is being tested or measured

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23
Q

Why are graduated cylinders more accurate than beakers?

A

They have smaller graduated increments

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24
Q

The _______ is the portion of the fluid’s surface that has a concave appearance; this concavity is caused by surface tension

A

meniscus

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25
Q

What is the difference between an absorbance curve and a standard curve?

A

An absorbance curve measures the absorbance of a sample over a series of wavelengths.
A standard curve is used to determine the unknown concentration of a sample.

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26
Q

What is the optimum range for bromophenol blue?

A

580-600nm

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27
Q

Know the names and functions of parts of a microscope

A

Know the names and functions of parts of a microscope

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28
Q

What is resolution?

A

The effectiveness by which two points can

be perceived as distinct

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29
Q

What is magnification?

A

Enlargement of something’s physical appearance

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30
Q

What is contrast?

A

The difference between the light and dark areas of an image; higher contrast means more difference

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31
Q

What is depth of field?

A

The range of distance in front of and behind an object focused by the microscope, within which other objects will also appear clear and sharply defined in the resulting image.

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32
Q

What is the index of refraction?

A

At higher magnifications, light is refracted, or bent, into the objective lens because the refractive index of air between the slide and the objective is lower than the refractive index of glass.

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33
Q

How does the addition of immersion oil solve this problem?

A

Immersion oil has a refractive index similar to glass and allows higher resolution at high magnification

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34
Q

How do calculate the total magnification?

A

Multiply the objective lens x 10

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35
Q

How do you calculate diameter of field of view?

If 4x has a f.o.v. of 4mm, then what would would the unknown f.o.v. be for 40x?

A

Take the total magnification of 4x (which is 40x). Divide the known magnification (40x) by the unknown magnification (400x) and then multiply it by 4mm = .4mm

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36
Q

How would you estimate the size of a cell depending upon the magnification and diameter of the field of view?

A

Take the diameter of FOV (micrometers) and divide it by the number of cells that would fit across the diameter.

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37
Q

What is one advantage and disadvantage of an electron microscope?

A

Advantage: use electrons to view details
Disadvantage: specimen is killed

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38
Q

When is it appropriate to use the coarse adjust? Fine adjust?

A

Course adjust: 4x and 10x

Fine adjust: 40x and 100x

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39
Q

What happens to the depth of field as you increase the magnification?

A

Increase magnification, decrease field of view

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40
Q

A drop of ___________ is used when viewing a specimen under the 100x objectives?

A

immersion oil

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41
Q

By staining the cells, you have improved the ______, the difference between light and dark parts of the image.

A

contrast

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42
Q

What is a prokaryote?

A

No nucleus, no membrane-bound organelles,

1-10micrometers in size

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43
Q

What is a eukaryote?

A

Have a nucleus, membrane-bound organelles, 10-100 micrometers in size

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44
Q

The DNA of prokaryotes is suspended within the cell’s aqueous interior, or _______.

A

cytosol

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45
Q

What are the most common prokaryotes?

A

Bacteria

46
Q

Prokaryotes divide by _______ _______

A

binary fission

47
Q

______, the microscopic inhabitants of pond water, are single celled eukaryotes.

A

Protists

48
Q

Cell wall gives shape and prevents cells from bursting due to ________ _______.

A

osmotic pressure

49
Q

As size ________, the SA to volume ratio ________, so larger cells have more trouble obtaining enough nutrients and ridding themselves of waste.

A

increase, decreases

50
Q

Which bacterium makes yogurt?

A

Lactobacillus

51
Q

What are the two prokaryotic organisms observed?

A

Lactobacillus and Cyanobacteria

52
Q

Which other six are eukaryotic?

A

Elodea, potato, onion, amoebae, paramecium, and hypermastigotes

53
Q

Which are photosynthetic?

A

Cyanobacteria, elodea, and (euglena)

54
Q

Which three organisms are heterotrophs?

A

Amoebae, paramecium, and hypermastigotes

55
Q

Do onion and potato cells have chloroplasts? If not, explain.

A

No, onion and potato cells do NOT have chloroplasts because they are underground and there is no light

56
Q

Which organism was previously know as ‘blue-green algae’?

A

Cyanobacteria

57
Q

Endosymbiont theory is a theory that offers an explanation for how plant cells acquired ________, the organelle where photosynthesis occurs. Evidence includes:

A

chloroplasts.
Evidence includes: chloroplasts similarity to cyanobacteria (1-10 micrometers size) double membranes around mitochondria and chloroplasts, and these organelles have possession of their own circular DNA

58
Q

Endosymbiont theory is the concept that…

A

mitochondria and chloroplasts evolved from an endosymbiotic relationship between two prokaryotes

59
Q

Cyanobacteria form enlarged cells called _________

A

heterocysts

60
Q

Heterocyst’s are capable of…

A

nitrogen fixation

61
Q

Do cyanobacteria have chloroplasts?

A

No

62
Q

Plant cells have ____ _____ and _______

A

cell walls and chloroplasts

63
Q

Animal cells have neither ____ ______ nor ________

A

chloroplast

64
Q

In______, the nuclei are almost transparent and hard to see unless stained.

A

Elodea

65
Q

The chloroplasts circulate around the cytoplasm, dragged along cytoskeletal filaments by tiny molecular motors known as _______

A

kinesins

66
Q

The SA to volume ratio of plant cells puts a limit on their size. What two mechanisms offset this problem?

A

Cytoplasmic streaming and large central vacuoles

67
Q

In potatoes, starch is stored in organelles known as _________.

A

amyloplasts

68
Q

Amoebae are a diverse group of ______.

A

protists

69
Q

Do amoebae have cell walls?

A

No

70
Q

An amoebae uses __________ (false feet) to slowly creep along a surface.

A

pseudopodia

71
Q

This ________ ________ occurs through cytoplasmic streaming, which is also used for capturing food.

A

amoeboid movement

72
Q

The protist Paramecium is covered with tiny, hair like ____ that the cell uses for propulsion.

A

cilia

73
Q

Paramecium use ________ _______ for nutrient uptake.

A

cytoplasmic streaming

74
Q

Hypermastigotes have a symbiotic relationship with ________.

A

termites

75
Q

Hypermastigotes are responsible for digesting ______

A

wood

76
Q

Where do we throw away toothpicks with cheek cells?

A

BioHazard Bin

77
Q

What is diffusion?

A

Diffusion is the movement of particles from an area of high concentration to an area of low concentration, until it reaches a state of dynamic equilibrium

78
Q

What is meant by diffusion down a concentration gradient?

A

Down a Concentration Gradient refers to going from regions of high concentration of some entity to regions of low concentration, and such movement generally occurs spontaneously, that is, if allowed to happen it happens.

79
Q

What is dynamic equilibrium?

A

When the particles are equally dispersed in both areas

80
Q

What is osmosis?

A

The movement of water across a semi-permeable membrane where water can cross but other solutes cannot.
Water molecules moving from an area of high concentration to an area of low concentration

81
Q

Explain hypertonic.

A

Solutions that have a relatively greater concentration of solute, so the water moves out of the cell

82
Q

Explain hypotonic.

A

Solutions that have lower concentration of solute, so the water moves into the cell

83
Q

Explain Isotonic.

A

Solutions that have the same concentration

84
Q

Why is osmosis important to cells?

A

Osmosis is important to cells because the cell membrane is permeable to water

85
Q

Why are cells in a hypotonic solution in danger?

A

They are in danger of swelling to the point of bursting

86
Q

How do animals cells and protists deal with osmosis?

A

Contractile vacuoles

87
Q

How do plant and bacteria cells deal with osmosis?

A

They have rigid cell walls

88
Q

What is pH?

A

The measure of hydrogen ions in a solution. It’s another factor that affects the livelihood of cells.

89
Q

Describe how paramecia and hypermastigotes differed in their sensitivity to environmental pH

A

The paramecium was moving freely in the pH 6, slowed in the pH 7, and was found dead in pH 8.
The hypermatigotes were not able to handle the changes in pH and died.
Hypermatigotes are found in termites stomachs and cannot tolerate changes in pH because of this. Paramecium are found in ponds, therefore they’re used to an unregulated pH.

90
Q

What’s the difference between quantitative and quantitative data?

A

There are two general types of data. Quantitative data is information about quantities; that is, information that can be measured and written down with numbers. Some examples of quantitative data are your height, your shoe size, and the length of your fingernails. Speaking of which, it might be time to call Guinness. You’ve got to be close to breaking the record.

Qualitative data is information about qualities; information that can’t actually be measured. Some examples of qualitative data are the softness of your skin, the grace with which you run, and the color of your eyes. However, try telling Photoshop you can’t measure color with numbers.

91
Q

These cells provide a favorable environment for cyanobacteria under extreme conditions…

A

Akinete

92
Q

Why are strawberries a good choice in terms of DNA extraction?

A

They are octaploid

93
Q

In DNA, what is the polymer? Monomer?

A

Polymer: polynucleotide
Monomer: nucleotide

94
Q

What is a nucleotide made up of?

A

Deoxyribose sugar, nitrogenous base, phosphate group

95
Q

What makes up the polynucleotide backbone?

A

Phosphate-sugar backbone (nitrogen base on the inside)

96
Q

Since DNA is charged and polar, it is __________

A

hydrophilic, and SOLUBLE in water

97
Q

Purine… __ fused rings. Consists of ________ and _______

A

2 fused rings.

Consists of adenine and guanine

98
Q

Pyrimidine… __ fused ring. Consists of _______ and _______

A

1 fused ring.

Consists of thymine and cytosine

99
Q

You can only pair a purine with a pyrimidine by

________ bonding

A

hydrogen

100
Q

Purines have __ H bonds

Pyrimidines have __ H bonds

A

Purines have 2 H bonds

Pyrimidines have 3 H bonds

101
Q

How is it possible to separate nucleic acids from the cells that contain them??

A

Break the cells open

102
Q

Why were DNA containing solutions kept on ice throughout the lab exercise?

A

To slow down the production of enzymes

103
Q

What was the purpose of shampoo?

A

To break open the cells and dissolve the membranes

104
Q

What was the purpose of baking soda?

A

To maintain pH

105
Q

What was the purpose of Isopropyl?

A

To precipitate the DNA

106
Q

What was the purpose of alcohol and salt?

A

To neutralize the negative charges on DNA, allowing the DNA to precipitate.

107
Q

At which ‘optimum’ wavelengths do DNA and protein absorb the most light?

A

DNA absorbs at 260 nm

Protein absorbs at 280 nm

108
Q

What does the absorbance ration 260 nm/280 nm tell us about a DNA sample?

A

used to assess the purity of DNA and RNA

109
Q

What happens on prolonged exposure to UV?

A

Extra energy absorbed by DNA can result in mutations and could give rise to cancer

110
Q

Why are GC bonds more stable than AT bonds?

A

GC bonds have 3 hydrogen bonds

AT bonds have only 2 hydrogen bonds

111
Q

What does OD stand for?

A

Optical density

112
Q

If given a DNA strand and asked to write the complimentary strand…

A

write the 3’ to 5’, then FLIP IT to make it 5’ to 3’

BSC2085 Lab (2 decks)

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