Copy and Edit

BMSC 240 Midterm and Final

Description

This quiz covers material from lectures 1-24
Emma Maelde
Quiz by Emma Maelde, updated more than 1 year ago
Emma Maelde
Created by Emma Maelde over 8 years ago
923
1
0

Resource summary

Question 1

Question
[blank_start]Science[blank_end] is the study of the world using scierntific method. [blank_start]Biology[blank_end] is the study of living things.
Answer
  • Science
  • Biology

Question 2

Question
[blank_start]Independent[blank_end] variables are what are altered in the experiment, while [blank_start]dependent[blank_end] variables are what you are observing in the experiment. Both of these are known as [blank_start]control[blank_end] variables.
Answer
  • control
  • dependent
  • Independent

Question 3

Question
A scientist is wanting to sterilize water from the bacteria it contains. An example of a positive control is/are:
Answer
  • Boiling the water, so no bacteria can grow
  • No treatment is done to ensure the bacteria still grows
  • Placing the water in an autoclave to remove bacteria

Question 4

Question
What are the two types of false results that can occur in an experiment?
Answer
  • False positive: occurs in positive control
  • False negative: occurs in a positive control
  • False negative: occurs in negative control
  • False positive: occurs in a negative control

Question 5

Question
Which of the following is an additional concern (as told by Professor Anderson) to scientists performing an experiment?
Answer
  • Is the experiment reproducible?
  • Are the animals safe?
  • Will anyone be harmed?

Question 6

Question
Sensitivity is when a positive result only comes from a truly positive sample.
Answer
  • True
  • False

Question 7

Question
An instrument has not been calibrated correctly. This is an example of:
Answer
  • Systematic error
  • Random error
  • Positive Control
  • Negative Control

Question 8

Question
Which of the following has a fragile glass probe?
Answer
  • Scale
  • Pipette
  • pH meter
  • Vortex mixer

Question 9

Question
A pH meter must be rinsed and stored in [blank_start]solution[blank_end] between uses. The random errors that can come from using a pH meter are not [blank_start]rinsing[blank_end], and measuring before [blank_start]stabilization[blank_end]. The systematic errors that can come from using a pH meter is if it is not [blank_start]calibrated[blank_end] correctly.
Answer
  • calibrated
  • rinsing
  • solution
  • stabilization

Question 10

Question
What happens if a pH meter is not stored in solution between uses?
Answer
  • The instrument will not turn on
  • The probe gets plugged
  • Electric current is increased and pH readings become only basic
  • The probe will only report solutions as being neutral

Question 11

Question
An example of random error for a scale is vibrations that can change numbers.
Answer
  • True
  • False

Question 12

Question
A vortex mixer:
Answer
  • is used to mix small quantities of solutions
  • contains a magnet in the base with adjustable spin speed
  • can cause the solution to become frothy
  • may be invaluable to mix some solutions and damaging to others
  • is coupled with a heating element to help dissolve

Question 13

Question
Differences between a micropipette and pipette are:
Answer
  • A micropipette measure between 10-1mL while a pipette measure anything larger
  • A pipette has disposable tips, while a micropipette does not
  • Mistakes made with a micropipette are proportionally larger than with a pipette
  • None of the above are correct

Question 14

Question
An [blank_start]acid[blank_end] is a proton donor, while a [blank_start]base[blank_end] is a proton acceptor.
Answer
  • acid
  • base

Question 15

Question
pH is represented on a log scale
Answer
  • True
  • False

Question 16

Question
pKa is:
Answer
  • When there is more weak acid in solution than base
  • When there is equal amounts of acid and weak base
  • When there is more base in solution than weak acid

Question 17

Question
A buffer is effective within 1.5 pH units from the pKa
Answer
  • True
  • False

Question 18

Question
What ratio of acetate ion to acetic acid would you need to make up an acetate buffer with a pH of 5.25? pKa = 4.74.
Answer
  • .4632
  • .3090
  • 4.567
  • 3.236

Question 19

Question
What acts as the acid and base, respectively, for the amino acid?
Answer
  • amino, carboxyl
  • R group, amino
  • carboxyl, amino
  • Amino, R group

Question 20

Question
At a low pH, both ends of the amino acid are [blank_start]protonated[blank_end]. At high pH, both ends of the amino acid are [blank_start]deprotonated[blank_end]. At moderate pH, the net charge is [blank_start]neutral[blank_end].
Answer
  • protonated
  • deprotonated
  • neutral

Question 21

Question
Which amino acid(s) have an R-Group that can act as an acid-conjugate base pair at pH 10?
Answer
  • Aspartic Acid
  • Cysteine
  • Tyrosine
  • Histidine
  • Glutamic Acid
  • Lysine
  • Arginine

Question 22

Question
What is pI on triprotic titration?
Answer
  • The average pKa's of the highest and lowest pKa
  • The average of pKa's surrounding the neutral charge
  • Equal to the smallest pKa
  • Equal to the middle pKa

Question 23

Question
Milk pasteurization works by increasing one factor of sterilization and decreasing another. What are they?
Answer
  • Increased conductance, decreased time
  • Increased time, decreased temperature
  • increased conductance, decreased temperature
  • Increased temperature, decreased time

Question 24

Question
Which should be used to sterilize heat-labile compounds?
Answer
  • Autoclave
  • Filtration

Question 25

Question
Which of the following are heat-labile compounds?
Answer
  • IPTG
  • Staphylococcus
  • Streptobacillus
  • Ammonium acetate
  • Ig E Antibodies

Question 26

Question
Quality of image from a microscope depends on:
Answer
  • Thickness of section
  • Quantity of bacteria
  • Size of bacteria
  • Staining of bacteria
  • Lighting from microscope

Question 27

Question
Magnification is the separation between two objects.
Answer
  • True
  • False

Question 28

Question
Improving resolution makes the resolution number smaller
Answer
  • True
  • False

Question 29

Question
How can resolution be improved?
Answer
  • Increase wavelength
  • Decrease Numerical Aperture
  • Change the refractive index

Question 30

Question
As magnification increases:
Answer
  • Resolution increases, field of vied decreases and numerical aperture decreases
  • Resolution decreases, field of vied decreases and numerical aperture decreases
  • Resolution increases, field of vied increases and numerical aperture increases
  • Resolution decreases, field of vied decreases and numerical aperture increases

Question 31

Question
Spectroscopy is the study of absorption and emission of radiation. Photometry is the measurement of intensity of radiation.
Answer
  • True
  • False

Question 32

Question
What is the shortest wavelength of light?
Answer
  • Red
  • Green
  • Blue
  • Yellow

Question 33

Question
[blank_start]Cuvette[blank_end]: A tube that holds the sample Transmittance: the proportion of light that the sample allows to [blank_start]pass[blank_end][blank_start]Absorbance[blank_end]: the amount of light the sample blocks [blank_start]Blank[blank_end]: a comparison sample with non of the measure substance Standard Curve: A series of [blank_start]known[blank_end] samples used to generate comparison data
Answer
  • Cuvette
  • known
  • Blank
  • Absorbance
  • pass

Question 34

Question
A cuvette containing water is an example of:
Answer
  • Negative Control
  • Positive Control
  • Specificity
  • Sensitivity

Question 35

Question
What is the beer lambert law?
Answer
  • A=elc
  • E=Al
  • C=Ael
  • L=EAl

Question 36

Question
Pure DNA has a value for 260/280 of:
Answer
  • 2.5
  • 2.0
  • .5
  • 1.5

Question 37

Question
The Bradford assay uses [blank_start]coomassie blue[blank_end] dye. Unbound dye has an absorbance max of [blank_start]465[blank_end]. Bound dye has an absorbance max of [blank_start]595[blank_end]. The upper limit for linear detection is 1 mg/mL.
Answer
  • 465
  • 595
  • coomassie blue

Question 38

Question
The Bradford assay has strongest interaction with acidic amino acids.
Answer
  • True
  • False

Question 39

Question
Why would someone choose to use the Biuret Assay over the Bradford Assay?
Answer
  • It has a higher useful range
  • It is much quicker
  • There is no absorbency max
  • A and C
  • None of the above

Question 40

Question
Copper 2 sulfate is used in the biuret assay as the binding dye.
Answer
  • True
  • False

Question 41

Question
Label the following shape or arrangement:
Image:
a7a9cd06-c3b3-4c15-9824-0f5e26ca1ba4 (image/jpeg)
Answer
  • Coccus
  • Bacillus
  • Spiracles
  • Diplo
  • Staphylo
  • Strepto

Question 42

Question
Prokaryotes:
Answer
  • Go through mitosis
  • Have circular chromosomes
  • Have no organelles

Question 43

Question
Gram negative cells stain pink.
Answer
  • True
  • False

Question 44

Question
Bacterial cell walls are made of:
Answer
  • Peptidoglycan
  • Lipids
  • NAG-NAM
  • Lysine and Arginine

Question 45

Question
Gram positive cell walls are up to [blank_start]80 nm[blank_end] thick, while gram negative cell walls are only [blank_start]8 nm[blank_end] thick. Although gram negative have smaller [blank_start]peptidoglycan[blank_end] layers, they contain a second [blank_start]phospholipid membrane[blank_end]. Gram positive cell walls also contain [blank_start]teichoic acid[blank_end] to keep layers together and increase the [blank_start]negative[blank_end] charge of the cell wall.
Answer
  • 80 nm
  • 8 nm
  • peptidoglycan
  • phospholipid membrane
  • teichoic acid
  • negative

Question 46

Question
Which of the following bacteria are gram negative?
Answer
  • Clostridium difficle
  • Vibrio Cholerae
  • Helicobacter Pylori
  • Bacillus Anthracis

Question 47

Question
A [blank_start]mordant[blank_end] is a charged molecule that interacts and makes it hard to wash off.
Answer
  • mordant

Question 48

Question
The steps of a gram stain are: 1. [blank_start]Crystal Violet[blank_end] 2. [blank_start]Iodine[blank_end] 3. [blank_start]Alcohol Wash[blank_end] 4. [blank_start]Counter Stain[blank_end] The mordant in a gram stain is [blank_start]iodine[blank_end].
Answer
  • Counter Stain
  • Alcohol Wash
  • Iodine
  • Crystal Violet
  • iodine

Question 49

Question
What are qualities of an acid fast stain?
Answer
  • Counterstain with coomassie blue
  • Primary dye is carbol-fuschin
  • Used for waxy cell walls
  • No decolorization is required

Question 50

Question
A [blank_start]capsule[blank_end] is neatly organized while a [blank_start]smile layer[blank_end] is unorganized or loose. These are both known as [blank_start]glycocalyx[blank_end]. To stain, a [blank_start]bulky[blank_end] charged dye, such as [blank_start]nigrosin[blank_end], is required. The cells are not fixed to slide and the dye creates a [blank_start]pocket[blank_end] for stain to get everywhere except on the [blank_start]bacteria[blank_end]. This requires staining to visualize [blank_start]bacteria[blank_end], such as [blank_start]crystal violet[blank_end].
Answer
  • capsule
  • slime layer
  • glycocalyx
  • bulky
  • nigrosin
  • pocket
  • bacteria
  • bacteria
  • crystal violet

Question 51

Question
What is required to stain the flagella?
Answer
  • Thickening of the flagella
  • A mordant
  • Crystal Violet Dye
  • All of the above

Question 52

Question
The most notable endospore forming groups are:
Answer
  • Only bacillus
  • Strep and Clostridium
  • Bacillus and Strep
  • Bacillus and Clostridium

Question 53

Question
Endospore stains require safranin, malachite green and moist heat.
Answer
  • True
  • False

Question 54

Question
Which of the following ranks bacteria in their optimal temperature zone from highest to lowest?
Answer
  • Psychrophiles, mesophiles, thermophiles, psychotrophs, hyperthermophiles
  • hyperthermophiles, mesophiles, thermophiles, psychotrophs, psychrophiles
  • Hyperthemophiles, thermophiles, mesophiles, psychotrophs, psychrophiles
  • Psychrophiles, Psychrotrophs, mesophiles, Thermophiles, hyperthermophiles

Question 55

Question
What salt concentration do extreme halophiles live in?
Answer
  • 10-20%
  • 2%
  • 30-40%
  • 50%

Question 56

Question
A [blank_start]defined medium[blank_end] is one where all chemicals are known and quantified, while a [blank_start]complex medium[blank_end] is one where we are not aware of every chemical.
Answer
  • defined medium
  • complex medium

Question 57

Question
In which of the following is it difficult to check for purity
Answer
  • broth
  • Plates
  • Slants
  • Semi-solid Deeps

Question 58

Question
Agar:
Answer
  • comes from the cell walls of certain bacteria living in caves
  • is a carbohydrate from cell walls of red algae
  • solidifies at 50 degrees
  • melts at 85 degrees
  • B, C, D
  • B, C
  • B, D

Question 59

Question
MacConkey Agar is:
Answer
  • selective
  • differential
  • enrichment

Question 60

Question
MacConnkey Agar selects against gram [blank_start]positive[blank_end] using bile salts and crystal violet. It contains [blank_start]lactose[blank_end] and [blank_start]pH indicators[blank_end]. Fermenters turn [blank_start]purple[blank_end] on the plate. MSA has a [blank_start]high salt concentration[blank_end] and contains mannitol. Fermenters turn [blank_start]yellow[blank_end] on the plate. It is useful for detecting [blank_start]staphylococcus aureus[blank_end]. BAP contains 5-10% [blank_start]sheep's blood[blank_end] and tests for [blank_start]hemolytic[blank_end] activity. The [blank_start]hemolysis[blank_end] may be enhanced in [blank_start]low-oxygen[blank_end] environments. [blank_start]Saboraud Dextrose Agar[blank_end] contains a high amount of glucose (2%). It selects for yeasts and [blank_start]molds[blank_end]. SIM Deep's are used to differentiate cells from [blank_start]sulfur reduction[blank_end], [blank_start]indole production[blank_end] and [blank_start]motility[blank_end]. An [blank_start]oxidase[blank_end] test is used to see if the organism can use oxygen to generate [blank_start]ATP[blank_end]. A [blank_start]positive[blank_end] result is blue/purple.
Answer
  • positive
  • lactose
  • pH indicators
  • purple
  • high salt concentration
  • yellow
  • staphylococcus aureus
  • sheep's blood
  • hemolytic
  • hemolysis
  • low oxygen
  • Sabouraud Dextrose Agar
  • molds
  • sulfur reduction
  • indole production
  • motility
  • oxidase
  • ATP
  • positive

Question 61

Question
Which of the following are a direct and total way to count bacteria?
Answer
  • Turbidity Estimates
  • Serial Dilution
  • Counting Chamber
  • All of the answers

Question 62

Question
The best source for antibiotics are soil dwellers
Answer
  • True
  • False

Question 63

Question
[blank_start]Penicillin[blank_end] and [blank_start]Cephalosporin[blank_end] are cell wall inhibitors. They contain a beta [blank_start]lactam ring[blank_end] that mimics the substrate to link peptidoglycan. This causes the cell wall to be weaker. Natural penicillin works only against gram [blank_start]positive[blank_end] cells.
Answer
  • Penicillin
  • Cephalosporin
  • lactam ring
  • positive

Question 64

Question
The following are protein synthesis inhibitors:
Answer
  • Daptomycin
  • Neomycin
  • Tetracycline
  • Quinolines
  • Streptomycin
  • Chlorsmphenicol

Question 65

Question
Which of the following is better as a topical antibiotic?
Answer
  • Polymxin
  • Daptomycin
  • Bacitracin
  • A and C
  • All of the above

Question 66

Question
[blank_start]Nucleic Acid Synthesis Inhibitors[blank_end] include: rifamycin or quinolones. Rifamycin inhibit [blank_start]mRNA synthesis[blank_end] and are highly [blank_start]permeable[blank_end] to the cell. Quinolones inhibit [blank_start]DNA gyyrase[blank_end] which inhibits DNA replication.
Answer
  • mRNA synthesis
  • Nucleic Acid Synthesis Inhibitors
  • permeable
  • DNA gyrase

Question 67

Question
Which of the following are examples of modes of resistance presented by bacteria?
Answer
  • Drug modification
  • Pathway protection
  • Cell suicide
  • Cell Fusion
  • Target Alteration
  • Rapid Efflux
  • Alternative Pathways

Question 68

Question
An [blank_start]enzyme[blank_end] is a protein that acts as a catalyst for a chemical reaction. The makes the reaction more [blank_start]favourable[blank_end] by lowering the [blank_start]activation energy[blank_end].
Answer
  • favourable
  • activation energy
  • enzyme

Question 69

Question
[blank_start]Reaction rate[blank_end] is how fast substrate is converted into product. Over time, reactions will slow down as [blank_start]substrate[blank_end] decreases[blank_start], product[blank_end] increases and [blank_start]enzyme molecules[blank_end] are lost to [blank_start]denaturation[blank_end]. The [blank_start]initial velocity[blank_end] is used to get non-attenuated rates.
Answer
  • Reaction rate
  • substrate
  • product
  • enzymes
  • denaturation
  • initial velocity

Question 70

Question
Rate can be limited by
Answer
  • availability of substrate
  • production of product
  • release of product
  • availability of substrate and production of product
  • All of the above
  • None of the above

Question 71

Question
Km is the concentration of [blank_start]substrate[blank_end] that leads to half-maximal [blank_start]velocity[blank_end].
Answer
  • substrate
  • velocity

Question 72

Question
Key features to Asian flush are:
Answer
  • Increase Km for NADH for ALDH2
  • Mutation in ALDH
  • Mutation in ALDH2
  • Rapid heart and breathing, redness, and hot flashes
  • ALDH1 has a lower Km
  • Acetaldehyde accumulates in the blood
  • if only one part of the protein is affected, the rest will work properly.

Question 73

Question
If you have higher affinity for a substrate, you have a higher Km
Answer
  • True
  • False

Question 74

Question
Which of the following are a correct match?
Answer
  • Competitive Inhibition: a compound binds the active site of the enzyme and excludes the reactant
  • Uncompetitive inhibition: a compound binds the active site of the enzyme and excludes the reactant
  • Noncompetitive inhibition: a compound binds the active site of the enzyme and excludes the reactant
  • Uncompetitive Inhibition: a compound binds the ES complex and slows release to E + P
  • Competitive Inhibition: a compound binds the ES complex and slows release to E + P
  • Noncompetitive inhibition: a compound binds the ES complex and slows release to E + P
  • Noncompetitive inhibition: a compound binds the enzyme and decreases the rate the enzyme can bind or react with the substrate
  • Competitive Inhibition: a compound binds the enzyme and decreases the rate the enzyme can bind or react with the substrate
  • Uncompetitive Inhibition: a compound binds the enzyme and decreases the rate the enzyme can bind or react with the substrate

Question 75

Question
Name the types of inhibition and how they affect the Km and Vmax
Image:
8be37bea-40eb-4479-9a4a-7c24b9ed4856.gif (image/gif)
Answer
  • Competitive Inhibition
  • Increases
  • Remains the same
  • Decreases
  • Decreases
  • Uncompetitive Inhibition
  • Noncompetitive Inhibition
  • Remains the same
  • Decreases

Question 76

Question
When someone drinks methanol, they are treated by drinking ethanol. This is an example of which of the following inhibition:
Answer
  • Competitive
  • Uncompetitive
  • Noncompetitive

Question 77

Question
[blank_start]Sonication[blank_end]: breaking the cell apart with sound waves that have high amplitude and frequency. May damage the sample as it will [blank_start]heat[blank_end] the sample. [blank_start]French press[blank_end]: increasing pressure from a piston and releasing to break cells apart [blank_start]Osmotic Shock[blank_end]: Putting into a hypotonic solution to put the cell in shock and causing them to burst. Good for cells who do not have a [blank_start]cell wall[blank_end]. [blank_start]Digestion[blank_end]: Using an enzyme to damage cell walls, but is not broken apart. [blank_start]Detergents[blank_end]: Amphipathic molecules that break down fats and oils by forming micelles [blank_start]Homogenization[blank_end]: Using force to break things apart (blender)
Answer
  • Sonication
  • French press
  • Osmotic Shock
  • Digestion
  • Detergents
  • Homogenization
  • cell wall
  • heat

Question 78

Question
The advantages to using controls in an experiment are that the results can be [blank_start]internal[blank_end] verified and experimental procedures can be [blank_start]validated[blank_end]. An experiment should contain both [blank_start]positive[blank_end] and [blank_start]negative[blank_end] controls to ensure it is working. Some additional concerns that a scientist may have are: 1. Are the experiments [blank_start]biased[blank_end]? 2. Are there adequate notes of [blank_start]materials and methods[blank_end]? 3. Is the experiment [blank_start]reproducible[blank_end]? 4.Is a test [blank_start]qualitative[blank_end] or [blank_start]quantitative[blank_end]? 5. Is a result [blank_start]statistically significan[blank_end]t? 6. Can you rule out correlation from causation? Correlation is the mutual [blank_start]relation[blank_end] of two or more things, parts, etc.: Example: Studies find a positive correlation between severity of illness and nutritional status of the patients.
Answer
  • internal
  • validated
  • positive
  • negative
  • biased
  • materials and methods
  • reproducible
  • qualitative
  • quantitative
  • statistically significan
  • relation

Question 79

Question
Sensitivity is:
Answer
  • A positive result only comes from a truly positive sample
  • The minimum amount of X needed to record a positive result
  • Error introduced with each measurement
  • How close the measurements are

Question 80

Question
A pH meter uses the [blank_start]current[blank_end] produced by the [blank_start]probe[blank_end] to compare with [blank_start]standards[blank_end] and reports a [blank_start]pH value[blank_end]. If the glass probe is [blank_start]cracked[blank_end], there is no longer a need to travel [blank_start]through[blank_end] the [blank_start]glass[blank_end] and the [blank_start]pH[blank_end] will change. A scale is primarily used to [blank_start]weigh[blank_end] chemicals in the lab. A stir plate has [blank_start]teflon[blank_end] coated [blank_start]magnets[blank_end] place in solutions.
Answer
  • current
  • probe
  • standards
  • pH value
  • cracked
  • through
  • glass
  • pH
  • weigh
  • teflon
  • magnets

Question 81

Question
A graduated pipette:
Answer
  • Measures only one volume
  • Has lines along the length to determine the volume
  • Measure 0.0002 mL

Question 82

Question
How small can a micropipette measure in mL?
Answer
  • 0.0002
  • 0.002
  • 0.02
  • 0.2
  • 2

Question 83

Question
Weak acids and their conjugate base:
Answer
  • completely dissociate
  • partially dissociate
  • do not dissociate at all

Question 84

Question
A buffer has a pKa of 6.5. The current pH of the buffer is 7.3. What will happen if more base is added?
Answer
  • It will tolerate much more base than acid
  • It will tolerate equal amounts of acid and base
  • It will tolerate much more acid than base

Question 85

Question
If pH is less than pKa...
Answer
  • There is more acid
  • There is more base
  • The acid % will be more than the base %
  • The base % will be more than the acid %
  • The acid moles will be more than the base moles
  • the base moles will be more than the acid moles

Question 86

Question
A 1 in 10 dilution means:
Answer
  • 1 part stock, to 9 parts water
  • 1 part stock, to 10 parts water
  • 9 parts stock to 1 part water
  • 10 parts stock to 1 part water

Question 87

Question
Which groups have a pH of less than 10?
Answer
  • Aspartic Acid - 4
  • Glutamic Acid - 4
  • Histidine - 6
  • Cysteine - 8
  • Aspartic Acid- 6
  • Glutamic Acid- 2
  • Cysteine - 5
  • Lysine -6
  • Tyrosine - 8
  • Arginine -12.5

Question 88

Question
The effectiveness of heat killing is altered by:
Answer
  • Temperature
  • Time
  • Conductance
  • Pressure
  • Staining
  • Water Absorbancy

Question 89

Question
At 15 PSI steam, the boiling point of water is
Answer
  • 120
  • 121
  • 123
  • 100
  • 125

Question 90

Question
The basic microscope can visualize objects down to [blank_start]0.2[blank_end] micrometers. The microscope consists of [blank_start]eyepiece[blank_end], [blank_start]specimen stage[blank_end], [blank_start]objective lens[blank_end], [blank_start]condenser[blank_end], [blank_start]light source[blank_end], and [blank_start]iris diaphragm[blank_end].
Answer
  • 0.2
  • eyepiece
  • specimen stage
  • objective lens
  • condenser
  • light source
  • iris diaphragm

Question 91

Question
DNA absorbs UV light at [blank_start]260[blank_end]. Absorbance of UV light for proteins depends on their [blank_start]side chains[blank_end], but is approximately [blank_start]280[blank_end]. The 260/280 ratio for pure protein is [blank_start]0.55[blank_end].
Answer
  • 260
  • 280
  • side chains
  • 0.55

Question 92

Question
The absorbency max for the biuret assay is
Answer
  • 540
  • 465
  • 595
  • 582

Question 93

Question
Technological minaturization:
Answer
  • cuvette less spectrophotometry
  • sample of 5 to 0.5 microliters
  • Path length of 0.2 mm to 0.5 mm
  • Takes 10 seconds
  • Path length of 1 cm
  • Takes 5 seconds
  • Sacrifices a great deal of your sample

Question 94

Question
If a solution is older, when performing your gram stain you expect to see:
Answer
  • Gram neagtive
  • Gram positive
  • Neither, they won't stain at all

Question 95

Question
When are acid-fast stains used?
Answer
  • Waxy cell walls
  • After gram stains
  • Endospores
  • Flagella

Question 96

Question
The stains for an acid fast stain are:
Answer
  • carbol-fuschin and methylene blue
  • carbol-fuschin and coomassie blue
  • malachite green and methylene blue
  • safranin only

Question 97

Question
What is the liefson stain used for? Which stains does it use?
Answer
  • Flagella: Crysal Violet and a mordant
  • Flagella: Only crystal violet
  • Endospore: Malachite green and moist heat
  • Endospore: Only Crystal Violet

Question 98

Question
The chemical needs of a cell are: [blank_start]Carbon[blank_end]: the backbone of most cells [blank_start]Oxygen[blank_end] & Hydrogen Nitrogen: All [blank_start]amino[blank_end] acids Phosphorus: [blank_start]DNA[blank_end], [blank_start]RNA[blank_end], [blank_start]ATP[blank_end] Sulfur: [blank_start]cysteine[blank_end], [blank_start]methionine[blank_end] and [blank_start]cofactors[blank_end] Calcium: [blank_start]Endspores[blank_end], [blank_start]signalling[blank_end] and [blank_start]cofactors[blank_end] Trace elements: Enzymatic [blank_start]cofactors[blank_end]
Answer
  • Carbon
  • Oxygen
  • amino
  • DNA
  • RNA
  • ATP
  • cysteine
  • methionine
  • cofactors
  • Endospores
  • signalling
  • cofactors
  • cofactors

Question 99

Question
Mannitol Salt Agar
Answer
  • Selective
  • Differential
  • Enrichment

Question 100

Question
Blood Agar Plates
Answer
  • Selective
  • Differential
  • Enrichment

Question 101

Question
SIM Deep
Answer
  • Selective
  • Differential
  • Enrichment

Question 102

Question
When is something considered healthy or sterile:
Answer
  • There are 1000 bacteria/ mL or less
  • There are 100000 bacteria/ mL or less

Question 103

Question
Rifamycin/Rifampin
Answer
  • most useful against mycobacterium
  • inhibits mRNA synthesis
  • highly permeable into cells
  • inhibits DNA gyrase
  • broad spectrum

Question 104

Question
If a series of reactions are done in parallel, we can alter all variables and compare enzyme rates
Answer
  • True
  • False

Question 105

Question
Under optimal conditions, and with an excess of substrate, the limiting steps in how fast the enzyme can catalyze is:
Answer
  • E + S -> ES
  • ES -> E+P
  • EP-> E+P

Question 106

Question
What does 1 Unit of enzyme mean?
Answer
  • How heavy the enzyme is
  • The enzyme will catalyze 1 micromole in 1 minute
  • The initial velocity is equal to the maximal velocity
  • The specific activity of the enzyme is the same in different pH conditions

Question 107

Question
Purification by properties: Solubility: [blank_start]salting out[blank_end] Ionic Charge: [blank_start]Ion[blank_end] [blank_start]exchange[blank_end] chromatography, electrophoresis, isoelectric focusing [blank_start]Polarity[blank_end]: Reverse phase and hydrophobic chromatography Size: Dialysis, [blank_start]size[blank_end]-exclusion chromatography, gel [blank_start]electrophoresis[blank_end] [blank_start]Binding[blank_end] [blank_start]specificity[blank_end]: affinity chromatography
Answer
  • salting out
  • Polarity
  • Ion
  • exchange
  • size
  • electrophoresis
  • Binding
  • specificity

Question 108

Question
What is initial purification, such as centrifuging, useful for?
Answer
  • If the protein is soluble, it can be partially purified by removed larger contaminants
  • If the protein is NOT soluble, it can be partially purified by removed larger contaminants
  • If the protein is soluble, it can be partially purified by removed significantly smaller DNA molecules
  • The protein does not need to go through initial purification

Question 109

Question
The supernatant after purification can be further treated by:
Answer
  • Altering temperature
  • Altering pH
  • Altering salinity
  • Altering nutrients

Question 110

Question
A method used where salt concentration is increased to purify proteins based on their solubility:
Answer
  • Ion Exchange Chromatography
  • Size-Exclusion Chromatography
  • Salting Out

Question 111

Question
Dialysis is the process of adding salt to a solution to continue purification
Answer
  • True
  • False

Question 112

Question
Dialysis:
Answer
  • Will occur perfectly after one step
  • Requires multiple steps as the salt concentrations equalize
  • Should not occur when purifying proteins

Question 113

Question
Which of the following are matched correctly?
Answer
  • Mobile Phase-a substance that the compounds to be separated pass by or interact with
  • Mobile Phase-the carrier for the compounds to be separated
  • Stationary Phase-a substance that the compounds to be separated pass by or interact with
  • Stationary Phase-the carrier for the compounds to be separated

Question 114

Question
Which of the following are in the correct order for filling a chromatography column?
Answer
  • Pouring, packing, loading, running, collecting
  • Packing, pouring, loading, running, collecting
  • Loading, packing, pouring, running, collecting
  • Packing, loading, pouring, running, collecting

Question 115

Question
When does more mobile phase liquid need to be added to the column?
Answer
  • When the level of liquid is equal to the solid beads
  • When the level of liquid is approximately 2 cm below the beads
  • You are never required to add more mobile phase

Question 116

Question
Which of the following travel through Vo? (Vo= volume outside the beads)
Answer
  • Large proteins
  • Moderate sized proteins
  • Small Proteins
  • None of the above

Question 117

Question
Which of the following through Vi? (Vi= volume inside the beads)
Answer
  • Large proteins
  • Moderate proteins
  • Small proteins
  • None of the above

Question 118

Question
The partition coefficient is the fraction of the volume of the column available to the sample
Answer
  • True
  • False

Question 119

Question
What is the partition coefficient for a protein with column volume 10 mL and void volume 4 mL for a small sized proteins?
Answer
  • 0.67
  • 0
  • 1

Question 120

Question
Which of the following ion exchange chromatography columns are matched correctly?
Answer
  • Anion exchange- Column is +, targets are -
  • Cation exchange- Column is +, targets are -
  • Cation exchange- column is -, targets are +
  • Anion exchange-column is -, targets are +

Question 121

Question
Which molecules elute fastest in an ion exchange chromatography?
Answer
  • Neutral
  • Highly positive charge
  • Highly negative charge
  • Depends on the charge of the column
  • A and D
  • B and C
  • They will transfer at the same rate

Question 122

Question
When trying to purify an antibody, the best type of chromatography to use is size exclusion
Answer
  • True
  • False

Question 123

Question
Which lists the chromatography options in most specific to least specific?
Answer
  • Affinity, Ion, Size
  • Size, Ion, Affinity
  • Affinity, Size, Ion
  • Ion, Affinity, Size

Question 124

Question
In an electrophoresis, velocity is directly proportional to [blank_start]charge[blank_end] and inversely proportional to [blank_start]size[blank_end] and [blank_start]shape[blank_end].
Answer
  • charge
  • size
  • shape

Question 125

Question
SDS-PAGE stands for [blank_start]sodium[blank_end] [blank_start]dodecyl[blank_end] [blank_start]sulfate[blank_end] [blank_start]polyacrylamide[blank_end] gel electrophoresis. SDS is a detergent that will [blank_start]denature[blank_end] proteins and give them a [blank_start]negative[blank_end] charge. Acrylamide is a plastic monomer, used industrially that can be chained together. Acrylamide is found to be [blank_start]toxic[blank_end] and is approximately [blank_start]4[blank_end] micrograms/g in one bag of chips. Toxic effects are seen at [blank_start]10[blank_end] mg/kg. You would require [blank_start]938[blank_end] bags of chips in one day to die if you weighed 75 kg.
Answer
  • sodium
  • dodecyl
  • sulfate
  • polyacrylamide
  • denature
  • negative
  • toxic
  • 4
  • 10
  • 938

Question 126

Question
Which of the following are acrylamide gel ingredients?
Answer
  • Suitable buffer solution
  • Bis-acrylamide- cross linking
  • Acrylamide- forms chains
  • Ammonium persulfate- forms free radicals to catalyze polymerization
  • TEMED- forms free radicals to catalyze polymerization
  • BIs-acrylamide- forms chains
  • Acrylamide- cross linking

Question 127

Question
Protein samples are boiled for [blank_start]5[blank_end] minutes in 5x loading buffer to be denatured. They are then coated with 10% [blank_start]SDS[blank_end], 20% [blank_start]glycerol[blank_end], 0.2 M Tris-HCl pH 6.8, 0.05% [blank_start]bromophenol[blank_end] blue, 10 mM B-mercaptoethanol. Gel is cast by mixing acrylamide, bisacrylamide, APS, TEMED, SDS and buffer. It is poured between glass or plastic plates. [blank_start]Oxygen[blank_end] will inhibit the polymerization.
Answer
  • 5
  • SDS
  • glycerol
  • bromophenol
  • Oxygen

Question 128

Question
When you are wanting to visualize a gel with coomassie blue stain, what is the procedure?
Answer
  • Stain 10 minutes, Soak in buffer for ten minutes, repeat
  • Stain for 25 minutes
  • Stain for 10 minutes, soak in buffer for 5 minutes. No repeated cycles required
  • No staining is required to visualize the gel

Question 129

Question
A stacking gel contains 2 gels, 2 buffers, and 2 pH's
Answer
  • True
  • False

Question 130

Question
Label the pH of each part of the gel (located on the left hand side), which part of the gels stacking or running (located in the middle), and which molecule is chlorine, glycine and protein.
Image:
5c4cf23d-f756-48b4-8987-1d8b3389f839.gif (image/gif)
Answer
  • 8.3
  • 6.8
  • 8.8
  • Stacking
  • Running
  • Glycine
  • Chlorine
  • Protein

Question 131

Question
What does a urea page gel separate proteins based on?
Answer
  • Size
  • Charge
  • Size and Charge
  • Temperature
  • Temperature and charge

Question 132

Question
What does a native gel separate proteins based on?
Answer
  • Conformation, Charge, Solubility
  • Conformation, Charge
  • Conformation, Solubility
  • Solubility, Charge

Question 133

Question
An acid urea gel will run the same was as an SDS-PAGE gel
Answer
  • True
  • False

Question 134

Question
A 2D-PAGE gel:
Answer
  • Separates based on size and charge
  • Requires ampholytes
  • Are ALWAYS separated by size first
  • Are time consuming
  • Do not require SDS

Question 135

Question
What is the usefulness of a 2D gel:
Answer
  • To compare samples from different sources to determine protein differences
  • To compare male and females chromosomal DNA
  • To compare the possible conformational structure of one proteins
  • They are rarely useful as they provide smudging

Question 136

Question
The difference between innate immunity and adaptive immunity is that innate is specific, while adaptive is not.
Answer
  • True
  • False

Question 137

Question
Which of the following antibodies are correctly matched with their "job"?
Answer
  • IgG- primary antibody account for 80% of antibodies
  • IgM- used in the external environments (gut, lungs, etc)
  • IgA-First secreted at sign of infection
  • IgD- dispensable, as the body does not REQUIRE them to get rid of an infection
  • IgE-causes histamine release

Question 138

Question
There are two questions the immune system asks itself before producing b cells. Which of the following is one of them?
Answer
  • Is there room for storage of the B cells within the body?
  • Does the B-cell make host binding antibodies?
  • Does the B-cell make useful antigens?

Question 139

Question
Which of the following are two ways B cells can be activated?
Answer
  • Mitosis
  • Chromosomal Signalling
  • Plasma cells
  • Memory cells
  • C and D
  • B and D

Question 140

Question
Which of the following are steps in the purification of antibodies from blood?
Answer
  • Cells are spun out to obtain serum
  • Ion exchange chromatography column is produced which binds Fc region of the antibody
  • Plasma is poured through column to bind antibodies
  • Elution is by a high pH buffer and then neutralized in a fraction tube
  • Samples are tested by SDS-PAGE to determine peak fraction

Question 141

Question
Horseradish peroxidase is often used in fluorescent labelling
Answer
  • True
  • False

Question 142

Question
A subset of lab IgG Uses: 1.[blank_start]Western[blank_end] [blank_start]Blot[blank_end]: To determine quanitity and bad identity on a gel 2. [blank_start]ELISA[blank_end]: To determine how much of a protein is present in a mixture 3. [blank_start]Agglutination[blank_end] [blank_start]test[blank_end]: to determine the identity of a pathogen 4. [blank_start]Ouchterlony[blank_end] [blank_start]Diffusion[blank_end] [blank_start]Assay[blank_end]: To determine antigens/antibodies present in a sample 5. [blank_start]Fluorescent[blank_end] staining: To localize proteins in a cell
Answer
  • Western
  • Blot
  • ELISA
  • Agglutination
  • test
  • Ouchterlony
  • Diffusion
  • Assay
  • Fluorescent

Question 143

Question
What is the half life of IgG in days?
Answer
  • 20
  • 21
  • 22
  • 23

Question 144

Question
What is the difference between ELISA and Western blotting techniques?
Answer
  • ELISA uses a membrane
  • Western blotting uses a membrane
  • ELISA does not us proteins
  • Western blotting uses DNA

Question 145

Question
Plasmid Types [blank_start]Conjugative[blank_end] plasmids- transmitted during conjugation, carry a variety of information [blank_start]Resistance[blank_end] plasmids- protect against environmental factors, multiple drug resistance plasmids [blank_start]Colicinogenic[blank_end] plasmids- codes for proteins that kill other microbes [blank_start]Degradative[blank_end] plasmids- contain genes for novel catholic enzymes [blank_start]Virulence[blank_end]- increases the pathogenicity of a bacteria
Answer
  • Virulence
  • Degradative
  • Colicinogenic
  • Resistance
  • Conjugative

Question 146

Question
Typical components of natural plasmids are: 1. [blank_start]Origin[blank_end] of [blank_start]replication[blank_end] to allow for more production 2. [blank_start]Positive[blank_end] selection gene to force cells to keep the plasmid at high numbers 3. [blank_start]Insert[blank_end] [blank_start]differentiation[blank_end] gene to allow differentiation from normal cells compared to plasmid containing cells 4. [blank_start]Cloning[blank_end] sites to allow places to insert foreign DNA
Answer
  • Origin
  • replication
  • Positive
  • Insert
  • differentiation
  • Cloning

Question 147

Question
Assays should be: Sensitive [blank_start]Specific[blank_end] Rapid [blank_start]Quantitative[blank_end]
Answer
  • Specific
  • Quantitative

Question 148

Question
The following are important volume concepts in chromatography: Vt- volume of the [blank_start]column[blank_end] Vo- volume [blank_start]outside[blank_end] the beads Vi-volume [blank_start]inside[blank_end] the beads Ve- volume at which the sample is [blank_start]eluted[blank_end]
Answer
  • eluted
  • inside
  • outside
  • column

Question 149

Question
Small proteins travel through Vt
Answer
  • True
  • False

Question 150

Question
Which of the following describe why a spin column is used?
Answer
  • To purify proteins through charge
  • To extract DNA from cleared bacterial lysate
  • TO purify proteins based on size

Question 151

Question
Which of the following could be purified using an affinity chromatography column?
Answer
  • Substrate
  • Carbohydrate
  • Neurons

Question 152

Question
A gel is used to [blank_start]slow[blank_end] down movement, prevent [blank_start]diffusion[blank_end] of the proteins and create [blank_start]separation[blank_end]
Answer
  • separation
  • diffusion
  • slow

Question 153

Question
Which of the following stains are matched with their correct procedures?
Answer
  • Coomassie Blue- stain 10 minute, soak in buffer 10 minutes, repeat
  • Sliver Nitrate- more complicated and time consuming. 11 solution changes and 2+ hours
  • Fluorescent- sensitive but requires specialized equipment
  • Coomassie Blue- more complicated and time consuming. 11 solution changes and 2+ hours
  • Coomassie Blue- sensitive but requires specialized equipment
  • Silver Nitrate-sensitive but requires specialized equipment
  • Sliver Nitrate- stain 10 minute, soak in buffer 10 minutes, repeat
  • Fluorescent- more complicated and time consuming. 11 solution changes and 2+ hours
  • Fluorescent stain 10 minute, soak in buffer 10 minutes, repeat

Question 154

Question
?Which of the following can help with band resolution?
Answer
  • Use more volume
  • Use less volume
  • Concentrate the sample
  • Run a stacking gel
  • Run a shorter gel
  • Run a longer gel

Question 155

Question
Acid urea gel contain running buffer contains 5% [blank_start]acetic acid[blank_end]. It will protonate some R-groups, giving many proteins an overall [blank_start]positive[blank_end] charge. It contains a high [blank_start]acrylamide[blank_end] content of 15%. It runs slower that an SDS-PAGE and [blank_start]backwards[blank_end].
Answer
  • acetic acid
  • positive
  • acrylamide
  • backwards

Question 156

Question
Native gels mobility of proteins depends on [blank_start]size[blank_end], [blank_start]charge[blank_end] and [blank_start]conformation[blank_end]. The charge depends on the buffer used. The gel runs substantially [blank_start]slower[blank_end] than SDS-PAGE and some sample may not enter the gel based on charge at their specific pH.
Answer
  • size
  • charge
  • conformation
  • slower

Question 157

Question
Sickle-cell anemia occurs because of the replacements of valine with glutamic acid
Answer
  • True
  • False

Question 158

Question
[blank_start]Western blotting[blank_end] is a method to look for a protein of interest from a gel using antibodies against the protein. A [blank_start]polyacrylamide[blank_end] protein gel i first run. The gel is then transferred to a membrane with a high [blank_start]affinity[blank_end] for protein such as [blank_start]capillary[blank_end] transfer or [blank_start]electrophoretic[blank_end] transfer. The membrane has a high affinity for protein so all empty spots much be filled with [blank_start]BSA[blank_end] or [blank_start]Skim[blank_end] [blank_start]Milk[blank_end] Powder. Once blocked, the [blank_start]primary[blank_end] antibody may be added to blot and allowed to bind A [blank_start]secondary[blank_end] protein may then be used to detect the presence of the primary antibody. They are helpful for detection of a [blank_start]protein[blank_end] from a sample, [blank_start]expression[blank_end] profiles of protein, verification of a [blank_start]transgenic[blank_end] organism, or to detect infections, such as [blank_start]HIV[blank_end].
Answer
  • Western blotting
  • polyacrylamide
  • affinity
  • capillary
  • electrophoretic
  • BSA
  • Skim
  • Milk
  • primary
  • secondary
  • protein
  • expression
  • transgenic
  • HIV

Question 159

Question
Which of the following labelling methods results in electrons exposing X-ray film layered over the blot as they decay?
Answer
  • Isotope Labelling
  • Enzyme labelling
  • Fluorescent Labelling

Question 160

Question
Which of the following is an example of enzyme labelling?
Answer
  • Horseradish phosphotase
  • Horseradish phosphate
  • ALkaline Phosphotase
  • Alkaline peroxidase

Question 161

Question
Which of the following labelling methods can often be found in crime scenes?
Answer
  • Enzyme labelling
  • Fluorescent labelling
  • Isotope Labelling

Question 162

Question
Fluorescence microscopy: Culture cells or tissue sections are placed on [blank_start]slides[blank_end]. Cells are fixed using [blank_start]paraformaldehyde[blank_end] or methanol/acetone and rinsed. Cells are permeabilized using dilute [blank_start]detergent[blank_end]. Cells are blocked to reduce [blank_start]nonspecific[blank_end] binding. [blank_start]Primary[blank_end] antibody is added/washed [blank_start]Secondary[blank_end] fluorescent antibody is added/ washed.
Answer
  • paraformaldehyde
  • slides
  • detergent
  • nonspecific
  • Primary
  • Secondary

Question 163

Question
Types of Fluorescent Microscopy: Standard: whole image is illuminated and out of focus light makes the in focus image [blank_start]fuzzy[blank_end] Pro: [blank_start]Cheap[blank_end] Cons: [blank_start]Fuzziness[blank_end] and [blank_start]photodamage[blank_end] Confocal: whole image is illuminated and out of focus light is [blank_start]blocked[blank_end] Pro: very good [blank_start]resolution[blank_end] Con: [blank_start]photodamage[blank_end] Two photon: less energetic light is used (infrared) and [blank_start]2[blank_end] photons must hit the dye simultaneously to [blank_start]excite[blank_end] it Pro: lower photo damage, better tissue [blank_start]penetration[blank_end] Con: [blank_start]costly[blank_end], somewhat [blank_start]inferior[blank_end] resolution to confocal
Answer
  • fuzzy
  • Cheap
  • Fuzziness
  • photodamage
  • resolution
  • photodamage
  • blocked
  • 2
  • excite
  • penetration
  • costly
  • inferior

Question 164

Question
Typical components of vectors: Original of [blank_start]replication[blank_end] [blank_start]Positive[blank_end] selection gene Insert [blank_start]differentiation[blank_end] gene [blank_start]Cloning[blank_end] sites
Answer
  • Positive
  • differentiation
  • Cloning
  • replication

Question 165

Question
How does EcoRI prevent it's own DNA from being cut?
Answer
  • Addition of methyl to all A's int eh sequence
  • Addition of methyl to the second A of GAATC sequence
  • Addition of methyl to the third A of GAATC sequence

Question 166

Question
How often will the sequence GAATTC show up in the DNA?
Answer
  • 4
  • 16
  • 64
  • 256
  • 4096

Question 167

Question
A [blank_start]low[blank_end] concentration allows for larger band to be resolved while small bands run through. A [blank_start]higher[blank_end] concentration allows small bands to be resolved while large bands stack together. [blank_start]Reptation[blank_end] occurs as large DNA (>25,000) reaches the resolvable limit and otherwise will not [blank_start]separate[blank_end]. The DNA will travel [blank_start]one[blank_end] way like a snake and no longer [blank_start]tumbles[blank_end]. Thus, the [blank_start]leading[blank_end] edge determine the speed and cannot change.
Answer
  • Reptation
  • separate
  • one
  • tumbles
  • low
  • higher
  • leading

Question 168

Question
A PFGE is used to show separation of DNA approximately 15000 bp or bigger
Answer
  • True
  • False

Question 169

Question
To isolate the plasmid: 1. Culture pelleted to remove broth 2. Cells are resuspended in [blank_start]Tris[blank_end], EDTA, [blank_start]Glucose[blank_end] or Salt 3. Cells are lysed with things such as NaOH, [blank_start]SDS[blank_end], Lysozymes, [blank_start]boiling[blank_end] 4. Solution is treated to [blank_start]precipitate[blank_end] debris 5. Spin out debris, [blank_start]plasmid[blank_end] remains in supernatant Plasmid precipitation: 1. Salt added to supernatant-[blank_start]NaCl[blank_end], LiCl, NaAc 2. 1-3 volumes of alcohol added to solution-[blank_start]ethanol[blank_end] or [blank_start]isopropanol[blank_end] 3. Chill on ice 4. Spin in centrifuge to collect DNA. The DNA is now found as the [blank_start]pellet[blank_end]. 5. Wash with 70% [blank_start]ethanol[blank_end] (to desalt) 6. Dry and resuspend in water or TE. Typically a buffer is chosen to provide [blank_start]protection[blank_end].
Answer
  • Tris
  • Glucose
  • SDS
  • boiling
  • precipitate
  • plasmid
  • NaCl
  • ethanol
  • isopropanol
  • pellet
  • ethanol
  • protection

Question 170

Question
Which of the following are basic components of PCR Mechanism?
Answer
  • Template DNA
  • Template RNA
  • Oligonucleotide primers
  • dNTP
  • Disaccharide primers
  • Polymerase
  • Heat-stable polymerase
  • Buffer

Question 171

Question
During which cycle do we find the first properly sized DNA fragments?
Answer
  • 1
  • 2
  • 3
  • 4

Question 172

Question
What is the annealing temperature of the following sequence? GGTAACTGAATT
Answer
  • 27
  • 32
  • 40
  • 35

Question 173

Question
Which control are we most concerned about in PCR?
Answer
  • Negative control
  • Positive control

Question 174

Question
When determining the annealing temperature, which PCR machine is best to use?
Answer
  • Gradient
  • Basic
  • Real-time
Show full summary Hide full summary

Want to create your own Quizzes for free with GoConqr? Learn more.

Similar

Media Studies Quiz
Amanda Louise Lord
AQA GCSE Chemistry Unit 2.5
Matthew T
GCSE Biology 4 OCR - The Processes of Life
blairzy123
Calculus I
GraceEChem
IT - The Online World
Summir
Project Scope Management Process
neeshar
4. The Skeletal System - bones of the skull
t.whittingham
Maths: Geometry
noajaho1
Legislative Branch
Mr. Vakhovsky
NSI / PSBD MODEL QUESTION 2019
Dhiraj Thapaliya
Browse Library