DNA QUANTI

*Question: What is the standard concentration range required for PCR amplification of human genomic DNA?
A) 1-10 ng/mL
B) 5-50 ng/mL
C) 10-100 ng/mL
D) 0.5-1 ug/mL

*Answer: B) 5-50 ng/mL

*Question: What does a smeared or smudged band on gel electrophoresis indicate?
A) High DNA concentration
B) Low DNA concentration
C) Degraded or destroyed DNA
D) Pure DNA sample

*Answer: C) Degraded or destroyed DNA

*Question: What is the appearance of good quality DNA on gel electrophoresis?
A) Smeared and diffuse
B) Absent bands
C) Intact with clear crescent and minimal smudging
D) Multiple faint bands

*Answer: C) Intact with clear crescent and minimal smudging

*Question: What happens when DNA concentration is too HIGH on gel electrophoresis?
A) No bands appear
B) DNA migrates too fast
C) DNA does not migrate and remains in the well
D) Bands appear smeared

*Answer: C) DNA does not migrate and remains in the well

*Question: What happens when DNA concentration is too LOW on gel electrophoresis?
A) DNA remains in the well
B) No bands appear
C) Multiple bands appear
D) DNA migrates too slowly

*Answer: B) No bands appear

*Question: If bad quality DNA is encountered after extraction, what is the correct next step?
A) Proceed to PCR regardless
B) Perform dilution
C) Repeat the entire process from extraction
D) Perform concentration step

*Answer: C) Repeat the entire process from extraction

*Question: Which law governs the principle of spectrophotometry?
A) Fick's Law
B) Boyle's Law
C) Beer-Lambert's Law
D) Dalton's Law

*Answer: C) Beer-Lambert's Law

*Question: According to Beer-Lambert's Law, absorbance and concentration are:
A) Inversely proportional
B) Directly proportional
C) Unrelated
D) Exponentially related

*Answer: B) Directly proportional

*Question: What is the relationship between concentration and transmitted light?
A) Direct
B) Inverse
C) Logarithmic
D) No relationship

*Answer: B) Inverse

*Question: At what wavelength is nucleic acid measured in spectrophotometry?
A) 230 nm
B) 270 nm
C) 280 nm
D) 260 nm

*Answer: D) 260 nm

*Question: What does a spectrophotometer consist of?
A) Fluorometer and photometer
B) Spectrometer and photometer
C) Spectrometer and fluorometer
D) Monochromator and fluorometer

*Answer: B) Spectrometer and photometer

*Question: Which part of the spectrometer selects a specific wavelength?
A) Lens
B) Light source
C) Wavelength selector (slit)
D) Photometer

*Answer: C) Wavelength selector (slit)

*Question: What does the photometer do in spectrophotometry?
A) Selects the wavelength
B) Provides the light source
C) Detects the signal and converts it to a numerical value
D) Separates the wavelengths

*Answer: C) Detects the signal and converts it to a numerical value

*Question: What principle does fluorometry use?
A) Measures absorbance of light
B) Measures fluorescence emitted after excitation
C) Measures refraction of light
D) Measures transmission of light

*Answer: B) Measures fluorescence emitted after excitation

*Question: In fluorometry, the intensity of emitted light is directly proportional to:
A) Protein concentration
B) Salt concentration
C) DNA concentration
D) Reagent concentration

*Answer: C) DNA concentration

*Question: How many times more sensitive is fluorometry compared to spectrophotometry?
A) 10-100 times
B) 100-500 times
C) 1000-10,000 times
D) 50-100 times

*Answer: C) 1000-10,000 times

*Question: Which method can provide purity ratios?
A) Fluorometry only
B) Both spectrophotometry and fluorometry
C) Spectrophotometry only
D) Neither

*Answer: C) Spectrophotometry only

*Question: Which quantification method is more widely available in the Philippines?
A) Fluorometry
B) Spectrophotometry
C) Both equally available
D) Neither

*Answer: B) Spectrophotometry

*Question: What is the main advantage of fluorometry over spectrophotometry?
A) Cheaper cost
B) Provides purity ratios
C) Higher sensitivity and specificity to target molecules
D) Faster sample preparation

*Answer: C) Higher sensitivity and specificity to target molecules

*Question: What is a major disadvantage of fluorometry?
A) Cannot detect concentration
B) Low sensitivity
C) Longer sample preparation time and higher cost
D) Cannot detect low concentrations

*Answer: C) Longer sample preparation time and higher cost

*Question: What volume of sample does the Nanodrop method require?
A) 20-25 uL
B) 10-15 uL
C) 1-2 uL
D) 5-10 uL

*Answer: C) 1-2 uL

*Question: What is the constant for dsDNA in the Nanodrop method?
A) A260 of 1 = 25 ug/mL
B) A260 of 1 = 50 ug/mL
C) A260 of 1 = 100 ug/mL
D) A260 of 1 = 10 ug/mL

*Answer: B) A260 of 1 = 50 ug/mL

*Question: What is the formula for calculating DNA concentration using the Nanodrop method?
A) C = A280 x 50 ug/mL x dilution factor
B) C = A260 x 25 ug/mL x dilution factor
C) C = A260 x 50 ug/mL x dilution factor
D) C = A230 x 50 ug/mL x dilution factor

*Answer: C) C = A260 x 50 ug/mL x dilution factor

*Question: A DNA sample was diluted 10-fold and showed A260 = 0.5. What is the concentration of the original sample?
A) 25 ug/mL
B) 50 ug/mL
C) 100 ug/mL
D) 250 ug/mL

*Answer: D) 250 ug/mL

*Question: What is the optimal 260/280 ratio for pure DNA?
A) 2.00
B) 1.80
C) 1.50
D) 2.20

*Answer: B) 1.80

*Question: What does the 260/280 purity ratio detect?
A) Salt contaminants
B) Organic contaminants
C) Protein contaminants
D) RNA contamination

*Answer: C) Protein contaminants

*Question: What is the optimal 260/230 ratio for pure DNA?
A) 1.80
B) 1.50
C) 2.00
D) 2.50

*Answer: C) 2.00

*Question: What does the 260/230 purity ratio detect?
A) Protein contaminants
B) Salt and organic contaminants
C) RNA contamination
D) DNA degradation

*Answer: B) Salt and organic contaminants

*Question: At what wavelength are proteins detected in spectrophotometry?
A) 230 nm
B) 260 nm
C) 270 nm
D) 280 nm

*Answer: D) 280 nm

*Question: At what wavelength are salt and organic contaminants detected?
A) 260 nm
B) 230 nm
C) 280 nm
D) 270 nm

*Answer: B) 230 nm

*Question: At what wavelength is phenol detected?
A) 230 nm
B) 260 nm
C) 270 nm
D) 280 nm

*Answer: C) 270 nm

*Question: What is the optimal 260/280 ratio for pure RNA?
A) 1.80
B) 1.60
C) 2.00
D) 2.20

*Answer: C) 2.00

*Question: What is the optimal 260/230 range for both RNA and DNA?
A) 1.80-2.00
B) 1.60-1.80
C) 2.00-2.20
D) 2.20-2.50

*Answer: C) 2.00-2.20

*Question: A DNA sample has a 260/280 ratio of 1.72. What does this indicate?
A) Pure sample
B) Protein contaminants present
C) Salt contaminants present
D) Sufficient concentration

*Answer: B) Protein contaminants present

*Question: A DNA sample has a 260/230 ratio of 0.21. What does this indicate?
A) Pure sample
B) Protein contamination
C) Salt and organic contaminants present
D) High DNA concentration

*Answer: C) Salt and organic contaminants present

*Question: A DNA sample has a 260/280 of 1.98 and 260/230 of 2.10, but a concentration of 258.83 ng/uL. What is the next step?
A) Repeat extraction
B) Discard the sample
C) Perform dilution
D) Proceed directly to PCR

*Answer: C) Perform dilution

*Question: If a DNA sample is impure but has a concentration within the optimal range, what should be done?
A) Proceed to PCR
B) Perform dilution
C) Repeat the entire extraction process
D) Perform concentration step

*Answer: C) Repeat the entire extraction process in

*Question: What is the Nanodrop concentration range for dsDNA without dilution?
A) 1-100 ng/uL
B) 2 ng/uL to 15,000 ng/uL
C) 5-50 ng/uL
D) 10-500 ng/uL

*Answer: B) 2 ng/uL to 15,000 ng/uL

*Question: How often should the spectrophotometer be re-blanked during use?
A) Every 10 minutes
B) Every 15 minutes
C) Every 30 minutes
D) Every hour

*Answer: C) Every 30 minutes

*Question: What should the drop look like when placed on the Nanodrop pedestal?
A) Flat and spreading
B) A perfect dome shape
C) Irregular and dispersed
D) Completely clear

*Answer: B) A perfect dome shape

*Question: What are the two principles used for nucleic acid quantification?
A) Gel electrophoresis and PCR
B) Spectrophotometry and fluorometry
C) Nanodrop and fluorometry
D) Beer-Lambert and Fick's Law

*Answer: B) Spectrophotometry and fluorometry

*Question: What type of spectrophotometer is the Nanodrop?
A) Visible light spectrophotometer
B) Infrared spectrophotometer
C) UV spectrophotometer
D) Fluorescence spectrophotometer

*Answer: C) UV spectrophotometer

*Question: What is the first step to take if DNA concentration is less than 5 ng after quantification?
A) Repeat extraction
B) Perform the concentration step
C) Discard and start over
D) Proceed to PCR

*Answer: B) Perform the concentration step

*Question: What is the correct action if DNA is still insufficient after the concentration step?
A) Proceed with PCR anyway
B) Perform dilution
C) Repeat the entire extraction process
D) Add more reagents

*Answer: C) Repeat the entire extraction process

*Question: Which step is considered the most crucial in molecular biology?
A) PCR amplification
B) Gel electrophoresis
C) DNA isolation
D) Nucleic acid quantification

*Answer: C) DNA isolation

*Question: What reagent is used in the Diphenylamine method for DNA quantification?
A) Ethidium bromide
B) Diphenylamine
C) SYBR Green
D) Phenol

*Answer: B) Diphenylamine

*Question: At what wavelength is the blue complex read in the Diphenylamine method?
A) 260 nm
B) 280 nm
C) 595 nm
D) 400 nm

*Answer: C) 595 nm

*Question: What is the chemical reaction in the Diphenylamine method?
A) DNA reacts with phenol to form a colored complex
B) 2-deoxyribose reacts with diphenylamine in acid to form a blue complex
C) RNA reacts with diphenylamine to form a red complex
D) Proteins react with diphenylamine to form a blue complex

*Answer: B) 2-deoxyribose reacts with diphenylamine in acid to form a blue complex

*Question: In the Diphenylamine method, what is plotted on the X-axis of the standard curve?
A) Absorbance
B) Wavelength
C) Concentration
D) Volume

*Answer: C) Concentration

*Question: In the Diphenylamine method, what is plotted on the Y-axis of the standard curve?
A) Concentration
B) Absorbance at 595 nm
C) Volume
D) Wavelength

*Answer: B) Absorbance at 595 nm

*Question: What treatment is performed after RNA isolation?
A) RNAse treatment
B) DNAse treatment
C) Phenol extraction
D) Ethanol precipitation

*Answer: B) DNAse treatment

*Question: What treatment is performed after DNA isolation?
A) DNAse treatment
B) RNAse treatment
C) Proteinase K treatment
D) Ethanol precipitation

*Answer: B) RNAse treatment

*Question: Which of the following is NOT a step performed post-DNA isolation?
A) RNAse treatment
B) Gel electrophoresis
C) PCR amplification
D) Nanodrop method

*Answer: C) PCR amplification

*Question: What quality of DNA is required for Restriction Enzyme (RE) Digestion?
A) 5 to 50 ng
B) 0.5 to 10 ug
C) Less than 1 ug
D) 10 to 50 ng

*Answer: B) 0.5 to 10 ug

*Question: What quantity of DNA is required for analyses using ligation and cloning?
A) 5-50 ng
B) 0.5-10 ug
C) 10 ug
D) Less than 1 ug

*Answer: C) 10 ug

*Question: What is the DNA quantity required for Cycle Sequencing?
A) 5-50 ng
B) 10 ug
C) 0.5-1 ug
D) Less than 1 ug

*Answer: D) Less than 1 ug

*Question: Which contaminant interferes with PCR amplification from heparinized blood samples?
A) Salts
B) Hemoglobin
C) Heparin
D) EDTA

*Answer: C) Heparin

*Question: Which contaminant can be compensated in PCR by increasing MgCl2 proportionally?
A) Organic solvents
B) SDS
C) EDTA
D) Heparin

*Answer: C) EDTA

*Question: What DNA quantity is required for Array-based genotyping?
A) 5-50 ng
B) 10-50 ng
C) 0.5-1 ug
D) 10 ug

*Answer: C) 0.5-1 ug

*Question: Which method uses fluorescent dyes that are specific to target molecules?
A) Spectrophotometry
B) Gel electrophoresis
C) Fluorometry
D) Diphenylamine method

*Answer: C) Fluorometry

*Question: In fluorometry, fluorescence occurs only when:
A) The sample is at high concentration
B) The fluorophore binds to the target molecule
C) Light is absorbed at 260 nm
D) The sample is pure

*Answer: B) The fluorophore binds to the target molecule

*Question: What happens to transmitted light when DNA concentration is HIGH?
A) Transmitted light increases
B) Transmitted light decreases
C) Transmitted light remains unchanged
D) Transmitted light is zero

*Answer: B) Transmitted light decreases

*Question: What is the role of the monochromator in a spectrophotometer?
A) Detects the signal
B) Provides the light source
C) Separates white light into different wavelengths
D) Selects specific wavelength

*Answer: C) Separates white light into different wavelengths

*Question: What is the recommended number of minimum measurements to take with a spectrophotometer?
A) Single measurement
B) At least duplicates
C) At least triplicates
D) Four measurements

*Answer: B) At least duplicates

*Question: What does a 260/280 ratio of 1.32 indicate?
A) Pure DNA
B) Presence of salt contaminants
C) Presence of protein contaminants
D) Sufficient DNA concentration

*Answer: C) Presence of protein contaminants

*Question: Which of the following is an advantage of the Nanodrop method?
A) Requires large sample volumes
B) Needs multiple reagents
C) Can measure DNA, RNA, and protein concentrations
D) Only measures one type of molecule

*Answer: C) Can measure DNA, RNA, and protein concentrations

*Question: What is the pH recommended for Nanodrop DNA purity measurements?
A) pH 6.0
B) pH 7.0
C) pH 7.5
D) pH 8.0

*Answer: C) pH 7.5

*Question: What buffer is recommended for Nanodrop purity measurements?
A) PBS
B) 10 mM Tris·Cl, pH 7.5
C) TE buffer
D) TAE buffer

*Answer: B) 10 mM Tris·Cl, pH 7.5

*Question: What does the lens (collimator) do in a spectrometer?
A) Selects wavelength
B) Gathers dispersed light and forms one straight beam
C) Detects the signal
D) Absorbs the light

*Answer: B) Gathers dispersed light and forms one straight beam

*Question: Which of the following correctly describes the specificity of fluorometry vs. spectrophotometry?
A) Spectrophotometry is more specific
B) Both have equal specificity
C) Fluorometry is highly specific; spectrophotometry is less specific
D) Neither is specific

*Answer: C) Fluorometry is highly specific; spectrophotometry is less specific

*Question: What is the correct workflow in molecular biology after nucleic acid extraction?
A) PCR → Quantification → Gel Electrophoresis
B) Quantification → PCR → Gel Electrophoresis
C) Gel Electrophoresis → Quantification → PCR
D) Quantification → Gel Electrophoresis → PCR

*Answer: B) Quantification → PCR → Gel Electrophoresis

*Question: What is the sensitivity level of spectrophotometry?
A) Very high
B) Moderate
C) Low
D) Negligible

*Answer: B) Moderate

*Question: Which of the following is NOT a possible contaminant detected by spectrophotometry?
A) Phenol at A270
B) Proteins at A280
C) Organic substances at A230
D) Lipids at A310

*Answer: D) Lipids at A310

*Question: Which is a disadvantage of spectrophotometry?
A) Cannot provide concentration
B) Limited sensitivity for low concentrations and less selective
C) Requires fluorescent labeling
D) Higher cost than fluorometry

*Answer: B) Limited sensitivity for low concentrations and less selective

*Question: What does the standard curve in the Diphenylamine method allow you to do?
A) Measure purity ratios
B) Interpolate sample DNA concentration from absorbance
C) Determine RNA concentration
D) Identify protein contaminants

*Answer: B) Interpolate sample DNA concentration from absorbance

*Question: A DNA sample has a concentration of 53.78 ng/uL, a 260/280 of 1.72, and 260/230 of 0.21. What is the correct next step?
A) Proceed to PCR with dilution
B) Perform concentration step
C) Repeat the entire extraction process
D) Proceed to PCR as concentration is sufficient

*Answer: C) Repeat the entire extraction process

*Question: What does the term "downstream experiments" refer to in the context of nucleic acid quantification?
A) Gel electrophoresis only
B) Experiments done before extraction
C) Experiments performed after quantification, such as PCR
D) Quality checking steps

*Answer: C) Experiments performed after quantification, such as PCR

*Question: Which of the following best explains why fluorometry has no information on sample purity?
A) It cannot detect nucleic acids
B) Its fluorophores bind only to the target molecule, ignoring contaminants
C) It uses UV light which cannot detect contaminants
D) It does not measure absorbance

*Answer: B) Its fluorophores bind only to the target molecule, ignoring contaminants

*Question: What is the DNA concentration required for Amplification-based SNP Genotyping?
A) 5-50 ng
B) 0.5-1 ug
C) 10-50 ng
D) Less than 1 ug

*Answer: C) 10-50 n