NMR and DNA Sequencing Quiz
23 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Why is fluorescence widely applied in DNA sequencing?

  • Some dyes strongly decrease their fluorescence signal upon binding to DNA
  • Many dyes easily bind to DNA
  • Some dyes highly increase their fluorescence quantum yield upon binding to DNA (correct)
  • Some dyes highly increase their absorption upon binding to DNA

What range of frequencies is typically utilized by medical ultrasound?

  • Above 100 kHz but below 20,000 kHz (correct)
  • Above 20 MHz
  • Below 100 kHz
  • Below 20 kHz but above 20 Hz

If a 4 Tesla magnet produces EM radiation of about 300 MHz, what frequency will an 8 Tesla magnet produce with its field directed opposite?

  • 300 MHz (correct)
  • 600 MHz
  • 900 MHz
  • 150 MHz

What is the frequency at 7.05T if 13C in a 4.7T field has a frequency of 25.2?

<p>50.4 (C)</p> Signup and view all the answers

What will the observed chemical shift be when the field strength is doubled from 5T to 10T with an initial shift of 6 PPM?

<p>12 PPM (D)</p> Signup and view all the answers

Why is 13C used for NMR imaging?

<p>Has more neutrons (D)</p> Signup and view all the answers

Which of the following statements accurately describes an acoustic wave?

<p>Transverse wave (A)</p> Signup and view all the answers

In an energy diagram, identifying the higher energy state is crucial. Which state is correct?

<p>Depends on frequency (B)</p> Signup and view all the answers

Why are atoms like 19F and 13C used in NMR?

<p>They have one more neutron as compared to natural (A)</p> Signup and view all the answers

How does the speed of an ultrasound wave in tissue compare to that in air?

<p>Higher (B)</p> Signup and view all the answers

What causes the chemical shift in NMR for different protons?

<p>Shielding of the magnetic field by electrons of various surrounding groups (C)</p> Signup and view all the answers

What is the correct definition of isotopes?

<p>Same number of protons and different number of neutrons (A)</p> Signup and view all the answers

If a magnet of 3 Tesla results in EM radiation of about 300 MHz, what radiation will a 9 Tesla magnet produce?

<p>600 MHz (A)</p> Signup and view all the answers

Which statement best describes isomers?

<p>Molecules with same chemical formula but different spatial arrangement of atoms (C)</p> Signup and view all the answers

If the observed chemical shift for the 5T field was 6 PPM, what could it indicate?

<p>A unique chemical environment (A)</p> Signup and view all the answers

What does a frequency of 500 MHz correspond to in terms of wavelength in air?

<p>600 um (C)</p> Signup and view all the answers

What is the result of H1-H2 coupling in NMR?

<p>Multiple lines in NMR (C)</p> Signup and view all the answers

What causes emission depolarization?

<p>Fast rotational mobility of molecules in the solution (C)</p> Signup and view all the answers

How is fluorescence lifetime best defined?

<p>The time after population of molecules in the excited state increases e times (D)</p> Signup and view all the answers

What characteristic does a solvent-sensitive fluorophore exhibit?

<p>Emission spectrum that depends on the fluorophore environment (D)</p> Signup and view all the answers

If a complex of two proteins dissociates, what happens to the emission anisotropy of a probe attached to one of them?

<p>It will decrease (A)</p> Signup and view all the answers

What signifies the end of a fluorescence lifetime?

<p>When the intensity of fluorescence decreases 10 times (B)</p> Signup and view all the answers

Which of the following is NOT a feature of emission from a fluorophore?

<p>Independent of temperature (A)</p> Signup and view all the answers

Flashcards

Fluorescence in DNA sequencing

Some dyes increase their fluorescence significantly when bound to DNA, making it useful in DNA sequencing.

13C NMR frequency (4.7T)

At a 4.7 Tesla magnetic field, the frequency for 13C is 25.2 MHz.

13C in NMR imaging

13C NMR is useful for imaging because it is naturally occurring, stable, and has detectable properties.

Higher energy state in a diagram

In an energy-level diagram, the higher energy state is typically the one with a higher wavelength, or state further along the vertical axis.

Signup and view all the flashcards

NMR isotopes

Isotopes like 19F and 13C are used in NMR due to their unique properties, allowing for the observation of different chemical environments within molecules.

Signup and view all the flashcards

Chemical shift in NMR

Chemical shifts in NMR arise from the electron environment shielding the atomic nucleus from the external magnetic field.

Signup and view all the flashcards

NMR frequency (9T)

At 9 Tesla, the NMR frequency would be approximately 600 MHz. , (assuming a direct proportionality relationship between field strength and frequency.)

Signup and view all the flashcards

Chemical shift (5T field)

The observed chemical shift at 5 Tesla is 6 ppm.

Signup and view all the flashcards

Chemical Shift Change (Field Strength Doubled)

When the magnetic field strength in an NMR experiment doubles, the observed chemical shift also doubles.

Signup and view all the flashcards

Ultrasound Frequency Range

Medical ultrasound frequencies typically range from above 15 MHz to below 20 MHz.

Signup and view all the flashcards

Ultrasound Wavelength

The typical wavelength of ultrasound waves generated by devices is in the millimeter range.

Signup and view all the flashcards

Opposite Magnetic Field Direction Shift

Reversing the direction of a magnetic field will result in a negative shift in electromagnetic radiation frequency.

Signup and view all the flashcards

Isotopes Definition

Isotopes are forms of the same element that have the same number of protons but a different number of neutrons.

Signup and view all the flashcards

Acoustic Wave Type

An acoustic wave (like sound) is a longitudinal wave.

Signup and view all the flashcards

Ultrasound Speed in Tissue vs Air

The speed of ultrasound waves in biological tissue is faster than in air.

Signup and view all the flashcards

Isomers Definition

Isomers are molecules that have the same chemical formula but a different arrangement of atoms in 3D space.

Signup and view all the flashcards

Isobars

Molecules with the same chemical formula but different isotopes of atoms.

Signup and view all the flashcards

NMR Wavelength Calculation

If the response of an NMR system results in a 500 MHz frequency, the corresponding wavelength in air is calculated using the equation: wavelength = speed of light / frequency.

Signup and view all the flashcards

H1-H2 Coupling in NMR

The interaction between two hydrogen atoms (H1 and H2) in a molecule results in multiple lines in the NMR spectrum.

Signup and view all the flashcards

Emission Depolarization

The phenomenon where the emitted fluorescence light is less polarized than the excitation light. This occurs due to the fast rotational mobility of molecules in solution.

Signup and view all the flashcards

Fluorescence Lifetime

The average time a molecule stays in its excited state before returning to the ground state.

Signup and view all the flashcards

Solvent-Sensitive Fluorophore

A fluorophore whose emission spectrum changes depending on the surrounding environment (solvent).

Signup and view all the flashcards

Emission Anisotropy Change

When a complex of two proteins dissociates, the emission anisotropy of a probe attached to one of them will decrease.

Signup and view all the flashcards

Study Notes

DNA Sequencing and Fluorescence

  • Fluorescence is widely used in DNA sequencing due to dyes that increase fluorescence upon binding to DNA.

NMR Frequency and Magnetic Field Strength

  • The frequency of 13C in a 4.7T magnetic field is 25.2.
  • In a 7.05T field, the corresponding frequency will be 50.4.

NMR Isotope Use

  • 13C is used for NMR imaging because it is not naturally occurring.
  • It is not stable and its decay can be observed
  • It has a lower molecular mass.

Energy States

  • In the provided diagram, state B has a higher energy than state A.

NMR Atom Use

  • 19F and 13C atoms are used in NMR because they have different numbers of neutrons.

Chemical Shift in NMR

  • Chemical shift differences in NMR are caused by interactions with solvents and shielding of the magnetic field by surrounding groups, electrons or protons.

NMR Radiation

  • A 3 Tesla magnet produces 300 MHz EM radiation.
  • A 9 Tesla magnet will produce 900 MHz radiation.

Chemical Shift Change

  • If a 5T field gives a 6PPM chemical shift, doubling the field to 10T will produce a 12 PPM shift.

Acoustic Waves

  • Acoustic waves are transverse waves.

Ultrasound Speed

  • Ultrasound speed in tissue is lower than that in air.

Isotopes

  • Isotopes are forms of an element with the same number of protons but a different number of neutrons.

Isomers

  • Isomers are molecules with the same chemical formula but different spatial arrangements of atoms.

NMR Wavelength

  • A 500 MHz NMR will produce a 600 mm wavelength.

H1-H2 Coupling

  • H1-H2 coupling produces multiple lines in NMR.

Emission Depolarization

  • Emission depolarization occurs due to the fast rotational mobility of molecules in solution .

Fluorescence Lifetime

  • The fluorescence lifetime is the time it takes for the initial fluorescence intensity to decrease to half its value. The fluorescence lifetime varies from the shortest time in which a molecule can stay in the excited state to the longest time it can stay.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Test 2 Practice Questions PDF

Description

Test your knowledge on the principles of fluorescence in DNA sequencing and the use of NMR in studying isotopes and energy states. This quiz covers topics from magnetic field strength to chemical shifts. Perfect for students in chemistry and biophysics courses.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser