Metabolic Pathways and Isotopes

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Questions and Answers

What is the primary purpose of a PET scan?

To measure blood flow in various organs

To diagnose structural abnormalities in tissues

To identify functional abnormalities in organs and tissues (correct)

To track radioactive tracer distribution in the body

Which radioisotope is primarily used in Positron Emission Tomography?

Fluorine-18 (correct)

Carbon-14

Technetium-99m

Iodine-131

What is the main role of the photomultiplier in mass spectrometry?

To convert fragment ions into mass ratios

To inject samples into the mass analyzer

To amplify the signal proportional to ion abundance (correct)

To separate ions based on their charge

How is ion fragmentation achieved in mass spectrometry?

By electron impact ionization Signup and view all the answers

What term is used to describe elements that emit radiation?

Radioactive Signup and view all the answers

In beta decay, what transformation occurs in the nucleus?

A neutron becomes a proton. Signup and view all the answers

In Gas Chromatography, what is the purpose of the carrier gas?

To transport the sample through the column Signup and view all the answers

What does the half-life of a radioactive isotope refer to?

The time taken for half of the atoms to decay. Signup and view all the answers

What is measured by the tracer to tracee ratio (TTR) in stable isotope studies?

The proportion of the tracer in relation to a compound of interest Signup and view all the answers

During a mass spectrometry analysis, what typically separates the samples based on their mass?

The mass analyzer Signup and view all the answers

Which type of radiation is particularly useful for medical diagnosis due to its ability to exit the body easily?

Gamma radiation Signup and view all the answers

What happens to a sample molecule during electron impact ionization?

It loses an electron resulting in the formation of a positive ion Signup and view all the answers

What is the primary purpose of using a radioisotope as a tracer in medical diagnostics?

To detect diseased states with minimal effects on body tissue. Signup and view all the answers

What does the vertical axis of a chromatogram represent?

Signal intensity Signup and view all the answers

What is the term for the time it takes for a component to travel from injection to detection in gas chromatography?

Retention time Signup and view all the answers

What would likely be observed in an imaging scan if an area of tissue is nonfunctioning?

A cold spot. Signup and view all the answers

Which of the following statements is true regarding gas chromatography?

It involves a mobile phase that is in gas form. Signup and view all the answers

Which of the following is NOT a typical use of medical radioisotopes?

Creating energy Signup and view all the answers

If a radioisotope shows increased activity in an imaging test, what does that indicate?

Rapidly dividing cancer cells. Signup and view all the answers

What are the two phases involved in gas chromatography?

Mobile phase and stationary phase Signup and view all the answers

Which compounds are unsuitable for analysis using gas chromatography-mass spectrometry (GC-MS)?

Non-volatile compounds Signup and view all the answers

What does metabolic flux indicate?

The passage of a metabolite through a pathway over time Signup and view all the answers

Which of the following factors can uniquely alter metabolic flux responses in cells?

Hormonal signals Signup and view all the answers

How can radioactive isotopes be used in studying metabolic pathways?

To trace the path of metabolites from reactant to product Signup and view all the answers

Which of the following is commonly used as a radiotracer in metabolic studies?

Hydrogen Signup and view all the answers

What determines the atomic number of an element?

The number of protons present Signup and view all the answers

Which statement about radioisotopes is incorrect?

They are only useful in studying animal metabolism Signup and view all the answers

What is the significance of understanding metabolic flux in disease conditions?

It provides insights for targeted treatment efforts Signup and view all the answers

What is the composition of an atom made up of?

Protons, neutrons, and electrons Signup and view all the answers

Study Notes

Metabolic Flux

Metabolic flux is the movement of a metabolite through a metabolic pathway over time.
Environmental factors, hormonal signals, and pharmacological interventions influence metabolic flux, contributing to diverse metabolic phenotypes.

Tracer-Based Methods

Tracer-based methods utilize radioisotopes or stable isotopes to measure biosynthesis and decomposition.
A radiotracer contains radioisotopes allowing for the detection of metabolite abundance.
The path of the radioisotope is traced from reactant to product.
Common radioisotopes used in metabolic pathway research include Hydrogen, Carbon, Phosphorous, Sulfur, and Iodine.

Atoms

An atom is composed of protons, neutrons, and electrons.
The number of protons determines the atomic number of an element.
The atomic mass is the sum of protons and neutrons.

Isotopes

Isotopes are atoms of the same element with differing neutron numbers.

Radioactivity

Radioactivity is the spontaneous release of energy from an atomic nucleus.
Radioactive elements emit radiation, a form of energy from natural and man-made sources.

Beta Decay

In beta decay, a neutron in the nucleus decays into a proton, releasing a high-energy electron.

Positron Emission

Positron emission occurs when a proton in the nucleus decays into a neutron, releasing a positron (antimatter electron).

Half-Life

The half-life of a radioactive isotope is the time it takes for half of the atoms in a sample to decay.
Decay is measured using a Geiger counter.

Medical Applications of Radioisotopes

Medical radioisotopes are used in diagnosing and treating diseased states.
Gamma emitters are preferred for diagnosis because gamma radiation can easily exit the body.
"Cold" spots indicate a nonfunctioning area of tissue, while "hot" spots highlight areas with increased activity, such as rapidly dividing cancer cells.

Positron Emission Tomography (PET) Scan

A PET scan is used to identify functional abnormalities in organs and tissues.
Fluorine-18 is used to measure metabolic activity in the brain.
PET scans are used to detect and diagnose neurological, cardiovascular, and cancer-related conditions.

Mass Spectrometry

Mass spectrometry is used to quantify the abundance of specific ions fragmented by electron impact ionization.
After ionization, fragmented ions travel through a mass analyzer and hit an electron multiplier to detect their presence.
The intensity of the signal is directly proportional to the abundance of the ions.

Gas Chromatography (GC)

GC separates compounds based on their volatility and affinity for a stationary phase.
The mobile phase (carrier gas) carries the sample through the column.
Differences in retention time allows for the separation and detection of different compounds.

Electron Ionization (EI)

EI is used to ionize molecules by bombarding them with an electron beam.
This method is suitable for small, stable molecules that can be vaporized.

Chromatogram

A chromatogram is a graphical representation of the signals detected by a GC detector.
It shows the signal intensity over time, with peaks representing the elution of individual compounds.
The retention time is the time it takes for a compound to elute from the column.

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Description

Explore the concepts of metabolic flux, tracer-based methods, and the fundamentals of atoms and isotopes in biochemistry. This quiz delves into the connections between environmental factors, radioactivity, and metabolic processes. Test your understanding of how these elements contribute to metabolic research and analysis.