36 Questions
What is the primary function of NAD/NADH and NADP/NADH in energy metabolism?
To act as energy carriers and donate electrons
What is the term for the controlled release of energy in enzyme-catalyzed metabolic pathways?
Energy conservation
What is the primary function of Coenzyme A/acetyl CoA in energy metabolism?
To carry acetyl groups in citric acid cycle
What is the role of NADP in metabolic reactions?
To replace NAD in anabolic reactions
What is the term for the process of building molecules, requiring energy, in metabolic pathways?
Anabolism
What is the function of flavins in metabolic reactions?
To act as hydrogen acceptors
What is the primary function of ATP in energy metabolism?
To store energy in the form of chemical bonds
What is the role of Acetyl-CoA in metabolic reactions?
To carry an acyl group (2 carbons)
Where are the metabolic pathways, including glycolysis, TCA cycle, β-oxidation, and oxidative phosphorylation, primarily localized in eukaryotic cells?
Mitochondria and cytosol
What is the structure of Coenzyme A (CoA)?
A dinucleotide with a vitamin and sulphur-containing group
What is the result of NAD+ reduction?
NADH + H+ is formed
What is the role of FAD in metabolic reactions?
To act as a hydrogen acceptor
What is the primary function of the metabolic breakdown of complex substances into smaller products?
To release energy for use by the cell or organism
Which of the following is a characteristic of anabolism?
Transforms simpler substances into more complex ones
What is the term for the totality of the chemical reactions and physical changes that occur in living organisms?
Metabolism
In which part of the mitochondria would you find the enzymes involved in the synthesis, breakdown, and interconversion of essential biomolecules?
Mitochondrial matrix
What is the result of the catabolic breakdown of carbon compounds?
Liberation of energy for use by the cell or organism
What is the primary difference between anabolism and catabolism?
Energy requirement
Which of the following is NOT a characteristic of catabolism?
Transformation of simpler substances into complex ones
What is the name of the space between the inner and outer mitochondrial membranes?
Intermembrane space
What is the process called when an amino acid is converted into another amino acid?
Transamination
Which amino acid undergoes a meaningful level of deamination in humans?
Glutamate
What is the byproduct of deamination of glutamate?
α-ketoglutarate
What is the role of glutamine in the body?
Carrying two nitrogen atoms
Where does the deamination of glutamate take place?
Liver
What is the outcome of glutamine formation from glutamate?
Addition of NH2
What happens to glutamate in the liver?
It is deaminated to α-ketoglutarate
What is the fate of NH4+ molecules in the liver?
They are converted to urea
In the electron transport chain, what is the final electron acceptor?
O2
What is the purpose of the electron transport chain in the mitochondria?
To pump protons into the intermembrane space
What is the result of proton flow through the ATP synthase protein complex?
The synthesis of ATP from ADP + Pi
What happens to the carbon skeleton of amino acids that are surplus to requirements?
It is further metabolized
What is the purpose of the electron transport chain in terms of ATP production?
To create an electrochemical gradient that drives ATP synthesis
What is the location of the electron transport chain in the mitochondria?
In the inner mitochondrial membrane
What is the result of the oxidation of NADH and FADH2 in the electron transport chain?
The reduction of O2 to form H2O
What is the term for the process by which the N from the α‑amino group is removed from amino acids?
Deamination
Study Notes
Introduction to Metabolism
- Metabolism is the totality of chemical reactions and physical changes that occur in living organisms, comprising anabolism and catabolism.
- Enzyme reactions involve synthesis, breakdown, and interconversion of essential biomolecules.
Catabolism and Anabolism
- Catabolism: the metabolic breakdown of complex substances into smaller products, including the breakdown of carbon compounds with the liberation of energy for use by the cell or organism.
- Anabolism: the energy-requiring part of metabolism in which simpler substances are transformed into more complex ones, as in growth or other biosynthetic processes.
Electron Carriers and Activated Carrier Molecules
- NAD+ and NADH: electron carriers involved in oxidation and reduction reactions.
- NADP+ replaces NAD+ in anabolic reactions, such as lipid synthesis.
- Flavin adenine dinucleotide (FAD) and FADH2: electron carriers involved in oxidation and reduction reactions.
- Acetyl-CoA: a carrier of an acyl group (2 carbons), not electrons or hydrogens.
Electron Transport Chain
- The electron transport chain is a series of protein complexes embedded in the inner mitochondrial membrane.
- Electrons are transported along the chain, finally reducing O2 to form H2O.
- The energy released is used to pump protons (H+) into the intermembrane space, creating an electrochemical gradient.
- Protons flow back through the membrane via ATP Synthase, driving the synthesis of ATP from ADP + Pi.
Amino Acid Metabolism
- Amino acid metabolism is also known as 'nitrogen metabolism'.
- Amino acids that are surplus to requirements are not stored, instead, the N from the α-amino group is removed and the remaining carbon skeleton is further metabolized.
- Deamination: removal of N from amino acids, occurs in the liver.
- Transamination: conversion of one amino acid to another, occurs in most tissues.
- Glutamine carries 2 nitrogen atoms and is a safe carrier of 2 N to the liver for deamination.
- Glutamate is reformed from glutamine in the liver, then deaminated to α-ketoglutarate, releasing NH4+.
This quiz covers the basics of metabolism and molecular biology, focusing on chapters 3 and 12 of the biochemistry textbook and chapters 3 and 13 of Essential Cell Biology.
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