NITROGEN METABOLISM & PROTEIN TURNOVER LECT 1 1404

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What is the primary reason for the dietary requirement of protein?

To compensate for the body's inability to synthesize certain amino acids (correct)

To support the growth of new tissues

To provide energy for the body

To maintain optimal protein synthesis rates

What is the net result of continuous protein synthesis and breakdown in the body?

Maintenance of optimally functioning proteins (correct)

An increase in the amount of damaged proteins

A complete halt in protein synthesis

A decrease in the total amount of protein in the body

What type of bond is formed between the first ubiquitin and the protein substrate in the ubiquitin/proteasome system?

Isopeptide bond (correct)

Disulfide bond

Hydrogen bond

Peptide bond

What is the primary function of the ubiquitin/proteasome system?

To target cytosolic and nuclear proteins for rapid proteolysis Signup and view all the answers

What is the term for the continual renewal or replacement of protein in the body?

Protein turnover Signup and view all the answers

What is the name of the network that regulates protein synthesis and degradation?

The proteostasis network Signup and view all the answers

What is the primary function of the proteasome in the ubiquitin-proteasome system?

To recognize and degrade polyubiquinated proteins Signup and view all the answers

What is the typical number of ubiquitin molecules required to target a protein for destruction?

4 or more Signup and view all the answers

What is the energy requirement for the ubiquitin-proteasome system?

ATP Signup and view all the answers

What is the primary function of the ubiquitin-like fold in ubiquitin?

To adopt a compact globular structure Signup and view all the answers

What is the result of ubiquitin serving as its own substrate?

Polyubiquitylation Signup and view all the answers

What is the first stage in the ubiquitin-proteasome system?

Ubiquitin activation Signup and view all the answers

What energy source fuels the ubiquitination reaction?

Hydrolysis of ATP Signup and view all the answers

Which enzyme is responsible for transferring Ub to a cysteine residue?

E2 conjugating enzyme Signup and view all the answers

What is the function of the 19S regulatory particle (RP) in the proteasome?

It recognizes ubiquitylated client proteins and unfolds them Signup and view all the answers

Which type of autophagy degrades soluble or unfoldable proteins in a molecule-by-molecule fashion?

Chaperone-mediated autophagy Signup and view all the answers

What is the criterion for a protein to be a putative CMA substrate?

Presence of a peptide sequence related to the KFERQ motif Signup and view all the answers

What is the term for the equilibrium between protein intake and losses?

Nitrogen balance Signup and view all the answers

What is the term for a state where nitrogen intake exceeds nitrogen output?

Anabolic state Signup and view all the answers

What is the optimal daily nitrogen balance for anabolism?

2-4g Signup and view all the answers

Which disease is caused by maternal deficiency of the E6-AP ubiquitin E3 ligase (UBE3A)?

Angelman syndrome Signup and view all the answers

What is the term for the process by which cytoplasmic contents are degraded within the lysosome/vacuole?

Autophagy Signup and view all the answers

What is the primary component of nitrogen output?

Urine urea nitrogen Signup and view all the answers

What is the recommended daily protein intake for a 72-kg man?

58 g protein/day Signup and view all the answers

What is the constant used to account for nitrogen losses from the skin and feces?

4 Signup and view all the answers

What is the term for the type of malnutrition caused by inadequate intake of both protein and energy?

Marasmus Signup and view all the answers

What is the purpose of dividing the daily protein intake by 6.25?

To calculate the total nitrogen intake Signup and view all the answers

What is the term for the condition that results from a negative nitrogen balance?

Protein-Energy Malnutrition Signup and view all the answers