L15: Energy Balance and Metabolism II Flashcards
Describe the generation of ATP
Combustion of carbs, fatty acids, proteins
Describe the function of ATP
Synthesis of cellular components Muscle contraction Active transport across membranes Glandular secretion Nerve conduction
Explain how phosphocreatine functions as an accessory storage depot for energy and as an “ATP Buffer.
Can transfer energy interchangeably with ATP
Has a high energy phosphate bond
Describe the pathway for the synthesis of alanine from pyruvic acid and define “transamination.”
Pyruvic acid is the keto acid precursor of the amino acid alanine. By the process of transamination, an amino radical is transferred to the alpha keto acid and the keto oxygen is transferred to the donor of the amino radical
Transamination is promoted by aminotransferases
List/describe the steps in the formation of a peptide bond.
Amino acid + ATP - > amino acid - AMP + 2 Pi
Amino acid - AMP + tRNA -> amino acid - tRNA + AMP
Attachment of tRNA to mRNA via codon-anticodon pairing
Formation of peptide bond with second amino acid using peptidyl transferase + GTP
What parts of the ornithine cycle occur in the mitochondria
Ammonia + CO2 -> carbamoyl phosphate
Carbamoyl phosphate _ ornithine -> citrulline
What parts of the ornithine cycle occur in cytoplasm
Citrulline + aspartate -> argininosuccinate
Argininosuccinate -> arginine + fumarate
Arginine -> urea + ornithine
Describe the formation of urea in the liver.
The ammonia released during deamination of amino acids is removed from the blood almost entirely by conversion into urea
Describe the relationship between the rate of a chemical reaction and the concentrations of substrate and enzymes.
Determines rate of overall chemical reaction
Give examples of reaction rates that are determined almost entirely by concentration of enzyme.
Diabetes mellitus and glucose
Define the rate-limiting step in a series of reactions.
The overall rate of a series of chemical reactions is determined by the rate of reaction of the slowest step in the series
What is the major rate-limiting factor in almost all energy metabolism in the body.
ADP
Describe the relationship of heat to reaction rates and metabolism.
About 35% of energy in foods becomes heat during ATP formation
More heat is produced in the transfer of energy from ATP to the functional systems of cells
Describe factors that influence metabolic rate.
Arousal vs sleeping Skeletal muscle Age Thyroid activity Testosterone Growth hormone Fever Sleep Malnutrition
Define basal metabolic rate; explain how it is calculated; what is its relationship to age and gender?
The minimal level of energy required to exist
It declines with age
