Control Of Metabolic Processes: Metabolic Disorders Flashcards
Define metabolism
All the chemical reactions taking place in the cell
-highly coordinated activity exchanging both matter and energy between cells and the environment
How do organisms maintain homeostasis
By keeping the concentrations of most metabolites at a steady state
Rate of synthesis equals the rate of…..
Breakdown
What are the principles of regulation
The flow of metabolites through pathways is regulated to maintain homeostasis
-flux is moderated by changes in the number of catalytic activity of regulator proteins
What ways can the levels for required metabolites be altered very rapidly
Increase the capacity of glycolysis during action
-reducing the capacity of glycolysis after action
- increase the capacity of gluconeogenesis after successful action
What does very low levels of cofactor availability lead to
Inhibition of enzyme activity , thus rate of metabolic pathway
Define product removal and give an example
The removal of the product could control the rate of its formation from the substrate
What are the 2 major types of regulatory enzymes
Allosteric enzymes and covalently modulated enzymes
What is an allosteric enzyme
Catalytic activity through the non- covalent binding of a specific metabolite outside the catalytic site
What is a covalently modulated enzyme
Are inter converted between active and inactive forms by the action of other enzymes - respond to non-covalent allosteric modulators
What time scale do regulatory enzymes act
Short time scale
- allosteric - within seconds
- covalently - within minutes
What other methods of regulation do regulatory enzymes provide
Proteolytic cleavage, feedback regulation, regulation by isoenzymes
What is proteolytic cleavage
Breakdown of peptide bonds between amino acids in proteins by peplidases,proteases, or proteodytic cleavage enzymes
What is feedback regulation
Product of a metabolic pathway influences its own production by controlling the amount and activity of other enzymes In the pathway
What is regulation by Isoenzymes
Homologous enzymes that catalyse the same reaction but differ in structure
- regulate the same reaction at different tissues
Main properties of allosteric enzymes
Possesses at least 2 spatially distinct binding sites, on the protein molecules the active or the catalytic site and the regulator or the allosteric site
- shows 2 different types of control, heterotrophic and homotrophic
What element of heterotrophic control is the modulator
Modulated by a molecule other than their substrate
What element of homotrophic control is the modulator
Substrate is the modulator
- 2 Or more binding sites
- more bound substrate leads to modulation.
What intrasteric control
Targeting of protein kinases to consensus sequence elements within proteins creates a means to regulate these kinases by a mechanism
What is induction ( in the control of enzyme synthesis)
Activation of enzyme synthesis and repression, are important mechanisms for the regulation of metabolism
What is (DM) diabetes mellitus
A chronic complex syndrome induced by absolute or relative deficit of insulin which is characterised by metabolic disorders of carbohydrates, lipids, and proteins.
What metabolic disturbances are caused by DM
loss of carbohydrate tolerance
• fasting hyperglycaemia
• Ketoacidosis
• decreased lipogenesis
• increased lipolysis
• increased proteolysis
What are the main types of DM
Type 1, type 2, gestational DM
How is type 1 DM caused?
What are the consequences?
What are the subtypes?
due to destruction of beta cells of pancreatic islets
Consequence: absolute deficit of insulin
A. subtype: induced by autoimmunity processes
B. subtype: idiopathic mechanism
How is type 2 DM caused
at the beginning-predominance of insulin resistance and relative
deficit of insulin (normo- or hyper -insulinemia), later - combination of impaired
insulin secretion and simultaneous insulin resistance (hyperinsulinemia, insulin
resistance)
How is gestational (DM) caused
glucose intolerance which onsets for the first time during
pregnancy
What are the main symptoms of DM
Feeling more thirsty than usual
• Urinating often
• Losing weight without trying
• Presence of ketones in the urine.
- a by-product of the breakdown of muscle and fat (low insulin)
• Feeling tired and weak
• Feeling irritable or having other mood changes
• Having blurry vision
• Having slow-healing sores
• Getting a lot of infections, such as gum, skin and vaginal infections
