RIN Met Lecture 1-Energy Reaction In Cells Flashcards
Define cell metabolism
Cell metabolism is defined as the highly integrated network of chemical reactions that occur within cells .
Functions of cell metabolism
Provides:
- energy for cell function and the synthesis of cell proteins
- building block molecules that are used in the synthesis of cell components needed for the growth , maintenance , repair and division of cell
- organic precursor molecules that are used to allow the interconversion of building block molecules
- biosynthetic reducing power used un the synthesis of cell components
Origins of cell nutrients
The diet
Synthesis in body tissues from precursors
Released from storage in body tissues
Fates of cell nutrients
- degradation to release energy
- synthesis of cell components -all tissue apart from mature erythrocytes
- storage :liver, adipose tissues and skeletal muscle
- Interconversion to other nutrients
- excretion :liver, kidney, lungs
Features of catholic pathways
- break down larger molecules into smaller ones (intermediary metabolites)
- release large amount of free energy
- oxidative process so H atoms are released :”reducing power”
Features of anabolic pathways
- synthesise larger important cellular components from intermediary metabolites
- use energy released from catabolism
- reductive :uses H atoms form catabolism
Definition of Energy
Capacity to do work
Types of work that requires energy in the body
- Biosynthetic work (anabolism ):synthesis of cellular components
- transport work :across membranes (maintenance of ion gradients and nutrient uptake )
- specialised functions such as mechanical work(muscle contraction), electrical work (nervous impulse conduction ) and osmotic work(kidney)
Difference between exergonic and endergonic reactions?
Exergonic - release energy
Endergonic - requires energy
Features of exergonic reactions
- occurs spontaneously
- value is negative
- free energy is <0
Features of endergonic reactions
- reaction is not spontaneous ; requires energy input
- free energy >0
- values are positive
Examples of H carrier molecules
Role of H carrier molecules
- NAD
- NADP
- FAD
Acts as carriers of reducing power for atp production and biosynthesis
What are H carrier molecules ?
Complex molecules that contain components from vitamin B
Converted to reduced form by adding 2 H atoms
What does high energy signals include ?
When ATP is high, anabolic pathways are activated (energy and reducing power used to drive synthesis of new molecules or produce work)
ATP
NADH
NADPH
FAD2H
What does low energy signal include ?
Low levels of ATP and high levels of ADP and AMP SO catabolic pathways activated
ADP AMP NAD+ NADP+ FAD
Role of creatine phosphate
Used as a quick supply of energy is cells that need to increase metabolic activity quick e.g skeletal muscle
What occurs when ATP levels are high ?
Phosphate Bond energy may be stored in phosphocreatine
Creatine + ATP (enzyme creatine kinase) phosphocreatine (CREATINE PHOSPHATE ) + ADP
Creatine phosphate is made
What occurs when ATP levels are low ?
Reaction of reverses to produce short term boost of ATP
What is creatine kinase(ck) used as an indication for and how ?
Used to diagnose heart attack
CK is released from cardiac myocytes when damaged in heart attack
Appears in blood after 2 hours
How is Creatinine produced?
Normal spontaneous breakdown of creatine and phosphocreatine
What is creatinine a useful clinical marker for ?
Muscle wasting
The rate of production of creatinine is proportional to the concentration of creatine in muscle and this related to skeletal muscle mass
What is the daily excretion of creatinine used as an indicator for?
Skeletal muscle mass
Increased excretion of creatinine may indicate active muscle wasting
What can be used as an indicator of kidney function ?
Measurements of the conc of creatinine in blood and urine
How is measurements of the conc of creatinine in blood and urine used as an indicator of kidney function ?
The kidney is normally very efficient at removing creatinine from the blood .
High blood creatinine with low urinary creatinine conc may indicate kidney function
