Chapter 9 Metabolism Flashcards
Definition of metabolism
Entire net work of chemical processes involved in maintaining life.
Metabolism pathway
A group of biomedical reactions that occur in the progression from beginning to end.
Intermediate
Compounds formed in the pathway.
Two categories of pathways
Anabolic(合成) and catabolic(分解)
What does metabolism do?
Releas new use energy from carb, alcohol, fat and protein. Synthesis new substances from another and prepare waste products for excretion.
The balance of anabolic and catabolic
Bodies strives to keep the balance. But sometimes one is more prominent than the other. Eg. During the growth, new compounds are synthesized(Anabolic), but during the weight loss or wasting disease(cancer), compounds are broken down(Catabolic).
Where is the energy initially come from?
Sun
adenosine triphosphate (ATP)
Body’s source of energy derived from catabolic reactions of macronutrients.
What can energy in ATP do?
Only the energy in ATP can directly use to synthesize new compounds, contract muscles, conduct nerve impulses, and pump ions across the membranes.
Structure of a ATP molecule
Consists of the organic compound adenosine bound to 3 phosphate groups.
High-energy phosphate bonds
The bonds between he phosphate groups contain energy.
Adenosine diphosphate (ADP)
To release the energy in ATP, cells break a high energy phosphate bonds and create a ADP plus Pi and a free phosphate group
Adenosine monophosphate (AMP)
Hydrolysis of ADP happens in the AMP.
Recycling of ATP
ATP is regenerated by adding phosphate back to AMP and ADP.
The recycling of ATP
A cell is constantly breaking down ATP for energy, then
rebuilding it to maintain a constant supply of fuel for the body .
Why the recycling of ATP is essential survival strategy?
Because the body contains only about 0.22 lb (100 g) of ATP at any given time, but a sedentary adult breaks down and resynthesizes about 88 lb (40 kg) of ATP each day. And an additional 66 lb (30 kg) of ATP are broken down and resynthesized when people do exercises.
Oxidation-Reduction Reactions氧化还原
Key Processes in Energy Metabolism.
Oxidized and Reduced
失电子是Oxidized,得电子是Reduced
If the compound gains oxygen or loses hydrogen, it has been oxidized.
If it loses oxygen or gains hydrogen, the compound has been reduced.
The synthesize of ATP from ADP and AMP
Involves the exchange of e-,(H+ from energy yielding compounds, fat, protein, carbs and alcohol) this process use Oxidation-Reduction reactions.
What controls OR reaction?
Enzymes.
Niacin and Riboflavin
Key Players in Energy Metabolism.
Two vitamin-Bs, assist dehydrogenase enzymes and play a role in transferring hydrogen ions from energy-yielding compounds to oxygen in the metabolic pathways of the cell.
Reaction between Pyruvate and Lactate
(Pyruvate)NAD+ —> NADH + H+ (Lactate)——> NAD+ (Pyruvate) Niacin plays as a coenzyme.