Metabolism Flashcards
What are the 3 stages of metabolism?
Stage 1: Digestion
Nutrients from our diet are digested and absorbed into the body
Stage 2: Storage and energy production
Anabolism and catabolism
Occurring within the cell
Stage 3: Catabolism for energy
Occurring within the mitochondria
Making bulk ATP
What is glycolysis, what is produced?
Glycolysis – Splitting glucose
Series of enzymatic reactions which breaks glucose molecules
Generates;
4 ATP (but uses 2 ATP)
-Products to yield more ATP from
-Pyruvic acid
-High energy electron carriers(NADH)
What is the citric acid cycle, what is produced?
Also known as Kreb’s Cycle
Products from glycolysis converted to Acetyl CoA
Enter the citric acid cycle (CAC/Kreb’s Cycle)
Produces
-2 ATP
-High energy electron carriers
-Waste – CO2
What is the electron transport chains, what is produced?
High energy electron carriers enter the ETC
-From Glycolysis and CAC
The high energy carriers drive enzymatic machinery
-ATP Synthase
Makes lots of ATP!
-~28 ATP from NADH (24 ATP) and FADH2 (4 ATP) from CAC
-4 ATP from NADH (from glycolysis)
Explain how our body deals with high BGL? (Hint: glycogenesis)
-Blood Glucose level is maintained by two hormones synthesised in the pancreas insulin and glucagon.
-When the body has high Blood Glucose Levels glucose and stored as glycogen through the process of glycogenesis.
-In a fed state where there is lots of ATP and a high blood glucose level glycolysis proceeds partially. The intermediates of glycolysis can be converted into fatty acids and glycerol creating triglycerides (lipogenesis)
What is a glycaemic index and what is the difference between low GI and high GI foods?
The glycaemic index is the measurement of the rate of glucose absorption from the GIT.
-High Gl are simple sugars and be metabolised faster
-low GI foods are complex sugars and take longer for the body to metabolise
Explain how our body deals with low BGL? (Hint: glycogenolysis and gluconeogenesis)
When there is low glucose levels it stimulates the release of glucose from stores in the body. It potentially uses other nutrients to generate ATP.
-Glycogenolysis id the freeing of glucose from glycogen and reverses glycogenesis
-Gluconeogenesis is the synthesis of glucose from alternative stores like fats and proteins. This is not the best source of energy as it requires more effort and forms more waste products.
What happens when we use proteins and fats for energy?
Lipid Metabolism is a potential energy reservior. in a fasting state lipolysis occurs and is the breakdown of fat stores to glycerol and fatty acids.
protein metabolism is another energy reservoir and can be catabolised to enable glucose synthesis and ATP synthesis. Catabolised products can enter Krebs to contribute to ATP synthesis.
What is diabetes mellitus, and how does it effect BGLs and metabolism?
Diabetes is the insufficient release of insulin by the pancreatic beta islet cells or resistance to insulin resulting in hyperglycaemia.
Diabetes effects metabolism as when the blood glucose levels are high the cells are starved leaving the person feeling fatigue, lethargy, irritability. this then signals for the release of energy stores known as glucagon (glycogenolysis and gluconeogenesis (forming glucose form triglycerids and protein). Ketones are formed creating ketoacidosis from liberated fatty acids leading to metabolic acidosis. The kidneys can’t cope with the blood glucose level. leading to tubular reabsorption saturated and glycosuria and polyuria.
Explain the difference between aerobic and anaerobic respiration?
Complete catabolism of glucose is aerobic
-Meaning we need O2
In anaerobic conditions catabolism is incomplete
Only glycolysis can proceed without O2
-But to enable this, must form lactic acid
Example:
At beginning of race
Muscles have
ATP
O2
Glucose
Aerobic respiration
As race continues
Metabolic demand increases
ATP/Glucose/O2 levels decrease
Anaerobic respiration
