B1 Metabolism & Nutrition Flashcards
What are the constituents of the average UK diet?
MACRONUTRIENTSCarbohydrateFatProteinDietary FibreVariety of MICRONUTRIENTS
What’s the difference between macronutrients and micronutrients?
Macronutrients-structural and energy-giving caloric components offoods,include carbohydrates, fats and proteins.Micronutrients-vitamins, minerals, trace elements, phytochemicals, and antioxidants essential for good health.
What are carbohydrates?
Starch + sugars
What is the difference between ATP formation via aerobic respiration and via glycolysis?
Aerobic respiration doesn’t produce lactate/ ethanolGlycolysis (which does make 2 molecules of ATP)ends with pyruvate which is reduced tolactate or converted to ethanol
Where does the body’s energy primarily come from?
Oxidation of carbohydrate and fatCarbohydrate - 4kcal/gFat - 9kcal/g
What’s the nutrition difference between starch and sugars?
Starch has a higher energy content than sugars
What is the the difference between glycogen, fat and protein as energy stores?
Fat - Long-term / Infinite (adipose tissue)Glycogen - Short-term / FiniteProtein - Source of glucose in absence of carbohydrate
True or false? The body can store protein and alcohol
FALSE
True or false? The brain has a specific requirement for glucose?
TRUE
What is the common intermediate of proteins, carbohydrates and fats?
Acetyl CoA
What are theother names for the Krebs cycle?
Citric Acid Cycle Tricarboxylic Acid Cycle (TCA) Krebs Cycle
Where are the coenzymes NAD and FAD derived from?
Niacin and Riboflavin
Where is glucose derived from?
Blood; the breakdown of glycogen
How can lactate be converted into glucose/ glycogen in the liver?
Gluconeogenesis (via Cori Cycle)- The reverse (ish) of the glycolysis reaction, but GTP is required along with ATP
What are the conditions under which ketone bodies are formed?
Fasting state
Why is glycolysis essential for red blood cells?
They have no mitochondria
Why is glycolysis essential for the kidney medulla?
The blood supply is poorer than the cortex
Why is glycolysis essential for the eye?
Blood vessels/ mitochondria would obscure light
What molecules can be converted into glucose/glycogen via gluconeogenesis?
Lactate Amino acids Glycerol
What is the next best alternative when there is no carbohydrate available for energy?
Gluconeogenesis - converting amino acids/ lactate/ glycerol into glucose/glycogen
There are two pathways acetyl CoA can follow. What are they?
Fed - through to Krebs cycleFasting - Conversion into ketone bodies (liver)
How do A/L/G participate in gluconeogenesis?
They can all be converted into pyruvate
How are fatty acids involved in metabolism?
They can be oxidised via beta- oxidation in the mitochondriaThe acetyl CoA formed can then join the Krebs cycle
What is the pentose phosphate pathway? (PPP)
Pathway which provides pentoses for DNA/ RNA synthesisProvides NADPH for fat synthesis
When does ketogenesis take place?
High rate of fatty acid oxidation in the liverWhen metabolism is impaired
Give examples of ketone bodies
AcetoacetateBeta hydroxybutyrateAcetone
Why are ketone bodies used as the alternative energy source to glucose, rather than fat.
Ketone bodies are water soluble (so can cross the bloodstream to the brain), fatty acids are insoluble in water.
How are ketone bodies excreted?
UrineThe lungsThey can be converted back to acetyl CoA
What is the difference between the fed state and the fasting state?
Fed- Ample fuels entering from the gutFasting- Utilization of the body’s reserves
What increases with increasing starvation?
Ketone bodies and free fatty acids
