3.(1-3) Energy Systems, ALL Flashcards
(39 cards)
List the macronutrients and micronutrients.
1.1
Macro: provide calories/energy & are required in large amounts
1. lipid (fat)
2. carbohydrate
3. protein
4. water
Micro: required in small amounts to orchestrate wide variety of physiological functions (not made by organism, except vitamin D)
1. vitamins
2. minerals
3. fibre
Outline the functions of macronutrients and micronutrients
1.2
State the chemical composition
of a glucose molecule.
1.3
C₆H₁₂O₆ (1:2:1 ratio)
simplest/empirical formula: CH₂O
Identify a diagram representing the basic structure of a glucose molecule
1.4
How are carbohydrates synthesized & classified?
Synthesized by plants from water & carbon dioxide via photosynthesis. Carbs= source of cellular metabolic energy
Classified by nr. of molecules present
1 Molecule: Monosaccharide
2 Molecules: Disaccharide
3-9 Molecules: Oligosaccharide
10 or more: Polysaccharide
Explain how glucose molecules can combine to form disaccharides and polysaccharides.
1.5
Condensation Reactions
- linking of monosaccharide to another monosaccharide, disaccharide or polysaccharide by removal of 1 water molecule
- basis synthesis of all important biological macromolecules (carbohydrates, proteins, lipids, nucleic acids) from simpler sub-units (monomers)
Give an overview of carbohydrate metabolism
Carbohydrates digested to monosaccharides -> abosrbed across gut lining & transported to liver. Then glucose transported to body’s cells.
Main users of glucose: RBC, brain, skeletal muscle, heart
Whats a monosaccharide?
most simple form of carbs (sugar), 1 molecule, easily absorbed by body, metabolic fuel
E.g.:
* Fructose
* Galactose
* Glucose
Whats a disaccharide?
Combination of 2 monosaccharides
Each disaccharide contains glucose
Formed by dehydration synthesis (condensation reaction) from removal of water
Examples:
* Glucose + Fructose = sucrose (+ water)
* Glucose + Galactose = lactose (+ water)
* Glucose + Glucose = maltose (+ water)
Whats a polysaccharide?
10 or more sugar molecules combined
energy stores
- starch: Plants store glucose in roots & tubers, seeds, grains & some fruits -> (How plants store glucose)
- glycogen: polysaccharide of glucose, main storage form of glucose in our bodies -> (How animals store glucose)
structural compounds
- Cellulose: Many glucose molecules bound together. Non-starch found in plant cell walls. Difficult to digest and is commonly known as: FIBER
State the composition of a
molecule of triacylglycerol.
1.6
Lipids (oils, fats, waxes): consist primarily of triacylglycerols (triglycerides), also as phospholipids & sterols.
Triglycerides: composed of glycerol molecule & 3 fatty acid chains
- Stored in adipose tissue & skeletal muscle
Function:
- Long-Term Energy Storage
- Fat in adipose tissue protects vital organs & helps to control body temp.
- Dietary Fat, synthesis of hormones, vitamin D (sterols) and cell membranes (sterols, phospholipids)
Distinguish between saturated
and unsaturated fatty acids.
1.7
Saturated Fats: no double bonds btw. individual carbon atoms of fatty acid chain.
- originate from animal sources (e.g. meat, poultry, full-fat dairy products, tropical oils)
- usually solid at room temp.
Unsaturated Fats: contain 1+ double bonds btw. carbon atoms in fatty acid chain
- originate from plant-based foods (e.g. oilive oil, olives, avocado, peanuts, cashew nuts, canola oil & seeds, sunflower oil & rapeseed)
- can be monounsaturated or polyunsaturated
State the chemical composition
of a protein molecule.
1.8
Protein= polymer of amino acids (AA)
- linked in chains via peptide bonds
- body breaks down food into AA & makes own protein
- composed of C,H,O,N
Distinguish between an essential
and a non-essential amino acid
1.9
Essential amino acids cannot be synthesized by human body & must be obtained from diet (8/20)
Non-essential amino acids can be synthesized by the human body.
Describe current
recommendations for a healthy
balanced diet.
1.10
Balanced Diet: provides all nutrients in right amount to maintain health & prevent disease
- methods used to identify level of adequate intake of nutrients vary internationally
Dietary Recommendations: recommended amounts of essential nutrients in the diet
- No internalional agreement about dietary recommendations
Dietary Guidelines: Recommended amount of foods, food groups or meals
State the approximate energy content per 100 g of carbohydrate, lipid and protein.
1.11
** Kilojoules (kJ)** common measure of amount of energy you get from consuming a food or drink
- Joule = a single unit of energy -> 1000J = 1kJ
100g protein: 1720kJ
100g lipid: 4000kJ
100g carb: 1760kJ
Discuss how the recommend energy distribution of the dietary macronutrients differs between endurance athletes and non-athletes.
1.12
Outline metabolism, anabolism, aerobic catabolism and anaerobic catabolism.
2.1
Metabolism: All the biochemical reactions that occur within an organism, including anabolic and catabolic reactions.
Anabolism: Energy requiring reactions whereby small molecules are built up into larger ones.
Catabolism: Chemical reactions that break down complex organic compounds into simpler ones, with the net release of energy.
- Aerobic catabolism: Compounds breaking down in the presence of oxygen
- Anaerobic catabolism: Compounds breaking down in the absence of oxygen
State what glycogen is and its major storage sites.
2.2
When body has more glucose than neeeded, it’s stored as glycogen predominantly in liver & muscle tissue.
State the major sites of triglyceride storage.
2.3
Adipose tissue and skeletal muscle
Explain the role of insulin in the formation of glycogen and the accumulation of body fat.
2.4
Insulin: tells body to store excess glucose as glycogen & stimulates lipogenisis/ formation & storage of triglycerides:
1. Uptake of fatty acids by fat cells, which are converted to triglycerides
2. Triglycerides stored for future use in adipose tissue as body fat
3. Conversion of excess glucose into triglycerides, which are also stored as body fat in adipose tissue
Outline glycogenolysis and lipolysis.
2.5
Glycogenolysis- Glyogen Breakdown into Glucose
When body needs more glucose than it obtains from diet, glycogen (stored in liver & muscle) is broken down back into glucose.
- liver glycogen used to maintian blood-glucose levels to meet needs of entire individual
- muscle glycogen used to meet needs of muscles only
Lypolysis- Fat Breakdown
1. Triglycerides are released into bloodstream & broken down into fatty acids & glycerol via lipolysis
2. Fatty acids transported to mitochondria
3. BETA oxidation of fatty acids to produce ATP
4. Fatty acids slowly broken down over 4 repeated stages, reducing carbon bonds each time -> produces ACETYL-CoA
5. Acetyl-CoA further metabolized in KREBS Cycle to produce large ATP amounts
Outline the functions of glucagon and adrenaline during fasting and exercise.
2.6
Energy metabolism controlled by hormones including: insulin, glucagon, adrenaline, cortisol, growth hormones
Glucagon
Exercise or prolonged time w/ no food caused drop in blood glucose which is detected by pancreas -> glucagon released by α-cells of pancreas to simulate glycogenolysis to increase blood glucose levels & use.
Adrenaline also increases w/ low gllucose levels & promotes glycogenolysis & lipolysis
Explain the role of insulin and muscle contraction on glucose uptake during exercise.
2.7
Insulin: Meal eaten and glucose levels rise which is detected by pancreas -> secretes insulin from β-cells to increase transport of glucose into cells (muscle and liver), while glycogenesis promoted & lipolysis inhibited. Results in decreased blood glucose levels.
Muscle Contraction: When insulin binds to its receptors on the skeletal muscle cell, a translocation of GLUT 4 (glucose transporter) from within the vesicles to the cell wall occurs. Muscle contraction causes the same translocation to happen. The translocation of GLUT 4 channel to the cell membrane allows glucose uptake into the cell from the bloodstream via facilitated diffusion.
