Nutrition and metabolism Flashcards
Basic description of metabolism?
Energy for activity comes from food
Need to release energy by oxidation
Metabolism comprises of catabolism and anabolism
Catabolism - break down
Anabolism - building back up
Function of metabolism?
Perform vital functions:
Provision of energy required to maintain the internal composition of the cell and support its specialised functions
Provision of metabolites for the biosynthesis of its constituents of the cell and any products released by the cell
Why do we care about metabolism?
To understand how nutrition effects performance we need to understand what happens in the body to provide energy
What are essential nutrients?
Cannot be synthesised (or not in sufficient quantities) by the body
Examples are vitamins, minerals, essential fatty acids, essential amino acids
What are non essential nutrients?
Can be made in sufficient quantities by the body
What are macronutrients?
Usually required in gram quantities
CHO, Fat, Protein, Water, Alcohol
Quantitatively largest part of the diet
Provide energy
What are micronutrients?
Usually needed in small amounts (smaller than 1g)
Vitamins, minerals, trace elements
Quantitatively largest family of nutrients
Describe carbohydrates?
Carbo = carbon, hydrate = hydrogen and oxygen
Hydrated carbons = (CH2O)
Example is glucose C6H12O6
There are monosaccharides, disaccharides, and polysaccharides
Describe the monosaccharide glucose?
most common sugar in the body
Describe the monosaccharide Fructose?
Cheaper than sucrose
Describe the monosaccharide Galactose?
Used in neural tissue development
Found in lactose from milk
Describe the disaccharide Sucrose?
Made from Glucose and Fructose
Describe the disaccharide Maltose?
Made up from 2 glucose
Fermented to make beer
Found in wheat and barley
Describe the disaccharide Lactose?
Made up of glucose and galactose
Widely used in food industry
Found in Milk
Describe the polysaccharide oligosaccharide?
Less than 10 monosaccharides
Rapidly ferments in the colon
Found in leek, onion, lentils, beans
Describe the polysaccharide starch?
80% amylopectin
20% amylase
Found in potatoes, cereals, beans
Describe the polysaccharide dietary fibre?
Non starch polysaccharide
Found in cellulose plant cell walls, which is resistant to digestion
Non cellulose version found in petins, gums, glucans
Describe dietary fats?
Triaglycerol comprises up to 95%
3 fatty acids to 1 glycerol
Concentrated source of energy
Usually stored in adipose
Insulating layer under skin
Vehicle for intake and absorption of fat soluble vitamins
Contribute to labour and palatability of food
Describe fatty acid chains?
Organic chains of C, H and O
Categorised based on the number and bonding of carbon atoms
Saturated = 0 double bonds
Monounsaturated = 1 double bond
Polyunsaturated = more than 1 double bond
n = omega = number of carbons from methyl end
Describe phospholipids?
Contain glycerol backbone and 2 FA (non-polar) and polar head with phosphoric
acid residue and either sugar or amino acids
Amphipathetic acting as interface between aqueous and lipid environments, therefore essential structural components of cell membranes (phospholipid bilayer)
Describe sterols?
Arranged in a ring structure with associated side chains
Cholesterol is main sterol, often associated with a fatty acid to form a cholesterol ester
Plays a key role in membrane structure, synthesis of hormones, and bile acids
Where are short chain fatty acids found (C4-C10)?
Milk products, butter
Where are SFA found (C14-C18)?
Animal foods and fats, palm oil
Where is MUFA, especially C18:1 found?
Olive and rapeseed oils
Where are PUFAs, n-6 found?
Linoleic and soybean oil
Where are PUFAs, n-3 found?
Eicosapentanoic acid and docosahexanoic acid: oily
Where is cholesterol found?
Foods of animal origin, organ meats
Where are phospholipids found?
Animal foods
Where are trans fats found?
Ruminant animals, hydrogenated fats in manufactured goods
Describe dietary protein?
Composed of C, H, O and N
N = excreted out as urea in urine, can be used to calculate protein requirements
Made up off amino acids in polypeptide chain, digested and used throughout the body
What does dietary protein provide?
Energy
Structural material for all tissues - promotion of growth and development as Muscle, soft tissues and organs consist largely of protein and are constantly turning over
Enzymes, carrier molecules, hormones, neurotransmitters, clotting factors
How is quality of dietary protein determined?
Digestibilty, nitrogen retention
(retained/absorbed) x 100
egg protein = 100
beef and fish = 75
Above 70 = sufficient to maintain growth
What’s dependent on vitamin D?
Calcium and phosphorus building blocks of skeleton,
What does iron help do?
Form components of the red blood cell and mitochondria
What mainly aids provision of energy, warmth and movement?
Mainly CHO and Fats
What mainly aids resisting and fighting infection?
Mainly vitamins, minerals and proteins
What mainly aids regulation of metabolism?
Enzymes are proteins, and require co-factors of vitamins to function
Whats the DRV?
Dietary reference values = 40 nutrients
This gives a notional mean requirement or estimated average requirement (EAR)
Reference nutrient intake (RNI) is 2 notional SD above EAR
✦ 2SD below mean is the lower RNI (LRNI) intakes below this line are likely to be deficient for most individuals
Problem with RDA?
RDA placed at same point as RNI
✦ But too prescriptive
✦ Suggests level must be taken
✦Implies below = deficiency
DRV much clearer, provides safe intake
Scientific basis for establishing DRV’s?
Panel found no single criterion to define requirements for all nutrients
✦ No method is perfect so DRV not reported with great confidence
✦ Some cases DRV cannot be determined especially non-essential nutrients
ome reliable experimental data / some epidemiological data
What should be on your plate?
All nutrients listed in DRV tables ✦ Supports health, work and leisure ✦ Provides sufficient reserve to protect during times of illness or deficiency ✦ Some protection from disease
What elements make up ethanol?
Carbon, Hydrogen, Oxygen
Need to know the 10 important functional groups in nutrients, the chemical structure, and where they are found
Aldehyde - sugars Amine - Proteins Amide - Vitamins Acyl - Triglycerides Carbonyl - Aldehydes, ketones, acids, amides Carboxyl - Acids Disulphide - Proteins Hydroxide - alcohols Ketone - Ketones Phosphate - High energy compounds
Need to know the 13 important ions within the body, chemical symbols, what they do?
Ammonium - Helps maintain acid-base balance
Bicarbonate - Helps maintain acid-base balance
Calcium - Component of bones and teeth, needed for blood clotting, muscle contraction and nerve transmission
Chloride - Helps maintain acid-base balance
Fluoride - Strengthens teeth and bones
Hydrogen - Helps maintain acid-base balance
Hydroxide - Helps maintain acid-base balance
Iron - RBC formation and function
Iodide - Part of thyroid hormones
Magnesium - Necessary for enzyme function
Phosphate - Helps maintain acid-base balance, Component of bones and teeth, involved in energy exchange
Potassium - Helps maintain membrane potential
Sodium - Helps maintain membrane potential and water balance
How is a triglyceride formed?
Glycerol reacts with 3 fatty acid chain via a condensation reaction to form an ester
Provides 3 molecules of water
Need to know the 2 most common co-enzymes?
NADH
FADH
non-protein compound necessary for the functioning of an enzyme
Need to know the 4 types of reactions and what they do?
hydrolysis - Water added, lactose + water = glucose + galactose
condensation - Water is removed, glucose + galactose = lactose + water
oxidation - reduction reactions (oxidation is loss of electrons) (reduction is gain of electrons)
energy and enzymatic - involves enzymes as catalysts to speed up the reaction as they lower the energy barrier
enzymes can be used repeatedly as they are not consumed by the reaction
Need to know how salts acids and bases differ in their structure?
salts - cations (positively charged ions) and anions (negatively charged ions) and are formed with the interaction of acids and bases
acids - higher concentratin of protons so proton donor
bases - higher concentration of electrons so proton acceptor 5
need to know the body’s energy currency and different forms of it?
ATP/ADP/AMP
Hormone definition?
a regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action.
Enzyme definition?
a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
What’s glycolysis?
breaking down of glucose into energy
occurs in the cytoplasm of the cell and is a set of reactions catalysed by enzymes
uses 2 ATPs -> 4ATPs and 2 NADH
so each cycle produces 2 ATP + 2 NADH + 2 pyruvate (can be used in (an)aerobic respiration)
What’s beta oxidation?
beta-oxidation is the catabolic process by which fatty acid molecules are broken down in the mitochondria
As well as to generate acetyl-CoA, which enters the citric acid cycle, and NADH and FADH2, which are co-enzymes used in the electron transport …
- What are the products of the electron transport chain?
NADH (oxidised) -> 3 ATP
FADH2 (oxidised) -> 2 ATP
each cycle produces 1 H2O
occurs across inner membrane of mitochondria
2 most common bonds in molecules?
Covalent - share of electrons
Ionic - attraction between oppositely charged ions
3 steps of protein synthesis?
- transcription - copying dna to mrna
- translation - initiation, elongation and termination reading of mrna to make polypeptide chain
- . post translation modifications - folding into useful structures
Facts about paper about importance of the importance of protein intake after exercise upon the development of muscle hypertrophy and strength during resistance training in elderly? (one MCQ)
Gmarck 2001 peer review
Primary research
Random control trial
If supplementation straight after changes occur
If 2 hours after it didn’t change
Equation for Work?
Force x distance
Equation for Power?
Work / Time
Different types of energy?
Chemical Mechanical Heat Electrical Light Nuclear
What’s the concept of turnover?
Molecules are constantly used (degraded) and restored (synthesised)
eg. energy, protein
What’s protein turnover?
Constant and concurrent processes of protein synthesis and breakdown
Features of ATP?
Adenosine tri phosphate
Energy currency of the cell
Energy source for cellular processes
24 kJ per mol of ATP
Its an immediate energy system
Describe ATP homeostasis?
Maintenance of constant intracellular ATP level
Role as common chemical intermediate
ATP degradation = ATP resynthesis
3 main systems in skeletal muscles to maintain ATP homeostasis?
Immediate
Nonoxidative (glycolytic)
Oxidative (aerobic)
Energy source of muscular work for power?
Duration: 0-3 sec
Rate of process: immediate
Storage form: ATP, PCr
Oxygen involved: No
Example: weight lifting
Energy source of muscular work for Speed?
Duration: 4-60 sec
Rate of process: Rapid
Storage form: Msc glycogen and glucose
Oxygen involved: NO
Example- 100m-400m sprint, 100m swim
Energy source of muscular work for endurance?
Duration: More than 1-2 min
Rate of process: slower but prolonged
Storage form: Glycogen, plc, lipid, AA
Oxygen involved: Yes
Example: More than 1500m run, 400m swim
What are ATPases?
Enzymes that split ATP by hydrolysis (combination with water) to form ATP + H2O = ADP + pi
Describe creatine phosphate (PCr) the immediate energy system?
5-6 greater size than ATP
PCr + ADP = ATP + Cr
High energy phosphorylated compound
PCr = Cr + Pi + Energy
Provides a reserve of phosphate energy to regenerate ATP so ADP + Pi + Energy = ATP
Reforms following exercise
Concentration and time to depletion of ATP?
24 mmol/kg dm
2 secs
Concentration, max rate of PCr resynth and time to depletion?
80 mol/kg dm
9 mol ATP/kg dm/s
8 secs
Describe the Myokinase reaction?
Catalysed by Adenylate kinase (myokinase)
2ADP = ATP + AMP
Myokinase reaction and breakdown of PCr work closely together to maintain intracellular ATP levels
Energy from ATP limited, but real importance of this reaction may be formation of AMP
Are changes in ATP conc good signals for control of metabolic rate?
no
Are changes in AMP conc good signals for metabolic control?
yes
Large amounts of AMP signal that more ATP needs to be resynthesised
What’s the energy charge of a cell?
Relative changes in adenylate determine the energy charge of the cell
Energy charge = ([ATP] + 0.5[ADP]) / ([ATP] + [ADP] + [AMP]
Is an indicator of a cell to do work
If the value is 1, the whole adenylate pool is in the form of ATP, cell has maximum free energy
If it’s 0, all ATP has been hydrolysed to AMP (only theoretically possible)
Normal charge of a cell?
0.9-.095
Higher AMP conc represents lower energy charge of the cell, how is it reduced?
Add H+ via AMP deaminase
= IMP (inosine monophosphate) + NH4+
What happens to IMP?
Either converted to inosine then hypoxanthine
Problem with this is that it leaves the muscle, resulting ni net loss of adenine nucleotides
Or
When exercise stops energy from GTP is used to convert IMP into ATP
Can fuel source such as PCr and CHO be depleted?
Yes
Can energy sources such as ATP, GTP and UTP be depleted?
No they are regulated
Equation for gross efficiency (%)?
(Work accomplished / energy expended) x 100
Equation for net efficiency (%)?
(Work accomplished / energy expended - REE) x 100
REE = Rest energy expenditure
Equation for work efficiency (%)?
(Work accomplished / energy expended - EE in unloaded) x 100
Equation for delta efficiency (%)?
( Change in work accomplished / change in EE) x 100
This is the best one, but most difficult to measure
Features of a bomb calorimeter?
The oxidation path of a human and bomb calorimeter differ
However the quantity of energy liberated from the complete breakdown of these foods remain the same
How many kcal per g of lipid?
9.45
95% digestibility
How many kcal per g of CHO?
4.3
97% digestibility
How many kcal per g of protein?
5.65
More nitrogen = more kcal
92% digestibility
Animal protein more digestible
How many kcal per g of alcohol?
7
100% digestibility
What do we use energy for?
Mainly basal metabolism
Also Physical activity
And thermogenesis
What organ uses most energy rest?
Liver - 27%
What’s TDEE?
Total daily energy expenditure
What’s ADMR?
Average daily metabolic rate
What’s BMR?
Basal metabolic rate
What’s RMR?
Resting metabolic rate
What’s TEF?
Thermic effect of food
What’s DIT?
Diet induced thermogenesis
What’s TEE?
thermic effect of exercise
What’s EEA?
Energy expenditure of physical activity
What are all the abbreviations?
components of energy expenditure
What’s a direct calorimetry chamber?
Small insulated chamber with adequate ventilation
Water flows through coils - absorbs heat showing metabolic rate
Air is recirculated with CO2 and H2O filtered out
What’s a respiration chamber?
No heat exchange measured
Measurement of oxygen in and carbon dioxide out
Food intake accurately measured
Food and urine collected
What’s indirect calorimetry?
Can use Douglas bag - sample of expired air collected
Or Breath by Breath systems
Heart rate method using accelerometer
Questionares
What’s doubly labelled water?
Has a heavy oxygen and hydrogen
Hydrogen is excreted independent of metabolic rate
Oxygen excreted as carbon dioxide and water
CO2 production = difference in H and O isotopes excretion
More O = increased energy expenditure
It’s expensive but free living
Energy cost of running?
1 kcal per kg of body mass per km run
What happens if you don’t intake enough calories?
loss of muscle mass Anaemia Secondary amenorrhea Decreased body mass Low mineral bone density
For every litre of oxygen used?
5kcal available from CHO
4.7 kcal from fat
What’s secretion?
water, acids, buffers, enzymes aid breakdown of food
What’s absorption?
95% via small intestine
What’s ingestion?
Taking food in
What’s motility?
Contraction and relaxation of smooth muscle
What’s defecation?
Indifestible substances, cells, digested materials not absorbed
if its been in your body it’s called excretion
What’s digestion?
Mechanical and chemical
Digestive system organs?
Mouth Salivary glands Stomach Pancreas Liver Gall bladder Small intestine Large intestine
Features of the oral cavity?
Consists of mouth and pharynx
Mastication - chewing of food = mechanical digestion = increased surface area of food
Saliva released from Parotid duct, sublingual gland, submandibular duct.
Mainly water but Contains electrolytes, Proteins (immunoglobin A, Lysozyme), Enzymes (amylase, Lipase)
Tongue aids swallowing and mixing
Deglutition = swallowing
Which duct produces most saliva?
Parotid duct
How does salivary gland release saliva?
Acinar (mucous cells) produce the saliva which is isotonic with plasma
Duct cells reabsorb Na+ and some Cl-
They also secrete K+ and HCO3- into it
Impermeable to water
Hypotonic saliva for lubricant
3 stages of deglutition?
Buccal phase - Bolus of food force to the back of the throat voluntarily
Pharyngeal phase - Respiratory passage closes, and food bolus enter the oesophagus
Oesophageal phase - food goes down the oesophagus
Features of the oesophagus?
Moves food from mouth to stomach
Tube with double layer of muscle:
Circular
Longitudinal
Food moves down from pressure and peristalsis
There is a oesophageal sphincter that can open and close just above the stomach - prevents acid reflux
Features of the stomach?
3 parts are Corpus, Antrum, Fundus (find locations)
Functions:
Storage
Mixing to create chyme (gastric juices)
Regulation of emptying chyme to duodenum
Once digested pyloric sphincter opens and allows food into small intestine
Formation of gastric juices?
Pepsins and Lipases from chief cells
Intrinsic factor (abosorption of vitamin B12) and HCl from parietal cells
Ions from mucous cells - protects lining of stomach
Regulation of gastric secretion?
Cephalic phase:
30% of response to meal
Prior to food arrival
Gastrin released - hormone that increase gastric juice release
Gastric phase:
60% of response to meal
Stretch and products of protein digestion in the stomach
Causes Gastrin to be released
All stimulate motility, larger meals increase rate of emptying
Intestinal phase: Chyme entering duodenum reduces gastrin secretion and motility Removal of peptide fragments pH goes down Duodenum distends = hormones released
Features of the pancreas?
Exocrine cell:
- Acinar cells secrete digestive enzymes (bicarbonate solution to increase pH of stomach acids to 7)
Duct cells
Endocrine cells
Features of small intestine?
Main site of digestion and absorption
Has microvilli to increase SA
3 parts are Duodenum, Jejunum, Ileum.
Good blood supply
Outer longitudinal muscle, and inner is circular, propels food over short distances
Segmentation - results in mixing of food and enzymes. Controlled by pacemaker cells and intrinsic enteric nervous system
Features of large intestine?
Enters through illeocecal sphincter / valve
Reabsorbs water
Stores faceces
Bacteria ferment remaining CHO, releasing H, CO2 and methane
Peristaltic and segmental movements are slow and non propulsive
Mass movements are infrequent
Chyme remains for a long time
Features of the liver?
Portal vein comes from the digestive tract and pancreas to the liver
Produces bile - digestion of fats, bile is from aged red blood cells
Used in metabolism
Processes drugs and hormones
Features of gall bladder?
Stores and concentrates bile
Stimulated release by secretin and CCK
90% reabsorbed and recycled
Can be removed
How long is food in each part of digestive system?
Mouth - 10 secs
Stomach - 2-4 hours
Small intestine - 3-10 hours
Large intestine - 24-72 hours
What’s diffusion?
High conc to low conc
Facillitated diffusion?
High conc to low conc with a carrier protein
Facillitated with sodium transport?
Requires ATP
Sodium ions usually involved
Can work against concentration gradient
Complex carb we ingest from plants?
starch
Complex carb we ingest from meat?
Glycogen
Carbohydrate digestion?
Polysaccharides, trisaccharides and disaccharides must be hydrolysed into monosaccharides
Collectively enzymes are glycosides or carbohydrases
Digestion starts in the mouth
Most digestion occurs in the small intestine through pancreatic a-amylase
Microvilli start breaking down the disaccharides
Absorption of monosaccharides and a few disaccharides?
Facilitated with sodium:
SGLT1 used to get Glucose and galactose into epithelial cell from the lumen, then GLUT 2 to get it into the capillary
Fructose uses facilitated diffusion with GLUT 5 to get fructose from the lumen into the epithelial cell, then GLUT 2 to get into the capillary
Features of protein digestion?
Stomach:
Gastrin
HCl
Pepsinogen produces Pepsin
Small intestine:
Endopeptidases (internal bonds broken)
Exopeptidases (external bonds broken)
Trypsin (controls the active form of enzymes above)
(50% used to digest food, 25% break down epithelial cells for new ones, 25% cause gut secretions)
What do proteins break down into?
Tripeptides, dipeptides or amino acids
What happens to amino acids in gut?
Absorbed into capillary via diffusion and sodium dependent diffusion
Digestion of fat?
Fats are hydrophobic
Bile salts emulsify fats (tiny droplets called micelles)
Lipid component of the diet:
Triaglycerols
Phospholipids
Sterols
Enzymes:
Lipase
Phospholipase
Cholesterol esterase
Features of triacyglycerol digestion?
Mouth:
Lingual lipase
Oesophagus:
none
Stomach:
Gastric lipase
Duodenum and jejunum: Lipases Bile salts pancreatic lipase Bicarbonate
What does a triglyceride split into?
Monoglyceride + free fatty acids
Describe fat absorption?
Micelles move into the space between the microvilli
The fatty acid then diffuse across the membrane
Re-esterified to Triglycerides
Form chylomicrons to allow transport in lymph and blood plasma
SCFA - diffuse onto portal vein bind with albumin
LCFA - chylomicrons - into the lacteal travel in lymph
What happens to glucose conc in blood?
Humps up then down
= 100
What happens to starch conc in blood?
Long shallow hump
What happens to amino acid conc in blood?
Big hump up then down
triglyceride conc in blood?
Takes far longer to peak conc
What does alcohol dehydrogenase convert to?
Acetaldehyde (less intoxicating)
fatty acids aid this as they slow gastric emptying, so keep the food in your stomach so more alcohol converted
Vitamin absorption?
Fat soluble:
Absorbed from micelle mostly in small intestine
Enter chylomicrons and lymph system
Water soluble:
Diffusion (high conc)
Active transport (low conc)
How is water absorbed?
Osmotic gradients - hypotonic solution increases water absorption
Describe the hormone Gastrin?
Released by stomach and Duodenum
Released as a response to food reaching the stomach/preperation for food
Function is to cause stomach to release HCl + Pepsinogen, and gastric and intestinal motility
Describe the hormone Cholecystokinin (CCK)?
Released by small intestine
Released when there is dietary fat in chyme
Causes release of pancreatic enzymes and bile from gall bladder
Describe the hormone secretin?
Released by small intestine
Response to acidic cyme as digestion progresses
Stimulates release of pancreatic bicarbonate
these 3 probably are in the exam
2 forms of NAD+?
Oxidised (NAD+) and reduced (NADH)
Features of glycolysis?
Can generate ATP
Can generate reduced coenzymes which can be used to form ATP
Can generate energy independent of oxygen
Breaks down glucose to precursors for fat and protein synthesis (acetyl-CoA)
Probably can delete glycolysis and tca notes on all the steps, just know the enzymes
Net result of glycolysis?
The net result of the breakdown of glucose to pyruvate is two molecules of ATP and 2 molecules of NADH
3 phases of glycolysis?
Preparation - glucose to fructose 1,6 biphosphate
Splitting - fructose 1,6 biphosphate to 2 three carbon compounds
Harvest - 3 carbons compounds to pyruvate
What happens if glycolysis is slow?
Sufficient NAD+ can be obtained from mitochondria respiration to allow the reaction from glucose to pyruvate to proceed
(Step 6 is dependent on NAD+)
What happens if glycolysis is fast?
Insufficient NAD+ can be obtained from mitochondrial respiration and NAD+ is obtained from the pyruvate to lactate reaction
Important control points of glycolysis?
Glycogen phosphorylase (GP) Glucose transport (GLUT4 in muscle) Hexokinase (HK) Phosphofructokinase (PFK) Lactate dehydrogenase (LDH) Pyruvate dehydrogenase (PDH)
Functions of the TCA cycle?
Decarboxylation of acetyl CoA (CO2 production)
ATP production
FADH2 production
NADH production
From one molecule of acetyl-COA entering the cycle?
3 NADH and 1 FADH2 are formed
Dose substrate level phosphorylation occur in TCA cycle?
yes
Things that can regulate the TCA cycle?
Substrate availability
Product inhibition
Allosteric regulation
Features of measuring resting metabolic rate?
measured after a 12 hour fast
no smoking or physical activity 24 hours before
Individual rested in supine position for 30 minutes before
BMR is done with overnight stay
RQ = ?
Volume of carbon dioxide produced / volume of oxygen consumed
Frayn equation to estimate carbohydrate and fat oxidation in grams per minute?
Carb:
(4.55 x VCO2) - (3.21 x VO2)
Fat:
(1.67 x VO2) - (1.67 x VCO2)
Can probably delete glycolysis and tca cycle in depth steps but keep general ones
ok
Where is CHO stored?
Liver and muscle
Examples of glycosaminoglycans?
Hyaluronic acid - good for skin
Keratan sulfate - Cornea, cartilage and bone
Heparan sulfate - animal tissue
Dermatan / chondroitin sulfate - skin, blood vessels, heart valves, tendons and lungs
Will be a short answer question on this
What’s gluconeogenesis?
Making of glucose from carbon sources
General digestion and absorption of CHO?
Monosaccharides absorbed
Transported via hepatic portal vein to liver
Glucose easy for body to use
Fructose and galactose produced
What’s more likely to spike then drop glucose or starch?
Glucose - also produces a larger area on a graph
Fructose metabolism?
Mainly occurs in the liver
Important for liver glycogen stores
Can result in triglyceride synthesis - if sedentary can lead to lipid accumulation = insulin resistance
Fructose isn’t insulin dependent - can be taken up by other cells by Glut 5
Endocrine functions of the pancreas?
Glucagon and insulin
Pancreas releases insulin into blood
Starts when we eat due to increased monosaccharides
Insulin increased glucose uptake in muscle, nerve and adipose tissue
Increases glycogen storage
How is some glucose taken up by liver cells?
Facilitated diffusion - due to Glut 2
Glucose accumulates
How does insulin act on liver?
Binds to receptor
GLUT 2
Activates glucokinase
Converts glucose into glucose 6 phosphate
Then glycogen synthesis can occur, or removal of phosphate group and release to blood stream if conc in blood has reduced again
Importance of blood glucose?
Important for the brain
Turnover that’s constantly happening requires glucose
Neurotransmitter synthesis
What are astrocytes?
Cells in brain that can store glycogen
Features of brain glucose use?
2% of body weight but uses 20% of our glucose
Where does most glucose go after a meal?
Brain heart bladder muscle
Describe insulin effect on skeletal muscle?
The same as on liver, but stimulates hexokinase
GLUT 4 transporter
Glucose can’t leave once entered, oxidised or stored
Capacity not as great as the liver
Also increased the amount of GLUT 4 going to the cell membrane = intracellular signalling
Another way to increase glucose in cell?
Exercise
Calcium released by muscle contraction: Release with contraction Translocated Glut-4 to membrane Increase glucose uptake Independent of insulin
Describe glycogen building?
UDP glucose attach initially to glycogenin molecule
After 8-10 glucose units in length = pro glycogen
Glycogen synthase (regulated by insulin) takes over = macro glycogen
Branching enzyme = branched structure
12 residues trek off at about 7 and attach to neighbour
Glycogen synthase regulation?
Normally in inactive form
Phosphate group blocks catalytic site
Can’t convert UDP glucose to glycogen
Insulin activates protein phosphatase on Glycogen synthase
Glycogen can now be made
Exercise stimulates Adrenaline and calcium ions stimulate protein kinase A
Increase inactive form of Glycogen synthase as need glucose for exercise
Describe glycogen breakdown?
Glycogen phosphorylase b (inactive form) (no phosphate group
Glycogen phosphorylase a (active form) (has a phosphate group)
Inactive to active occurs during exercise, increased Ca+, increased adrenaline, increased glucagon, and increased AMP+ due to glycogen phosphorylase kinase (Inhibited with ATP and G-6-P)
Active to inactive occurs when there is increased insulin, through glycogen phosphorylase phosphatase
Main features of adrenaline in metabolism?
Released due to fight of flight
Stimulates glucose breakdown
Main features of insulin?
Released after CHO ingestion
Reduce breakdwon
Stimulate storage
main features of glucagon?
Released after periods of no food
Stimulate breakdown
Inhibit storage
Describe pyruvate dehydrogenase control?
Overall equation is Pyruvate to acetly-CoA to the TCA cycle
Inactive is phosphorylated (PDH b)
Active is PDH a (active)
PDH phosphatase causes the active form, due to Pyruvate (Ca2+ and Mg2+)
PDH kinase causes inactive form, due to NADH/NAD, Acetyl CoA and ATP/ADP
Describe the rate limiting factors from glycolysis of Hexokinase?
Role is Glucose to Glucose-6- phosphate
Inhibited by Glucose-6- phosphate
Describe the rate limiting factors from glycolysis of Phosphofructokinase?
Role is Phosphorylates fructose-6- phosphate forming fructose-1,6-biphosphate
Stimulated by ADP, Pi, low pH, NH4+
Inhibited by ATP, PCr, Citrate
Describe the rate limiting factors from glycolysis of Pyruvate kinase?
Role is Transfers phosphate from PEP to ADP
Inhibited by ATP, PCr
Describe the rate limiting factors from glycolysis of Lactate dehydrogenase?
Role is Conversion from lactate to pyruvate and pyruvate to lactate
Inhibited by ATP
Describe the rate limiting factors from glycolysis of Pyruvate dehydrogenase?
Conversion of pyruvate to Acetyl-CoA
Stimulated by Ca2+, ADP, AMP. Pi
Inhibited by ATP, NADH, acetyl- CoA
Describe the rate limiting factors from tca cycle of Citrate synthase?
Role is Catalyses condensation reaction of acetyl CoA and oxaloacetate to form citrate
Stimulated by reaction of acetyl CoA and oxaloacetate to form citrate
High oxaloacetate Ca2+
ADP
Inhibited by High citrate
Describe the rate limiting factors from tca cycle of Isocitrate dehydrogenase?
Role is Decarboxylation isocitrate to oxalosuccinate and then alpha ketoglutarate
Stimulated by ADP Ca2+
Inhibited by ATP
Describe the rate limiting factors from tca cycle of Alpha ketoglutarate dehydrogenase?
Converts alpha- ketoglutarate to Succinyl- CoA giving off Carbon dioxide and NADH
Stimulated by ADP Ca2+
Inhibited by High succinyl-CoA ATP
NADH
Describe the electron transport chain?
4 large complexes
Electrons pass from electron donors to electron acceptors
Each electron acceptor wants the electron more than the last one
Final stage produces water
Describe glujconeogeneis? Liver (kidneys)
Once 100g depleted by overnight fast of glucose in the liver (glucostat)
Glucose made from non CHO sources
Fatty acids and glycerol concs go up
Fatty acids can’t be used as precursor directly
PDH and pyruvate kinase reactions are irreversible ( so can’t reverse glycolysis to get glucose)
Acetyl-CoA from fatty acids cannot form glucose
Only carbon backbone that we can use is OAA
However Acetyl Co A stops PDH working
Causes pyruvate to be converted into OAA
Via Malate (aspirate shuttle)
OAA to PEP now reversal to glucose can occur
How does factors of gluconeogenesis aid production of glucose?
TG break down:
Beta oxidation helps inhibit PDH
Glycerol can be converted to glycerol 3 phosphate and enter reversal process
Muscle breakdown:
Alanine can make pyruvate
Lactate production:
Muscle and Red Blood cell
Converted to pyruvate
First slide on lecture 10th of feb has the questions that will be in the exam
ok
How are complex lipids different to just lipids?
Contain other groups as well
eg. phospholipids
Features of lipoproteins?
Lipids aren’t soluble = coalesce together
Lipoproteins can carry triglycerides and cholesterol esters in t =he core
Hydrophillic shell, hydrophobic core
Apoproteins on surface determine function
4 types of blood lipoprotein?
Chylomicrons:
TriAcylGlyecerol (TAG) (90%) and Cholesterol esters (CE)
From intestine
VLDL:
TAG and CE carrier
Made in liver
LDL:
Only CE
‘bad cholesterol’
HDL
Only CE
‘Good cholesterol’
What happens postprandial (after meal) fatty meal?
Want to store the TAG and cholesterol esters
Lymphatics secrete chylomicrons into subclavian vein
Chylomicrons dock onto lipoprotein lipase of non liver tissues (adipose tissue and muscles) - releasing fatty acids and glycerol
Fatty acids that are produced go into adipose tissue and stored and repackaged as TAG as FA binds with Glycerol
Repackaged as TAG (glycerol is from glucose here) Go into muscle cell for fuel use / intramuscular triacylglycerol for later use
When stored esterified with glycerol-3-phosphate
Remnants taken up by liver and recycled to Very low density lipoproteins (VLDL)
Functions of cholesterol?
Plasma membranes
Helps make bile
Makes steroid hormones
Remnants form cholesterol pool in liver
Taken to other sites via LDL
HDL transfers cholesterol back to liver
If LDL is bigger than HDL a problem occurs
What’s de nove syntehsis?
Making cholesterol in the body
More features of VLDL (very low density lipoprotein)?
If eats lots of fat and CHO
Cant store CHO so store as fat
De novo synthesis occurs in liver making TAG
VLDL take the TAGs away from the liver so don’t get fatty liver
Remnants return to the liver
Describe the post absorptive state (all food absorbed)?
No chylomicrons
Liver produces VLDL to carry TAG
TAG in adipose tissue hydrolysed into FA + glycerol by hormone sensitive lipase
FA out of adipocytesnow
Bind to albumin to prevent coalescing
FA then utilised by other tissues
Regulation of fatty acid utilisation control points?
Lipolysis of triacylglycerol to form free fatty acids
Re-esterfication of the fatty acids, or mobilisation from adipose tissue
Transport of acyl-CoA into the mitochondria
Availability of FAD and NAD for beta oxidation
Features of fatty acid lipolysis and mobilisation from adipose tissue?
When stressed/ post absorptive or just done exercise
TAG mobilised for oxidation
Similar to glycogen mobilisation as under similar circumstances and under hormonal control
Describe lipolysis enzyme regulation?
Hormone sensitive lipase
Hydrolyses TAG into FA and glycerol
There is pancreatic lipase (digestive enzyme)
And Lipoprotein lipase (adipose epithelial cell)
HSL activated by protein kinase
Regulated by phosphorylation, phosphorylated when active
Inactivated by phosphatase
Describe when inactive form of HSL occurs?
When inactive (anabolic)
More re-esterification
More Insulin about
Describe when active form of HSL occurs?
Active (catabolic)
Break down of TAG
Exercise
Adrenaline
Growth hormone
Cortisol
Lipolysis vs re-esterification?
Need fatty acids out the cell
Difficult due to re esterification
Adipose tissue good at making TAG
Glycerol has to leave when released
With exercise there is increased lipolysis (more FA leaves the cell) and reduced glucose uptake so less glycerol for re esterification
Describe how fatty acids are mobilised with exercise?
Interstitial fluid = between circulation and plasma membrane of muscle cell (sarcolemma)
Fatty acids arise in albumin or VLDL or chylomicrons
LPL acts on the endothelial cell of capillary and Fatty acid is released and transported into the cell down a conc gradient
Hence the conc gradient is a site of regulation
Rate limiting steps (not rlly) of mobilisation?
Getting fatty acids out of adipose down conc grad and into blood bound to albumin isn’t rate limiting but takes a while
Then getting fatty acids out of blood into cell down a conc grad is slow as well
Describe fatty acid transport across cell membranes?
Dependent on plasma fatty acid concentration
‘Flip-Flop’ and carrier mediated process
Functional protein carriers are:
Fatty acid binding protein (FABP)
Fatty acid translocate (FAT/CD36)
Fatty acid tranport protein (FATP)
Once inside the cell fatty acids become activated by family of acyl-CoA synthethase enzymes to fatty acyl CoAs
Make sure papers from seminar are noted in notes
ok
Describe fatty acyl CoAs storage in muscle?
can undergo incorporation into other lipid pools or oxidation by mitochondria
In lipid pools are intramuscular fat droplets - similar synthesis to adipose tissue triacyglycerol droplets
Intramuscular fat droplets readily available fuel source for mitochondria
Localised with mitochondria
In the muscle what hormone sensitive lipase stimulated into it’s active form by?
Calcium ions
Adrenaline
AMP
Describe the carnitine shuttle?
Wan to get Acyl Co-A into the tca cycle in the mitochdonria
In mitochondria outer membrane is permeable to lipids, and the inner is impermeable
CPT 1 sits on outer mitochondria membrane
Carnitine attaches to acyl and coA removed
CACT helps across inner membrane
CPT2 removes carnnitine and attaches CoA
So basically acyl-CoA binds to carnitine to get across membrane
Beta oxidation then occurs
Describe beta oxidation?
Acyl-CoA to multiple AcetlyCoA
Each carbon cycle removes 2 carbon fragments
Acetyl CoA enters TCA cycle
Continues cycle until no carbons left
Beta HAD is rate limiting enzyme
Cofactors are also rate limiting
What’s the problem with LDL?
LDL lasts 1.5-2 days
Chylomicrons/VLDL last few hours
So LDL subject to damage
Damage to LDL enables bind to new receptor on macrophages (SR-A)
Good as this clears LDL from blood
Macrophage doesn’t have a cholesterol sensor tho
So it keeps consuming the LDL via endocytosis
This turns the macrophage into a foam cell (due to toxins, free radicals, excess glucose)
What’s Atherosclerosis?
Foam cells larger than macrophages
And accumulate in the blood vessels
Characterised by: Vascular inflammation Infiltration of lipids Cholesterol in vessel wall Cellular debris in vessel wall Plaque formation
So it’s not cholesterol its bad its the environment its in
Why is HDL the good cholesterol?
Best predictor of cardiovascular disease (more = less chance)
Cells (except macrophages) express SR-B when there is too much cholesterol
HDL attaches to SR-B
Removes excess cholesterol
Transport cholesterol to liver
What increases HDL?
Exercise
Diet
Drugs
What do statins do?
Prevent are body creating it’s own cholesterol
Liver can’t make it so intracellular levels drop
The cell will therefore need more C, so it expresses more LDL receptor on its membrane
This means that more LDL leaves the blood and enters the cell
Therefore we have lowered LDL levels in the blood
Great success
What are resins?
Prevent bile acids being re absorbed
More Cholesterol is excreted
What does ezetimbe do?
Inactive specific membrane protein
Means you can’t absorb Cholesterol in the first place.
Describe carbohydrate oxidation during prolonged exercise?
Cycle for 3 hours at 60-70% VO@
CHO oxidation decline over time as deplete glycogen stores
Want to maintain output - ATP demand of contraction, as this isn’t maintain when CHO oxidation falls
So Fat oxidation increases over time, so it’s contribution increases to maintain output
kJ energy from CHO oxidation = ?
g x 15.6
kJ energy from fat oxidation = ?
g x 39.4
Plasma fatty acid concentration during prolonged exercise?
Muscles initially take up fatty acids so there is a decrease in plasma, also slow FA mobilisation from adipose tissue
However it increases over time due to adipose tissue lipolysis
Insulin is reduced
Adrenaline is increased
Overall fatty oxidation is increased
How do fatty acids increase drive fatty acid oxidation increase?
More fatty acids results in greater efflux
Gives opportunity for muscle to take up fat and it will
Thus fat oxidation increases
Thus, plasma fatty acid availability drives fatty acid oxidation
How does “fatty acids increase drive fatty acid oxidation increase?” effect CHO?
Increased fatty acid flux will increase acetyl-coA
Increased acetyl-coA inhibits PDH
Increasing citrate accumulation
This inhibits PFK
Therefore G6P accumulates
GLycoggenolysis inhibited
Reduced conc grad for glucose uptake
Therefore reduced CHO oxidation
How can a high fat diet effect exercise?
Results higher fatty acid flux
Good if you want to spare muscle and liver glycogen stores so good if you are ultra endurance
Not good for high intensity exercise
Predominant fuel at low exercise intensity?
Fat
Predominant fuel at high exercise intensity?
Carbohydrates
How do you know when the fat oxidation rte = 0?
When the RER is bigger than 1 = fatmin
FatMax is the exercise intensity at which the highest rate of fat oxidation was observed.
Fat max zone?
Range of exercise intensities with fat oxidation rates within 10% of fat oxidation rates at Fatmax. The lower limit will be referred to as “low” and the upper limit as “high.”
CHO oxidation = ?
(4.55 x VCO2) - (3.21 x VO2)
Fat oxidation = ?
(1.67 x VO2) - (1.67 x VCO@)
3 important digestive hormones?
CCK
Secretin
Gastrin
Whats a an alpha - ketoacid?
Amino acid without the amine group
What can happen to amino acid pools that are made from dietary protein?
Turned into body proteins and other N (excreted as sloughed hair and skin), then also converted back into amino acid pools (very small amount in urinary excretion)
Can be turned into CHO and Fat by the removal of NH3, which is converted into urea, and excreted in urine
Non essential amino acids can be formed from CHO and Fat
Features of amino acids?
20 amino acids in human protein
Contain: Carbon Hydrogen Oxygen Nitrogen (amino group)
They are R group specific
What happens to amino acid digestion when your in the fed state?
Insulin is already elevated
Amino acids arrive at the liver
Transport to other tissues
Storage as Tri acyl glycerides or glycogen
What happens to amino acid digestion when your in the fasted state?
Body needs to make energy
Breakdown of amino acids to get their carbon skeletons
The breakdown of muscle occurs to reach these amino acids
Amino acid fates?
Feed into the TCA cycle
Glucogenic = stored as CHO
Ketogenic = Stored as fat
Leucine and lysine are the only ketogenic ones
Describe alpha keto acids in more detail?
Don’t have the nitrogen amine group
To convert into an alpha keto acid:
Transanimate the amino acid (AA) with alpha keto acid
Move nitrogen from amino acid to alpha keto acid
Deamination through dehydrogenase:
Remove nitrogen
More features about transaminase’s?
Important for the production of non essential amino acids
Needed to expose amino acid carbon backbone to be used for energy
Transaminases enzymes are freely reversible - depends on substrate availability
Often include use of glutamate (Glu)
Occurs in most tissue including muscle
Describe Alanine (amino acid) transaminase reaction?
will be an mcq
Alanine + alpha keto acid = (reverisble, enzyme is alanine aminotransferase) Pyruvate + Glutamate (amino acid)
Describe Aspartate (amino acid) transaminase reaction?
will be an mcq
Aspartate + a-keto glutarate = (reversible, enzyme is aspartate aminotransferase) Oxaloacetate + glutamate (amino acid)
What is Aspartate important for?
Nitrogen excretion
Alanine impoirtant for?
Uptake from the blood into the liver
Describe oxidatative demainition in more detail?
Occurs in mitochdonrial matrix of the liver
Results in an alpha keto acidand ammonia
Example:
Glutamate = (glutamate dehydrogenase is enzyme) Alpha keto glutarate + Ammonia
Reversible
Substarte dependent
Which amino acid contains 2 nitrogens? in the exam
GLutamine
Describe glutamine?
It’s glutamate + another nitrogen group
It’s the most abundnant free amino acid in skeletal muscle and blood
Used in ammoina transport
its a gluconeogenic precursor
Important in carbon + nitrogen transport between skeletal muscle and the kidneys
USed as fuel for immune cells and GI tract
If glutamine leaves muscles its known as?
Cataplerotic loss
Describe nitrogen excretion?
Catabolic
Purine njcelotide cycle produces ammonia
ammonia is toxic
Ammonia is converted into urea, then urine then excreted
Urea cycle occurs in the liver:
Involves energy and enzymes
Describe the urea cycle in more detail?
Carbomoyl phosphate creation from CO2 and ammonia:
Irreversible and requires energy
Asparate enters
Fumarate created - in the TCA cycle
flux relies on the amount of ammonia put in
Urea created
Urea leaves as sweat or urine
3 branched chain amino acids?
Leucine
Isoleucine
Valine
Can be oxidised in skeletal muscle (only ones that are)
Occurs in mitochondria
Not in liver
Describe Leucine oxidation in skeltal muscle?
Transaminate with alpha ketoglutarate (remove amino group)
Enzyme is aminotransferase
= glutamate + which can be converted into alanine by alanine aminotransferase, works both ways
So alanine can be converted into glutamate and a-ketoisocaproate
The a-ketoisocaproate then has it’s hydrogen and carbon removed by ketoisocaproate dehydrogenase with NAD+ to form Isovaleryl CoA + CO2 and NADH
This reaction is irreverisble and highly regulated
Wont have to known this in detail for the exam, so can simplify it, just know the big products
Then through ATP isovaleryl CoA is turned into acetoacetate then acetly CoA which is fed into the TCA cycle
What can aid in BCAA oxidation?
Vitamin B12 and Biotin are involved in the energy pathways
Why is alanine impoirtant?
Important for inter tissue transport
Released from muscles
Taken up by liver
Describe the glucose alanine cycle?
Glycogenolysis results in glucose 6 phosphate in muscle from the stored glycogen
Glycolysuis occurs and pyruvate is made
Go through transamination with an amino acid to form alanine
Alanine is transported into the blood
Alanine is taken up by the liver
Alanine undergous transamination with alpha keto glutarate to form pyruvate and glutamate
Pyruvate goes through gluconeogeneis
Glucose is released back into the blood
glucose is taken back into the muscle
Glutamate is demainiated
Amminoia is lost thoigj urea or creates plasma proteins
What is muscle protein synthesis?
Building up of amino acids into functioning muscle
What is muscle protein breakdown?
Degradation of polypeptide chains within a muscle
What is net balance?
Relationship between synthesis and breakdown
What is protein turnover?
Constant use and restoration of protein, how much breakdown and building up is happening
so not the same as net balance
Changes in tissue protein result from?
Amino acids in blood going to amino acids in cell which can be made into proteins in the cell
Net protein balance=?
Protein synthesis - protein breakdown
How much energy used on protein turnover?
20% of basal energy
Formation of RNA
Making peptide chain
Selective Gene expression, then the activation (or modification or conversion) of the proteins
Why are some enzymes used in proteins have less than 1< half life?
So can respond to changing conditions
Overview of protein synthesis?
Sense strand and a non sense strand are in the double helix
Sense strand binds to another strand to form mRNA via RNA polymerase via complementary base pairing
This is transcription, occurs in the nucleus
Translation occurs, ribosome attaches, tRNA attach via complementary base pairing
All MRNA chains start with AUG, so UAC tuna binds so amino acid MET binds
the amino acids bind together to form a polypeptide
Then post translational modification and targeting to ensure proteins are activated
Describe transcriptional control?
Transcription factors:
Activators:
Bind to enhancer sites and cause transcription
Coactivator proteins:
Make signals that aid the activators bind
Repressors:
Bind to silencer sites, reduce rate of transcription
Regulation of RNA polymerase:
General factors
Specific factors
Hormones - specific steroids, secondary messengers such as cAMP
Describe tRNA charging?
Amino acid + ATP + tRNA = aminoacyl-tRNA + Amp + Pi
Each tRNA has a specific anti codon, which binds to specific amino acids
tRNA synthesise contains proofreading site
tRNA charging is an irreversible process
3 steps of translation?
Initiation
Elongation
Termination
Describe translation initiation?
Involves 40S and 60S ribosomal subunits, mRNA molecule, the initial aminoacyl-tRNA (tRNA molecule with methionine attached), a number of protein factors to control the initiation process and energy from GTP
Describe elongation in transaltion?
Involves the addition of amino acids to the carboxyl terminal end of the polypeptide chain
The process occurs because the anticodon of aminoacyl-tRNA recognises the second codon on the mRNA
A peptide bond occurs between the carboxyl group of MET and the second amino acid which is still attached to its tRNA
Describe termination translation?
Stops when stop codon is reached
A termination factor releases the complete polypeptide chain from the last tRNA and the 80s disassociates to its tow 40S and 60S subunits
Describe post translational processing?
After the polypeptide is released from the translational apparatus, it requires further processing it is in:
Physiologically active form and the cell location where it becomes functional
A growing protein will begin to fold as it is being made and proteins have the capacity to self fold, however many complex proteins need help to fold out
Such as:
Molecular chaperones or chaperonins, eg heat shock proteins (Hip)
Scaffolding proteins
Control sites of translation?
Elongtion factors and initation factors
Control sires of post translational processing?
Chaperones and scuffling proteins
Describe protein breakdown?
Quality control:
Remove mutants
Remove damaged proteins
Turnover:
Short life
Lost activity / not needed
Provision of AA
Energy (Alpha ketoacids)
Protein synthesis
5 main pathways for protein synthesis breakdown ?
ubiquitin - proteasome:
Specific protein marked for degradation
Marking = ubiquitin
Lysosomal:
Endocytosis
Caspases:
Programmed cell death
Matrix metalloproteinases:
Remove extracellular matrix
Calpain:
Calcium activated
Measurement of muscle growth/loss?
Fractional synthetic rate (FSR)
✦ Fractional breakdown rate (FBR)
At rest breakdown rate larger than synthesis rate
What does exercise do to muscle protein synthesis and breakdown?
Increases synthesis more than breakdown (both still increase)
Synthesis stays higher, and far more prominent in untrained individuals
Eccentric and concentric exercise both works
Net balance before and after exercise of muscle protein balance?
Negative before exercise
Becomes less negative after exercise
In untrained can see up to 48h
Will only go positive with extra amino acids
How do you maximal protein synthesis?
Work to failure
In longer term, strength not defiently related to strength
Is there evidence in humans muscle protein synthesis goes down with exercise?
No, can’t recreate an exercise intensity that would do that
What muscle proteins do we have?
Mitochondrial proteins
Sarcoplasmic proteins
Myofibrillar proteins
Collagen
Normally resistance training increases myofibrillar proteins, and endurance increased mitochondrial
Difference in muscle protein synthesis between trainined and untrained?
Trained will peak earlier but decrease sooner
How to get most net muscle protein balance?
Exercise rest and amino acids
What does exercise do to protein balance over a day?
Go less into negative balance when hungry
And go into a larger positive balance after a meal
Nutrient consumption following exercise stimulates muscle protein synthesis and inhibits the exercise-induced rise in protein breakdown
is way muscle mass is gradually increased
What is appetite?
Desire to eat
External and psych factors
Driven by senses
What is hunger?
Internal drive to eat
Central:
Hypothalamus
Vagus nerve
Peripheral:
Blood glucose
Hormones
Which Hormones make you not hungry?
CCK
Pancreatic Polypeptide
Peptide YY
Glucagon like peptide 1
Leptin
What hormones makes you hungry?
Excess glucocorticoids
Ghrelin
Insulin (some people says it decreases)
Neuropeptide y
What’s adiponectin?
Energy regulating hormone but doesn’t effect hunger
Neural drives for the hypothalamus?
Taste of food
Smell of food
Nutrients
Memory
Time of day
Social situation
Stress
Exercise physical activity
Describe the gut hormone Ghrelin?
Released from stomach
It’s Orexigenic = hungry
Only appetite stimulator outside the brain
Lower in obese, rise in during diet induced weight loss
Active / inactive form
Stimulates release of Neuropeptide y
Describe process of Ghrelin release?
Hunger stimulates the release of gherkin from the stomach
Ghrelin travels in the blood to the hypothalamus where it acts
Stimulates appetite
Eating causes blood levels of gherlin to decrease
Describe Leptin?
Released from white adipose tissue
Stimulates release melanocyte - stimulating hormone (MSH) (stops you feeling hungry)
Controls level of stored body fat, so more is released the higher your fat stores
Dosent work as well when obese
Decreases release of Neuropeptide y
Describe the Hut hormone CCK?
Released from small intestine
Rises 15 after eating
Urge to eat is decreased
When applied to rodents decreasing feeding centrally, and decreases meal size and duration of time eating peripherally
Describe gut hormone PP?
Acts on hypothalamus
Supresses hunger after eating
Describe PPY?
Influenced by energy and composition
Released 1 h post feeding
It decreases want to eat
Describe GLP-1?
Released from small intestine and colon
Proportional to energy intake
Promotes weight loss
Describe OXM?
Co released with GLP-1
Proportional to Energy intake
Supresses hunger
What does adiponectin do?
Role in energy homeostasis
What does insulin do to leptin?
stimulates its release
What does glucocorticoids do?
Defiency = anorexia
Excess = hyperphagia
Hormonal response to exercise in lean and obese?
GLP-1 increase greater in Obese
Supression of circulating deacylated ghelin greater in obese
PYY increase was greater in lean
No effect on food intake - so hormones not all that is important
Problem with ad lib buffet could have problems
Is energy intake greater in the cold?
yes - mainly carbs
could be a problem for obese people trying to lose weight
Does hypoxia supress appetite?
yes
Hypoxia has lower acylated ghrelin
Appetite responses to exercise do not appear to be influenced by exercise modality
Does hypoxia supress appetite?
yes
Hypoxia has lower acylated ghrelin
Appetite responses to exercise do not appear to be influenced by exercise modality
How to test for a reducing sugar?
Benedict’s reagent
Add to the food and boil in a water bath
Initial colour is blue goes to a brick red precipitate if positive
How to test for starch?
Add iodine reagent
Just add it to the food
Initial colour is yellow/brown, goes blue/black if positive
How to test for protein / amino acids?
Add biuret reagent
Just add it to the food
Initial colour is blue goes lilac/purple if positive
How to test for fat?
Add ethanol to the food to dissolve the fat then add water
Initially colourless then white emulsion appears if positive
What are vitamins?
Essential organic molecules
Not made in the body
13 identified
Water soluble = B and C
Fat soluble = A , D, E and K
Vitamins as antioxidants?
A, C and E (ACE!)
During exercise there is free radical production (oxidative damage) and maybe tissue damage
Antioxidants protect you from free radical production
Large doses of them are not needed just get them from diet
Features of water soluble vitamins?
All of the vitamin B’s and C
Dissolve in water
Consume daily
Destroyed by high heats and bright light
Excreted if excess
Role of water soluble B vitamins?
Needed for energy release (1, 2, 3 ,5 ,6, 7)
Hematopoietic = red blood cell production (5, 6, 9 and 12)
Describe B vitamins acting as a co enzyme?
Binds to inactive enzyme making it an active enzyme
Role in energy metabolism
What could exercise increase need for energy metabolism related B vitamins?
Probably not true so idk if need to know
Altered absorption
Increased turnover
Biochemical adaptations
Increased mitochondria
Increased tissue repair
Higher intakes of macronutrients
What could make athletes need more Haemopoietic B vitamins?
Probably not true so idk if need to know
Altered absorption
Increased turnover, metabolism loss
Biochemicals adaptations
Increased tissue repair
Altering RBC fragility
A deficiency in Vitamin B1 results in?
Beriberi
A deficiency in vitamin B2 results in?
Ariboflavinosis
A deficiency in vitamin B3 results in?
Pellagra
A deficiency in vitamin B9 or B12 results in?
Megaloblastic anemia
Do deficiency in B vitamins result in decrease in exercise performance?
yes
They don’t need more just need enough
Describe vitamin C (Ascorbic acid)?
Name is in the exam
Antioxidant
Aids synthesis in body
Aids catabolism
Required for normal iron absorption
Facilitattes cytochrome P450 enzyme function
Immune function
Vitamin C dosage?
10-1000mg a day
Too much results in GI distress and kidney oxalate stone formation
Too little results in scurvy and poor health
Describe Vitamin A?
Fat soluble
Retinol
Vision, reproduction, bone, immune, skin
Stored as retinal esters = pre form
Obtain from plant (beta carotene) and animal sources (retinol)
Describe Vitamin D?
Fat soluble
Calciferol
Absorb calcium, bone, immune
Made from the sun in the skin from cholesterol
Activated in kidney and liver
Regulates calcium balance:
Urinary excretion and intestinal absorption
Describe Vitamin E?
Fat soluble
Tocopherol
Antioxidant, Immune, toxins
Potent antioxidant, aids selenium metabolism
Founds in nuts
No clear deficiency disease just feel ill
High dose can interfere vitamins absorption
Describe vitamin K?
Fat soluble
Medanione
Blood clotting factors, bone health
Does clotting
Synthesised by gut bacteria - antibiotics reduce it
Blood clotting
Formation of bone
Deficiency in vitamin A?
Loss of vision and skin issues
Toxicity can result if too much
Vitamin D deficiency?
Rickets, osteomalacia, osteoporosis
Toxicity if too much results in hyper;caemia and bone demineralisation
Deficiency in vitamin K?
Bloody vomit, bleeding into joint capsules, bruising or bleeding gums
Too much (toxicity) Jaundice anaemia or hyperbilirubinemia
Does taking more vitamins aid performance?
no sufficient is fine
There is no energy in them
Difference between macro and micro nutrients?
Macro need more than 100mg a day
Ca, Cl, Mg
micro is less than 100mg a day
Fe, Zn, Cu
Describe mineral absorption?
Some minerals such as calcium and iron are difficult to absorb
Excess can be harmful
Calcium stops Fe and Zn
Zn stops Cu
Moderate excess the kidneys will excrete
Role of Iron in the body?
Oxygen transport and utilisation
Components:
Haemoglobin
Myoglobin
Cytochromes
In immune cells
Males need more - females loss more in menustration
How do we store iron?
Stored with a protein called Ferritin
In Lier, sleep and bone marrow
There is soluble ferritin (dependent on ferritin conc), and transferrin (ingested foods to tissues)
Normal iron status male and females?
Hb (g/L) - males 140, females 120
Serum ferritin (ug/L) - males 110, females 30
Serum transferrin - 20-40 for both
What’s Iron depletion?
Low serum ferritin everything else is normal
Common in athletes and there is no performance effect
Lots of Iron can be loss through sweat and only 25% absorbed in gut
Features of Sodium?
Maintain normal body fluid balance, osmotic pressure and blood pressure
Can be lost in swear
High intake can result in hypertension
Increase in extracellular fluid volume as water is pulled from cells to maintain normal sodium concentrations
RDA = 2.4 g (6g of salt)
Features of Zinc?
Energy production as co enzyme
Macronutrient metabolism
Enzyme roles - LDH and ADH
Allows you to consume alcohol
Roles in nucleic acids and hormones
Aids protein synthesis and wound healing
Most present in muscle then some in bone (bone most responsive to changes in diet)
Zinc and appetite?
Zn not consumed a lot in athletes who are not already meeting energy requirement
Can cause anorexia as Zn has a role in reduced appetite
Features of magnesium?
Essential cofactor of enzymes in energy metabolism
Mg is also required for maintenance of electrical potentials in muscles and nerves
Too much fibre stops Mg absorption
Vitamin D aids Mg absorption
Mg too high or too low?
400-420mg for males
310-320 mg for females
Defiency neuromuscular abnormalities, muscle weakness, cramps, bad mood
Too high = diarrhoea
Features of calcium?
Osteoblasts and osteoclasts are responsible for bone modelling
Turnover -calcitonin and parathyroid hormones
Inadequate Ca results in osteoporosis eventually protected by 1000-1200 mg/day Ca
Locating graves?
Vegetation disturbance
Topography - dips and rises
Geophysics
How to tell age from bones?
Bone fusion state Tooth eruption Tooth wear Tooth cementum annuli Tooth amino acid racemization
How to determine sex with bones?
Pelvis Facial features Statures Robusticity DNA Protein peptide markers in teeth
2 general groups of immune systems?
Innate
Acquired
Describe innate system?
Born with, activated when infected
Anatomical barriers eg. skin
Chemical barriers
Phagocytes:
Neutrophils, Eosinophils, Basophils, Monocytes, Macrophages
Natural killer cells
Describe acquired immune system?
Develops through age, and past infections
Specific
Cells:
Cell-mediated
Cytptoxic t lymphocytes
Humoral:
Antibodies (B-Lymphocytes)
Immunoglobulins
Function and blood count (x10^9/L) of neutrophils?
Phagocytosis
2-8
Function and blood count (x10^9/L) of Eosinophils?
Destroy parasites
0.04-0.4
Function and blood count (x10^9/L) of Basophils?
Trace
Inflammation
Function and blood count (x10^9/L) of Lymphocytes?
Immune response
1.5-3
Function and blood count (x10^9/L) of Monocytes?
Phagocytosis
0.2-0.8
Does running a marathon increase your risk of a respiratory infection and worse symptoms?
yes
Moderate is least amount of risk (in the exam)
Low is bad as well (not as bad as high)
This is the J shaped curve
It becomes an S shaped curve if the individual is trained (not as bad)
What is Biphasic leukocytosis during exercise composed of?
Neutrophils and lymphocytes increase
Then neutrophils increase again (but they have reduced function)
Due to more blood flow hence shear stress
Shear stress decrease adherence of white blood cells
Catecholamines also decrease adherence this is called demmargination
What does the hypothalamus release to in turn cause mobilisation of neutrophils from the bone marrow?
Cortisol by stimulating the adrenal cortex
What is lymphoctopenia?
Fall in lymphocytes after exercise bellow basal level, they then increase again
Gives you a window of time for you to be infected
How to measure how well neutrophils are working?
Elastase release
Overview on what exercise does to neutrophils?
Acute:
Increase neutrophils
Inhibit function
Chronic:
Reduce function
Deplete bone marrow reserves
Whats selective proliferation?
Producing T cell or B cell with specific surface antigen receptor to foreign agent
Exercise decreases this ability in lymphocytes during the window of more likely infection
Addition of Cortisol can prevent this
Describe lymphocytes?
Start as T helper cells then turn into T or B lymphocytes
T:
Release cytotoxins target viruses
B:
Release antibodies and target bacteria
Also exercise causes inhibitory responses and counter regulation so you are more likely to produce B cells
Does decrease in salivary IgA represent more risk of infection?
yes
40% decrease does
What can you do if you are training intensely to maintain your immune function?
CHO during exercise prevents rise in cortisol and adrenaline hence reduces secondary rise in neutrophils which is good?
Also maintains your blood glucose levels
Prevents fall in IFN-y, good as IFN-y released from t lymphocytes (so keeps there levels high), (go back and check this interaction between B and T lymphocytes)
Can take Querectin, maybe reduces infection rate
Maybe beer
Probiotics help
Protein is important for immune cells (maybe intense training)
Vitamin C and D is good
How is nitric oxide produced?
L-argine + O2 is turned into NO via nitric oxide synthase
NO then turns into Nitrite NO2-
This is then turned into Nitrate NO3-
Why is NO important in exercise?
Control/regulation of:
Vascular tone and blood flow Mitochondrial respiration Muscle excitation-contraction coupling Glucose and calcium homeostasis Neurotransmission
Where do we get nitrate from?
Green leafy vegetables and beetroot
What reduces NO3- into NO2- in the body?
Faculative bacteria
What happens when nitrite enters your body?
GO across intestinal wall into systemic circulation
Gets into your saliva gland
On our tongue is where the bacteria live which cause the reduction
Swallowed NO2- reaches systemic circulation
Circulating NO2- forms NO and other reactive nitrogen species
NO causes bioactivity
Does antibiotic mouthwash decrease benefit of eating salads?
YES
Does nitrate improve muscle efficiency?
yes
8mmol is best amount to take
In athletes are the effects less of beetroot juice?
yes
This could be due to:
Higher NOS activity
Higher baseline plasma [Nitrite]
Better muscle oxygenation
Higher mitochondrial volume and efficiency
Nitrate dose already high and duration of supplementation
Higher proportion of type 1 fibres
Does Nitrate improve cognitive decisions?
yes
Mechanisms in which nitrite aids performance?
Maybe mitochondria become more efficient
ATP requirement for mitochondria goes down
More blood flow so more oxygen, directed to muscle region that is oxygen deficient
Nitrate supplementation and training together?
Improved exercise tolerance/performance:
Mitochondrial biogenesis
Angiogenesis
Change your muscle fibre type
Training is better than just having beetroot juice (both still improve)
It’s also better to take natural nitrite as has other benefits
23-30 describes where things are found
ok
83-91 are just equations or numbers that can be looked up
ok
156-165 is glycolysis
ok
