Flashcards in Metabolism Deck (86):
Nutrients are provided by what?
The foods we eat
What is metabolism?
What we do with the nutrients once they are delivered to the cell
Provide 6 examples of nutrients used for growth repair and maintenance
Carbohydrates, proteins, fats, minerals, water, vitamins
Why must essential nutrients be included in the diet?
Because they cannot be synthesised by the body
Glucose, fructose and galactose are which types of carbohydrate?
Name 3 disaccharides
Sucrose, lactose, maltose
Name 3 polysaccharides
Starch, lycogen, cellulose
All carbohydrates generate what?
What are the 3 uses of carbohydrates
Converted to energy (RBCs and neurons depend on glucose)
Form structural components of other molecules eg glycoproteins
Provide energy stores - glycogen, excess converted to fat
What is the approx GDA of carbohydrates?
What are the effects of fibre on digestion?
Absorbs water into the intestines and softens stools, provides bulk so speeds up the transit time
What is the daily requirement of fibre?
What does excess fibre intake interfere with?
Mineral absorption eg calcium, iron
What percentage of body mass is constituted by proteins?
What are proteins broken down into and where does this take place in the body?
Amino acids in the digestive tract
How many amino acids are there?
How many amino acids are essential?
What are the GDA requirements of protein?
What are the 4 uses of lipids?
Absorption of fat soluble vitamins
Plasma membranes and myelin
Precursor of steroids, bile salts, vitamin D and prostaglandins
What is the GDA of fats and what portion of this should be saturates?
Are lipids water soluble?
How are lipids transported?
•Transported in the blood as lipoprotein droplets
–core of cholesterol & triglycerides
–outer coating of proteins and phospholipids
Synthesis of larger molecules from smaller ones
Breaking down of larger molecules into smaller ones
Give an example of a carbohydrate?
Pasta, potatoes, rice
What does the body use carbohydrates for?
Convert to energy
Form structural components of molecules eg glycoproteins
Provide energy stores eg glycogen
What are the major sources of fibre?
Fruit skin, brown bread
What are the functions of fibre?
Absorbs water into the intestines and softens stools
Provides bulk to speed up the transit time
What does excess fibre interfere with?
Mineral absorption - calcium, iron etc
What are the sources of complete proteins? How many of the amino acids do they contain?
All amino acids - Eggs, meat, milk
What are the sources of incomplete proteins and how many amino acids do they provide?
Lack one or more essential amino acids, rice, beans, pulses
What are the functions of proteins?
Broken down into amino acids in the digestive tract, synthesis of new proteins. Transamination in liver
What are the functions of lipids?
Absorption of fat soluble vitamins
Plasma membranes and myelin
Precursor of steroids, bile salts, vit D and prostaglandins
Sources of lipids?
Butter, cream, cheese, eggs
What do vitamins do?
Act as co enzymes in metabolic activities and carry out many other functions
Where can you obtain vitamins?
Meat and vegetables
Name 4 fat soluble vitamins.
Name 2 water soluble vitamins
B and C
What are the sources of minerals
Vegetables, milk, eggs, meat, fish and shell fish
Name some minerals
Calcium, phosphorus, iron, magnesium, manganese, chlorine, folate and other electrolytes
What is the recommended sodium intake, required amount and average intake amount?
Red - 6g/day
Required - 2g
Average - 4.5g
1kcal = ? KJ
1kcal = ?
Amount of heat required to heat 1litre water by 1 degrees
Metabolic rate = ?
Rate of energy released from cells
Basal metabolic rate =
Energy released required to support vital organs at rest
Describe carbohydrate metabolism during anabolism
Glucose is converted to glycogen or triglycerides for storage
Describe carbohydrate metabolism during catabolism?
Glucose is used to form ATP by glycolysis or the TCA cycle
Fuel molecule required for energy
Stored form of glucose
Hormone involved in breaking glycogen to glucose
Transforms glucose to glycogen
Describe the sequence of events that occur during glycolysis
Glucose releases ATP, glucose transformed to 2x pyruvic acid - lactic acid and acetyl coenzyme A.
Acetyl coenzyme a - oxaloetic acid to the citric acid (krebs) cycle. Producing oxidative phosphorylation, ATP, h20 and co2. Anaerobic process (no oxygen required)
Describe protein metabolism anabolism?
Amino acids used to form new proteins
What is glycolysis?
Glucose broken down to form energy
Describe protein metabolism, catabolism?
Amino acids can enter TCA cycle,
Deaminated by removal of NH2 (ammonia) - toxic substance converted to urea by the liver and excreted in the urine
In the presence of oxygen begat happens to pyruvic acid?
Passes into the mitochondrion to enter the TCA cycle and the electron transport chain - produces 36 ATP
How many ATP are left altogether from glycolysis and the TCA cycle with electron transport chain?
Describe lipid metabolism - anabolism?
Fatty acids and glycerol converted to triglycerides
Lipogenesis - triglycerides formed from amino acids and glucose
Describe lipid metabolism - catabolism?
Lipolysis - breaking down fat for fuel eg
Glycerol - glycolysis
Fatty acids - acetyl co a - TCA cycle
The absorptive metabolic state occurs when and is what process?
Up to 4 hours after a meal
The post absorptive metabolic state occurs when and is a mainly what process?
From 4 hours after meal to next meal
No absorption occurring
Mainly catabolic processes
What is normal blood plasma glucose?
3.5 - 8.0 mmol/L
What is normal fasting blood plasma glucose?
Syntheses of glycogen from glucose
Breakdown of glycogen into glucose
Synthesis of glucose from amino acids
What happens to glucose in the absorptive state?
Blood glucose is high - insulin is secreted by beta cells of pancreas, insulin lowers blood glucose by increasing entry of glucose into cells (increase carriers for facilitated diffusion), stimulating glycogenesis, stimulating fat and protein synthesis, inhibiting gluconeogenesis
What is the aim during the post absorptive state?
Prevent blood glucose falling
Name the 3 hormones involved in maintaining blood glucose levels during the post absorptive state?
Glucagon, adrenaline and glucocorticoids.
Where is glucagon secreted?
Pancreatic alpha cells
What does glucagon stimulate?
Glycogenolysis, gluconeogenesis and lipolysis
Where is adrenaline released?
SNS and adrenal medulla
What does adrenaline stimulate?
Glycogenolysis and lipolysis especially during injury, fear and stress.
Where are glucocorticoids such as cortisol and cortisone released?
What do glucocorticoids stimulate?
When are ketones formed?
When the liver breaks down fats into proteins
Too much acetyl co a to enter TCA cycle so is converted to ketone bodies
What do some cells such as the heart and kidney use ketones for?
Too many ketones leads to what?
What else can lead to ketoacidosis?
Lack of insulin in diabetes patients
What does insulin do to blood glucose?
What does glucagon do to blood glucose?
Increase blood glucose
What are the risk factors for gestational diabetes?
Previous big baby
Close relative with diabetes
Previous gestational diabetes
How can gestational diabetes be controlled?
Diet and exercise
May need oral hypoglycaemia or insulin
Explain type I diabetes mellitus
Insulin - dependant diabetes
Children and young adults
Absence of insulin secretion
Explain type II diabetes mellitus
90% of cases
Obesity, lifestyle, age, genetic factors
Diet and or drugs for treatment