Physiology: Basic Nutrition Flashcards
Why do we need to eat?
Maintenance of the body
–repair
–growth
–function
ESSENTIAL nutrients:
not made by the body. Need to be part of the diet • Amino Acids •Fatty acids •Vitamins •Minerals
What are the Macronutrient requirements?
50% carbohydrates
35% fats
15% proteins
What is the definition of metabolism?
chemical reaction taking place within the body, allowing the release of energy for further processes: repair, growth and function.
All reactions are either?
CATABOLIC or ANABOLIC
What is Catabolism?
breakdown of complex molecules to release energy (exergonic)
What is Anabplism?
building of complex molecules, requires energy (endergonic)
What is the role of Adenosine trio phosphate (ATP)?
transfers energy to enable reactions
What is the formula for ATP in Anabolic reactions?
ATP → ADP + P + energy
Energy used to build complex molecules
What is the formula for ATP I’m Catabolic reactions?
Catabolic:
ADP + P → ATP + heat
Molecules broken down for oxidation (energy release) or reused in anabolism
How many ways is Glucose used as?
- As an immediate energy source - either aerobic or anaerobic metabolism
- Synthesis of amino acids (occurs in many cell types)
- Synthesis of glycogen for storage (mainly hepatocytes and muscle cells)
- Formation of triglycerides (formed in hepatocytes, stored in adipose tissue
Where are monosaccharides converted into glucose?
Hepatocytes- liver cells
What reaction do monosaccharides undergo? And where?
aerobic and anaerobic will both produce energy : different amounts and speeds. Feeds the electron transport chain for the production of ATP
Mitochondria
What does ATP production depend on?
ATP production will depend on the activity and resources available.
How much ATP is produced in the Anaerobic pathway?
2 ATP
How much ATP is produced in the Aerobic pathway?
36-38 ATP in total
What is Glycogenesis?
Making of glycogen for glucose from the blood (energy control)
What is glycogenolysis ?
The breaking of glycogen for glucose into the blood
What happens in the absence of insulin?
Glycogen is broken down into glucose in the absence of insulin (and the presence of glucagon) to increase blood glucose level
What happens in the presence of Insulin?
stimulation of hepatocytes and skeletal muscle cells by insulin to convert glucose into glycogen
What is Gluconeogeesis?
Glucose production from protein or fat rather than carbohydrates
What activates Gluconeogenesis?
Starvation
Low carb diets
Endocrine disorder i.e. hyperthyroidism
Endurance exercise
What regulates Gluconeogenesis?
Cortisol and pancreatic glucagon relationship to stress. Increase in glucose availability to facilitate
What are hepatocytes?
Liver cells that converts triglycerides, lactic acid and amino acid into glucose
How is lactic acid produced?
by anaerobic carbohydrate metabolism is slowly converted back to glucose via pyruvic acid (Reduction reaction adding H+).
How do lipids get through the lymphatic system?
Diffuse across cell membranes into the lymphatic system. No energy required
Why are lipids oxidised?
To produce ATP
What is the role of fatty acids?
Used to synthesise triglycerides and phospholipids or catabolism to generate ATP
What is the role of triglycerides?
Protection
Insulation
Energy storage
What is the role of phospholipids?
Cell membrane
What are steroids?
Cholesterol Bile salts Vitamin D Adrenocortical hormones Sex hormones
What is the role of cholesterol?
Component of all animal cell membranes
What is the role of sex hormones?
Reproductive functions
What is the role of Eicosanoids ?
Modify response to hormones
What are Eicosanoids?
Prostaglandins
Leukotrienes
Define lipolysis
Triglycerides break down into fatty acids and glycerol
Fatty acids produce more ATP than glycerol in the Krebs cycle,
True or False
True
Define lipogenesis
Excess carbohydrates, proteins and fats are stored as triglyceride
Fatty acids from glucose and protein can also be turned into lipoproteins, phospholipids and cholesterol
True or false?
True
What increases Lipolysis?
Lipolysis is increased as a result of increased levels of hormones adrenalin, noradrenalin and cortisol
When does Lipogenesis increase?
When blood levels of insulin increase
Amino acids are transported from the GI by active transport
True or false
True
What stimulates Anabolism with proteins?
Anabolism is stimulated by Insulin-like Growth Factors (IGFs), Thyroid Hormones, Insulin, Oestrogen, Testosterone
What stimulates protein catabolism?
By cortisol
What is the result of protein catabolism?
Proteins are catabolised (broken down) into αα used for growth and repair
αα can’t be stored, so some excess are used for ATP through Kreb’s cycle
What is Ketosis?
where energy comes from the breakdown of ketone bodies.
•Sign of diabetes or low carb diet
•Characterised by acidic breath from the metabolically inert aceton
What is ketone is?
Ketone bodies are detected in blood
Nutrition requirements for a healthy diet?
Energy: 8,400 kJ/2,000kcal. Total fat: less than 70g. Saturates: less than 20g. Carbohydrate: at least 260g. Total sugars: 90g. Protein: 50g. Salt: less than 6g.
Micronutrients are required as co-enzymes, antioxidants, components of crucial enzymes
True or false?
True
Absence or lack of micronutrients causes severe medical problems
True or false?
True
Different diets come with their own health considerations
True or false?
True
Role of Vitamins?
■Excess watersoluble vitamins are lost in urine
■Required as co-enzymes to facilitate metabolism
■Involved in protein synthesis
■Blood cell production and clotting
■RNA and DNA production
■Antioxidants
■Growth of bones and teeth (regulation of cells and Ca++ absorption)
■Wound healing
■Cell growth
In order to lose fat mass you need to expend more than you consume
True or false
True
You might NOT lose fat mass with physical activity alone
True or false?
True
