Metabolism L1: Introduction to metabolic pathway Flashcards
What are the 3 stages after chew and swallow food?
- Digestion
- Absorption
- Metabolism
_____ are the only ones that diffuse passively across the membrane
Lipids
What is digestion?
Food is broken down into minuscule nutrients in the stomach
What is absorption?
The nutrients are absorbed into the blood stream from the small intestine
What is metabolism?
After the nutrients are absorbed into the blood stream and travel to all cells of all the body, metabolism occurs
Your body _____ the food you eat, both, to use immediately or to store as energy for later demands
metabolises
What are 6 macronutrients?
- Carbohydrates
- Fat
- Protein
- Vitamins
- Minerals
- Fibre
What is the function of carbohydrates?
Fast (easy-access) energy
What are 5 functions of fat?
- Stored energy
- insulation
- vitamin
- hormone building
- cell membranes
What are 4 functions of protein?
- Building cell structures
- oxygen transport
- immune defenses
- chemical reactions
What are the building blocks of carbohydrates?
Saccharides (sugars)
What are the building blocks of fat?
Fatty acids
What are the building blocks of protein?
Amino acids
What are some examples of carbohydrates?
Glucose, sucrose, dextrose, maltose, lactose, fructose, cellulose, amylose
What are some examples of fat?
Unsaturated and saturated fats
What are some examples of proteins?
Membrane receptors, hemoglobin, antibodies, enzymes
___ % of our energy comes from carbohydrates.
45-65%
___ % of our energy comes from fats.
<30%
___ % of our energy comes from protein.
12-20%
getting sufficient vitamins and minerals are sometimes a problem for people in ________.
developing countries
In carbohydrates, ______ is the principle fuel in the short term
Glucose
Why is carbs the principle fuel in the short term?
Highest amount of ATP compared to others
Sugar based –> taken up by body and used as energy first
Carbohydrates (glucose) yields is about ____kcal/g
4
Glucose is stored as _____
glycogen
Humans can synthesis ____ (all/some/none) the carbohydrates they need
all
What are 4 characteristics of carbohydrates (glucose)?
- Glucose is the principle fuel in the short term
- It yields is about 4kcal/g
- Stored as glycogen
- Humans can synthesis all the carbohydrates they need
Lipids have the highest calorific value of _____kcal/g
9
Lipids are secreted as _____
fatty acids
Lipids are stored as ______ (fatty acids + glycerol)
triacylglycerols
Lipids are use when fuel is ______ or _______.
short supply; prolonged energy expenditure
What are 4 characteristics of lipids?
- Stored as triacylglycerols (fatty acids + glycerol)
- Highest calorific value 9kcal/g
- Secreted as fatty acids
- Used when fuel is in short supply or prolonged energy expenditure
Proteins are polymers of ______
amino acids
Proteins are ____ amino acids, _____ cannot be synthesised by humans = essential amino acids
20; 9
What are essential amino acids?
cannot be synthesised by humans
How many essential amino acids are there?
9
What are 3 characteristics of proteins?
Not stored for energy but can be used as a fuel source in times of need
Polymers of amino acids
– 20 amino-acids, 9 cannot be synthesised by
humans = essential amino acids
– Not stored for energy but can be used as a
fuel source in times of need
Why are proteins almost never used for energy? What do you use amino acids for?
- Building blocks for cells and build proteins
- Only used in malnutrition (as 9 amino acids cant be synthesised) –>Start to digest yourself (eating up muscles)
What are vitamins?
Organic compounds occurring in small amounts in food
Vitamins can assist with physiological function often as ______ or as ______
EXAM QUESTION
coenzymes; antioxidants
There are _____essential vitamins needed (____ fat soluble and ____ water soluble)
13; 4; 9
Vitamins _____(can/cannot) be synthesised in the body (with the exception of Vit ____and Vitamin _____)
cannot; D; K
Deficiencies are ____(common/rare) in developed economies. But in developing countries that can be ____ (common/rare)
rare
What are the 13 essential vitamins?
EXAM QUESTION
What happens to water soluble vitamins?
Wont be able to store them Lost in urine (get rid)
What happens to fat soluble vitamins?
- Stored for longer in fat
- Eg. vitamin c (have to be careful how much you take/eat)
- Don’t want to overingest –> Can be stored
How is vitamin B12 absorbed?
EXAM QUESTION
Intrinsic factors in the mucosa of the stomach by the parietal cells
What is vitamin B12 important for?
EXAM QUESTION
Important for blood cell formation (red blood cells)
What are 3 chemical reactions involving minerals?
- Cell growth and repair
- Metabolism
- Nerve and muscle function
What are 4 features that affect the balance of minerals in the body?
- certain diseases (GIT, kidney)
- an unbalanced diet
- taking mineral supplements
- removing certain foods or food groups from the diet - missing out on important minerals
What are 9 minerals important for good health?
- Calcium
- Chlorine
- Iron
- Magnesium
- Phosphorus
- Potassium
- Sodium
- Sulfur
- Zinc
What are 2 most common mineral deficiencies in Australia? What do they lead to?
- Calcium, leading to osteoporosis
- Iron, leading to anaemia
How to introduce the majority of our minerals?
Specificity –> water (lots of minerals)
Thus, usually ingest enough minerals to sustain ourselves for daily living except for iron and calcium
What is fibre?
plant substances that are resistant to digestion and absorption in the human small intestine and undergo complete or partial fermentation in the large intestine because
The diets rich in fibre such as ____, ______, _____ and _____
cereals, nuts, fruits and vegetables
What are 3 diseases that fibre may protect us against?
- cardiovascular disease
- diabetes
- colon cancer
Can we digest/break down fibre?
No
What are 4 main sources of energy from highest to lowest?
Source of energy (highest to lowest)
- Alcohol a. Use that energy straight away b. It is a poison for our body = trying to get rid of this (reduce alcohol)
- Glucose
- Lipids
- Proteins
Worst source of energy (rarely used)
What are 3 other which are essential for normal function of system and pathways (get from glucose into ATP)?
- Vitamins
- Minerals
- Fibre
- Unable to be digested
What is the short term control of food intake?
Wjhat are 2 phases of the GIT?
- Cephalic-gastric
- Intestinal
What is the problem with obesity?
Control of food intake is lost
What is metabolic rate (MR)?
the rate at which energy is spent in the body in a given period of time (kcal/hr or kcal/day)
What is the basal metabolic rate (BMR)?
Physical and mental rest; no food within 12 h
Comfortable room temperature
- Male BMR = 7,100 kJ/day (1,700 kcal/day)
- Female BMR = 5,900 kJ/day (1,400 kcal/day)
What is the average male BMR?
7,100 kJ/day (1,700 kcal/day)
What is the average female BMR?
5,900 kJ/day (1,400 kcal/day)
When will the average BMR change?
- Will change depending of physical activity (will increase if doing sports or studying) Doesn’t matter whether actually sitting if actively doing sometime –> still using energy
- Brain uses almost 30% of glucose ingested
- When revising, seems to always hungry –> carbs –> brain is demanding glucose This is different if sitting on couch watching Netflix
GIT helps break down carbs, fats, proteins into smaller molecules –> move into tissue cells –> able to change or transform nutrients into _____(this occurs in the mitochondria of the cell) _____ is the only energy that is able to be taken up by the body (currency)
energy ; ATP
What does metabolism refer to?
all chemical reactions that occur within the body cells.
What is the function of metabolism?
Provides energy to maintain homeostasis and perform essential functions
What are 3 reactions that metabolism involves?
- degradation
- synthesis
- transformation
of 3 classes of energy-rich organic molecules (carbohydrates/protein/fat) known as intermediary metabolism
What does metabolism provide?
Metabolites
Metabolism = _____Reactions + _____ Reactions
Catabolic ; anabolic
What are catabolic reactions?
break down larger molecules, such as carbohydrates, lipids, and proteins from ingested food, into smaller parts
What are catabolic reactions?
EXAM QUESTION
break down larger molecules, such as carbohydrates, lipids, and proteins from ingested food, into smaller parts
What are anabolic reactions?
EXAM QUESTION
biosynthetic reactions, synthesize larger molecules from smaller constituent parts, using ATP as the energy source.
Which one should always be higher/one step ahead between anabolic and catabolic? Which one makes energy?
Anabolism
Try to have energy coming from catabolism
Any way to have any sort of anabolic reaction is to have energy coming from catabolism. Cannot have a situation where anabolic reaction is happening without energy
What are 6 characteristics of the liver as a metabolic organ?
- Intestinal blood supply flows directly to the liver - gets all nutrients/metabolites
- Linked closely to pancreatic blood supply - insulin/glucagon hormones exert their effects in the liver first
- Stores glucose as glycogen (Glycogenesis) which it can breakdown when required (Glycogenolysis) and release to the rest of the body
- Can synthesise “new glucose” (Gluconeogenesis)
- Can synthesise ketones, from fatty acids and amino acids (Ketogenesis) as an alternative energy source when carbohydrates are scarce
- Can synthesise lipids (fatty acids and triglycerides) from glucose and aminoacids (Lipogenesis)
What is glycogenesis?
EXAM QUESTION
- Synthesizes glycogen from glucose
- Occurs when glucose supplies exceed demand for ATP
What is glycogenolysis?
EXAM QUESTION
- Breaks down glycogen to release glucose
- Stimulated by low blood glucose
What is an example for glycogenesis?
- Just had 3 pieces of cake
- Too much/high amount of blood glucose
- Occurs when release a hormone (insulin) from the pancreas
- Stored as glycogen in the cell
What is an example for glycogenolysis?
• Haven’t had food for 8 hours • Low amount of blood glucose • Hormone (glucagon) is release from pancreas • Opposite effect to insulin Stimulates the liver to metabolism glycogen to give glucose
This balance between _____ and _____ is very important
glycogenesis; glycogenolysis • Something goes wrong = diabetes Not capable to deal with glucose in the system
Too much glucose stored as glycogen and back to glucose when needed, activated by ___ and _____.
insulin;glucagon
What are 3 characteristics of muscle tissue?
- major mass tissue (approx 40% body weight):
- Utilises glucose as energy source during fed state and activity, utilises lipids as energy source during fasting
- Stores glucose as glycogen - only be used by muscle cells (Glycogenesis / Glycogenolysis)
What are 3 characteristics of muscle tissue (metabolic tissue)?
- major mass tissue (approx 40% body weight):
- Utilises glucose as energy source during fed state and activity, utilises lipids as energy source during fasting
- Stores glucose as glycogen - only be used by muscle cells (Glycogenesis / Glycogenolysis)
What are 5 characteristics of adipose tissue (metabolic tissue)?
- key metabolic regulator of lipid storage and release. Is now recognised as an endocrine organ releasing adipokines (e.g. Leptin)
- Stores fatty acids as triglyceride
- Releases fatty acids
- Not ALL fat depots are the same!
- ie sub-cutaneous vs visceral fat, white fat vs brown fat
What is white fat?
Easy to get rid of
What is brown fat?
(visceral- dangerous–> sits around heart and lungs -> need to pump more) • Extremely hard to get rid off During adolescents and sometimes stored for the rest of your life
What are 4 characteristics of the brain (metabolic tissue)?
The brain has a very high metabolic rate
- High blood supply : 50ml/100g/minute vs. 2-5ml/100g/minute in resting skeletal muscle;
- The brain depends almost entirely on glucose
- The brain oxidises about 120g of glucose per day
- Wide variation in blood glucose levels have little effect on brain uptake of glucose - levels have to fall severely low (2 mmol/L) for impaired function to become evident
What are 4 characteristics of the kidneys (metabolic tissue)?
- produce urine - maintaining the osmolarity and pH of the body fluids
- Although constituting only 0.5% of body mass, kidneys consume 10% of the oxygen used in cellular respiration = needed for reabsorption
- Filters urea out
- Recovers metabolites such as glucose
Why is insulin telling my body to start anabolic reactions?
- Excessive glucose
- Must need to do all reactions to survive
- Produce ATP Increase protein synthesis
What does increase blood glucose look like?
What does decrease blood glucose look like?
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