Fuels Flashcards
What happens if there is a lack of oxygen (in terms of producing energy)
When there is a lack of oxygen, amino acids and fatty acids could be used and be implemented into this process to contribute to certain parts and ultimately contribute to cellular respiration
Explain the process of oxidation of fatty acids and its contribution to energy production
They are long hydrocarbon chains. The fatty acid chains break into 2 carbon acetic acid molecules
Each acetic molecule combines with enzyme CoA to form acetyl CoA. The Acetyl CoA can be fed into the overall cellular respiration process and is used up in the Krebs cycle to produce NADH and ATP to be used in electron chain
What is the structure of an amino acid
Has a nitrogenous portion and a carboxyl group (COOH)
Explain the process of the oxidation of amino acids and its contribution to energy production
Amino acid degradation produces sugars that can be converted to glucose or utilised in Kreb’s cycle
The amino group (NH2) and extra H is used to remove it in the form of ammonia (NH3). The non nitrogenous portion (acid group) becomes a keto acid (ketone body)
These ketone bodies can be taken up from the blood and reconverted into acetyl CoA to be inserted into the Krebs Cycle
What happens to amino acids in starvation conditions
They can be turned into pyruvate to be used (?)
not too sure about this one
WHen O2 is available how can lactate contribute to energy production
Lactate can be converted into pyruvate to be used in further cell respiration
What happens when oxygen is limiting (anaerobic conditions)
No krebs cycle, electron chain transport etc. because they require oxygen.
Instead, it relies on process of glycolysis of transfer from glucose to pyruvate which produces 2 ATP. However, this leads to a process of lactic acid fermentation
What is lactic acid fermentation
This is when lactate production increases due to an increased demand for ATP which exceeds supply and oxygen is limiting
I.e. occurs during strenuous exercise, inadequate blood supply etc
Pyruvate is reduced to form lactate.
NADH is oxidised to NAD+
Ultimately 1 glucose molecule turns into 2 ATP, 2 x lactate
Does our body exist in a dynamic catbolic-anabolic state
Yes. Some nutrients are used to build bits and pieces of you while others are broken down
How long can nutrients absorbed from meals supply energy for
Around 4 hours
Nutrients stored as glycogen and fat to give energy until next meal
What does our body do to get energy in fasting state
Rely on energy that has been stored (particularly glycogen)
What are the preferred metabolic substrate(s) of the brain
Glucose (prioritise this)
(Ketone bodies under starvation)
What are the preferred metabolic substrate(s) of the skeletal muscle
Fatty acids, glucose, ketone bodies
What are the preferred metabolic substrate(s) of the heart muscle
Fatty acids, lactate, ketone bodies
What are the preferred metabolic substrate(s) of the red blood cells
Glucose
A little bit of lactate
What happens when the brain lacks glucose
Headache
Trembling
Sweatiness
Hunger
Blurry vision
Irritability
Ringing in ears
Feelings of anxiety
Increased heart rate
Weakness or tiredness
How much atp does 1 gram of fatty acid produce
around 106 aatp
How much atp is produced by glycolysis
2 ATP
How much atp is produced by 1 gram of glucose (aerobic respiration)
~34 atp
What are some uses of ATP
Energy source for >95% of cellular activity:
Contractility and motility (actin and myosin)
Ion pumps
Signalling
Biosynthesis
Heart uses around 0.135 micromols of ATP per second and around 6kg per day. Runs out of ATP within 10 seconds if ATP production is inhibited
What happens to the brain, heart muscle and skeletal muscle in terms of preference for metabolic substrates during fasting state (4-30 hours)
Tissues other than brain reduce glucose usage (because prioritising glucose to go brain)
Brain uses glucose produced from glcogen and amino acids in liver
What happens to the brain, heart muscle and skeletal muscle in terms of preference for metabolic substrates during starving state (after 30 hours)
Brain starts using ketone bodies rather than glucose
Other tissues stop using glucose
Liver makes ketone bodies from fatty acids
Liver and kidney make glucose from amino acids –> loss of muscle mass
What is keto acidosis
High serum and urine concentration of ketone bodies
What is diabetic ketoacidosis
Life threatening complication of diabetes.
It occurs when the body starts breaking down fat at a rate that is much too fast. The liver processes the fat into a fuel called ketones, which causes the blood to become acidic.
What is starvation ketoacidosis
Occurs when body is deprived of glucose and relies on fatty acids
What is our breath smelling like acetone a sign of
Ketosis is a metabolic state that occurs when your body burns fat for energy instead of glucose.
