Simple Stuff About Processes and what you need to know slides Flashcards
What is glycolysis?
The breakdown of glucose by enzymes, releasing energy and pyruvic acid
When is glycolysis up regulated?
When we need energy rapidly
When is glycolysis down regulated?
During rest (check)
Where in the cell does glycolysis take place and in which tissues?
Every cell in the body can generate energy from glycolysis
Takes place in the cytoplasm
In which types of exercise is glycolysis likely to be activated?
Exercise at high intensities
Or
When glycogen stores start running low
How many steps are involved in glycolysis and how many of them are irreversible?
10
3 are irreversible
What is the energy yield of glycolysis?
Two ATP
What is glycogenesis?
The formation of glycogen from sugar (glucose)
When is glycogenesis activated?
When you have plenty of glucose in the cell and insulin has been secreted (this is all likely to occur after we have eaten carbohydrates) (after a CHO meal)
When is glycogenesis inhibited?
When there is already a large amount of glycogen or a large amount of glucagon has been released
What is glycogenolysis?
The breakdown of glycogen into glucose
When is glycogenolysis up regulated?
During times of fasting/hunger/high intensity exercise
When is glycogenolysis inhibited?
In a fed state/during rest
When is the TCA cycle activated? What does it depend on?
During exercise up to 3 minutes
The amount it occurs is also dependent on the amount of pyruvate being produced and thus Acetyl CoA entering the TCA cycle
Describe the link reaction
This is where pyruvate is converted to Acetyl CoA by the enzyme PDH
During this reaction NAD+ becomes NADH and a CO2 is produced
It occurs in the mitochondria
What enzyme regulates the ‘link reaction’?
Pyruvate dehydrogenase
When is PDH up regulated? (Check)
Exercise activates PDH
What is the active form of PDH?
Non-phosphorylated
What is the inactive form of PDH?
Phosphorylated
When is PDH inhibited? (Check)
During rest
What can go into the TCA cycle?
CHO
PRO
FAT
What is the starting molecule for the TCA cycle?
What is the final molecule before it comes back to the start?
Acetyl CoA
Oxaloacetate
What are the products of the TCA cycle?
1 ATP
3 NADH
1 FADH2
What is the energy yield for 1 cycle?
Actual energy yield = 1 ATP
Potential yield from one cycle = 12 ATP
What happens to NADH and FADH2 after the TCA cycle?
They get sent to the electron transport chain (ETC)
Is the TCA cycle an aerobic or anaerobic process?
Aerobic
What is an anabolic reaction? (Give examples)
Synthesis of new molecules
E.g: Protein synthesis Lipogenesis Gluconeogenesis Glycogenesis
What is a catabolic reaction? (Give examples)
The breakdown/degradation of molecules
E.g: Proteolysis Lipolysis Glycolysis Glycogenolysis
How do enzymes function?
They speed up reactions
Lower activation energy
They bind to a substrate forming an enzyme substrate complex
What effects an enzymes function?
Substrate concentration
pH
Enzyme concentration
Temperature
What are the different fuel sources and metabolic pathways that can be used to generate ATP?
Phosphocreatine Glycolysis Carbohydrate oxidation Fat oxidation Protein breakdown
What are the four main elements in the body
Oxygen (65%)
Carbon (18%)
Hydrogen (10%)
Nitrogen (3%)
What is the composition of an atom?
Proteins and neutrons in the nucleus
Electrons surround the nucleus in outer shells
What is a covalent bond?
Where atoms share electrons
What is an ionic bond?
Giving/receiving electrons from another atom
What are redox reactions?
This occurs when atoms share electrons and one atom becomes oxidised, the other becomes reduced (reduction)
When are redox reactions important in exercise metabolism?
Long duration exercise when ATP turnover is high
What is the function of the cytoplasm?
Several important energy generating reactions take place here
What is the function of the mitochondria?
Generates lots of ATP
What is the function of the cell membrane?
It is the gatekeeper of the cell
Which metabolic pathways are actives during very big intensity exercise?
PCr and glycolysis
Slide 6, lecture 3
Contributions to exercise
What are the metabolic pathways activated during intermittent exercise such as team sports?
They’ll all be activated at different points
What are the possible causes of fatigue during high intensity and intermittent exercise? (Slide 27, lecture 3)
PCr depletion
Acidosis
Sodium-potassium dysfunction
Reactive oxygen species
Where does the electron transport chain take place?
Inner mitochondrial membrane
The folds (Cristae) of the mitochondria
What is the difference between substrate level and oxidative phosphorylation?
ATP yield is much greater with oxidative phosphorylation and much smaller with substrate level phosphorylation
Also oxidative phosphorylation is with oxygen where as substrate level is not as you can get energy much quicker but less of it without O2
What are the roles of NADH and FADH2?
To perform redox reactions which are used to generate ATP
How do the protein complexes on the ETC function - where is the electron affinity greatest?
It is greatest at column IV, this allows the electrons to be dragged across from column I to column IV
How is the ETC regulated?
Dependent upon the energy status of the cell (dependent upon how much NADH/ADP/Pi is being sent to the ETC from the TCA cycle and glycolysis)
What type of exercise utilised the ETC?
Prolonged endurance exercise
When are the alternative energy pathways (that make glucose) activated?
After 10-18hr fasting, during prolonged exercise, or when energy in the cell is low - little ATP
What happens to lactate in the Cori Cycle?
It is reconverted back into pyruvate
What are the 4 major substrates used in gluconeogenesis?
Amino acids (glutamate and alanine)
Lactate
Glycerol
How many irreversible reactions does gluconeogenesis need to overcome to create glucose?
Three
What is the end product of the pentode phosphate pathway?
Ribulose 5-C
Peptides and phosphates
What energy does the pentode phosphate pathway generate?
2 x NADPH
What is gluconeogenesis?
A metabolic pathway that results in the generation of glucose from certain non-carb cabin substrates
When is gluconeogenesis up regulated?
When glucose is not consumed (a prime time for this is during sleep)
Gluconeogenesis is also activated after 30-45 min of steady state exercise
How can gluconeogenesis be inhibited?
Consume a sports drink
What is the free amino acid pool? And what feeds into it?
It represent the AAs in the circulation and extracellular fluids
Protein we eat feeds into it as we do not store any protein
What is transamination?
It is the process by which other amino acids (not ones consumed in diet) are formed
What is oxidative deamination?
Removing the amino group from the newly formed AA resulting from transamination
What is the urea cycle? Why and where does it occur? (Can’t fins answer for second question)
It is the removal of ammonia
It occurs to remove excess amino acids
Slide 31, lecture 8, what you really need to know slide
Bottom point
What are the processes involved in protein turnover?
Synthesis (generation of new muscle) and degradation (removal of old muscle)
Why is protein synthesis important for athletes?
Protein synthesis and degradation can help an athlete become stronger and achieve their desired level of muscle
Recap, lecture 9
The basic process of building new proteins - the difference between transcription and translation
What is a codon? (Protein synthesis)
A sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis
What is an anti-codon (protein synthesis)
Sequences of nucleotides that are complementary to codons
What is tRNA? (Protein synthesis)
Transfer RNAs main function is to deliver amino acids required for the process of protein synthesis
What are the two main pathways for protein degradation?
Lysosomal pathway
Ubiquitin pathway
When is ATP generation greater with lipids than carbohydrates?
At rest
During prolonged low intensity exercise
What are the metabolic processes involved in lipolysis? Lecture 10
What you really need to know slide
Can’t find
What are the processes involved in beta oxidation?
The carnitine shuttle
What does Malonyl CoA do and why is it relevant?
Is it an important regulator of the carnitine Acyl transferase I enzyme. This dictates how much fat is getting into the mitochondrial matrix for beta oxidation to occur
Less Malonyl CoA allows for more beta-oxidation to occur
How lipid metabolism is regulated?
Hormones such as glucagon/insulin
These hormones stimulate lipase enzymes to split the TAGs into glycerol and FFA
Lipid metabolism during different intensity and durational exercise
High intensity - low
Low intensity - high
Definition of lipolysis
The breakdown of fats and other lipids by hydrolysis to release fatty acids
When is lipolysis up regulated
During low intensity prolonged exercise
When is lipolysis inhibited?
During high intensity exercise
Definition of beta oxidation
The process by which fatty acids are broken down to generate Acetyl CoA
When is beta oxidation up regulated?
During exercise
When is beta oxidation inhibited?
During rest
Process of fatty acid synthesis - should be drawn out
Under lecture 11
How are fatty acids stored?
Triglycerides
When would FA be promoted?
Doesn’t make sense
Lecture 11, what you really need to know slide
How are triglycerides formed?
Joining three fatty acids together with a glycerol
What are ketone bodies?
There’s three different main ketone bodies - only produced in small quantities
They are a fuel source for the brain when glucose stores are low
When are ketone bodies increased in the body?
When glucose levels are low
What is lipogenesis?
The metabolic process through which Acetyl - CoA is converted to triglyceride for storage in fat
When is FA synthesis up regulated?
When there is excess glucose and/or a decrease in FA availability
When is FA synthesis inhibited?
When there are plenty of fatty acids in the cell
What is lipolysis?
The breakdown of triglycerides
Only the liver can use glucose to make glycogen but muscle can convert what to glycogen?
Glucose-6-P
What is the main difference between the sequential and concerted models?
The sequential model allows for mixed molecules
