3.3 Nutrition and energy systems Flashcards
Annotate a diagram of the ultrastructure of a generalized animal cell
Ribosomes: protein synthesis
Rough Endoplasmic Reticulum: protein synthesis
Lysosomes: digestion and waste
Golgi Apparatus: Package, sort, transport of proteins
Mitochondrion: ATP synthesis
Nucleus: storing genetic information
Annotate a diagram of the ultrastructure of a mitochondrion
Outer membrane
Inner membrane
cristae
matrix
Cell Respiration
The controlled release of energy in the form of Adenosine Triphosphate (ATP) from organic compounds in cells.
Explain how adenosine can gain and lose a phosphate molecule
Gaining a Phosphate Molecule:
Process: Adenosine gains a phosphate molecule through phosphorylation, resulting in the formation of ATP (adenosine triphosphate).
Mechanism: In the mitochondria, adenosine diphosphate (ADP) combines with an inorganic phosphate (Pi) through the action of the enzyme ATP synthase during cellular respiration or phosphorylation processes. This addition of a phosphate group converts ADP into ATP, which stores energy for cellular functions.
Losing a Phosphate Molecule:
Process: Adenosine loses a phosphate molecule through dephosphorylation, converting ATP into ADP.
Mechanism: When ATP is used for energy, it is hydrolysed by the enzyme ATPase. The reaction removes one phosphate group from ATP, producing ADP and releasing energy that the cell uses for various processes. This reaction is crucial for providing the energy needed for muscle contraction, active transport, and other cellular activities.
Adenosine gains a phosphate molecule to form ATP, which stores energy, and loses a phosphate molecule to form ADP, releasing energy for cellular functions.
Explain the role of ATP in muscle contraction
Energy Supply: ATP provides the necessary energy for muscle contraction by enabling the interaction between actin and myosin filaments.
Cross-Bridge Cycling: ATP binds to myosin heads, allowing them to detach from actin and reset for another cycle, facilitating the repeated pulling action that shortens the muscle.
Calcium Pumping: ATP powers the calcium pumps in the sarcoplasmic reticulum, which actively transport calcium ions back into storage, helping the muscle relax after contraction.
Maintenance of Contraction: ATP is essential for maintaining the contraction and preventing muscle fatigue by replenishing energy stores during intense activity.
Describe the re-synthesis of ATP by the ATP-CP system
Creatine phosphate
- High energy molecule
- broken down
- to provide a phosphate molecule for the resynthesis of ATP which has been used up during initial stages of exercise.
Explain the phenomena of O2 deficit and O2 debt
O2 debt: known as EPOC: Excess Post-exercise Oxygen Consumption
O2 Deficit:
Definition: The lag in oxygen uptake at the start of exercise where the body’s oxygen consumption is lower than the required level for the activity.
Mechanism: During the initial phase of exercise, the body cannot immediately increase oxygen supply to match energy demands, leading to an oxygen deficit. The body relies on anaerobic energy systems, such as glycolysis, to meet energy needs until aerobic metabolism catches up.
O2 Debt:
Definition: The amount of additional oxygen required post-exercise to restore the body to its pre-exercise state and repay the oxygen deficit.
Mechanism: After exercise, the body continues to consume oxygen at an elevated rate to replenish depleted energy stores, clear lactate, and restore normal metabolic functions. This elevated oxygen consumption is referred to as excess post-exercise oxygen consumption (EPOC), or O2 debt.
Describe the production of ATP from glucose and fatty acids by the aerobic system
In the presence of oxygen
- pyruvate is processed by the Krebs cycle (in mitochondria)
- liberating Hydrogen ions for the Electron Transport Chain
- Releasing ATP
In the presence of Oxygen
- fatty acids are broken down by beta oxidation
- liberating a greater number of electrons
- therefore generating more ATP
Protein is only ever used in extreme cases to generate ATP
Discuss the characteristics of the 3 energy systems and their relative contribution during exercise
- All energy systems work to resynthesise ATP
-The system which is most dominant depends on the intensity, duration and recovery opportunities in the exercise.
ATP-PC System
0 - 10 or 12sec
at 95-100% max effort
Fuel: PC
Stored: muscle
Recovery: 50% 30 sec or 100% 3-7 mins
Lactic Acid System
30-90 sec
85-95% effort
Fuel: Glucose
Stored: as glycogen in liver & muscles
Recovery: Active - 24hrs, Passive - 48hrs
By products (taken out during recovery): removal of H ions and lactates
Aerobic Glycolysis
2 min +
60-85%
Fuel: Glucose
Stored: as glycogen in muscles and liver
Recovery: 24-48 hrs
Lipolysis
below 60%
2 mins +
no recovery needed
Lipids (triglycerides)
Stored: Muscle adipose tissue
** poppy add amount of ATP produced
Evaluate the relative contributions of the 3 energy systems during different types of exercise
