Muscles / Respiration Flashcards
Skeletal Muscles
Skeletal muscle: Muscle used for movement
- Skeletal muscle is attached to bones by tendons.
- Ligaments attach bones to bones.
Antagonistic pairs
Muscles work in antagonistic pairs and work oppositely.
What are skeletal muscles made of?
They are made from bundles of long cells called muscle fibres.
- Sarcolemma: the cell membrane of muscle fibres
- Sarcoplasm: muscle cell cytoplasm
- T tubules: these transfer electrical impulses across the muscle
- Sarcoplasmic reticulum stores calcium ions.
- Multi-nucleated cells and contain mitochondria
- Contain cylinder organelles called myofibrils that are made of filament proteins
Actin and Myosin
These are myofilaments:
- Actin: Thin myofilament
- Myosin: Thick myofilament
Dark and Light bands of myofibrils
Dark bands are covered by thick myosin Light bands contain thin actin filaments - I band: Contains only Actin - Z line: end of each sarcomere - M line: middle of the myosin filament - H zone: Only contains Myosin filament - A band: Contain both filaments
Sliding Filament Theory
Myosin and Actin slide over each other making the sarcomere contract. The simultaneous contraction of many sarcomeres causes the myofilament and muscle to contract.
- Myosin has globular heads that have actin-myosin binding sites and ATP binding site.
- Tropomyosin and Troponin are also found on the actin filament and are attached to each other.
- Unstimulated the binding site is blocked by Tropomyosin and Troponin.
- When an A.P depolarises the sarcolemma an increase of Ca+ ions into the sarcoplasm. Calcium binds to troponin causing it to change shape. Tropomyosin is pulled out of the way to expose the site
- Myosin head binds to form A.M cross bridge
- ATP is broken down to provide energy for contraction
- Energy pulls the Actin filament in a rowing action
- ATP also breaks A.M bridge, myosin detaches and troponin moves back to original shape pulling the tropomyosin with it.
- Sarcomere then lengthens
Slow twitch Vs Fast Twitch
SLOW:
- Contract slowly
- Muscles used for posture
- Good for endurance
- Energy release through aerobic respiration
- Rich in myoglobin
FAST:
- Contract fast
- Used for fast movement
- Short burst of energy and power
- Tire very fast
- Lower in myoglobin and release energy via anaerobic respiration
Aerobic Respiration
Energy is released with glucose is split into Co2, H2 and O2
- Equation: C6H12O6+6O2 = 6Co2+ Energy
- Energy released phosphorylates ADP to ATP.
Coenzymes
Coenzymes reduce or oxidise a molecule.
NAD and FAD are coenzymes that transfer hydrogen.
Glycolysis
- Occurs in the cytoplasm
- Does not require energy to occur
1) - Glucose is phosphorylated by 2ATP this creates 2 triose phosphates
2) - Triose phosphates oxidised forming 2 pyruvate molecules. - 2 NADH are formed
- 2ATP gained
Link Reaction
- Takes place in the mitochondrial matrix
1) - Pyruvate is decarboxylated - NAD is reduced changing pyruvate into acetate
- Acetate combines with Acetyl CoA.
- LINK REACTION OCCURS 2 TIMES FOR EACH GLUCOSE MOLECULE
Krebs Cycle
Occurs in the matrix of mitochondria
- Acetyl CoA combines with oxaloacetate to form citrate
- CoA is reused in Link reaction
- 6c Molecule converted to 5c and Co2 is removed and NADH is formed
- 5c molecule is converted into 4c molecule, 1 FADH molecule is produced and ATP is produced
- Citrate has now been converted into oxaloacetate
Products of Krebs
- FOR 2 MOLECULES :
- 2 CoA molecules
- Oxaloacetate
- 4Co2 moelcules
- 2ATP molecules
- 6 NADH
- 2 FADH
Oxidative Phosphorylation
Occurs in inner mitochondrial membrane
- H+ atoms from NADH and FADH split into protons and electrons
- electrons move down E.T.C losing energy at each carrier
- This energy pumps protons into the inner membrane to form the electrochemical gradient.
- Protons move back down the gradient via ATP synthase, this movement synthesises ATP from ADP
- The movement of H+ ions across the membrane to generate ATP is chemiosmosis
- Oxygen combines with O2 and Electrons
38 ATP made from one glucose molecule.
Measure Rate of Respiration
A respirometer measures vol. of oxygen being taken up in a given time.
- Two tubes containing soda lime to absorb Co2
- Use manometer with coloured dye in
- Control tube with glass balls and other with woodlice
- Leave for 20 mins
- After a decrease in volume of air in the tube with woodlice as they respire.
- This reduces pressure so the liquid will move towards them.
- Measure distance moved and calculate vol. of oxygen used in set time
