Topic 7 Muscles and respiration Flashcards
Describe the structure of a myofibril
Long chain of sarcomeres attached together
Describe the structure of a sarcomere
Myosin and actin with tropomyosin and troponin bound to the actin.
Explain the role of Calcium ions in muscle contraction
Released from sarcoplasmic reticulum, bind to troponin and causes it to move which pulls tropomyosin to move away from myosin binding sites on actin so myosin can bind to actin and begin contraction
Describe the sequence of events from the arrival of a nerve impulse at the neuromuscular junction to the contraction of a muscle
Nerve impulse causes release of Ca2+ from sarcoplasmic reticulum, Ca2+ binds to troponin and causes troponin to move and tropomyosin to be pulled away from myosin binding sites on actin, Myosin binds to actin forming crosslink and releases ADP + P, Myosin head rotates towards the centre of the sarcomere, pulling actin to centre, ATP binds to myosin head which causes it to detach from actin, ATP hydrolysed to ADP + P, Myosin head rotates back to original position and forms another crosslink
Explain what would need to happen in order to get a muscle to relax following contraction
Ca2+ not being released means troponin moves back to original position so tropomyosin covers myosin binding sites again so myosin can no longer form crosslinks so Actin is no longer pulled towards middle of sarcomere causing it to return to original position
State where glycolysis takes place
Cytoplasm
State the site of glycolysis
Cytoplasm
Describe the process of glycolysis
Glucose, 2 ATP turn into ADP and glucose phosphorylated, causing it to turn into an unstable molecule and split into two 3 carbon sugars. Each 3 carbon sugars phosphorylates 2ADP into 2ATP and reduces an NAD to form NADH, 3 carbon sugar turns into pyruvate
State the ratio of glucose to pyruvate formed in glycolysis
1 : 2
State the net gain of ATP in glycolysis
2 ATP
Give a definition of decarboxylation
Removal of a carbon.
Give a definition of dehydrogenation
Removal of Hydrogen / Oxidation
Locations of the link reaction and Krebs cycle
Matrix of mitochondria
Describe the process of the link reaction
Pyruvate reduces NAD to form NADH, Pyruvate gets decarboxylated, releasing CO2 and Acetate is formed, which combines with Coenzyme A to form Acetyl coenzyme A.
Describe the process of the Krebs cycle
Acetate delivered by Acetyl coenzyme A, Acetate and oxaloacetate (4C) combine to make Citrate (6C). Citrate Reduces NAD to form NADH and gets decarboxylated, releasing CO2 and forming a 5C compound. 5C compound reduces NADH to form NADH and gets decarboxylated, releasing CO2 and forming a 4C compound. 4C compound reduces NAD, forming NADH, reduces FAD, forming FADH and causes phosphorylation of ADP to form ATP, and forms Oxaloacetate (4C). Cycle repeats
State the role of NADH and FADH
Coenzymes responsible for the transport of Hydrogen.
Explain why the link reaction and Krebs cycle can only occur if sufficient oxygen is present
Oxygen is required for oxidation of NADH and FADH to allow them to be reduced once again during the Krebs cycle.
Devise a valid and reliable method for investigating the rate of respiration at different temperatures
IV: Temperature 10, 20, 30, 40, 50 degrees
DV: distance respirometer moved in mm
CV: Time allowed for respiration (3 mins), Mung beans used.
- Mung bean with respirometer
Describe bhow you would calculate the rate of respiration of an organism in a given time period
Respirometer for 3 mins, measure respirometer at start and end of 3 mins in mm and find the difference, divide difference by 180 to find mm/s
Define stroke volume
Volume of blood released from left ventricle per beat
Define cardiac output
Volume of blood released from heart per minute
State what tidal volume is and how it is calculated using a spirometer graph
Volume breathed in/out in one breath cycle, dm^3, height of one regular spike on a spirometry graph from peak to trough.
State what breathing rate is and how it is calculated using a spirometry graph.
Number of breaths performed per minute, it is calculated by counting the number of peaks within a given time period on a spirometry graph and multiplying it to get to 60s worth of peaks
State what the minute volume is and how it is calculated using a spirometry graph
Volume of air breathed in one minute. Tidal volume x breathing rate
State what oxygen consumption is and how it is calculated using a spirometry graph
Volume of oxygen consumed within one minute of regular breathing. Caluclated by finding the difference between the heights of the first and last peaks within a minute of regular breathing on a spirometry graph
Explain how hormones bring about a response in a target cell.
Hormones bind to target cell, Transcription factors activated, Transcription factors and RNA polymerase bind to the promoter region of a specitic gene, Gene is transcribed into mRNA, mRNA translated into the protein, Protein produced determines the function of the cell.
