muscle contraction

• What are the two main components of the actin filament?

  Actin and the troponin complex

  
• What is the effect of calcium ions binding to troponin in the muscle contraction cycle?

  • Calcium ions cause tropomyosin to shift
  • This exposes the myosin binding sites on actin

  
• What happens to ATP during the muscle contraction cycle?

  ATP is hydrolyzed

  
• What is released when the myosin head binds to actin during the power stroke?

  Inorganic phosphate $(P_i)$ and ADP

  
• How do the two heads of a myosin molecule work during muscle contraction?

  They work independently, with only one head attaching to actin at a given time

  
• Why does the thin filament move in the direction of its (-) end during the power stroke?

  Because the myosin head is firmly attached and pulls the thin filament towards its (-) end

  
• What are the key components shown in the image?

  • DNA double helix structure
  • Nucleotide monomers
  • Phosphate-sugar backbone
  • Hydrogen bonds between base pairs
  • Base pairing rules

  
• What are the two main types of muscle filaments in sarcomeres?

  Myosin and Actin

  
• What is the name of the dark bands in sarcomeres that are composed primarily of $myosin?$


  A band

  
• What is the name of the light bands in sarcomeres that are composed primarily of $actin?$


  I band

  
• What is the primary function of $myosin$ in muscle contraction?


  Generates force for muscle contraction by forming cross-bridges with $actin$ filaments

  
• What is the role of $actin$ in muscle contraction?


  To be pulled by $myosin$ cross-bridges, leading to muscle shortening

  
• How do $myosin$ and $actin$ filaments interact to cause muscle contraction?


  By forming cross-bridges that pull $actin$ filaments inward and repeat this cycle

  
• What structures mark the boundaries between sarcomeres?

  Z lines

  
• What are the main structural components of a sarcomere?

  • $myosin$ filaments (A band)
  • $actin$ filaments (I band)
  • Z lines

  
• What happens to the sarcomere length during muscle contraction?

  The sarcomere shortens

  
• How does the sarcomere structure change during muscle contraction?

  • The sarcomere shortens.
  • The H zone and I band both shorten.
  • The A band remains constant.

  
• What are the aerobic conditions for cellular respiration?

  • Oxygen is available

  
• What is the first stage of aerobic cellular respiration called?

  Glycolysis

  
• What is the outcome of the glycolysis stage in aerobic cellular respiration?

  • Converts one glucose molecule into two pyruvic acid molecules
  • Produces $2 \, ATP$

  
• In which cellular compartment does glycolysis occur?

  Cytosol

  
• What molecule is the input for the glycolysis stage?

  Glucose

  
• What molecule is the primary output of glycolysis?

  Pyruvic acid

  
• How many ATP are produced during glycolysis?

  2 ATP

  
• Which stage of cellular respiration occurs after glycolysis?

  Citric acid cycle

  
• What is the electron transport chain used for in aerobic cellular respiration?

  It is used to generate ATP through oxidative phosphorylation.

  
• What are the main outcomes of the citric acid cycle and electron transport chain in aerobic respiration?

  • Produces $34 \, ATP$
  • Produces $CO_2$
  • Produces $H_2O$

  
• What are the waste products generated during aerobic respiration?

  $CO_2$ and $H_2O$

  
• How many ATP are produced during the citric acid cycle and electron transport chain?

  34 ATP

  
• What is the primary function of adenosine triphosphate (ATP) in cells?

  • ATP serves as the main energy currency of the cell.
  • It powers many cellular processes.
  • It is produced through cellular respiration.

  
• How is ATP typically produced in cells?

  • Through cellular respiration.
  • Involves glycolysis, citric acid cycle, and oxidative phosphorylation.

  
• What is the main energy currency of the cell?

  Adenosine triphosphate (ATP)

  
• What are the three main processes involved in cellular respiration?

  Glycolysis, citric acid cycle, and oxidative phosphorylation

  
• What are the end products of glycolysis?

  $2$ ATP and $2$ NADH

  
• What is the main role of NADH in cellular respiration?

  It carries electrons to the electron transport chain

  
• Where does the citric acid cycle occur in the cell?

  In the mitochondrial matrix

  
• What are the main products of the citric acid cycle?

  • $2$ ATP
  • $6$ NADH
  • $2$ FADH₂
  • $4$ $CO_2$

  
• What are the main end products of the citric acid cycle?

  2 ATP, 6 NADH, 2 FADH₂, and 4 $CO_2$

  
• How is ATP produced in oxidative phosphorylation?

  • Through the electron transport chain and chemiosmosis.
  • NADH and FADH₂ deliver electrons.
  • Protons are pumped across the inner mitochondrial membrane.
  • ATP synthase utilizes the proton gradient to synthesize ATP.

  
• What two main components are involved in oxidative phosphorylation?

  Electron transport chain and chemiosmosis