Bio 112 Exam Verified Exam Questions and Answers Latest update
2026/2027
Question:
Nervous system aids animals in sensing and responding to stimuli
Answer:
Internal and external
Question:
Neuron
Answer:
a nerve cell; the basic building block of the nervous system
Question:
Postsynaptic cell
Answer:
muscle fibers (aka muscle cell)
Question:
Presynaptic neuron
Answer:
Motor neuron
Question:
Synapse
Answer:
Neuromuscular junction
Question:
Neurotransmitter
Answer:
acetylcholine
Question:
Where signals are recieved
Answer:
motor end plate, contains ligand-gated Na+ channels
,Question:
All muscles use actin and myosin to produce contractions
Answer:
skeletal and cardiac have a striated/striped appearance because actin and myosin arranged in regular,
repeating units
- smooth has irregular arrangement actin and myosin
- the arrangement of these filaments differs between muscle types- affects appearance under a
microscope
Question:
Muscle fibers
Answer:
are compromised pf many myofibrils but sarcomeres are the repeating functional unit that gives the
striated appearance
Question:
Myofibril
Answer:
parallel arrangement of actin and myosin
Question:
Each sarcomere contains..
Answer:
overlapping thin filaments (actin) and thick filaments (myosin)
Question:
Structure of a sarcomere
Answer:
Z discs anchor thin filaments (actin) and titin holds thick filaments (myosin) in place
Question:
Length of sarcomere
Answer:
changes by changing amount of overlap between actin and myosin
*neither length of myosin or length of actin changes
, Question:
Thin (actin) filament
Answer:
Actin has binding sites for myosin and is associated with a protein called tropomyosin
Question:
Thick (myosin) filament
Answer:
The globular heads of myosin are what bind actin -> forms a cross- bridge between the two
Question:
How we are able to do this has to do with structural features of actin and myosin proteins
Answer:
muscle relaxed (NO signal from neuron) -> tropomyosin blocks myosin binding sites -> no sliding
Question:
During contraction
Answer:
tropomyosin gets moved -> cycles of bind actin, power and stroke, and detach from actin
*involves converting energy stored in ATP to kinetic energy (movement)
Question:
How does tropomyosin get moved to allow myosin to bind actin?
Answer:
tropomyosin's position is regulated by the troponin complex
-> Ca2+ binding is what regulates the troponin complex
Question:
Excitation- contraction coupling
Answer:
signal from a motor neuron (excitation) leads to contraction (i.e., Ca2+ only gets released when the
muscle fiber receives a signal)
Question:
Ca2+ is stored in the...
Answer:
Sarcoplasmic reticulum (SR) surrounding myofibrils (recall 1 muscle fiber is compromised of many
myofibrils)
2026/2027
Question:
Nervous system aids animals in sensing and responding to stimuli
Answer:
Internal and external
Question:
Neuron
Answer:
a nerve cell; the basic building block of the nervous system
Question:
Postsynaptic cell
Answer:
muscle fibers (aka muscle cell)
Question:
Presynaptic neuron
Answer:
Motor neuron
Question:
Synapse
Answer:
Neuromuscular junction
Question:
Neurotransmitter
Answer:
acetylcholine
Question:
Where signals are recieved
Answer:
motor end plate, contains ligand-gated Na+ channels
,Question:
All muscles use actin and myosin to produce contractions
Answer:
skeletal and cardiac have a striated/striped appearance because actin and myosin arranged in regular,
repeating units
- smooth has irregular arrangement actin and myosin
- the arrangement of these filaments differs between muscle types- affects appearance under a
microscope
Question:
Muscle fibers
Answer:
are compromised pf many myofibrils but sarcomeres are the repeating functional unit that gives the
striated appearance
Question:
Myofibril
Answer:
parallel arrangement of actin and myosin
Question:
Each sarcomere contains..
Answer:
overlapping thin filaments (actin) and thick filaments (myosin)
Question:
Structure of a sarcomere
Answer:
Z discs anchor thin filaments (actin) and titin holds thick filaments (myosin) in place
Question:
Length of sarcomere
Answer:
changes by changing amount of overlap between actin and myosin
*neither length of myosin or length of actin changes
, Question:
Thin (actin) filament
Answer:
Actin has binding sites for myosin and is associated with a protein called tropomyosin
Question:
Thick (myosin) filament
Answer:
The globular heads of myosin are what bind actin -> forms a cross- bridge between the two
Question:
How we are able to do this has to do with structural features of actin and myosin proteins
Answer:
muscle relaxed (NO signal from neuron) -> tropomyosin blocks myosin binding sites -> no sliding
Question:
During contraction
Answer:
tropomyosin gets moved -> cycles of bind actin, power and stroke, and detach from actin
*involves converting energy stored in ATP to kinetic energy (movement)
Question:
How does tropomyosin get moved to allow myosin to bind actin?
Answer:
tropomyosin's position is regulated by the troponin complex
-> Ca2+ binding is what regulates the troponin complex
Question:
Excitation- contraction coupling
Answer:
signal from a motor neuron (excitation) leads to contraction (i.e., Ca2+ only gets released when the
muscle fiber receives a signal)
Question:
Ca2+ is stored in the...
Answer:
Sarcoplasmic reticulum (SR) surrounding myofibrils (recall 1 muscle fiber is compromised of many
myofibrils)
