Bio 2301 Lecture Exam 2 Questions
with Complete Solutions
What is the sarcolemma and what role does it play with muscle contraction? -
ANSWER-Plasma membrane covering muscle fibers. It is where AP's are created.
What is the T Tubule and what role does it play with muscle contraction? -
ANSWER-Tunnel like extensions of the sarcolemma. It is how the AP travels.
What is the sarcoplasmic reticulum (SR) and what role does it play with muscle
contraction? - ANSWER-Network of fluid filled membranous enclosed tubules. It
stores calcium and myoglobin. Where the voltage gated channels are- allows
calcium channels to open and release calcium from SR
What is the sarcomere and what role does it play with muscle contraction? -
ANSWER-Arrangement of myofibrils to make a functional unit of contraction. Where
contraction happens, and where calcium goes when released from the SR. h
Explain every step of muscle contraction, from beginning with the motor neuron to
the end where filaments bind and relax. - ANSWER-1) Ach is released from the
motor neuron
2)Ach binds to nicotinic receptors on the motor end plate
3)EPSP's create AP
4)AP is generated along the sarcolemma down to the T tubules
5)Voltage gated calcium channels open and causes Ca channels in the sarcoplasmic
reticulum to open and release calcium.
6) The calcium that is released binds to troponin
7) Ca2+ concentration remains elevated in the sarcoplasm and contraction lingers
after single AP
8)ATP is required to pump Ca2+ back into the SR via active transport.
Describe muscle twitch vs tetanus. What produces the maximum force possible for
the muscle cell? - ANSWER-Twitch is a single action potential. Force is determined
by the number of units contracting and the frequency.
Tetanus is when multiple contractions are occurring.
Fused tetanus produces the greatest amount of force.
What happens when someone engages in endurance or strength exercises? What
changes are seen? What happens when someone is inactive and not using
muscles? - ANSWER-*this may not be 100% correct*
When someone is not using their muscles they atrophy. When someone engages in
strength exercises, it builds muscle endurance.
What does the term recruitment mean and when does it occur? - ANSWER-Motor
unit activation. The body needs to produce a more forceful contraction. It "recruits"
more motor units.
, What are three ways a muscle fiber/cell can produce ATP? - ANSWER-1) creatine
phosphate (CP)
2) Anaerobic glycolysis
3) Aerobic respiration (oxidative phosphorylation)
How long can each pathway supply the ATP? What path produces the most ATP
and what produces the least ATP? - ANSWER-CP/(stored ATP) lasts about 5-10
secs- least ATP
Anaerobic is used briefly after CP, converts to aerobic when O2 is available
Aerobic goes thru about 70% of maximum workout intensity and then returns to
glycolysis (most ATP)
What path requires oxygen to be present? What are typical activities of this path? -
ANSWER-Aerobic requires o2. It is a series of reactions where glucose is fully
broken down with high yield of ATP. Uses glucose, fatty acids, and amino acids.
What do the other two paths use to produce ATP? What are typical activities of this
path? - ANSWER-CP uses ADP to create an ATP providing short term energy.
Anaerobic uses glucose from glycogen breakdown. Glycolysis which produces ATP
and pyruvic acid (which goes on to produce lactic acid)
What effect does lactic acid have on a muscle? Is it what causes muscle soreness a
day or two later? - ANSWER-It diffuses into the bloodstream to create an energy
source for the liver, kidneys, and heart.
It is not what causes muscle soreness. Lactic acid is removed from muscle tissues
within 30-60 minutes. Delayed Onset Muscle Soreness (DOMS) is typically due
microtraumas of individual muscle fibers.
What is oxygen debt? Why is it important? - ANSWER-O2 debt is when the muscle
requires too much O2 and pulls from stores in hemoglobin/myoglobin. It is important
to repay said debt to replenish the hemoglobin/myoglobin levels, to allow calcium
back into the SR, and to metabolize lactic acid.
What happens with rigor mortis? - ANSWER-*may not be fully correct*
Happens hours after death. Joints and muscles stiffen.
What are the 3 skeletal muscle fiber types? - ANSWER-Slow Oxidative (IA)
Fast oxidative glycolytic (IIA)
Fast glycolytic (IIX)
Which skeletal muscle is most resistant to fatigue and used at a lower intensity? -
ANSWER-Slow Oxidative
What skeletal muscle is used for a longer duration and a higher intensity? -
ANSWER-Fast oxidative glycolytic
What skeletal muscle can be used for the shortest duration and is the least fatigue
resistant? - ANSWER-Fast glycolytic
with Complete Solutions
What is the sarcolemma and what role does it play with muscle contraction? -
ANSWER-Plasma membrane covering muscle fibers. It is where AP's are created.
What is the T Tubule and what role does it play with muscle contraction? -
ANSWER-Tunnel like extensions of the sarcolemma. It is how the AP travels.
What is the sarcoplasmic reticulum (SR) and what role does it play with muscle
contraction? - ANSWER-Network of fluid filled membranous enclosed tubules. It
stores calcium and myoglobin. Where the voltage gated channels are- allows
calcium channels to open and release calcium from SR
What is the sarcomere and what role does it play with muscle contraction? -
ANSWER-Arrangement of myofibrils to make a functional unit of contraction. Where
contraction happens, and where calcium goes when released from the SR. h
Explain every step of muscle contraction, from beginning with the motor neuron to
the end where filaments bind and relax. - ANSWER-1) Ach is released from the
motor neuron
2)Ach binds to nicotinic receptors on the motor end plate
3)EPSP's create AP
4)AP is generated along the sarcolemma down to the T tubules
5)Voltage gated calcium channels open and causes Ca channels in the sarcoplasmic
reticulum to open and release calcium.
6) The calcium that is released binds to troponin
7) Ca2+ concentration remains elevated in the sarcoplasm and contraction lingers
after single AP
8)ATP is required to pump Ca2+ back into the SR via active transport.
Describe muscle twitch vs tetanus. What produces the maximum force possible for
the muscle cell? - ANSWER-Twitch is a single action potential. Force is determined
by the number of units contracting and the frequency.
Tetanus is when multiple contractions are occurring.
Fused tetanus produces the greatest amount of force.
What happens when someone engages in endurance or strength exercises? What
changes are seen? What happens when someone is inactive and not using
muscles? - ANSWER-*this may not be 100% correct*
When someone is not using their muscles they atrophy. When someone engages in
strength exercises, it builds muscle endurance.
What does the term recruitment mean and when does it occur? - ANSWER-Motor
unit activation. The body needs to produce a more forceful contraction. It "recruits"
more motor units.
, What are three ways a muscle fiber/cell can produce ATP? - ANSWER-1) creatine
phosphate (CP)
2) Anaerobic glycolysis
3) Aerobic respiration (oxidative phosphorylation)
How long can each pathway supply the ATP? What path produces the most ATP
and what produces the least ATP? - ANSWER-CP/(stored ATP) lasts about 5-10
secs- least ATP
Anaerobic is used briefly after CP, converts to aerobic when O2 is available
Aerobic goes thru about 70% of maximum workout intensity and then returns to
glycolysis (most ATP)
What path requires oxygen to be present? What are typical activities of this path? -
ANSWER-Aerobic requires o2. It is a series of reactions where glucose is fully
broken down with high yield of ATP. Uses glucose, fatty acids, and amino acids.
What do the other two paths use to produce ATP? What are typical activities of this
path? - ANSWER-CP uses ADP to create an ATP providing short term energy.
Anaerobic uses glucose from glycogen breakdown. Glycolysis which produces ATP
and pyruvic acid (which goes on to produce lactic acid)
What effect does lactic acid have on a muscle? Is it what causes muscle soreness a
day or two later? - ANSWER-It diffuses into the bloodstream to create an energy
source for the liver, kidneys, and heart.
It is not what causes muscle soreness. Lactic acid is removed from muscle tissues
within 30-60 minutes. Delayed Onset Muscle Soreness (DOMS) is typically due
microtraumas of individual muscle fibers.
What is oxygen debt? Why is it important? - ANSWER-O2 debt is when the muscle
requires too much O2 and pulls from stores in hemoglobin/myoglobin. It is important
to repay said debt to replenish the hemoglobin/myoglobin levels, to allow calcium
back into the SR, and to metabolize lactic acid.
What happens with rigor mortis? - ANSWER-*may not be fully correct*
Happens hours after death. Joints and muscles stiffen.
What are the 3 skeletal muscle fiber types? - ANSWER-Slow Oxidative (IA)
Fast oxidative glycolytic (IIA)
Fast glycolytic (IIX)
Which skeletal muscle is most resistant to fatigue and used at a lower intensity? -
ANSWER-Slow Oxidative
What skeletal muscle is used for a longer duration and a higher intensity? -
ANSWER-Fast oxidative glycolytic
What skeletal muscle can be used for the shortest duration and is the least fatigue
resistant? - ANSWER-Fast glycolytic
