PCS Unit 1 Practice Test Questions and Study Guide 2026
Why is RNA thought to have been the first genetic material? - correct answer ✔✔RNA can
catalyze its own replication
Describe the main features of a synovial joint. - correct answer ✔✔Articular cartilage on bone
surface.
Joint cavity.
Articular (fibrous) capsule connecting the bones.
Synovial membrane inside the articular capsule.
Synovial fluid in the cavity (made up of lots of GAGs).
What is calcium's role in muscle contraction (excitation contraction coupling)? - correct answer
✔✔AP propagated down motor neurone.
Ca2+ channel on pre-synaptic membrane opens, Ca2+ in.
ACh vesicles move towards membrane - released into synaptic cleft.
ACh binds with post-synaptic cell (muscle).
Triggers Na+ to be release into post-synaptic cell.
,Sarcolemma propagates AP in both directions so all muscle contracted.
ACh released more than needed so guaranteed contraction.
AP along sarcolemma down transverse tubules causes sarcoplasmic reticulum to release Ca2+.
Ca2+ binds to troponin, causes movement of tropomyosin. This opens the actin binding sites.
Called exitation contraction coupling as calcium plays a role in both exitatory synapse
transmission and also a key role in physiology of contraction of muscle filaments.
What are the 4 steps of the sliding filament theory. - correct answer ✔✔1. The myosin head
binds to exposed actin binding sites in a complex with bound ADP + Pi.
2. The ADP and Pi are released and the myosin head pivots pulling the actin filament toward the
centre.
3. ATP binds to the myosin head, breaking the cross bridge.
4. ATP is hydrolysed to ADP+Pi by ATPase enzyme, this "cocks" the head back so that it is reset
and ready for another power stroke.
What is an isometric contraction? - correct answer ✔✔A contraction in which the muscle fibres
do not change length, increasing tension.
What do length tension curves show? - correct answer ✔✔They demonstrate the different
tensions of myofilaments at different sarcomere lengths.
, At rest the sarcomere length is optimal for maximum force of contraction as the most myosin
head interaction can take place.
If sarcomere is too large or small then tension decreases.
How does cardiac muscle differ from skeletal muscle? - correct answer ✔✔Myocytes are
smaller and have a single central nucleus; skeletal muscle cells are multinucleate.
Intercalated discs between myocytes to allow rapid transmission of AP's for coordinated
contraction.
Cardiac muscle tension increases with stretching (frank starling law) until "bust"; whereas
skeletal muscle is most tense at rest.
Skeletal has a rapid onset of contraction but can be rapidly fatigued, Cardiac is slow but cannot
be fatigued.
Action potential differs as cardiac muscle has pacemaker potential.
What are the 4 basic types of tissue and the specialised types of connective tissue? - correct
answer ✔✔Epithelia
Muscle
Nerve
Connective
Specialised connective:
Proper - Dense regular.
Why is RNA thought to have been the first genetic material? - correct answer ✔✔RNA can
catalyze its own replication
Describe the main features of a synovial joint. - correct answer ✔✔Articular cartilage on bone
surface.
Joint cavity.
Articular (fibrous) capsule connecting the bones.
Synovial membrane inside the articular capsule.
Synovial fluid in the cavity (made up of lots of GAGs).
What is calcium's role in muscle contraction (excitation contraction coupling)? - correct answer
✔✔AP propagated down motor neurone.
Ca2+ channel on pre-synaptic membrane opens, Ca2+ in.
ACh vesicles move towards membrane - released into synaptic cleft.
ACh binds with post-synaptic cell (muscle).
Triggers Na+ to be release into post-synaptic cell.
,Sarcolemma propagates AP in both directions so all muscle contracted.
ACh released more than needed so guaranteed contraction.
AP along sarcolemma down transverse tubules causes sarcoplasmic reticulum to release Ca2+.
Ca2+ binds to troponin, causes movement of tropomyosin. This opens the actin binding sites.
Called exitation contraction coupling as calcium plays a role in both exitatory synapse
transmission and also a key role in physiology of contraction of muscle filaments.
What are the 4 steps of the sliding filament theory. - correct answer ✔✔1. The myosin head
binds to exposed actin binding sites in a complex with bound ADP + Pi.
2. The ADP and Pi are released and the myosin head pivots pulling the actin filament toward the
centre.
3. ATP binds to the myosin head, breaking the cross bridge.
4. ATP is hydrolysed to ADP+Pi by ATPase enzyme, this "cocks" the head back so that it is reset
and ready for another power stroke.
What is an isometric contraction? - correct answer ✔✔A contraction in which the muscle fibres
do not change length, increasing tension.
What do length tension curves show? - correct answer ✔✔They demonstrate the different
tensions of myofilaments at different sarcomere lengths.
, At rest the sarcomere length is optimal for maximum force of contraction as the most myosin
head interaction can take place.
If sarcomere is too large or small then tension decreases.
How does cardiac muscle differ from skeletal muscle? - correct answer ✔✔Myocytes are
smaller and have a single central nucleus; skeletal muscle cells are multinucleate.
Intercalated discs between myocytes to allow rapid transmission of AP's for coordinated
contraction.
Cardiac muscle tension increases with stretching (frank starling law) until "bust"; whereas
skeletal muscle is most tense at rest.
Skeletal has a rapid onset of contraction but can be rapidly fatigued, Cardiac is slow but cannot
be fatigued.
Action potential differs as cardiac muscle has pacemaker potential.
What are the 4 basic types of tissue and the specialised types of connective tissue? - correct
answer ✔✔Epithelia
Muscle
Nerve
Connective
Specialised connective:
Proper - Dense regular.
