AQA/EDEXCEL / OCR A LEVEL BIOLOGY- CARDIAC
CYCLE COMPLETE COMPREHENSIVE ACTUAL
FINAL PRACTICE EXAM PREP WITH REAL WELL
ELABORATED AND MOST TESTED EVALUATION 100
PRACTICE QUESTIONS AND 100% CORRECT
VERIFIED ANSWERS FULLY SOLVED (BASED ON
OFFICIAL IDOI OUTLINE) WITH ACCURATE
RELIABLE RATIONALES PLUS APPROVED ANSWER
KEY (100% COMPLETE SOLUTIONS) LATEST
UPDATED VERSION 2026-2027 Q&A 93% SCORE AND
ABOVE INSTANT DOWNLOAD PDF
Question 1:
Which valve prevents backflow of blood from the
left ventricle into the left atrium during ventricular
systole?
A) Aortic semilunar valve
B) Pulmonary semilunar valve
C) Bicuspid (mitral) valve
D) Tricuspid valve
Correct Answer: C) Bicuspid (mitral) valve
,*Rationale: The bicuspid (mitral) valve is located
between the left atrium and left ventricle. During
ventricular systole, increased pressure in the left
ventricle forces this valve closed, preventing blood
from flowing back into the left atrium. *
Question 2:
What is the normal resting heart rate range for a
healthy adult human?
A) 20-40 beats per minute
B) 40-60 beats per minute
C) 60-100 beats per minute
D) 100-140 beats per minute
Correct Answer: C) 60-100 beats per minute
*Rationale: The sinoatrial node (SAN) initiates
impulses at approximately 60-100 times per
minute in a healthy adult at rest, establishing this
as the normal resting heart rate range. *
,Question 3:
Which structure is known as the pacemaker of the
heart?
A) Atrioventricular node (AVN)
B) Bundle of His
C) Sinoatrial node (SAN)
D) Purkyne fibres
Correct Answer: C) Sinoatrial node (SAN)
*Rationale: The sinoatrial node (SAN) is a
specialised group of cells in the wall of the right
atrium that spontaneously generates electrical
impulses, setting the basic rhythm of the heart and
earning it the title of pacemaker. *
Question 4:
During which phase of the cardiac cycle do the
semilunar valves open?
A) Atrial systole
B) Ventricular systole
, C) Atrial diastole
D) Ventricular diastole (early)
Correct Answer: B) Ventricular systole
*Rationale: During ventricular systole, the pressure
in the ventricles rises above the pressure in the
aorta and pulmonary artery, forcing the semilunar
valves open and allowing blood to be ejected from
the heart. *
Question 5:
What causes the first heart sound ('lub')?
A) Opening of the semilunar valves
B) Closing of the atrioventricular valves
C) Opening of the atrioventricular valves
D) Closing of the semilunar valves
Correct Answer: B) Closing of the atrioventricular
valves
*Rationale: The first heart sound ('lub') is produced
by the closure of the atrioventricular valves
CYCLE COMPLETE COMPREHENSIVE ACTUAL
FINAL PRACTICE EXAM PREP WITH REAL WELL
ELABORATED AND MOST TESTED EVALUATION 100
PRACTICE QUESTIONS AND 100% CORRECT
VERIFIED ANSWERS FULLY SOLVED (BASED ON
OFFICIAL IDOI OUTLINE) WITH ACCURATE
RELIABLE RATIONALES PLUS APPROVED ANSWER
KEY (100% COMPLETE SOLUTIONS) LATEST
UPDATED VERSION 2026-2027 Q&A 93% SCORE AND
ABOVE INSTANT DOWNLOAD PDF
Question 1:
Which valve prevents backflow of blood from the
left ventricle into the left atrium during ventricular
systole?
A) Aortic semilunar valve
B) Pulmonary semilunar valve
C) Bicuspid (mitral) valve
D) Tricuspid valve
Correct Answer: C) Bicuspid (mitral) valve
,*Rationale: The bicuspid (mitral) valve is located
between the left atrium and left ventricle. During
ventricular systole, increased pressure in the left
ventricle forces this valve closed, preventing blood
from flowing back into the left atrium. *
Question 2:
What is the normal resting heart rate range for a
healthy adult human?
A) 20-40 beats per minute
B) 40-60 beats per minute
C) 60-100 beats per minute
D) 100-140 beats per minute
Correct Answer: C) 60-100 beats per minute
*Rationale: The sinoatrial node (SAN) initiates
impulses at approximately 60-100 times per
minute in a healthy adult at rest, establishing this
as the normal resting heart rate range. *
,Question 3:
Which structure is known as the pacemaker of the
heart?
A) Atrioventricular node (AVN)
B) Bundle of His
C) Sinoatrial node (SAN)
D) Purkyne fibres
Correct Answer: C) Sinoatrial node (SAN)
*Rationale: The sinoatrial node (SAN) is a
specialised group of cells in the wall of the right
atrium that spontaneously generates electrical
impulses, setting the basic rhythm of the heart and
earning it the title of pacemaker. *
Question 4:
During which phase of the cardiac cycle do the
semilunar valves open?
A) Atrial systole
B) Ventricular systole
, C) Atrial diastole
D) Ventricular diastole (early)
Correct Answer: B) Ventricular systole
*Rationale: During ventricular systole, the pressure
in the ventricles rises above the pressure in the
aorta and pulmonary artery, forcing the semilunar
valves open and allowing blood to be ejected from
the heart. *
Question 5:
What causes the first heart sound ('lub')?
A) Opening of the semilunar valves
B) Closing of the atrioventricular valves
C) Opening of the atrioventricular valves
D) Closing of the semilunar valves
Correct Answer: B) Closing of the atrioventricular
valves
*Rationale: The first heart sound ('lub') is produced
by the closure of the atrioventricular valves
