Online Test — Respiration and Circulation
40 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 40
Cellular respiration mainly breaks down which food substance to release energy?
Glucose
Water
Oxygen
Vitamins
Explanation: Respiration breaks down glucose to release energy stored as ATP.
Question 2 of 40
The energy released in respiration is stored in molecules of:
DNA
ATP
Chlorophyll
Bile
Explanation: ATP is the cell's energy currency, storing released energy.
Question 3 of 40
Aerobic respiration takes place in the presence of:
Carbon dioxide
Oxygen
Nitrogen
Sunlight
Explanation: Aerobic respiration requires oxygen to break glucose down completely.
Question 4 of 40
The products of aerobic respiration are carbon dioxide, water, and:
Glucose
Energy (ATP)
Oxygen
Starch
Explanation: Aerobic respiration releases CO₂, water, and energy (about 38 ATP).
Question 5 of 40
Most aerobic respiration occurs in the:
Nucleus
Mitochondria
Vacuole
Cell wall
Explanation: Mitochondria, the powerhouses of the cell, are the main site of aerobic respiration.
Question 6 of 40
Anaerobic respiration is the breakdown of glucose:
With plenty of oxygen
Without oxygen
Using sunlight
In the nucleus
Explanation: Anaerobic respiration releases energy from glucose without oxygen.
Question 7 of 40
Anaerobic respiration releases about how many ATP per glucose?
38
2
100
0
Explanation: Without oxygen, glucose is only partly broken down, giving about 2 ATP.
Question 8 of 40
Anaerobic respiration in human muscles produces:
Alcohol
Lactic acid
Oxygen
Glucose
Explanation: Muscles produce lactic acid during anaerobic respiration.
Question 9 of 40
The products of anaerobic respiration in yeast are:
Lactic acid only
Ethanol and carbon dioxide
Water and oxygen
Glucose and oxygen
Explanation: Yeast produces ethanol (alcohol) and carbon dioxide.
Question 10 of 40
The build-up of which substance causes muscle ache after hard exercise?
Alcohol
Lactic acid
Glucose
Bile
Explanation: Lactic acid build-up in muscles causes the aching, cramping feeling.
Question 11 of 40
As air passes through the nasal cavity, it is:
Cooled and dried
Warmed, moistened, and filtered
Digested
Turned into oxygen
Explanation: The nasal cavity warms, moistens, and filters incoming air.
Question 12 of 40
The windpipe, kept open by C-shaped cartilage rings, is the:
Bronchus
Trachea
Alveolus
Oesophagus
Explanation: The trachea (windpipe) is held open by cartilage rings.
Question 13 of 40
The trachea divides into two tubes called:
Alveoli
Bronchi
Bronchioles
Villi
Explanation: The trachea divides into two bronchi, one for each lung.
Question 14 of 40
Gas exchange in the lungs takes place in the:
Bronchi
Trachea
Alveoli
Nose
Explanation: The alveoli are the tiny air sacs where gases are exchanged.
Question 15 of 40
When we breathe in, the diaphragm:
Flattens (contracts)
Rises into a dome
Disappears
Stops moving
Explanation: During inhalation the diaphragm flattens, enlarging the chest.
Question 16 of 40
Gases are exchanged between the alveoli and blood by the process of:
Active pumping
Diffusion
Digestion
Filtration
Explanation: Gas exchange occurs by diffusion from higher to lower concentration.
Question 17 of 40
At the alveoli, oxygen moves:
From blood into the air
From the air into the blood
In both directions equally
Nowhere
Explanation: Oxygen diffuses from the alveolar air into the blood.
Question 18 of 40
Diffusion of a gas takes place from a region of ______ to ______ partial pressure.
Lower; higher
Higher; lower
Equal; equal
Cold; hot
Explanation: Gases diffuse from higher to lower partial pressure (concentration).
Question 19 of 40
Oxygen is carried in the blood mainly by:
Plasma only
Haemoglobin in red blood cells
White blood cells
Platelets
Explanation: Haemoglobin in red blood cells binds and transports oxygen.
Question 20 of 40
Haemoglobin releases its oxygen mainly at the:
Alveoli
Body tissues (low oxygen)
Trachea
Nose
Explanation: In oxygen-poor tissues, haemoglobin releases oxygen to the cells.
Question 21 of 40
The muscular organ that pumps blood around the body is the:
Lung
Heart
Kidney
Liver
Explanation: The heart pumps blood through the circulatory system.
Question 22 of 40
The human heart has how many chambers?
Two
Three
Four
Five
Explanation: The heart has four chambers: two atria and two ventricles.
Question 23 of 40
The lower chambers of the heart that pump blood out are the:
Atria
Ventricles
Valves
Capillaries
Explanation: The ventricles are the lower chambers that pump blood out.
Question 24 of 40
"Double circulation" means the blood passes through the heart:
Once per circuit
Twice per circuit
Never
Only at rest
Explanation: In double circulation blood passes through the heart twice per full circuit.
Question 25 of 40
The circuit that carries blood from the heart to the lungs is the:
Systemic circuit
Pulmonary circuit
Digestive circuit
Lymphatic circuit
Explanation: The pulmonary circuit carries blood between the heart and lungs.
Question 26 of 40
The pale-yellow liquid part of blood that carries dissolved substances is:
Plasma
Haemoglobin
Platelets
Bile
Explanation: Plasma is the liquid part of blood that transports many substances.
Question 27 of 40
Which blood cells carry oxygen using haemoglobin?
White blood cells
Red blood cells
Platelets
Plasma cells
Explanation: Red blood cells contain haemoglobin and carry oxygen.
Question 28 of 40
The blood cells that defend the body against germs are the:
Red blood cells
White blood cells
Platelets
Plasma
Explanation: White blood cells fight germs and protect against infection.
Question 29 of 40
Platelets in the blood mainly help in:
Carrying oxygen
Clotting of blood
Digesting food
Producing hormones
Explanation: Platelets help the blood clot and seal wounds.
Question 30 of 40
The four blood groups of the ABO system are:
X, Y, Z, W
A, B, AB, O
Rh, Hb, Pl, Pl
1, 2, 3, 4
Explanation: The ABO system has blood groups A, B, AB, and O.
Question 31 of 40
Blood vessels that carry blood away from the heart are:
Veins
Arteries
Capillaries
Valves
Explanation: Arteries carry blood away from the heart.
Question 32 of 40
Which blood vessels have valves to prevent backflow of blood?
Arteries
Veins
Capillaries
None
Explanation: Veins have valves because their blood is at low pressure.
Question 33 of 40
The smallest blood vessels, with walls one cell thick, are:
Arteries
Veins
Capillaries
Bronchi
Explanation: Capillaries are the thinnest vessels, where exchange occurs.
Question 34 of 40
Exchange of gases, food, and wastes between blood and cells occurs in the:
Arteries
Veins
Capillaries
Heart
Explanation: The one-cell-thick capillaries allow exchange with the cells.
Question 35 of 40
Compared with veins, arteries have walls that are:
Thinner and weaker
Thicker and more muscular
The same
Made of valves
Explanation: Arteries have thick, muscular walls to withstand high pressure.
Question 36 of 40
The pale fluid that drains from the tissues into lymph vessels is called:
Plasma
Lymph
Bile
Urine
Explanation: Lymph is the fluid (from leaked plasma) that drains into lymph vessels.
Question 37 of 40
Small bean-shaped structures that filter lymph and trap germs are:
Alveoli
Lymph nodes
Villi
Nephrons
Explanation: Lymph nodes filter lymph and house white blood cells.
Question 38 of 40
Lymph is moved through the lymph vessels mainly by:
The heart's pumping
Squeezing of nearby muscles
Gravity only
Breathing only
Explanation: Lymph is not pumped by the heart; muscle movement squeezes it along.
Question 39 of 40
The lymphatic system is especially important for the body's:
Digestion
Immunity (defence)
Breathing
Eyesight
Explanation: The lymphatic system plays a major role in immunity.
Question 40 of 40
Lymph nodes often swell when the body is:
Resting
Fighting an infection
Sleeping
Growing taller
Explanation: Nodes swell as white blood cells multiply to fight an infection.