Practice 148 Bioenergetics MCQs — Page 1 of 3
Question 1: The Krebs cycle takes place in the:
- A Inner mitochondrial membrane
- B Thylakoid membrane
- C Mitochondrial matrix
- D Cytoplasm
Explanation: Krebs cycle enzymes are in the mitochondrial matrix. Useful for: MDCAT 2027, NUMS 2027.
Question 2: The light reactions of photosynthesis occur in the:
- A Stroma
- B Thylakoid membranes
- C Cytosol
- D Mitochondrial matrix
Explanation: Thylakoids contain the photosystems. Useful for: MDCAT 2027, NUMS 2027.
Question 3: The Calvin cycle takes place in the:
- A Mitochondrial matrix
- B Cytoplasm
- C Thylakoid membrane
- D Stroma
Explanation: The Calvin cycle fixes CO2 in the chloroplast stroma. Useful for: MDCAT 2027, NUMS 2027.
Question 4: The net ATP gain from glycolysis per glucose molecule is:
- A 2 ATP
- B 4 ATP
- C 36 ATP
- D 0 ATP
Explanation: Glycolysis uses 2 ATP and produces 4, a net of 2. Useful for: MDCAT 2027, NUMS 2027.
Question 5: The final electron acceptor in aerobic respiration is:
- A Carbon dioxide
- B NAD+
- C Oxygen
- D Water
Explanation: Oxygen accepts electrons at the end of the electron transport chain. Useful for: MDCAT 2027, NUMS 2027.
Question 6: Which bond joins amino acids in a protein?
- A Peptide bond
- B Hydrogen bond
- C Ester bond
- D Glycosidic bond
Explanation: Amino acids are linked by peptide bonds. Useful for: MDCAT 2027, NUMS 2027.
Question 7: Which carbohydrate is the storage form of glucose in animals?
- A Glycogen
- B Cellulose
- C Starch
- D Chitin
Explanation: Glycogen is stored in the liver and muscles. Useful for: MDCAT 2027, NUMS 2027.
Question 8: Which lipid is a membrane component and a precursor of steroid hormones?
- A Cellulose
- B Cholesterol
- C Triglyceride
- D Keratin
Explanation: Cholesterol is the precursor of steroid hormones. Useful for: MDCAT 2027, NUMS 2027.
Question 9: Cellulose is a polymer of:
- A Fructose
- B α-glucose
- C Galactose
- D β-glucose
Explanation: Cellulose consists of β-1,4-linked glucose units. Useful for: MDCAT 2027, NUMS 2027.
Question 10: Which bond joins adjacent nucleotides in a DNA strand?
- A Peptide bond
- B Phosphodiester bond
- C Ionic bond
- D Hydrogen bond
Explanation: The sugar-phosphate backbone is formed by phosphodiester bonds. Useful for: MDCAT 2027, NUMS 2027.
Question 11: Which organelle is responsible for modifying, packaging and secreting proteins?
- A Lysosome
- B Peroxisome
- C Golgi apparatus
- D Centriole
Explanation: The Golgi apparatus processes and sorts proteins for secretion. Useful for: MDCAT 2027, NUMS 2027.
Question 12: Which organelle contains hydrolytic enzymes for intracellular digestion?
- A Ribosome
- B Lysosome
- C Nucleolus
- D Centrosome
Explanation: Lysosomes break down waste and cellular debris. Useful for: MDCAT 2027, NUMS 2027.
Question 13: The fluid mosaic model of the plasma membrane was proposed by:
- A Robert Hooke
- B Singer and Nicolson
- C Schleiden and Schwann
- D Watson and Crick
Explanation: Singer and Nicolson proposed it in 1972. Useful for: MDCAT 2027, NUMS 2027.
Question 14: Which structure is present in plant cells but absent in animal cells?
- A Mitochondria
- B Cell wall
- C Ribosomes
- D Plasma membrane
Explanation: Plant cells have a cellulose cell wall. Useful for: MDCAT 2027, NUMS 2027.
Question 15: The movement of water across a semi-permeable membrane is called:
- A Exocytosis
- B Endocytosis
- C Active transport
- D Osmosis
Explanation: Osmosis is the diffusion of water from higher to lower water potential. Useful for: MDCAT 2027, NUMS 2027.
Question 16: During which stage of mitosis do sister chromatids separate?
- A Prophase
- B Telophase
- C Metaphase
- D Anaphase
Explanation: Chromatids are pulled apart during anaphase. Useful for: MDCAT 2027, NUMS 2027.
Question 17: Crossing over occurs during which phase of meiosis?
- A Anaphase II
- B Metaphase I
- C Prophase I
- D Telophase I
Explanation: Homologous chromosomes exchange segments in prophase I. Useful for: MDCAT 2027, NUMS 2027.
Question 18: The lock-and-key model of enzyme action was proposed by:
- A Eduard Buchner
- B Emil Fischer
- C Daniel Koshland
- D Louis Pasteur
Explanation: Fischer proposed it in 1894. Useful for: MDCAT 2027, NUMS 2027.
Question 19: A molecule that competes with the substrate for the active site is a:
- A Product
- B Coenzyme
- C Cofactor
- D Competitive inhibitor
Explanation: Competitive inhibitors resemble the substrate. Useful for: MDCAT 2027, NUMS 2027.
Question 20: The optimum pH of pepsin is approximately:
- A 7
- B 5
- C 9
- D 2
Explanation: Pepsin works best in the acidic stomach. Useful for: MDCAT 2027, NUMS 2027.
Question 21: Natural selection as a mechanism of evolution was proposed by:
- A Charles Darwin
- B Jean-Baptiste Lamarck
- C Gregor Mendel
- D Hugo de Vries
Explanation: Darwin presented it in 1859. Useful for: MDCAT 2027, NUMS 2027.
Question 22: Who proposed the double helix model of DNA?
- A Griffith
- B Hershey and Chase
- C Meselson and Stahl
- D Watson and Crick
Explanation: Watson and Crick proposed it in 1953. Useful for: MDCAT 2027, NUMS 2027.
Question 23: Which codon is the universal start codon?
- A UAG
- B UGA
- C UAA
- D AUG
Explanation: AUG codes for methionine and starts translation. Useful for: MDCAT 2027, NUMS 2027.
Question 24: A cross between two heterozygous tall plants (Tt × Tt) gives a phenotypic ratio of:
- A 9:3:3:1
- B 3:1
- C 1:2:1
- D 1:1
Explanation: Three tall plants appear for each dwarf plant. Useful for: MDCAT 2027, NUMS 2027.
Question 25: Down syndrome is caused by:
- A Trisomy 18
- B Trisomy 21
- C Trisomy 13
- D Monosomy X
Explanation: An extra copy of chromosome 21 causes Down syndrome. Useful for: MDCAT 2027, NUMS 2027.
Question 26: Turner syndrome has which karyotype?
- A 47, XYY
- B 45, X
- C 46, XX
- D 47, XXY
Explanation: Turner syndrome is monosomy X. Useful for: MDCAT 2027, NUMS 2027.
Question 27: Sickle cell anaemia results from a mutation in the gene for:
- A Collagen
- B Haemoglobin (beta chain)
- C Insulin
- D Keratin
Explanation: A point mutation alters the beta-globin chain. Useful for: MDCAT 2027, NUMS 2027.
Question 28: Ultrafiltration of blood in the nephron occurs in the:
- A Loop of Henle
- B Glomerulus
- C Collecting duct
- D Distal tubule
Explanation: Blood is filtered through the glomerulus into Bowman's capsule. Useful for: MDCAT 2027, NUMS 2027.
Question 29: Which hormone lowers blood calcium levels?
- A Parathyroid hormone
- B Aldosterone
- C Insulin
- D Calcitonin
Explanation: Calcitonin from the thyroid lowers blood calcium. Useful for: MDCAT 2027, NUMS 2027.
Question 30: Which hormone is released from the posterior pituitary?
- A Prolactin
- B Growth hormone
- C TSH
- D Oxytocin
Explanation: Oxytocin and ADH are released by the posterior pituitary. Useful for: MDCAT 2027, NUMS 2027.
Question 31: Which part of the brain controls balance and coordination?
- A Hypothalamus
- B Cerebellum
- C Cerebrum
- D Medulla oblongata
Explanation: The cerebellum coordinates movement and balance. Useful for: MDCAT 2027, NUMS 2027.
Question 32: The natural pacemaker of the heart is the:
- A Purkinje fibres
- B SA node
- C AV node
- D Bundle of His
Explanation: The sinoatrial node initiates each heartbeat. Useful for: MDCAT 2027, NUMS 2027.
Question 33: Which vessel carries oxygenated blood from the lungs to the heart?
- A Pulmonary vein
- B Aorta
- C Vena cava
- D Pulmonary artery
Explanation: The pulmonary vein returns oxygenated blood. Useful for: MDCAT 2027, NUMS 2027.
Question 34: Which enzyme digests proteins in the stomach?
- A Amylase
- B Pepsin
- C Lipase
- D Trypsin
Explanation: Pepsin is secreted as pepsinogen in the stomach. Useful for: MDCAT 2027, NUMS 2027.
Question 35: Gas exchange in the lungs takes place in the:
- A Alveoli
- B Bronchi
- C Trachea
- D Bronchioles
Explanation: Alveoli have thin walls and a rich capillary supply. Useful for: MDCAT 2027, NUMS 2027.
Question 36: A bacterium shaped like a rod is called a:
- A Bacillus
- B Coccus
- C Vibrio
- D Spirillum
Explanation: Bacillus means rod-shaped. Useful for: MDCAT 2027, NUMS 2027.
Question 37: The causative agent of malaria is:
- A Plasmodium
- B Entamoeba
- C Giardia
- D Trypanosoma
Explanation: Malaria is caused by Plasmodium species. Useful for: MDCAT 2027, NUMS 2027.
Question 38: HIV primarily infects which cells?
- A B cells
- B Helper T cells (CD4+)
- C Platelets
- D Red blood cells
Explanation: HIV destroys CD4+ T lymphocytes. Useful for: MDCAT 2027, NUMS 2027.
Question 39: Which tissue transports water in plants?
- A Phloem
- B Cambium
- C Parenchyma
- D Xylem
Explanation: Xylem carries water and minerals upward. Useful for: MDCAT 2027, NUMS 2027.
Question 40: The pH of 0.01 M HCl is:
- A 12
- B 1
- C 2
- D 0.01
Explanation: pH = −log(0.01) = 2. Useful for: MDCAT 2027, NUMS 2027.
Question 41: A buffer solution consists of:
- A A strong acid and a strong base
- B A weak acid and its conjugate base
- C Water and a salt
- D Two strong acids
Explanation: Buffers resist changes in pH. Useful for: MDCAT 2027, NUMS 2027.
Question 42: The conjugate base of H₂O is:
- A OH⁻
- B H₃O⁺
- C O²⁻
- D H₂
Explanation: Water loses a proton to give hydroxide. Useful for: MDCAT 2027, NUMS 2027.
Question 43: The number of neutrons in carbon-14 is:
- A 6
- B 14
- C 8
- D 7
Explanation: Neutrons = 14 − 6 = 8. Useful for: MDCAT 2027, NUMS 2027.
Question 44: Which quantum number determines the shape of an orbital?
- A Azimuthal quantum number (l)
- B Spin quantum number (s)
- C Principal quantum number (n)
- D Magnetic quantum number (m)
Explanation: The value of l determines s, p, d, f shapes. Useful for: MDCAT 2027, NUMS 2027.
Question 45: The maximum number of electrons in the third shell (n = 3) is:
- A 32
- B 8
- C 2
- D 18
Explanation: The maximum is 2n² = 18. Useful for: MDCAT 2027, NUMS 2027.
Question 46: The electronic configuration of sodium (Z = 11) is:
- A 1s² 2s² 2p⁶ 3s²
- B 1s² 2s² 2p⁵ 3s²
- C 1s² 2s² 2p⁶ 3p¹
- D 1s² 2s² 2p⁶ 3s¹
Explanation: Sodium has a single 3s electron. Useful for: MDCAT 2027, NUMS 2027.
Question 47: Isotopes of an element have the same:
- A Atomic number
- B Number of neutrons
- C Mass number
- D Physical properties
Explanation: Isotopes differ only in neutron number. Useful for: MDCAT 2027, NUMS 2027.
Question 48: Which is the simplest amino acid?
- A Serine
- B Valine
- C Alanine
- D Glycine
Explanation: Glycine has only a hydrogen as its side chain. Useful for: MDCAT 2027, NUMS 2027.
Question 49: The shape of a water molecule is:
- A Bent (V-shaped)
- B Trigonal planar
- C Tetrahedral
- D Linear
Explanation: Two lone pairs bend the molecule. Useful for: MDCAT 2027, NUMS 2027.
Question 50: The type of bond in sodium chloride is:
- A Covalent
- B Ionic
- C Metallic
- D Hydrogen
Explanation: Sodium transfers an electron to chlorine. Useful for: MDCAT 2027, NUMS 2027.
Frequently Asked Questions
How many Bioenergetics MCQs are available on TestMasterMCQs?
There are currently 148 Bioenergetics MCQs on this page, each with four options, the correct answer and a short explanation to help you understand the concept — not just memorise the answer.
Are these Bioenergetics MCQs useful for PPSC, FPSC, NTS, CSS and MDCAT?
Yes — our Bioenergetics questions follow the syllabus of common Pakistani competitive exams including CSS, PMS, PPSC, FPSC, NTS, and university entry tests like MDCAT and ECAT.
How should I practice Bioenergetics MCQs for better retention?
Attempt 15–20 questions at a time, read the explanation after every question (even the ones you get right), and revisit wrong answers after 24 hours to reinforce memory.