🔬 Biology — Cell Biology and Physiology

1. Who first observed and named the 'cell' after examining thin slices of cork under a microscope?

1. Robert Brown
2. Robert Hooke
3. Matthias Schleiden
4. Rudolf Virchow

Robert Hooke examined thin slices of cork in 1665 and, seeing box-like compartments, was the first to use the term 'cell'. (JAMB recommended text — Ndu, Ndu & Ememe/Ramalingam 'Modern Biology for Senior Secondary Schools' (history of the cell), aligned to JAMB Biology Syllabus 'The cell')

2. Which of the following structures is present in a plant cell but absent in a typical animal cell?

1. Mitochondrion
2. Nucleus
3. Cellulose cell wall
4. Ribosome

Plant cells possess a rigid cellulose cell wall, a large central vacuole and chloroplasts, structures absent in typical animal cells. (JAMB UTME Biology Syllabus, 'Structure and functions of cell components; differences between plant and animal cells')

3. Which cell organelle controls the metabolic activities of the cell and carries the hereditary material?

1. Nucleus
2. Golgi apparatus
3. Lysosome
4. Centriole

The nucleus controls the cell's metabolic activities and carries the hereditary material in the form of chromosomes/DNA. (JAMB UTME Biology Syllabus, 'Cell structure and functions of cell components — the nucleus')

4. The mitochondrion is described as the 'powerhouse of the cell' because it is mainly the site of which process?

1. Protein synthesis
2. Photosynthesis
3. Storage of cell sap
4. Aerobic respiration and ATP production

Mitochondria are the site of aerobic respiration, where energy is released and trapped as ATP, earning them the name 'powerhouse of the cell'. (JAMB UTME Biology Syllabus, 'Cell components and their functions')

5. Which organelle contains chlorophyll and is the site of photosynthesis in a green plant cell?

1. Mitochondrion
2. Chloroplast
3. Ribosome
4. Vacuole

Chloroplasts contain chlorophyll and are the organelles in which photosynthesis takes place in green plant cells. (JAMB UTME Biology Syllabus, 'Cell components' and 'Nutrition — photosynthesis')

6. Which cell organelle is responsible for protein synthesis?

1. Ribosome
2. Golgi apparatus
3. Lysosome
4. Chloroplast

Ribosomes, whether free in the cytoplasm or attached to the rough endoplasmic reticulum, are the sites of protein synthesis in the cell. (JAMB UTME Biology Syllabus, 'Structure and functions of cell components')

7. In the equation 6CO2 + 6H2O → C6H12O6 + 6O2, which two conditions must be present for photosynthesis to occur?

1. Heat and oxygen
2. Water and ATP
3. Light and chlorophyll
4. Enzymes and pH

The overall photosynthesis equation proceeds only in the presence of light energy and the pigment chlorophyll. (JAMB UTME Biology Syllabus, 'Nutrition — Photosynthesis (process and products)')

8. During aerobic respiration, glucose is completely oxidised using oxygen to release carbon dioxide, water and what else?

1. Lactic acid
2. Ethanol
3. Chlorophyll
4. A large amount of energy

Aerobic respiration completely oxidises glucose using oxygen, releasing carbon dioxide, water and a large amount of energy (about 38 ATP). (JAMB UTME Biology Syllabus, 'Respiration — aerobic and anaerobic respiration')

9. Which statement correctly describes the products of anaerobic respiration in yeast and in mammalian muscle?

1. Yeast produces lactic acid; muscle produces ethanol and carbon dioxide
2. Yeast produces ethanol and carbon dioxide; muscle produces lactic acid
3. Both yeast and muscle produce ethanol and carbon dioxide
4. Both yeast and muscle produce lactic acid

In anaerobic respiration, yeast ferments glucose to ethanol and carbon dioxide, while mammalian muscle converts glucose to lactic acid; both release comparatively little energy. (JAMB UTME Biology Syllabus, 'Respiration — anaerobic respiration in yeast and muscle')

10. The net movement of molecules or ions from a region of higher concentration to a region of lower concentration, without the use of metabolic energy, is called:

1. Diffusion
2. Active transport
3. Osmosis
4. Mitosis

Diffusion is the net movement of molecules or ions down a concentration gradient and does not require energy. (JAMB UTME Biology Syllabus, 'Movement of substances — diffusion, osmosis and active transport')

11. Which statement correctly describes how active transport differs from diffusion?

1. It moves substances down a concentration gradient without using energy
2. It occurs only in plant cell walls
3. It moves substances against a concentration gradient using ATP
4. It is restricted to the movement of water molecules across membranes

Unlike diffusion, active transport moves substances from a region of lower to higher concentration and requires metabolic energy supplied by ATP. (JAMB UTME Biology Syllabus, 'Movement of substances — active transport')

12. A cell dividing by mitosis produces two daughter cells that are:

1. Genetically identical to the parent cell, but with half the chromosome number
2. Four in number and haploid
3. Genetically different from the parent cell
4. Genetically identical to the parent cell, with the same (diploid) chromosome number

Mitosis produces two daughter cells that are genetically identical to the parent and retain the diploid chromosome number, unlike meiosis which produces four haploid cells. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

13. Which organ is the principal site for the removal of nitrogenous waste from the blood in mammals?

1. Liver
2. Kidney
3. Lung
4. Skin

The kidney is the principal excretory organ in mammals, responsible for removing nitrogenous waste such as urea from the blood. (JAMB UTME Biology Syllabus, 'Excretion — excretory organs in animals')

14. What name is given to the structural and functional unit of the kidney where filtration and reabsorption occur?

1. Neuron
2. Alveolus
3. Nephron
4. Villus

The nephron is the structural and functional unit of the kidney, where filtration and reabsorption of substances occur. (JAMB UTME Biology Syllabus, 'Excretion — structure and function of the kidney/nephron')

15. What is the main nitrogenous waste product excreted by the human kidney?

1. Urea
2. Uric acid
3. Ammonia
4. Glucose

Urea, formed in the liver from excess amino acids, is the main nitrogenous waste product excreted by the human kidney. (JAMB UTME Biology Syllabus, 'Excretion — nitrogenous waste products')

16. The process by which blood pressure forces small molecules from the glomerulus into the Bowman's capsule is known as:

1. Selective reabsorption
2. Osmosis
3. Secretion
4. Ultrafiltration

Ultrafiltration is the process by which blood pressure forces small molecules from the glomerulus into the Bowman's capsule. (JAMB UTME Biology Syllabus, 'Excretion — kidney function: ultrafiltration and reabsorption')

17. Which excretory structure is characteristic of insects such as the grasshopper and cockroach?

1. Nephridia
2. Malpighian tubules
3. Contractile vacuole
4. Kidney

Malpighian tubules are the excretory structures found in insects such as the grasshopper and cockroach. (JAMB UTME Biology Syllabus, 'Excretion — excretory organs in animals (invertebrates)')

18. Osmoregulation is best defined as:

1. The regulation of blood glucose level
2. The regulation of body temperature
3. The regulation of the water and solute (salt) content of body fluids
4. The regulation of the rate of respiration

Osmoregulation refers to the control of the water and solute concentration of an organism's body fluids to maintain internal balance. (JAMB UTME Biology Syllabus, 'Excretion and osmoregulation')

19. Which hormone increases the permeability of the distal tubule and collecting duct to water, thereby concentrating the urine?

1. Antidiuretic hormone (ADH)
2. Insulin
3. Adrenaline
4. Thyroxine

Antidiuretic hormone increases the permeability of the distal tubule and collecting duct to water, reducing water loss and concentrating the urine. (JAMB UTME Biology Syllabus, 'Osmoregulation — hormonal control of water balance')

20. In the freshwater protozoan Amoeba, excess water entering the cell by osmosis is expelled mainly by the:

1. Nucleus
2. Cell membrane alone
3. Mitochondria
4. Contractile vacuole

In freshwater Amoeba, excess water that enters by osmosis is collected and expelled by the contractile vacuole. (JAMB UTME Biology Syllabus, 'Osmoregulation in unicellular organisms')

21. Birds and insects mainly excrete nitrogenous waste as a semi-solid paste in order to conserve water. This waste product is:

1. Ammonia
2. Uric acid
3. Urea
4. Carbon dioxide

Birds and insects excrete nitrogenous waste mainly as uric acid, a semi-solid, low-toxicity paste that conserves water. (JAMB UTME Biology Syllabus, 'Excretion — nitrogenous waste products in different organisms')

22. The process that returns useful substances such as glucose and some water from the nephron filtrate back into the blood is called:

1. Ultrafiltration
2. Tubular secretion
3. Selective reabsorption
4. Egestion

Selective reabsorption returns useful substances such as glucose, amino acids and some water from the filtrate back into the blood along the nephron. (JAMB UTME Biology Syllabus, 'Excretion — kidney function: reabsorption')

23. Ammonia is the main nitrogenous waste of most bony fish mainly because:

1. It is highly soluble and toxic but can be rapidly diluted and removed by the surrounding water
2. It requires large amounts of energy to conserve water
3. It is the least toxic nitrogenous waste, so no dilution is needed
4. It conserves water better than urea or uric acid

Ammonia is very toxic and highly soluble, but aquatic animals can safely excrete it because the surrounding water immediately dilutes and carries it away. (JAMB UTME Biology Syllabus, 'Excretion — nitrogenous waste products in aquatic organisms')

24. Which sequence correctly represents the order of processes occurring during urine formation in the nephron?

1. Selective reabsorption, then ultrafiltration, then tubular secretion
2. Tubular secretion, then ultrafiltration, then selective reabsorption
3. Selective reabsorption, then tubular secretion, then ultrafiltration
4. Ultrafiltration, then selective reabsorption, then tubular secretion

Urine formation begins with ultrafiltration at the glomerulus, followed by selective reabsorption of useful substances and then tubular secretion of additional wastes. (JAMB UTME Biology Syllabus, 'Excretion — stages of urine formation in the nephron')

25. What is the main purpose of mitosis in multicellular organisms?

1. Growth and repair of body tissues
2. Formation of gametes for sexual reproduction
3. Reduction of the chromosome number by half
4. Introduction of new genetic combinations

Mitosis produces two genetically identical diploid daughter cells, which are used for growth, tissue repair and asexual reproduction. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

26. At the end of mitosis, how many daughter cells are produced and what is their chromosome number compared to the parent cell?

1. Two daughter cells with the same (diploid) chromosome number as the parent
2. Four daughter cells with half the chromosome number of the parent
3. Two daughter cells with half the chromosome number of the parent
4. Four daughter cells with the same chromosome number as the parent

Mitosis produces two daughter cells that are genetically identical to the parent cell and retain the same diploid chromosome number. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

27. Meiosis results in the formation of how many daughter cells from one parent cell?

1. Four haploid daughter cells
2. Two diploid daughter cells
3. Two haploid daughter cells
4. One diploid daughter cell

Meiosis involves two successive divisions of a diploid parent cell, producing four haploid daughter cells with half the chromosome number. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

28. Which type of cell division is responsible for the formation of gametes (sex cells) in animals and plants?

1. Meiosis
2. Mitosis
3. Binary fission
4. Budding

Meiosis reduces the chromosome number by half, producing haploid gametes that restore the diploid number at fertilization. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

29. A human somatic cell with a diploid number of 46 chromosomes undergoes meiosis. How many chromosomes will each resulting daughter cell contain?

1. 23
2. 46
3. 92
4. 12

Meiosis halves the chromosome number, so each of the four daughter cells produced from a diploid cell with 46 chromosomes will contain 23 chromosomes. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

30. During which stage of mitosis do the chromosomes line up singly along the equatorial plate of the cell?

1. Metaphase
2. Prophase
3. Anaphase
4. Telophase

In metaphase, chromosomes attach to spindle fibres and align at the cell's equator in preparation for separation. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

31. What event takes place during anaphase of mitosis?

1. Sister chromatids separate and move to opposite poles of the cell
2. Chromosomes condense and become visible for the first time
3. The nuclear membrane reforms around each set of chromosomes
4. Homologous chromosomes pair up along the equator

In anaphase, the centromeres split and spindle fibres pull the sister chromatids apart towards opposite poles of the cell. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

32. Crossing over, an important source of genetic variation, occurs between which structures during meiosis I?

1. Non-sister chromatids of homologous chromosomes
2. Sister chromatids of the same chromosome
3. Centrioles located at opposite poles
4. Ribosomes and the nuclear membrane

During prophase I of meiosis, homologous chromosomes pair up and exchange segments between their non-sister chromatids, producing new combinations of alleles. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

33. Which sequence correctly describes the order of stages in mitosis?

1. Prophase, Metaphase, Anaphase, Telophase
2. Metaphase, Prophase, Telophase, Anaphase
3. Anaphase, Telophase, Prophase, Metaphase
4. Telophase, Anaphase, Metaphase, Prophase

Mitosis proceeds in the order prophase, metaphase, anaphase and telophase, followed by cytokinesis. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

34. Meiosis is completed through two successive nuclear divisions. What are these two divisions called?

1. Meiosis I and Meiosis II
2. Prophase and Telophase
3. Interphase and Cytokinesis
4. Mitosis I and Mitosis II

Meiosis I separates homologous chromosomes and meiosis II separates sister chromatids, together producing four haploid cells. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')

35. Apart from halving the chromosome number, why is meiosis important for sexually reproducing organisms?

1. It introduces genetic variation among offspring through crossing over and independent assortment
2. It duplicates the chromosome number to support growth
3. It prevents the formation of gametes in the gonads
4. It ensures that all offspring are genetically identical to the parent

Crossing over and the independent assortment of homologous chromosomes during meiosis generate new gene combinations, increasing genetic variation in offspring. (JAMB UTME Biology Syllabus, 'Cell division — mitosis and meiosis')