Grade 10 general science – The Cell Quiz
1. Which of the following is a correct statement from the cell theory?
One of the main points of cell theory is that cells come from pre-existing cells by cell division. Not all cells have a nucleus (bacteria do not), organisms can be multicellular, and spontaneous generation is incorrect.
2. Which organelle is the site of most ATP production in a eukaryotic cell?
Mitochondria are the sites of aerobic respiration and produce most of the cell's ATP. Ribosomes make proteins, Golgi packages them, and ER is involved in synthesis and transport.
3. Which cell structure contains chlorophyll and carries out photosynthesis in plant cells?
Chloroplasts contain chlorophyll and are the site of photosynthesis in plant cells. Mitochondria produce ATP, vacuoles store substances, and lysosomes break down waste.
4. Which structure gives plant cells a definite shape and strength?
The cell wall, made mainly of cellulose in plants, provides rigidity and protection. The cell membrane controls movement of substances, the nucleus stores genetic material, and the Golgi modifies proteins.
5. What is osmosis?
Osmosis specifically refers to the passive movement of water across a partially permeable membrane from higher to lower water concentration (or lower to higher solute concentration). The other options describe different processes.
6. Which cell structure mainly controls entry and exit of substances into and out of the cell?
The cell membrane is selectively permeable and regulates transport of materials. The nucleus holds genetic material, cytoplasm is the matrix of the cell, and the cell wall (in plants) provides support but does not control selective transport.
7. Which organelle is responsible for protein synthesis?
Ribosomes are the sites where amino acids are assembled into proteins according to mRNA instructions. Lysosomes digest material, chloroplasts photosynthesize, and centrioles assist in cell division in animals.
8. Which best describes mitosis?
Mitosis is nuclear division that produces two genetically identical nuclei with the same chromosome number as the parent. Fusion of gametes is fertilisation, production of four different cells describes meiosis, and exchange in bacteria is conjugation.
9. Which organelle modifies, sorts and packages proteins for secretion?
The Golgi apparatus processes and packages proteins and lipids for transport or secretion. Mitochondria produce energy, ribosomes synthesise proteins, and the nucleolus makes ribosomal RNA.
10. Which structure is NOT present in a typical bacterial cell?
Bacteria are prokaryotes and lack a true nucleus; their DNA is not enclosed in a nuclear membrane. They do have a cell membrane, ribosomes, and many have a cell wall.
11. Which human cell type carries oxygen around the body?
Red blood cells (erythrocytes) contain haemoglobin that binds and transports oxygen. Neutrophils and lymphocytes are white blood cells involved in defence; platelets are involved in blood clotting.
12. Which of these is an example of a unicellular organism commonly studied in schools?
Amoeba is a single-celled organism. Sunflowers, frogs and human tissues are multicellular organisms.
13. What is a major function of the large central vacuole in plant cells?
The plant vacuole stores water and solutes and maintains turgor pressure which keeps the plant rigid. Protein synthesis occurs at ribosomes, ATP at mitochondria, and cells move by other means.
14. Which microscope is commonly used in Kenyan school laboratories to observe cell shape and some internal structures?
Compound light microscopes are common in school labs and allow observation of cell shape and some organelles. Electron microscopes give much higher detail but are not commonly available in schools.
15. Which cell structure stores the cell's hereditary information (DNA) in most eukaryotic cells?
The nucleus contains chromosomes made of DNA in eukaryotic cells. Mitochondria have their own small DNA but are not the main store; ribosomes make proteins and vacuoles store materials.
16. Which type of endoplasmic reticulum is associated with ribosomes and protein synthesis?
Rough ER has ribosomes attached and is involved in synthesis and initial folding of proteins. Smooth ER lacks ribosomes and is involved in lipid synthesis and detoxification.
17. Which statement best describes active transport across a cell membrane?
Active transport requires energy (ATP) to move substances against their concentration gradient (from low to high). Movement from high to low without energy is passive transport; osmosis is water movement.
18. Which organelle contains digestive enzymes used to break down worn-out organelles and waste?
Lysosomes contain hydrolytic enzymes that digest cellular waste and damaged organelles. Chloroplasts photosynthesise, the nucleus stores DNA, and the Golgi packages materials.
19. Which two structures are present in plant cells but generally absent in animal cells?
Plant cells have chloroplasts for photosynthesis and a rigid cell wall made of cellulose; animal cells do not. Mitochondria, ribosomes, nucleus, membrane, Golgi and lysosomes are found in both (though abundance may vary).
20. Why do very large cells tend to divide rather than just grow bigger?
As a cell grows its volume increases faster than its surface area, making diffusion of nutrients and wastes less efficient. To maintain efficient exchange, cells divide. The other options are incorrect.
21. Which structure is hair-like and used for movement and feeding in Paramecium?
Paramecium moves and feeds using many short hair-like cilia. Pseudopodia are used by amoebae, flagella are longer whip-like structures used by some cells, and cell walls are rigid coverings in plants.
22. What are chromosomes mainly made of?
Chromosomes consist of long DNA molecules packaged with proteins (histones) to form chromatin. Carbohydrates, lipids, RNA or minerals are not the main structural components.
23. Which process allows oxygen to move from air into leaf cells without the use of energy?
Oxygen moves by diffusion from an area of higher concentration (air spaces) to lower concentration (inside cells) without energy. Active transport requires energy, endocytosis is bulk uptake of materials, and osmosis is water movement.
24. Which feature is a key difference between prokaryotic and eukaryotic cells?
Eukaryotes have a true nucleus and membrane-bound organelles. Prokaryotes lack these structures. The other statements are incorrect generalisations.
25. Which statement about multicellular organisms is correct?
In multicellular organisms cells differentiate and specialise (e.g., muscle, nerve, blood cells) to carry out particular tasks. Not all cells are identical, multicellular organisms can be large, and cells still divide for growth and repair.
26. Which statement is part of the cell theory taught in Kenyan basic science?
One key point of cell theory is that new cells are produced by division of existing cells; the other options contradict established biology.
27. What is the main function of the nucleus in a typical plant or animal cell?
The nucleus contains DNA which stores genes and controls cell activities; ATP production is mainly mitochondrial, digestion is by lysosomes, and light capture is by chloroplasts.
28. Which organelle is primarily responsible for producing most of the cell's energy (ATP)?
Mitochondria carry out cellular respiration to produce ATP, whereas Golgi modifies proteins, ribosomes make proteins, and cell wall provides support.
29. Where does photosynthesis take place in green plant cells such as a maize leaf?
Chloroplasts contain chlorophyll and are the site of photosynthesis; mitochondria carry out respiration and lysosomes digest waste.
30. Which structure provides rigid support and protection to plant cells but is absent from animal cells?
Plant cells have a rigid cell wall made of cellulose for support; cell membrane is in both cell types and centrioles are typically in animal cells.
31. What is the main role of the cell membrane?
The cell membrane is selectively permeable and regulates transport; storage of starch is in plastids or vacuoles, and ribosomes are made in the nucleolus.
32. Which organelle is the site of protein synthesis?
Ribosomes translate mRNA to make proteins; smooth ER is involved in lipid synthesis, Golgi modifies and packages proteins, and vacuoles store substances.
33. Which of these distinguishes prokaryotic cells from eukaryotic cells?
Prokaryotes (like bacteria) have no membrane-bound nucleus; they do not have mitochondria or chloroplasts and are usually unicellular.
34. Which structure modifies, sorts and packages proteins for secretion or use in the cell?
The Golgi apparatus processes and packages proteins and lipids; ribosomes make proteins and mitochondria produce energy.
35. What is the function of a large central vacuole in plant cells?
Plant vacuoles store water and dissolved substances and maintain turgor; protein synthesis is by ribosomes and digestion by lysosomes.
36. Which process describes the movement of water across a partially permeable membrane from a region of high water concentration to low water concentration?
Osmosis is specifically the movement of water across a membrane; diffusion is for solutes, and active transport requires energy.
37. Diffusion is best described as:
Diffusion is passive movement down a concentration gradient and does not require energy; active transport moves against a gradient.
38. Which statement about active transport is true?
Active transport uses ATP to move ions or molecules against their concentration gradient and can occur in many cell types including root cells.
39. In animal cells which organelle contains enzymes that digest worn-out organelles and foreign materials?
Lysosomes contain hydrolytic enzymes for intracellular digestion; chloroplasts perform photosynthesis and ribosomes make proteins.
40. Which structure is present in plant cells but not in most animal cells and helps in photosynthesis and storage of starch?
Plastids (including chloroplasts and amyloplasts) are plant organelles for photosynthesis and starch storage; flagella, centrosomes and cilia are typical of some animal cells or protists.
41. What is the role of the rough endoplasmic reticulum (RER)?
RER has ribosomes and is involved in protein synthesis and transport; lipid synthesis and detoxification are functions of smooth ER.
42. Which of the following best describes chromosomes?
Chromosomes are made of DNA and contain genes which determine characteristics; the other options describe organelles or functions that chromosomes do not perform.
43. A microscope has an eyepiece lens of 10x and an objective lens of 40x. What is the total magnification?
Total magnification is the product of eyepiece and objective magnifications: 10 x 40 = 400.
44. Which cell process results in two daughter cells genetically identical to the parent cell and is important for growth?
Mitosis divides the nucleus and cytokinesis divides the cytoplasm producing two identical daughter cells; meiosis produces genetically different gametes.
45. Which molecule makes up the main structural component of the cell membrane?
Cell membranes consist mainly of a phospholipid bilayer with proteins; cellulose is in cell walls and peptidoglycan is in bacterial cell walls.
46. Which of the following best explains cell specialization (differentiation)?
Differentiation produces specialized cells (like root hair cells or muscle cells) with specific structures for their roles while still using DNA.
47. What is found in bacterial cells but not in animal cells?
Many bacteria have plasmids (small circular DNA) and lack membrane-bound organelles found in eukaryotes such as nuclei, mitochondria, or chloroplasts.
48. Which of these best describes the cytoplasm of a cell?
Cytoplasm contains organelles and is the site of many chemical reactions; the rigid covering is the cell wall and chromosomes are stored in the nucleus in eukaryotes.
49. Which process moves glucose into a cell when its concentration outside is lower than inside and requires energy?
Active transport uses ATP to move substances like glucose against a concentration gradient; diffusion and facilitated diffusion are passive and move down gradients.
50. Which organelle is responsible for packaging materials into vesicles for transport within or out of the cell in plant or animal cells found in Kenyan schools?
The Golgi apparatus modifies and packages proteins and lipids into vesicles for transport; the nucleolus makes ribosomal RNA.