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.