Class 9 Practice Level 3 – Set 1 – The Fundamental Unit of Life Leave a Comment / By Gulam Hamza / August 26, 2024 Class 9 Practice Level 3 – Set 1 - The Fundamental Unit of Life Total questions: 15 1. Which of the following statements best explains the fluid mosaic model of the cell membrane? Topic: Cell Membrane Dynamics The cell membrane is a rigid structure composed of proteins and lipids. The cell membrane is composed of a lipid bilayer with embedded proteins that can move laterally. The cell membrane contains a static arrangement of carbohydrates and lipids. The cell membrane is impermeable to all substances. None 2. Which of the following is not a product of the light-dependent reactions of photosynthesis? Topic: Photosynthesis ATP NADPH Oxygen Glucose None 3. Which enzyme is responsible for unwinding the DNA helix during replication? Topic: Nucleic Acids DNA polymerase Helicase Ligase Primase None 4. During translation, the codon AUG codes for which amino acid? Topic: Protein Synthesis Serine Glycine Methionine Proline None 5. Which stage of cellular respiration produces the most ATP? Topic: Cellular Respiration Glycolysis Krebs cycle Electron transport chain Fermentation None 6. Which molecule acts as a second messenger in many signal transduction pathways? Topic: Signal Transduction Pathways ATP AMP DNA RNA None 7. The G1 checkpoint in the cell cycle is primarily influenced by Topic: Cell Cycle Control The size of the cell The availability of nutrients DNA damage All of the above None 8. Which transport mechanism involves the movement of water molecules through a semi-permeable membrane? Topic: Membrane Transport Active transport Facilitated diffusion Osmosis Endocytosis None 9. Cellular differentiation is primarily regulated by: Topic: Cellular Differentiation Environmental factors Genetic factors Both a and b None of the above None 10. Which of the following factors does not affect enzyme activity? Topic: Enzyme Function pH Temperature Substrate concentration Light intensity None 11. In which part of the mitochondria does the Krebs cycle occur? Topic: Cellular Respiration Outer membrane Inner membrane Matrix Intermembrane space None 12. The sodium-potassium pump is an example of: Topic: Cell Membrane Passive transport Facilitated diffusion Active transport Osmosis None 13. Which photosynthetic pigment is most directly involved in the conversion of light energy to chemical energy? Topic: Photosynthetic Pigments Chlorophyll a Chlorophyll b Carotenoids Xanthophylls None 14. The genetic code is described as degenerate because: Topic: Genetic Code It has multiple codons for a single amino acid It contains stop codons It has start codons universal None 15. Which molecule is the final electron acceptor in the electron transport chain? Topic: Cellular Respiration NAD+ FAD Oxygen Water None 1 out of 15 Time's up
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