Biology Cellular and Molecular 1 — Questions and Answers
Question 1: What is the powerhouse of the cell?
- Nucleus
- Mitochondria (Correct answer)
- Ribosome
- Endoplasmic Reticulum
Correct answer: Mitochondria
Mitochondria are famously known as the 'powerhouses of the cell' because they are the primary sites for cellular respiration. During this metabolic process, mitochondria generate adenosine triphosphate (ATP), which is the main energy currency that fuels nearly all cellular activities and functions.
Question 2: Which molecule carries the genetic instructions in most living organisms?
- Protein
- Lipid
- DNA (Correct answer)
- RNA
Correct answer: DNA
Deoxyribonucleic acid (DNA) is the fundamental molecule that carries the complete genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses. It contains the blueprint for synthesizing proteins and regulating cellular activities, making it the central repository of hereditary information.
Question 3: What process describes the movement of water across a selectively permeable membrane?
- Diffusion
- Osmosis (Correct answer)
- Active Transport
- Endocytosis
Correct answer: Osmosis
Osmosis is a specialized type of passive diffusion that specifically describes the net movement of water molecules across a selectively permeable membrane. This movement occurs from an area of higher water concentration (lower solute concentration) to an area of lower water concentration (higher solute concentration) to achieve equilibrium.
Question 4: What is the primary function of ribosomes in a cell?
- Producing energy
- Synthesizing proteins (Correct answer)
- Storing genetic information
- Packaging and shipping molecules
Correct answer: Synthesizing proteins
Ribosomes are essential cellular organelles responsible for protein synthesis, a process also known as translation. They read the genetic code carried by messenger RNA (mRNA) and use this information to accurately assemble amino acids into specific protein chains, which then perform various functions within the cell.
Question 5: Which phase of the cell cycle involves DNA replication?
- G1 phase
- S phase (Correct answer)
- G2 phase
- M phase
Correct answer: S phase
The S phase, or synthesis phase, is a critical stage within the interphase of the cell cycle. During this phase, the cell meticulously replicates its entire genome, ensuring that each chromosome is duplicated to form two sister chromatids. This DNA replication is essential to provide each daughter cell with a complete and identical set of genetic material after cell division.
Biology Cellular and Molecular 1
What is the powerhouse of the cell?