They shrink because water leaves them
Explication
In a concentrated salt or sugar solution, water moves out of the cells by osmosis, causing them to shrink. In plain water, the cells would swell instead.
Protein synthesis
Explication
Ribosomes are the sites of protein synthesis, either free in the cytoplasm or attached to the endoplasmic reticulum. They do not store lipids or replicate DNA.
Leucoplast
Explication
Leucoplasts are colourless plastids that store food materials such as starch, oils, or proteins. Chromoplasts contain pigments, while chloroplasts carry out photosynthesis.
Four gametes with half the chromosome number and genetic variation
Explication
Meiosis is a two-step division in reproductive organs that forms four gametes, each with half the chromosome number and increased genetic variation. The other choices describe mitosis or incorrectly reduce meiosis to one division.
Cells
Explication
Hooke examined cork and named the box-like structures he saw "cells." The other options refer to different biological levels or structures.
It modifies, sorts, and packages proteins or lipids
Explication
The Golgi apparatus processes and packages proteins and lipids into vesicles for transport or secretion. ATP production and DNA storage are functions of other organelles.
The diffusion of water across a selectively permeable membrane
Explication
Osmosis is specifically the diffusion of water across a selectively permeable membrane. It is not the movement of all particles or the release of energy.
An entangled mass of thread-like DNA-protein material
Explication
Chromatin is the loose, thread-like DNA-protein material found when the cell is not dividing. Chromosomes are the condensed rod-shaped form seen before division.
They release energy from glucose during cellular respiration
Explication
Mitochondria release energy from glucose during cellular respiration, and that energy is stored in ATP. The other choices describe different organelles or functions.
Ribosomal subunits
Explication
The nucleolus is the site where ribosomal subunits are synthesized. These later combine to form ribosomes in the cytoplasm.
It produces two genetically identical daughter cells for growth and repair
Explication
Mitosis produces two daughter cells that are genetically identical to the parent cell, which is why it is important for growth and repair. The other options describe meiosis or a mix-up between the two processes.
400×
Explication
Total magnification is calculated by multiplying eyepiece magnification by objective magnification, so 10× × 40× = 400×. This is a direct application of the microscope rule.
Mémorisez les réponses avec 12 flashcards sur Fundamentals of Cell Structure and Division.
Cell discovery — who?
Robert Hooke observed cells in 1665.
Microscope types — two?
Light and electron microscopes.
Cell membrane — role?
Protects cell and controls substance passage.
Consultez la fiche de révision complète sur Fundamentals of Cell Structure and Division.
Voir la fiche →Importe ton cours et l'IA génère des QCM avec corrections en 30 secondes.
Générateur de QCM