Practice MDCAT Biology Cell Structure and Function MCQs with explanations — PMC, ETEA, NUMS entry test preparation.
Q1. During the cytokinesis of a plant cell, a student identifies the first layer to be deposited between the two newly formed daughter cells.
Answer: Middle lamella
Explanation: Middle lamella is the first layer formed during cytokinesis; the primary wall is tempting but it develops after the middle lamella.
Q2. A researcher analyzing the plasma membrane identifies a conjugate molecule consisting of a carbohydrate covalently bonded to a lipid.
Answer: Glycolipids
Explanation: Glycolipids are carbohydrate-lipid conjugates; glycoproteins are tempting but involve proteins rather than lipids as the base molecule.
Q3. While observing a staining pattern in a eukaryotic nucleus, a technician notices a non-membranous, dense body responsible for rRNA synthesis.
Answer: Nucleolus
Explanation: The nucleolus is the site of ribosomal RNA synthesis; the chromatin is tempting but it contains the genetic blueprints instead.
Q4. A biochemist isolates ribosomes from a human liver cell and determines the sedimentation coefficients of their two distinct subunits.
Answer: 40S and 60S
Explanation: Eukaryotic ribosomes consist of 40S and 60S subunits; 30S and 50S are tempting but are specific to prokaryotic cells.
Q5. In a patient suffering from drug overdose, which organelle in the liver cells would be most active in detoxifying the harmful chemicals?
Answer: Smooth Endoplasmic Reticulum
Explanation: SER is primarily responsible for detoxification in the liver; RER is tempting but focuses on protein synthesis instead.
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