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QLDBiologyQuick questions
Unit 1: Cells and multicellular organisms
Quick questions on Cellular components and the fluid mosaic membrane (QCE Biology Unit 1)
15short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is cytosol?Show answer
Aqueous gel-like solution filling the cell. Site of glycolysis and many biosynthetic reactions.
What is cytoskeleton?Show answer
Three protein filament systems.
What is nucleus?Show answer
Bounded by a double membrane (nuclear envelope) studded with nuclear pores. Contains the linear chromosomes and the nucleolus (where ribosomal subunits are assembled). Site of DNA replication and transcription.
What are ribosomes?Show answer
Not membrane-bound. Translate mRNA into polypeptides. Free in the cytosol or bound to the rough ER.
What is mitochondrion?Show answer
Double membrane; the inner membrane is folded into cristae that increase surface area. Matrix contains the enzymes of the Krebs cycle and mitochondrial DNA. Site of aerobic respiration (Krebs cycle, electron transport chain, ATP synthesis).
What is chloroplast?Show answer
Double membrane enclosing the stroma; thylakoid membranes stacked into grana. Site of photosynthesis (light reactions on thylakoids, Calvin cycle in stroma).
What is endoplasmic reticulum?Show answer
A network of flattened sacs continuous with the nuclear envelope.
What is golgi apparatus?Show answer
A stack of flattened cisternae. Modifies, sorts and packages proteins and lipids arriving from the ER. Cis face receives, trans face dispatches.
What are vesicles?Show answer
Small membrane-bound sacs that ferry cargo between organelles and to the plasma membrane.
What are lysosomes?Show answer
Membrane-bound sacs of hydrolytic enzymes (acid hydrolases, optimal pH around 5). Digest worn organelles, phagocytosed material and (programmed) the cell itself in apoptosis.
What are vacuoles?Show answer
Membrane-bound storage sacs. Plant cells have a single large central vacuole that stores water, sugars, pigments and waste, and supports turgor pressure.
What is cell wall?Show answer
External to the plasma membrane.
What is q1?Show answer
Name the organelle responsible for each function and describe one structural feature that suits it to that function: (a) ATP synthesis, (b) modification and packaging of proteins, (c) digestion of worn organelles. [3 marks]
What is q2?Show answer
An electron micrograph of a pancreatic acinar cell shows extensive rough ER, a prominent Golgi stack and many secretory vesicles near the plasma membrane. Interpret what this organelle profile indicates about the cell's function. [3 marks]
What is q3?Show answer
Compare a plant mesophyll cell with an animal liver cell with respect to the named organelles. (a) Identify two organelles found only in the plant cell. (b) Identify two organelles abundant in the liver cell and link each to a metabolic role.