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VICBiologyQuick questions
Unit 1: How do organisms regulate their functions?
Quick questions on Cell organelles and the endosymbiotic theory: VCE 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 the major organelles?Show answer
Nucleus. Double-membrane envelope (nuclear envelope) with pores. Contains linear chromosomes (DNA + histones). The nucleolus inside makes ribosomal RNA. Function: stores the genome, controls transcription, dictates cell function.
What is plant cells vs animal cells?Show answer
Both have: nucleus, ribosomes, ER, Golgi, mitochondria, cytoskeleton, plasma membrane.
What is endosymbiotic theory?Show answer
Proposed by Lynn Margulis in the 1960s. It explains the origin of mitochondria and chloroplasts in eukaryotic cells.
What is nucleus?Show answer
Double-membrane envelope (nuclear envelope) with pores. Contains linear chromosomes (DNA + histones). The nucleolus inside makes ribosomal RNA.
What is ribosomes?Show answer
Two subunits made of rRNA and protein. Found free in the cytosol or attached to rough ER. Cytosolic ribosomes are 80S in eukaryotes; ribosomes inside mitochondria and chloroplasts are 70S.
What is rough endoplasmic reticulum?Show answer
Folded membrane network studded with ribosomes, continuous with the nuclear envelope. Function: synthesis of membrane proteins and secreted proteins; entry point to the endomembrane system.
What is smooth endoplasmic reticulum?Show answer
Same network as RER but without ribosomes. Function: lipid and steroid synthesis, detoxification (in liver cells), calcium storage (in muscle cells).
What is golgi apparatus?Show answer
Stack of flattened membrane sacs (cisternae) with a cis face (receiving from RER) and a trans face (releasing vesicles). Function: modifies, sorts and packages proteins and lipids; directs them to lysosomes, the plasma membrane, or secretion.
What is mitochondrion?Show answer
Double membrane: smooth outer, heavily folded inner (cristae) enclosing the matrix. Contains its own circular DNA and 70S ribosomes. Function: aerobic cellular respiration.
What is chloroplast?Show answer
Double membrane plus internal thylakoid membranes stacked into grana, surrounded by the stroma. Contains its own circular DNA, 70S ribosomes, and chlorophyll. Function: photosynthesis.
What is lysosome?Show answer
Single membrane-bound sac full of hydrolytic (digestive) enzymes at low internal pH. Function: digests damaged organelles (autophagy), pathogens (after phagocytosis), and worn-out macromolecules.
What is vacuole?Show answer
Membrane-bound sac. In plant cells, a large central vacuole stores water, ions, pigments and waste; it provides turgor pressure that keeps the plant rigid. Animal cells have many smaller vacuoles for storage and transport.
What is peroxisome?Show answer
Single-membrane organelle containing oxidative enzymes. Function: breaks down fatty acids and detoxifies hydrogen peroxide.
What is cytoskeleton?Show answer
Network of protein filaments (microfilaments of actin, intermediate filaments, microtubules) through the cytoplasm. Function: cell shape, organelle movement, chromosome separation (spindle in mitosis), cell division.
What is plasma membrane?Show answer
Phospholipid bilayer with proteins, cholesterol and carbohydrates. Function: semi-permeable boundary controlling what enters and leaves; cell signalling; cell recognition. (Covered in detail in the plasma membrane dot point.)