HSC Biology – Chapter 1: Cell Biology Fundamentals

50 vocabulary flashcards covering key terms and definitions from Chapter 1 of the HSC Biology First Paper lecture notes.

Theophrastus

Ancient Greek scholar honored as the “Father of Botany” for his early systematic study of plants.

Robert Hooke

English scientist who first coined the word “cell” after observing cork and published the book Micrographia in 1665.

Micrographia

Robert Hooke’s 1665 book that recorded early microscopic observations, including the discovery of cork cells.

Antonie van Leeuwenhoek

Dutch microscopist who first saw living cells such as bacteria and protozoa using handcrafted lenses.

Cell

The structural, functional, and hereditary unit of life, bounded by a semipermeable membrane and capable of self-reproduction.

Ostrich egg

The largest known single cell, measuring roughly 17 × 12.5 cm.

Mycoplasma (PPLO)

Pleuropneumonia-like organism; the smallest known living cell (about 0.1–0.3 µm).

Motor neuron (human)

The longest human cell; may extend up to about 1.37 m in length.

Oparin–Haldane hypothesis

Theory that life arose in a primordial soup of organic molecules formed in Earth’s early reducing atmosphere.

RNA world hypothesis

Proposes that self-replicating RNA molecules preceded DNA and proteins at the origin of life.

Endosymbiotic theory

Explains the origin of mitochondria and chloroplasts from free-living bacteria engulfed by ancestral eukaryotic cells.

Mitochondrion

Double-membrane organelle derived from aerobic bacteria; site of cellular respiration.

Plastid (Chloroplast)

Photosynthetic organelle that evolved from cyanobacteria; performs photosynthesis in plants.

Cell (formal definition)

“A unit of biological activity delimited by a semipermeable membrane and capable of self-reproduction” (Loewy & Siekevitz).

Father of modern cytology (P. Swanson)

Scientist credited with founding modern cell biology techniques and studies.

Cell theory

Principle that all organisms are composed of cells, the cell is the basic unit of life, and new cells arise from pre-existing cells.

Omnis cellula e cellula

Rudolf Virchow’s phrase meaning “every cell originates from another cell.”

Somatic cell

Any non-reproductive body cell involved in growth, repair, and normal functions.

Germ cell

Reproductive cell (sperm or ovum) that transmits genetic information to progeny.

Prokaryotic cell

Cell lacking a true nucleus and membrane-bound organelles; DNA resides in a nucleoid and ribosomes are 70 S.

Eukaryotic cell

Cell with a membrane-bound nucleus, organelles, histone-associated DNA, and 80 S ribosomes.

Nucleoid

Irregular region in prokaryotes where circular DNA is located.

70 S ribosome

Prokaryotic ribosome consisting of 50 S and 30 S subunits.

80 S ribosome

Eukaryotic cytoplasmic ribosome consisting of 60 S and 40 S subunits.

Operon

Cluster of genes controlled by a single promoter functioning as one transcriptional unit in prokaryotes.

Intron

Non-coding sequence within a gene removed from pre-mRNA during splicing.

Amitosis

Direct cell division without spindle formation, typical of prokaryotes.

Mitosis

Eukaryotic nuclear division producing two genetically identical diploid cells.

Cell wall

Rigid extracellular layer (plants, fungi, bacteria) that gives shape, strength, and protection.

Middle lamella

Pectin-rich cementing layer between primary walls of adjacent plant cells.

Primary cell wall

Thin, flexible first wall layer composed mainly of cellulose, hemicellulose, and glycoproteins.

Secondary cell wall

Thick, rigid layer rich in cellulose and lignin deposited internal to the primary wall.

Plasmodesmata

Cytoplasmic channels through plant cell walls that connect adjacent cells for transport and signaling.

Cellulose

Linear β-1,4-glucan polysaccharide forming microfibrils in plant cell walls.

Lignin

Complex phenolic polymer that strengthens and waterproofs secondary cell walls.

Cell membrane (Plasma membrane)

Semi-permeable phospholipid bilayer that encloses cytoplasm and regulates substance transport.

Sandwich model (Danielli–Davson)

Early membrane concept: a phospholipid bilayer sandwiched between two protein layers.

Unit membrane model

Robertson’s idea that all biological membranes share a trilaminar ultrastructure seen in electron micrographs.

Fluid Mosaic Model

Singer & Nicolson’s model describing membranes as a fluid phospholipid sea with proteins floating like icebergs.

Phospholipid

Amphipathic molecule with a hydrophilic phosphate head, glycerol, and two hydrophobic fatty acid tails forming bilayers.

Integral protein

Protein embedded within or spanning the lipid bilayer of membranes.

Peripheral protein

Protein loosely attached to the surface of a membrane.

Glycocalyx

Carbohydrate-rich layer of glycolipids and glycoproteins on the external plasma-membrane surface.

Phagocytosis

Active process by which a cell engulfs large solid particles into vesicles (“cell eating”).

Pinocytosis

Endocytic uptake of extracellular fluid and dissolved substances (“cell drinking”).

Ribosome

Non-membranous RNA–protein complex that translates mRNA into polypeptides; termed the “protein factory.”

Endoplasmic reticulum (ER)

Network of membranous tubules and sacs involved in protein and lipid synthesis and transport.

Rough ER

ER studded with ribosomes; synthesizes membrane and secretory proteins.

Smooth ER

ER lacking ribosomes; synthesizes lipids, detoxifies chemicals, and stores calcium ions.

Golgi body (Golgi apparatus)

Stack of flattened cisternae that modifies, sorts, and packages proteins and lipids for secretion or delivery within the cell.

Theophrastus

Ancient Greek scholar honored as the “Father of Botany” for his early systematic study of plants.

Robert Hooke

English scientist who first coined the word “cell” after observing cork and published the book Micrographia in 1665.

Micrographia

Robert Hooke’s 1665 book that recorded early microscopic observations, including the discovery of cork cells.

Antonie van Leeuwenhoek

Dutch microscopist who first saw living cells such as bacteria and protozoa using handcrafted lenses.

Cell

The structural, functional, and hereditary unit of life, bounded by a semipermeable membrane and capable of self-reproduction.

Ostrich egg

The largest known single cell, measuring roughly 17 \times 12.5 cm.

Mycoplasma (PPLO)

Pleuropneumonia-like organism; the smallest known living cell (about 0.1–0.3 µm).

Motor neuron (human)

The longest human cell; may extend up to about 1.37 m in length.

Oparin–Haldane hypothesis

Theory that life arose in a primordial soup of organic molecules formed in Earth’s early reducing atmosphere.

RNA world hypothesis

Proposes that self-replicating RNA molecules preceded DNA and proteins at the origin of life.

Endosymbiotic theory

Explains the origin of mitochondria and chloroplasts from free-living bacteria engulfed by ancestral eukaryotic cells.

Mitochondrion

Double-membrane organelle derived from aerobic bacteria; site of cellular respiration.

Plastid (Chloroplast)

Photosynthetic organelle that evolved from cyanobacteria; performs photosynthesis in plants.

Cell (formal definition)

“A unit of biological activity delimited by a semipermeable membrane and capable of self-reproduction” (Loewy & Siekevitz).

Father of modern cytology (P. Swanson)

Scientist credited with founding modern cell biology techniques and studies.

Cell theory

Principle that all organisms are composed of cells, the cell is the basic unit of life, and new cells arise from pre-existing cells.

Omnis cellula e cellula

Rudolf Virchow’s phrase meaning “every cell originates from another cell.”

Somatic cell

Any non-reproductive body cell involved in growth, repair, and normal functions.

Germ cell

Reproductive cell (sperm or ovum) that transmits genetic information to progeny.

Prokaryotic cell

Cell lacking a true nucleus and membrane-bound organelles; DNA resides in a nucleoid and ribosomes are 70 S.

Eukaryotic cell

Cell with a membrane-bound nucleus, organelles, histone-associated DNA, and 80 S ribosomes.

Nucleoid

Irregular region in prokaryotes where circular DNA is located.

70 S ribosome

Prokaryotic ribosome consisting of 50 S and 30 S subunits.

80 S ribosome

Eukaryotic cytoplasmic ribosome consisting of 60 S and 40 S subunits.

Operon

Cluster of genes controlled by a single promoter functioning as one transcriptional unit in prokaryotes.

Intron

Non-coding sequence within a gene removed from pre-mRNA during splicing.

Amitosis

Direct cell division without spindle formation, typical of prokaryotes.

Mitosis

Eukaryotic nuclear division producing two genetically identical diploid cells.

Cell wall

Rigid extracellular layer (plants, fungi, bacteria) that gives shape, strength, and protection.

Middle lamella

Pectin-rich cementing layer between primary walls of adjacent plant cells.

Primary cell wall

Thin, flexible first wall layer composed mainly of cellulose, hemicellulose, and glycoproteins.

Secondary cell wall

Thick, rigid layer rich in cellulose and lignin deposited internal to the primary wall.

Plasmodesmata

Cytoplasmic channels through plant cell walls that connect adjacent cells for transport and signaling.

Cellulose

Linear \beta-1,4-glucan polysaccharide forming microfibrils in plant cell walls.

Lignin

Complex phenolic polymer that strengthens and waterproofs secondary cell walls.

Cell membrane (Plasma membrane)

Semi-permeable phospholipid bilayer that encloses cytoplasm and regulates substance transport.

Sandwich model (Danielli–Davson)

Early membrane concept: a phospholipid bilayer sandwiched between two protein layers.

Unit membrane model

Robertson’s idea that all biological membranes share a trilaminar ultrastructure seen in electron micrographs.

Fluid Mosaic Model

Singer & Nicolson’s model describing membranes as a fluid phospholipid sea with proteins floating like icebergs.

Phospholipid

Amphipathic molecule with a hydrophilic phosphate head, glycerol, and two hydrophobic fatty acid tails forming bilayers.

Integral protein

Protein embedded within or spanning the lipid bilayer of membranes.

Peripheral protein

Protein loosely attached to the surface of a membrane.

Glycocalyx

Carbohydrate-rich layer of glycolipids and glycoproteins on the external plasma-membrane surface.

Phagocytosis

Active process by which a cell engulfs large solid particles into vesicles (“cell eating”).

Pinocytosis

Endocytic uptake of extracellular fluid and dissolved substances (“cell drinking”).

Ribosome

Non-membranous RNA–protein complex that translates mRNA into polypeptides; termed the “protein factory.”

Endoplasmic reticulum (ER)

Network of membranous tubules and sacs involved in protein and lipid synthesis and transport.

Rough ER

ER studded with ribosomes; synthesizes membrane and secretory proteins.