Unit 1 Principles and Applications of Biology Revision

Comprehensive vocabulary flashcards covering cell structure and organelles, microscopy, prokaryotic features, Gram staining, specialised cell adaptations, epithelial tissues, and cardiovascular/pulmonary pathology from Unit 1 Principles and Applications of Biology.

Nucleus

The membrane-bound organelle in eukaryotic cells containing genetic material in the form of DNA and chromatin.

Ribosome

The cellular organelle that serves as the site of protein synthesis.

Golgi Apparatus

The organelle composed of flattened cisternae that modifies, packages, and sorts proteins for secretion or intracellular delivery.

Lysosome

A membrane-bound organelle filled with hydrolytic digestive enzymes used to break down waste, foreign material, and cellular debris.

Smooth Endoplasmic Reticulum (SER)

The organelle lacking ribosomes that synthesises lipids, phospholipids, and carbohydrates.

Rough Endoplasmic Reticulum (RER)

An endomembrane system studded with ribosomes on its outer surface, involved in the synthesis and folding of proteins.

$80\text{S}$ Ribosomes

The size classification of ribosomes found in the cytoplasm of eukaryotic cells.

Chloroplast

The plant organelle containing thylakoids and chlorophyll that serves as the site of photosynthesis.

Centriole

The cellular organelle responsible for organising the formation of spindle fibres during cell division.

Plasmodesmata

Microscopic channels through plant cell walls that facilitate transport and communication between adjacent plant cells.

Cytoplasm

The gel-like cellular fluid within the plasma membrane where most metabolic chemical reactions take place.

Plasma Membrane

The selectively permeable phospholipid bilayer that regulates the entry and exit of substances in and out of the cell.

Nucleolus

The dense, darker region within the nucleus rich in chromatin where ribosomal RNA is synthesised and ribosome subunits are assembled.

Mitochondrion

The double-membraned organelle containing cristae that acts as the site of aerobic respiration to generate ATP.

Cell Wall

The rigid external layer found outside the plasma membrane in plant cells that provides structural support and maintains cell shape.

Vacuole

A permanent fluid-filled compartment in plant cells that stores cell sap, mineral salts, and water.

Tonoplast

The selectively permeable membrane surrounding the permanent vacuole in plant cells.

Electron Microscope

A type of microscope using an electron beam to achieve significantly higher magnification and resolving power than a light microscope.

Resolution

The minimum distance between two points at which they can still be distinguished as separate entities under a microscope.

Actual Size Calculation

The relationship defined by $\text{Actual Size} = \frac{\text{Image Size}}{\text{Magnification}}$; for an image size of $0.5\,\text{mm}$ at a magnification of $\times 500$, the actual size is $0.001\,\text{mm}$ or $1\,\mu\text{m}$.

Prokaryotic Cell

A simple single-celled organism that lacks a distinct nucleus and membrane-bound organelles.

$70\text{S}$ Ribosomes

The smaller size classification of ribosomes found within prokaryotic cells.

Flagellum

A whip-like appendage on the surface of some cells that provides motility; in prokaryotes, it is made of flagellin and rotates, unlike the microtubular structure of eukaryotic flagella.

Plasmid

A small, circular, self-replicating loop of DNA in prokaryotes carrying non-essential accessory genes, such as antibiotic resistance genes.

Nucleoid

The irregularly shaped, non-membrane-bound region in a prokaryotic cell where the circular chromosomal DNA is concentrated.

Pili

Hair-like surface appendages on prokaryotic cells used for attachment to surfaces and the exchange of genetic material during conjugation.

Capsule

The outermost protective polysaccharide or protein layer surrounding certain prokaryotic cells that prevents desiccation and phagocytosis.

Peptidoglycan

A mesh-like polymer of sugars and amino acids that forms the cell wall of bacteria.

Gram Stain

A differential staining procedure used to classify bacteria based on their cell wall characteristics and evaluate their susceptibility to antibiotics.

Crystal Violet

The primary violet stain added first during the Gram staining procedure.

Alcohol Wash (Ethanol)

The decolourising solvent used in Gram staining to remove the crystal violet-iodine complex from the cell walls of Gram-negative bacteria.

Safranin

The red or pink counterstain used in Gram staining to stain decolourised Gram-negative bacteria.

Gram-Negative Bacteria

Bacteria that possess two membranes (an inner plasma membrane and an outer membrane) sandwiching a thin peptidoglycan layer, staining pink/red.

Gram-Positive Bacteria

Bacteria that possess a single membrane and a thick peptidoglycan wall, staining purple and showing higher susceptibility to penicillin.

Tissue

A group of specialised cells working together to carry out a specific common function.

Organ

A structure composed of different types of tissues working together to perform a specific physiological task.

Palisade Mesophyll Cell

A specialised columnar plant cell located near the upper leaf surface, densely packed with chloroplasts to carry out photosynthesis.

Sperm Cell

A specialised male gamete containing numerous mitochondria to supply energy for locomotion and an acrosome for fertilisation.

Acrosome

A membrane-bound vesicle at the tip of a sperm head containing digestive enzymes that hydrolyse the protective layers of the egg cell.

Corona Radiata

An outer layer of follicular cells surrounding the mammalian unfertilised egg cell.

Zona Pellucida

The glycoprotein coat surrounding the egg cell that undergoes structural changes upon fertilisation to prevent polyspermy.

Phagocyte

A category of white blood cell (such as a neutrophil or macrophage) that engulfs, digests, and destroys pathogens via phagocytosis.

Platelet

A small cellular fragment lacking a nucleus that plays a vital role in blood clotting and haemostasis.

Axon

The long, slender projection of a neurone that conducts electrical action potentials away from the cell body.

Myelin Sheath

An insulating lipid-rich sheath surrounding neuronal axons that speeds up the transmission of electrical nerve impulses.

Erythrocyte

A biconcave red blood cell that lacks a nucleus and organelles to maximise internal space for haemoglobin to transport oxygen.

Haploid

The condition of having a single complete set of unpaired chromosomes ($n$), characteristic of gametes like sperm and egg cells.

B Lymphocyte

A white blood cell that differentiates into plasma cells to produce antigen-specific antibodies.

T Lymphocyte

A class of lymphocyte involved in cell-mediated immunity and the production of regulatory or helper immune cells.

Ciliated Columnar Epithelium

The tissue lining parts of the respiratory tract (such as the trachea and bronchi) featuring cilia on its surface to sweep away mucus.

Cilia

Microscopic, hair-like projections on the apical surface of columnar epithelial cells that beat rhythmically to move mucus out of the airways.

Goblet Cells

Specialised mucus-secreting epithelial cells located within columnar respiratory and intestinal epithelium.

Mucus

A viscous secretion that traps inhaled dust, dirt, and pathogens in the respiratory tract while maintaining tissue hydration.

Squamous Epithelial Tissue

A single layer of thin, flattened cells found lining structures like the alveoli and capillaries, providing a short diffusion path for gases.

Emphysema

A progressive pulmonary disease characterised by the destruction and loss of elasticity of the alveolar walls.

Chronic Bronchitis

A pulmonary disorder involving long-term inflammation, excessive mucus production, and scarring of the bronchial airways.

Carbon Dioxide ($\text{CO}_2$)

The metabolic waste gas whose removal from the body is impaired by Chronic Obstructive Pulmonary Disease (COPD).

Endothelium

The delicate single layer of squamous epithelial cells lining the interior surface of blood vessels.

Atherosclerosis

The cardiovascular condition initiated by damage to the arterial endothelium, promoted by risk factors including smoking, high blood pressure, and elevated blood cholesterol.

Atheroma

A fatty deposit or plaque that accumulates beneath a damaged arterial endothelium, narrowing the lumen and restricting blood flow.