Cell Structure and Function – Lecture Vocabulary

Vocabulary flashcards covering key terms from the lecture on cell structure, specialised cells and microscopy.

Cell

The basic structural and functional unit of living organisms.

Cytoplasm

Jelly-like living material inside the cell where metabolic reactions occur and organelles are suspended.

Nucleus

Large organelle that controls cell activities and contains genetic material (DNA).

Chromosome

Thread-like structure in the nucleus composed of DNA and proteins; visible during cell division.

Gene

Section of DNA that codes for a particular protein and controls a specific trait or function.

DNA (Deoxyribonucleic Acid)

Chemical that makes up genes and carries hereditary information.

Cell Membrane

Thin, partially permeable boundary that regulates substance movement into and out of the cell.

Ribosome

Small cytoplasmic structure where protein synthesis takes place.

Mitochondrion

Organelle in which aerobic respiration releases energy for the cell.

Aerobic Respiration

Energy-releasing process that uses oxygen to break down glucose in mitochondria.

Cell Wall

Rigid outer layer of plant (and bacterial) cells that provides support; in plants made of cellulose.

Cellulose

Tough carbohydrate forming the plant cell wall.

Sap Vacuole

Large, permanent, fluid-filled cavity in mature plant cells that stores sugars and ions and maintains turgor.

Chloroplast

Green organelle containing chlorophyll; site of photosynthesis in plant cells.

Chlorophyll

Green pigment in chloroplasts that absorbs light energy for photosynthesis.

Turgor / Turgid

State of a plant cell swollen with water, pressing against the cell wall and providing support.

Root Hair Cell

Specialised epidermal cell with a long extension that increases surface area for water and mineral uptake.

Xylem Vessel

Hollow, lignified tube formed from dead cells that conducts water and minerals in plants.

Lignin

Woody, waterproof substance deposited in xylem walls, strengthening and preventing collapse.

Haemoglobin

Red pigment in red blood cells that binds and transports oxygen.

Biconcave Disc

Flattened, indented shape of a mature red blood cell that increases surface area-to-volume ratio.

Plasmid

Small circular DNA molecule in bacteria containing genes such as antibiotic resistance.

Peptidoglycan

Complex polysaccharide-protein compound forming the bacterial cell wall.

Capsule (Slime Layer)

Additional protective layer outside some bacterial cell walls that prevents drying and offers defense.

Flagellum

Long, whip-like appendage that rotates to propel a bacterial cell through liquid.

Cell Differentiation

Process by which unspecialised cells become specialised in structure and function under genetic control.

Magnification

Ratio of an image’s size to the actual size of the object being viewed.

Osmosis

Diffusion of water molecules through a partially permeable membrane from high to low water potential.

Diffusion

Net movement of molecules from an area of higher to lower concentration down a concentration gradient.

Active Transport

Energy-requiring movement of substances against a concentration gradient via carrier proteins in membranes.

Cell

The basic structural and functional unit of all living organisms.

Cytoplasm

Jelly-like living material inside a cell where metabolic reactions occur and organelles are suspended.

Nucleus

Large organelle that controls cellular activities and houses genetic material.

Chromosome

Thread-like structure made of DNA that carries many genes; visible when a cell divides.

Gene

Segment of DNA that codes for a specific protein and controls a trait or cellular function.

DNA (Deoxyribonucleic acid)

The nucleic acid molecule that stores genetic information in cells.

Ribosome

Small organelle that is the site of protein synthesis.

Mitochondrion

Organelle where aerobic respiration releases energy for the cell; plural mitochondria.

Cell membrane

Thin, partially permeable boundary that controls substance movement into and out of a cell.

Cell wall

Rigid outer layer in plant, fungal and bacterial cells that provides shape and support.

Cellulose

Tough carbohydrate that makes up plant cell walls.

Chloroplast

Green plant organelle containing chlorophyll and carrying out photosynthesis.

Chlorophyll

Green pigment inside chloroplasts that absorbs light energy for photosynthesis.

Sap vacuole

Large permanent fluid-filled cavity in mature plant cells storing sugars and ions.

Turgor

The pressure of cell contents against the cell wall, keeping a plant cell turgid and firm.

Osmosis

Diffusion of water molecules through a partially permeable membrane from dilute to more concentrated solution.

Diffusion

Passive movement of particles from a region of higher to lower concentration.

Active transport

Energy-requiring movement of substances against a concentration gradient across a membrane.

Aerobic respiration

Energy-releasing process that uses oxygen to break down glucose inside mitochondria.

Metabolic reactions

All chemical reactions taking place within the cytoplasm of a cell; collectively the cell’s metabolism.

Organelle

Specialised sub-cellular structure with a particular function, e.g., nucleus or ribosome.

Bacterium

Unicellular prokaryote typically 1-2 µm long, lacking a true nucleus.

Peptidoglycan

Complex polysaccharide-protein compound forming the bacterial cell wall.

Capsule (slime layer)

Extra protective coating outside some bacterial cell walls that prevents drying and shields the cell.

Plasmid

Small circular DNA ring in bacteria carrying additional genes such as antibiotic resistance.

Flagellum

Tail-like structure enabling many bacteria to swim with a propeller-like motion.

Root hair cell

Elongated epidermal cell on plant roots that increases surface area for water and mineral uptake.

Xylem vessel

Dead, lignified tube in plants that transports water and minerals from roots to leaves.

Lignin

Woody, waterproof substance deposited in xylem walls, strengthening and supporting the plant.

Haemoglobin

Red pigment in red blood cells that binds and transports oxygen.

Biconcave disc

Flattened, indented shape of mature red blood cells that increases surface area and flexibility.

Tissue

Group of similar cells working together to perform a specific function.

Organ

Structure composed of several tissues working together to perform a complex function.

Cell differentiation

Process by which unspecialised cells develop specialised structures and functions under genetic control.

Magnification

Degree to which an image of an object is enlarged compared to its actual size.

Scale bar

Line on a micrograph or diagram indicating a known actual length to gauge size.

Micrometre (µm)

Unit of length equal to one-millionth of a metre; common measure of cell size.