GCSE Cell Biology: Cell Structure, Microscopy, Specialised Cells, and Transport Mechanisms

Comprehensive vocabulary flashcards covering cell biology concepts, including cell theory, organelle structures and functions, microscopy principles and formulas, specialised animal and plant cells, levels of biological organisation, and molecular transport mechanisms (diffusion, osmosis, active transport).

Cell

The basic building block and smallest functional unit of life that makes up all living organisms.

Robert Hooke

The scientist who discovered cells in 1665 after observing regular, box-like shapes in thin sections of cork.

Cell Theory

The foundational biological principle realised by Schleiden and Schwann stating that all organisms are composed of one or more cells and that the cell is the basic unit of life.

Cell Membrane

A thin barrier surrounding the cell that controls the movement, entry, and exit of substances into and out of the cell.

Nucleus

A large organelle inside the cell containing chromosomes and genetic material that controls all cell activities and development.

Cytoplasm

A jelly-like fluid containing chemicals where most of the cell's chemical reactions occur.

Mitochondria

Small, rod-shaped organelles found in the cytoplasm that serve as the site of aerobic respiration, releasing energy from sugar.

Ribosomes

Tiny cellular structures responsible for synthesising proteins within the cell.

Temporary Vacuole

A small, transient membrane-bound compartment in animal cells involved in feeding and the removal of waste.

Cell Wall

A rigid outer layer found outside the cell membrane in plant cells, made of cellulose, which strengthens and supports the cell.

Permanent Vacuole

A fluid-filled internal cavity in plant cells containing cell sap (a watery sugar solution); when swollen, it pushes against the cell wall to provide structural support and keep the cell firm.

Chloroplast

Small disc-shaped organelles located in the cytoplasm of plant cells containing the green pigment chlorophyll, which traps light energy for photosynthesis.

Chlorophyll

The green pigment contained inside chloroplasts that traps light energy required for photosynthesis.

Light Microscope

An optical instrument that uses visible light and a combination of lenses (eyepiece and objective) to magnify specimens.

Electron Microscope

A large, high-powered microscope that uses a beam of electrons instead of light to focus and visualise specimens at much higher magnification and resolution.

Magnification

A measure of how many times larger an image appears compared to the actual size of the specimen.

Resolution

The ability of a microscope to distinguish between two close, separate points to show clear, fine detail.

Total Magnification Formula

The equation used to determine a microscope's overall power: $\text{Total magnification} = \text{eyepiece lens} \times \text{objective lens}$.

Magnification Equation Triangle

A calculation relationship represented by $I = A \times M$, where $\text{Magnification} = \frac{\text{Image Size}}{\text{Actual Size}}$ and $\text{Actual Size} = \frac{\text{Image Size}}{\text{Magnification}}$.

Methylene Blue

A chemical stain added to animal cells, such as human cheek cells, on a glass slide to make cellular structures clearly visible under a microscope.

Differentiation

The biological process by which unspecialised cells develop specific structural adaptations to perform particular jobs or functions.

Stem Cells

Undifferentiated cells that are not specialised to perform a specific function but retain the ability to divide and differentiate into any of an organism's specialized cell types.

Red Blood Cell

A specialised animal cell that lacks a nucleus, is small with a large surface area, and contains haemoglobin to pick up and transport oxygen to body tissues.

Neurone

A specialised nerve cell with short extensions that receive impulses and a long nerve fibre insulated by a fatty sheath to conduct electrical signals without signal loss.

Muscle Cell

A specialised, elongated cell packed with contractile proteins that shorten the cell to generate force and cause movement.

Sperm Cell

A specialised male reproductive cell featuring a long flagellum for swimming and a head containing a nucleus designed to transfer paternal DNA to an egg cell.

Ciliated Epithelial Cell

A specialised tall, column-shaped epithelial cell tightly grouped together and lined with hair-like cilia that beat rhythmically to move fluids and particles.

Palisade Cell

A specialised column-shaped plant cell located in the upper portion of a leaf, packed tightly with numerous chloroplasts to trap light efficiently for photosynthesis.

Root Hair Cell

A specialised cell found in young plant roots with a long outward extension that increases the surface area for absorbing water and mineral ions from soil.

Xylem

A specialised plant vascular tissue consisting of hollow cells with hardened, thick cell walls that transport water and minerals from roots to leaves and provide structural strength.

Phloem

A specialised plant transport tissue made of mainly hollow cells with perforated end walls (sieve plates) supported by adjacent living cells that supply energy to transport sugars.

Tissue

A group of similar, specialised cells working together to perform a specific function (e.g., heart muscle tissue).

Organ

A distinct biological structure composed of different tissues working together to execute a specific function (e.g., heart).

Organ System

A group of different organs collaborating to perform complex physiological body functions (e.g., circulatory system).

Single-Celled Organism

A living thing composed of only one independent cell capable of performing all essential life processes (e.g., yeast, bacteria, amoeba, paramecium).

Multicellular Organism

An organism built of many specialised cells organised into tissues, organs, and organ systems (e.g., humans, mice, trees).

Diffusion

The net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient until evenly distributed.

Concentration Gradient

The difference in particle concentration between two regions; a steeper gradient results in a faster rate of diffusion.

Osmosis

The net movement of water molecules from an area of high water concentration (a dilute solution) to an area of low water concentration (a more concentrated solution) across a selectively permeable membrane.

Selectively Permeable Membrane

A membrane containing microscopic pores that permits small molecules like water to pass through freely while blocking larger solute molecules such as glucose or sucrose.

Active Transport

An energy-consuming transport process where cells pump molecules against/up a concentration gradient from an area of low concentration to an area of high concentration.

Isotonic Solution

A solution that has the exact same solute and water concentration as the inside of a cell, resulting in no net movement of water.

Hypotonic Solution

A solution with a lower solute concentration (higher water concentration) than the cytoplasm of a cell, causing water to enter the cell by osmosis (leading to cell swelling/lysing in animal cells or turgidity in plant cells).

Hypertonic Solution

A solution with a higher solute concentration (lower water concentration) than the cell interior, causing water to exit by osmosis (making animal cells shrivel and plant cells plasmolysed).

Turgid

The normal, firm condition of a plant cell when its vacuole is fully swollen with water via osmosis, forcing the cytoplasm hard against the cell wall.

Plasmolysed

The state of a plant cell that has lost water by osmosis in a hypertonic solution, causing the cell membrane and cytoplasm to pull away from the cell wall.