Cell Biology: Structure, Organisation, and Transport Mechanisms

Vocabulary flashcards covering cell structure (animal and plant cells), biological levels of organisation, and cellular transport mechanisms including diffusion, osmosis, active transport, and factors affecting exchange.

Diffusion

The net movement of particles from a region of high concentration to a region of low concentration down a concentration gradient.

Concentration

The amount of a substance in a given volume.

Concentration Gradient

The difference in concentration of a substance between two areas.

Particle

A small unit of matter such as an atom or molecule.

Net Movement

The overall movement of particles in one direction.

Selectively Permeable Membrane

A membrane that allows some substances to pass through while preventing others from passing through.

Osmosis

The net movement of water molecules from a dilute solution to a concentrated solution through a selectively permeable membrane.

Water Potential

A measure of the tendency of water molecules to move from one place to another.

Dilute Solution

A solution containing a high concentration of water and a low concentration of solute.

Concentrated Solution

A solution containing a low concentration of water and a high concentration of solute.

Turgid

The state of a plant cell when water enters by osmosis and the cell becomes firm and fully inflated.

Plasmolysis

The process occurring in plant cells placed in a concentrated solution where water leaves by osmosis, causing the cell membrane to pull away from the inside of the cell wall.

Flaccid

The limp, soft state of a plant cell when water leaves by osmosis and it is no longer firm or rigid.

Lysis

The bursting of an animal cell caused by water entering by osmosis when placed in a dilute solution.

Crenation

The shrinking or wrinkling of an animal cell caused by water leaving by osmosis when placed in a concentrated solution.

Hypotonic Solution

A solution with a lower solute concentration than the inside of a cell, causing water to move into the cell.

Hypertonic Solution

A solution with a higher solute concentration than the inside of a cell, causing water to move out of the cell.

Isotonic Solution

A solution with an equal solute concentration inside and outside the cell, resulting in no net movement of water.

Active Transport

The movement of substances from an area of low concentration to an area of high concentration against the concentration gradient, using energy released from respiration.

Root Hair Cell

A specialized plant cell adapted to absorb water and mineral ions from the soil.

Mineral Ion

A nutrient absorbed by plant root hair cells from the soil, often against a concentration gradient.

Absorption

The process of taking substances into a cell or organism.

Surface Area

The total area of an organism or cell that is exposed for exchange.

Volume

The amount of three-dimensional space occupied by an object or cell.

Surface Area to Volume Ratio

The comparison between a cell's surface area and its volume, which decreases as the size of the cell or object increases.

Diffusion Distance

The distance that particles must travel during diffusion; shorter distances result in faster rates of exchange.

Rate of Diffusion

A measure of how quickly substances move from one place to another over time.

Exchange Surface

A specialized surface or boundary where substances move into and out of cells.

Organelle

A specialized structure within a cell that carries out a specific function.

Cell

The basic unit and building block of life.

Tissue

A group of similar cells of similar structure working together to perform a particular function.

Organ

An aggregation of different tissues working together to perform a specific function.

Organ System

A group of organs working together to perform a particular function.

Organism

A living thing made up of organ systems functioning together.

Specialised Cell

A cell adapted with specific structural features to carry out a particular function.

Multicellular

Composed of many cells working together.

MRS GREN

An acronym representing the seven life processes of living organisms: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition.

Prokaryotic Cell

A small, simple cell lacking a true nucleus, whose genetic material forms a single circular loop of DNA and plasmids in the cytoplasm.

Eukaryotic Cell

A complex cell containing membrane-bound organelles and genetic material enclosed within a nucleus.

Nucleus

The organelle that contains genetic material ($\text{DNA}$) and controls the activities of the cell.

Cytoplasm

The jelly-like substance within a cell where chemical reactions take place, controlled by enzymes.

Cell Membrane

A barrier surrounding a cell that controls the movement of substances into and out of the cell.

Mitochondria

Organelles that serve as the site of aerobic respiration and energy release within a cell.

Ribosome

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

Cell Wall

A rigid outer layer made of cellulose that strengthens and structurally supports plant cells.

Cellulose

The carbohydrate substance that makes up the cell wall of plant cells, providing strength and protection.

Chloroplast

A plant cell organelle containing chlorophyll that serves as the site of photosynthesis.

Chlorophyll

A green pigment located in chloroplasts that absorbs light energy required for photosynthesis.

Permanent Vacuole

A large fluid-filled organelle in plant cells containing cell sap that maintains turgor and cell structure.