AQA GCSE Biology - Topic 1: Cell Biology Vocabulary

Vocabulary flashcards based on Topic 1: Cell Biology notes from AQA Biology GCSE, covering cell structure, cell specialization, microscopy, microbiology, cell division, stem cells, and transport mechanisms.

Eukaryotic Cell

A type of cell (such as animal and plant cells) that contains a cell membrane, cytoplasm, and a nucleus containing DNA.

Prokaryotic Cell

A smaller cell type (such as bacterial cells) that has a cell wall, cell membrane, cytoplasm, a single circular strand of DNA, and plasmids instead of a nucleus.

Organelles

Structures inside a cell that perform different specific functions.

Plasmids

Small rings of DNA found floating within the cytoplasm of bacterial cells.

Nucleus

An organelle enclosed in a nuclear membrane that contains DNA coding for particular proteins needed to build new cells.

Cytoplasm

The liquid substance in a cell where chemical reactions occur, containing enzymes and organelles.

Mitochondria

Organelles in cells where aerobic respiration reactions occur, providing energy for the cell.

Ribosomes

Organelles found on the rough endoplasmic reticulum where protein synthesis occurs.

Chloroplasts

Organelles in plant cells containing chlorophyll pigment that harvest light for photosynthesis.

Permanent Vacuole

A structure found in the cytoplasm of plant cells containing cell sap that improves the cell's rigidity.

Cell Wall

A rigid outer layer that provides strength to the cell, made from cellulose in plant and algal cells, and peptidoglycan in bacterial cells.

Differentiation

A process involving a cell gaining new sub-cellular structures to become suited to its specific role.

Acrosome

The structure at the top of a sperm cell's head containing digestive enzymes that break down the outer layers of the egg cell membrane.

Neurotransmitters

Special transmitter chemicals produced using energy from mitochondria at nerve endings that allow electrical impulses to pass from one cell to another.

Xylem Cells

Specialised hollow plant cells strengthened with spirals of lignin that form continuous tubes to transport water and mineral ions up from the roots to the shoots.

Phloem Cells

Specialised plant cells with sieve plates that carry the products of photosynthesis to all parts of the plant, supported by energy from companion cells.

Mitosis

The step in the cell cycle where a cell divides to produce $2$ identical daughter cells.

Resolution

The ability of a microscope to distinguish between two points, affected by its resolving power.

Light Microscope

An optical microscope using objective and eyepiece lenses with a maximum magnification of approximately $\times 2000$ and a resolving power of $200\,\text{nm}$.

Electron Microscope

A microscope developed in the 1930s using electron beams that reaches magnifications up to $\times 2\,000\,000$ to view sub-cellular structures.

Autoclave

An oven used to sterilise Petri dishes and culture media prior to growing microorganisms.

Binary Fission

The process by which bacteria multiply by splitting into two, occurring as fast as every $20\,\text{minutes}$ under optimal conditions.

Inhibition Zone

The clear area left on an agar plate where bacteria have died around an antibiotic or disinfectant paper disc.

Gene

A short section of DNA on a chromosome that codes for a specific protein and controls a characteristic.

Interphase

Stage 1 of the cell cycle where the cell grows, increases organelle counts, synthesises proteins, replicates DNA, and increases energy stores.

Cytokinesis

Stage 3 of the cell cycle where the cytoplasm and cell membranes divide to form two identical daughter cells.

Embryonic Stem Cells

Undifferentiated cells formed when an egg and sperm fuse into a zygote that can differentiate into any cell type in the body.

Meristems

Stem cells found in root and shoot tips of plants that retain the ability to differentiate into any type of plant cell throughout the plant's life.

Therapeutic Cloning

The creation of an embryo with the exact same genes as the patient, allowing harvested embryonic stem cells to be used without medical rejection.

Diffusion

The spreading out of particles in a solution or gas resulting in a net movement from an area of higher concentration to an area of lower concentration.

Osmosis

The passive movement of water from a less concentrated solution to a more concentrated solution across a partially permeable membrane.

Isotonic

Refers to an external solution that has the exact same solute/sugar concentration as the internal concentration of a cell.

Hypertonic

Refers to an external solution that has a higher solute/sugar concentration than the inside of a cell, causing water to leave the cell.

Hypotonic

Refers to an external solution that has a lower solute/sugar concentration than the inside of a cell, causing water to enter the cell.

Plasmolysis

The condition of a plant cell when it loses water in a hypertonic solution, causing its cell membrane to pull away from the cell wall.

Active Transport

The movement of particles from an area of lower concentration to an area of higher concentration against a concentration gradient, requiring energy from respiration.