AQA Biology GCSE Topic 1: Cell Biology

Comprehensive vocabulary flashcards covering AQA Biology GCSE Topic 1: Cell Biology based on the lecture notes.

Eukaryotic cells

Cells found in animal and plant cells that contain a cell membrane, cytoplasm, and a nucleus containing DNA.

Prokaryotic cells

Cells found in bacteria that are much smaller than eukaryotic cells, containing a cell wall, membrane, cytoplasm, a single circular strand of DNA, and plasmids.

Plasmids

Small rings of DNA found in the cytoplasm of bacterial cells.

Organelles

Structures within a cell that perform specific functions.

Centi

A prefix used to multiply a unit of measurement by $0.01$.

Milli

A prefix used to multiply a unit of measurement by $0.001$.

Micro

A prefix used to multiply a unit of measurement by $0.000, 001$.

Nano

A prefix used to multiply a unit of measurement by $0.000, 000, 001$.

Nucleus

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

Cytoplasm

A liquid substance containing enzymes where chemical reactions occur and organelles are found.

Cell membrane

A structure that controls which substances enter and leave the cell.

Mitochondria

The site of aerobic respiration reactions that provide energy for the cell.

Ribosomes

The site of protein synthesis, often found on the rough endoplasmic reticulum.

Chloroplasts

Organelles in plant cells where photosynthesis occurs; they contain chlorophyll pigment to harvest light.

Permanent vacuole

A plant cell organelle containing cell sap that improves the cell’s rigidity.

Cell wall (Plants)

A structure made from cellulose that provides strength to the plant cell.

Peptidoglycan

The compound used to make the cell wall in bacterial cells.

Differentiation

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

Sperm cells

Specialised cells with a streamlined head, long tail, and many mitochondria designed to carry male DNA to the ovum.

Acrosome

The tip of a sperm cell's head containing digestive enzymes to break down the outer layers of the egg cell membrane.

Nerve cells

Cells specialised to transmit electrical signals quickly using a long axon and branched dendrites.

Neurotransmitters

Special chemicals that allow nerve impulses to be passed from one cell to another via nerve endings.

Muscle cells

Cells containing myosin and actin proteins that slide over each other to cause contraction, often storing glycogen for respiration.

Root hair cells

Plant cells with a large surface area specialised for taking up water by osmosis and mineral ions by active transport.

Xylem cells

Specialised plant cells that transport water and mineral ions; they are hollow, joined end-to-end, and reinforced with lignin.

Phloem cells

Plant cells specialised to carry products of photosynthesis (food) through sieve plates, supported by companion cells.

Stem cells

Undifferentiated cells that can divide to produce more similar cells or differentiate into various specialised cell types.

Mitosis

The process involving a cell dividing into two identical daughter cells for growth and repair.

Resolving power

A measure of the ability of a microscope to distinguish between two separate points.

Electron microscope

An instrument using electrons to form images with much higher magnification and resolving power than light microscopes.

Culture medium

A nutrient-rich substance, such as nutrient broth or agar gel, used for growing microorganisms in a lab.

Inoculating loops

Wire loops used to spread microorganisms over agar; they must be sterilised in a flame before use.

Binary fission

The process by which bacteria multiply by splitting into two; can occur as fast as every $20$ minutes.

Inhibition zone

The clear area on an agar plate where bacteria have died due to the presence of an antibiotic.

Chromosomes

Coiled DNA structures found in the nucleus, normally appearing in $23$ pairs in human body cells.

Gene

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

Therapeutic cloning

The production of an embryo with the same genes as a patient to harvest stem cells that will not be rejected.

Diffusion

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

Osmosis

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

Hypotonic

A solution where the concentration of sugar is lower than that inside the cell, causing water to move in.

Hypertonic

A solution where the concentration of sugar is higher than that inside the cell, causing water to move out.

Active transport

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