AQA Biology GCSE Topic 1: Cell Biology Flashcards

Comprehensive vocabulary flashcards covering AQA Biology GCSE Topic 1: Cell Biology, including cell structures, specialization, microscopy, and transport mechanisms.

Eukaryotic cells

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

Prokaryotic cells

Cells such as bacteria that are much smaller than eukaryotic cells and contain a cell wall, cell membrane, cytoplasm, a single circular strand of DNA, and plasmids.

Plasmids

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

Organelles

Structures in a cell that have different functions, such as the cell membrane or nucleus.

Nano

A prefix indicating the unit should be multiplied by $0.000,000,001 \text{ or } 10^{-9}$.

Nucleus

The 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

The structure that controls what enters and leaves the cell.

Mitochondria

The organelle where aerobic respiration reactions occur, providing energy for the cell.

Ribosomes

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

Chloroplasts

Organelles in plant cells where photosynthesis takes place, containing chlorophyll pigment to harvest light.

Permanent vacuole

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

Cell wall

A structure made from cellulose in plant and algal cells (or peptidoglycan in bacterial cells) that provides strength to the cell.

Differentiation

A process that involves a cell gaining new sub-cellular structures to become specialised for a specific role.

Stem cells

Cells that have the ability to differentiate throughout their whole life.

Sperm cells

Animal cells specialised to carry male DNA to the ovum, featuring a streamlined head, long tail, many mitochondria, and an acrosome.

Acrosome

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

Nerve cells

Animal cells specialised to transmit electrical signals quickly, featuring a long axon, dendrites, and neurotransmitters.

Dendrites

Extensions from the nerve cell body that allow branched connections to form with other nerve cells.

Neurotransmitters

Special transmitter chemicals released by nerve endings that allow impulses to be passed from one cell to another.

Muscle cells

Animal cells specialised to contract quickly, containing filaments of myosin and actin, plus glycogen for respiration.

Root hair cells

Plant cells specialised to take up water by osmosis and mineral ions by active transport, featuring a large surface area and a large permanent vacuole.

Xylem cells

Plant cells specialised to transport water and mineral ions up the plant, featuring hollow tubes joined end-to-end and reinforced with spirals of lignin.

Phloem cells

Plant cells specialised to carry the products of photosynthesis, featuring sieve plates and companion cells to supply energy.

Resolution

The ability to distinguish between two points; lower resolving power results in more detail being seen.

Scanning electron microscope (SEM)

A type of electron microscope that creates 3D images with a resolving power of $10,nm$.

Transmission electron microscope (TEM)

A type of electron microscope that creates 2D images detailing organelles with a resolving power of $0.2,nm$.

Binary fission

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

Agar gel plate

A culture medium used to grow bacterial colonies on a surface.

Inoculating loops

Wire loops used to spread microorganisms over agar, which must be sterilised by passing through a flame.

Inhibition zone

The clear area left on an agar plate where bacteria have died, used to indicate the effectiveness of an antibiotic.

Chromosomes

Coils of DNA found in the nucleus, normally appearing in $23$ pairs in human body cells.

Gene

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

Mitosis

The stage of the cell cycle where the cell divides to produce two identical daughter cells.

Interphase

Stage 1 of the cell cycle where the cell grows, organelles increase, and DNA is replicated into an 'X' shape.

Cytokinesis

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

Therapeutic cloning

A process where an embryo is produced with the same genes as the patient to harvest stem cells that will not be rejected.

Meristems

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

Diffusion

The passive spreading out of particles 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 one through a partially permeable membrane.

Active transport

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

Isotonic

A solution is said to be this if its concentration is the same as the internal concentration of the cell.

Hypertonic

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

Hypotonic

A solution with a lower concentration than the internal concentration of the cell, causing water to move in.

Plasmolysis

The condition where the cell membrane moves away from the cell wall in a plant cell because of water loss.