AQA GCSE Biology Topic 1: Cell Biology Flashcards

Flashcards covering key vocabulary, cell structures, microscopy, cell division, and transport mechanisms from AQA GCSE Biology Topic 1.

Eukaryotic cells

Cells that have their genetic material (DNA) enclosed in a nucleus, such as plant and animal cells.

Prokaryotic cells

Cells where genetic material (DNA) is not enclosed in a nucleus, such as bacterial cells, which are much smaller than eukaryotic cells.

Plasmids

Small rings of DNA found in prokaryotic cells in addition to the single loop of DNA.

Order of magnitude

A power to the base 10 used to quantify and compare size; for example, 10 times bigger is $10^1$ (1 order of magnitude) and 100 times bigger is $10^{2}$ (2 orders of magnitude).

Centimetre (cm)

Unit of length equivalent to $10^{-2}\text{m}$.

Millimetre (mm)

Unit of length equivalent to $10^{-3}\text{m}$.

Micrometre (\mu m)

Unit of length equivalent to $10^{-6}\text{m}$.

Nanometre (nm)

Unit of length equivalent to $10^{-9}\text{m}$.

Cell membrane

Controls the movement of substances in and out of the cell.

Cytoplasm

A gel-like substance where chemical reactions take place.

Nucleus

Contains genetic material (DNA) and controls the activities of the cell.

Mitochondria

The site of aerobic respiration which releases energy from glucose.

Ribosomes

The site of protein synthesis.

Cell wall

Found in plant and algal cells and made of cellulose, it functions to strengthen the cell.

Chloroplasts

Organelles in plant cells containing chlorophyll to absorb light for photosynthesis to make glucose.

Permanent vacuole

A plant cell structure filled with cell sap that helps keep the cell turgid to support the plant.

Total magnification formula

$\text{Magnification of eyepiece lens} \times \text{magnification of objective lens}$.

Sperm cell specialisation

Features a long tail (flagellum) for movement and many mitochondria to release energy for swimming.

Nerve cell specialisation

Long with many branches to carry electrical signals over long distances and connect to other cells.

Root hair cell specialisation

Features a long projection to increase surface area for water absorption and many mitochondria for active transport of mineral ions.

Xylem cell

A plant cell specialized to transport water and mineral ions, featuring lignin in the cell wall for strength and hollow tubes.

Phloem cell

A plant cell specialized to transport dissolved sugars, characterized by having no nucleus and pores in the end walls.

Cell differentiation

The process where a cell acquires different sub-cellular structures to become a specialized cell for a certain function.

Magnification

The number of times bigger an image is compared to the real object.

Resolution

The shortest distance between two points that can be seen as separate points (the level of detail).

Binary fission

The simple cell division process used by bacteria to multiply.

Aseptic technique

Methods used to prevent contamination by microorganisms, such as sterilizing petri dishes and inoculating loops.

Zone of inhibition

The clear area on an agar plate where bacteria have been killed or their growth prevented by an antibiotic or antiseptic.

Chromosomes

Tightly coiled strands of DNA molecules found in the nucleus that carry a large number of genes.

Mitosis

A stage of the cell cycle where one set of chromosomes is pulled to each end of the cell and the nucleus divides.

Stem cell

An undifferentiated cell which can give rise to more cells of the same type and differentiate into certain other cells.

Therapeutic cloning

Producing an embryo with the same genes as a patient so that stem cells are not rejected by the patient's immune system.

Meristems

Growing regions in plant roots and shoot tips where stem cells allow the plant to differentiate throughout its lifetime.

Diffusion

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

Osmosis

The diffusion of water from a dilute solution to a more concentrated solution through a partially permeable membrane.

Active transport

The movement of substances from a dilute to a more concentrated solution against a concentration gradient, requiring energy from respiration.