02. OCR A Biology - 2.1.1 Cell Structure - Chapter 2 - Year 1

Keywords for OCR A Biology - 2.1.1 Cell Structure - Chapter 2 - Year 1

Artefacts

Objects or structures seen through a microscope that have been created during th processing of the specimen.

Cell wall

A strong but flexible layer that surrounds some cell-types.

Centrioles

Component of the cytoskeleton of most eukaryotic cells, composed of microtubules.

Chloroplasts

Organelles that are responsible for photosynthesis in plant cells. Contain chlorophyll pigments, which are the site of the light reactions of photosynthesis.

Contrast

Staining or treating specific cell components so they are visible compared to untreated components.

Counterstain

Application of second stain with a contrasting colour to sample for microscopy.

Cytoplasm

Internal fluid of cells, composed of cytosol (water, salts and organic molecules), organelles and cytoskeleton.

Cytoskeleton

A network of fibres in the cytoplasm of a eukaryotic cell.

Differential staining

Using specific stains to distinguish different types of cell.

Electron microscopy

Microscopy using a microscope that employs a beam of electrons to illuminate the specimen. As electrons have a much smaller wavelength than light they produce images with higher resolutions than light microscopes.

Eukaryotic cells

Cells with a nucleus and other membrane-bound organelles.

Golgi apparatus

Organelle in most eukaryotic cells formed from an interconnected network of flattened, membrane-enclosed sacs, or cisternae. Play a role in modifying and packaging proteins into vesicles.

Laser scanning confocal microscope

A microscope that employs a beam of fluorescence and a pin-hole aperture to produce an image with a very high resolution.

Light microscope

An instrument that uses visible light and glass lenses to enable the user to see objects magnified many times.

Organelle

Membrane-bound compartments with varying functions inside eukaryotic cells.

Prokaryotic cells

Cells with no membrane-bound nucleus or organelles.

Resolution

The shortest distance between two objects that are still seen as separate objects.

Scanning electron microscopy

An electron microscope in which a beam of electrons is sent across the surface of a specimen and the reflected electrons are focused to produce a three- dimensional image of the specimen surface.

Scanning electron microscopy (SEM)

An electron microscope in which a beam of electrons is sent across the surface of a specimen and the reflected electrons are focused to produce a threedimensional image of the specimen surface.

Smooth endoplasmic reticulum

Endoplasmic reticulum lacking ribosomes; the site of lipid and carbohydrate synthesis, and storage.

Stage graticule

A slide with a scale in micrometres (μm) etched into it. Used to measure the size of a sample under a light microscope.

Stains (staining)

Dyes used in microscopy sample preparation to increase contrast or identify specific components.

Transmission electron microscopy (TEM)

An electron microscope in which a beam of electrons is transmitted through a specimen and focused to produce an image.

Ultrastructure

Fine internal cellular details that can be resolved using an electron microscope.

Vacuoles

Membranous sacs used to transport materials in the cell.