The Cell Flashcards
Cytosol
Semi-fluid medium found in cytoplasm
Cytoplasm
The region between nucleus and cell membrane
Light Microscope (LM)
Lenses bend visible light to magnify images of specimens
Organelle
Any of several membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells
Electron microscope (EM)
Uses magnets to focus an electron beam on or through a spectrum, greater resolution than LM
Scanning electron microscope (SEM)
Uses an electron bean to scan the surface of the sample coated with metal atoms, to study details of it’s topography
Transmission electron microscope (TEM)
Passes an electron beam through very thin sections stained with metal atoms and is primarily used to study the internal ultrastructure of cells
Cell Fractionation
The disruption of a cell and separation of its parts by centrifugation at successively higher speeds
Eukaryotic cell
Type of cell with membrane-enclosed nucleus and membrane-enclosed organelles.
Prokaryotic cell
No nucleus.
DNA is in an unbound region called the nucleoid.
No membrane-bound organelles.
Cytoplasm bound by the plasma membrane.
Nucleoid
A non-membrane-bounded region in a prokaryotic cell where the DNA is concentrated.
Plasma membrane
The membrane at the boundary of every cell that acts as a selective barrier, regulating the cell’s chemical composition.
Nucleus
An atom’s central core, containing protons and neutrons; the organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made up of chromatin; a cluster of neutrons.
Nuclear envelope
In a eukaryotic cell, the double membrane that surrounds the nucleus, perforated with pores that regulate traffic with the cytoplasm. The outer membrane is continuous with the endoplasmic reticulum. Two lipid bilayers.
Nuclear lamina
A netlike array of protein filaments that lines the inner surface of the nuclear envelope and helps maintain the shape of the nucleus.
Chromosome
A cellular structure carrying genetic material, found in the nucleus of eukaryotic cells. Each chromosome consists of one very long DNA molecule and associated proteins
Chromatin
The complex of DNA and proteins that makes up eukaryotic chromosomes. When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope.
Nucleolus
A specialized structure in the nucleus, consisting of chromosomal regions containing ribosomal RNA (rRNA) genes along with ribosomal proteins imported from cytoplasm; site of rRNA synthesis and ribosomal subunit assembly.
Ribosome
A complex of rRNA and protein molecules that function as a site of protein synthesis in the cytoplasm; consists of a large and small subunit. In eukaryotic cells, each subunit is assembled in the nucleolus. Free ribosome found in cytosol. Bound ribosomes attached to ER.
Endomembrane system
The collection of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles; includes the plasma membrane, the nuclear envelope, the smooth and rough ER, the Golgi apparatus, lysosomes, vesicles, and vacuoles.
Vesicle
A membranous sac in the cytoplasm of a eukaryotic cell
Endoplasmic Reticulum (ER)
An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.
Smooth ER
The portion of the ER that is free of ribosomes. Functions: synthesizes lipids, phospholipids, and steroids (hormones). Participates in carbohydrate metabolism. Detoxifies drugs & poisons. Stores calcium ions for muscle contraction.
Rough ER
The portion of the ER with ribosomes attached. Functions: protein synthesis. Membrane production.
Glycoprotein
A protein with one or more covalently attached carbohydrates.
Transport vesicle
A small membranous sac in a eukaryotic cell’s cytoplasm carrying molecules produced by the cell.
Golgi apparatus
An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the ER and synthesize some products, notably noncellular carbohydrates. The cis face accepts transport vesicles from ER. The trans face pinches off vesicles.
Lysosome
A membrane-enclosed sac of hydrolytic enzymes (produced in rough ER) found in the cytoplasm of animal cells and some protists. Contains a stockpile of digestive enzymes, important in breaking down nutrients, destroying bacteria, recycling, and development.
Phagocytosis
A type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It’s carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophilis, and dendritic cells)
Vacuole
A membrane-bounded vesicle whose specialized function varies in different kinds of cells.