Ch.6 A Tour of the Cell Flashcards
Light Microscope
An optical instrument with lenses that refract (bend) visible light to magnify images of specimens
Organelles
Any of several membranes-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells
Electron Microscope
A microscope that uses magnets to focus an electron beam on/through a specimen, resulting in a practical resolution that is 100x greater than a light microscope
Transmission Electron Microscope
A microscope that passes an electron beam through very thin sections stained w/metal atoms and is primarily used to study the internal structure of cells
Cell Fractionation
The disruption of a cell and separation of its parts by centrifugation at successively higher speeds
Cells
The basic structural and functional units of every organism
Cytosol
Semifluid portion of the cytoplasm in which subcellular components are suspended
Nucleoid
A non-membrane enclosed region in a prokaryotic cell where its chromosome is located
Eukaryotic Cell
A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles
Prokaryote Cell
A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles
Fimbriae
Attachment structures on the surface of some prokaryotes
Cell Wall
Rigid structure outside the plasma membrane
Glycocalyx
Outer coating of many prokaryotes consisting of a capsule or a slime layer
Flagella
Locomotion organelles of some prokaryotes
Cytoplasm
The contents of the cell bounded by the plasma membrane; in eukaryotes, the portion exclusive of the nucleus
Plasma Membrane
The membrane at the boundary of every cell that acts as a selective barrier, regulating the cell’s chemical composition
Microvilli
Long, thin projections from cells surface which increase surface area without an appreciable increase in volume
Nucleus
Organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made up of chromatin
Nuclear Envelope
The double membrane that surrounds the nucleus, perforated with pores that regulate traffic with the cytoplasm. The outer membrane is continuous with the ER
Pore Complex
A protein structure that lines each pore and plays an important role in regulating the entry and exit of proteins and RNAs, as well as large complexes of macromolecules
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
Nuclear Matrix
A framework of protein fibers extending throughout the nuclear interior
Chromosomes
Structures that carry the genetic information. Each contains one long DNA molecule associated with many proteins.
Nucleolus
A specialized structure in the nucleus, consisting of chromosomal regions containing ribosomal RNA (rRNA) genes along w/ribosomal proteins imported from the cytoplasm; site of rRNA synthesis and ribosomal subunit assembly
Ribosomes
A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a large and small subunit
Free Ribosomes
Are suspended in the cytosol and make proteins that function within the cytosol
Bound Ribosomes
Ribosomes that are attached to the outside of the ER or nuclear envelope
Functions of Bound Ribosomes
Make proteins that are destined for insertion into membranes, packaging within certain organelles such as lysosomes, or export from the cell (secretion)
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
Organelles of the Endomembrane System
Nuclear Envelope
Endoplasmic Reticulum
Golgi Apparatus
Lysosomes
Vacuoles
Plasma Membrane
Vesicle
A membranous sac in the cytoplasm of the eukaryotic cell whose job is to pinch off from one membrane, transport proteins to another organelle, and then fuse with it
Endoplasmic Reticulum (ER)
An extensive membranous network in eukaryotic cells, continuous w//the outer nuclear membrane and composed of ribosome studded (rough) and ribosome free (smooth) regions
Smooth ER
Portion of ER that is free of ribosomes
Rough ER
Portion of the ER with ribosomes attached
Functions of Smooth ER
Synthesizes lipids
Metabolizes carbohydrates
Detoxifies drugs and poisons
Stores calcium ions
Functions of Rough ER
Is a membrane factory for the cell; all of our membrane proteins are made and inserted into the membrane of the rough ER
Functions of Bound Ribosomes at Rough ER
Make three types of proteins:
Membrane Proteins
Proteins that are going to be exported or secreted by the cell
Proteins that are going to be sent to a specific location
Glycoproteins
A protein w/one or more covalently attached carbohydrates; rough ER ribosomes secrete glycoproteins
Transport Vesicles
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 noncellulose carbohydrates
Functions of the Golgi Apparatus
Modifies products of the ER
Manufactures certain macromolecules
Sorts and packages materials into transport vesicles
Cisternae
Flattened membranous sacs in the Golgi
Cis Face of Golgi
Receives vesicles containing ER products
Trans Face of Golgi
Dispatches vesicles
Lysosomes
A membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some protists
Where are hydrolytic enzymes and lysosomal membranes made?
Made by the rough ER and then transferred to Golgi for further processing
Function of Lysosomes
Carry out intracellular digestion (….)
Phagocytosis
A type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It is carried out by some protists and by certain immune cells of animals
Macrophages
A type of white blood cell that helps defend the body by engulfing and destroying bacteria and other invaders
Autophagy
When lysosomes use enzymes to recycle the cell’s organelles and macromolecules; by digesting big macromolecules/polymers, the monomers can then move out of the food vacuole and into the cytosol and can be used for the cell
Food Vacuoles
Formed by phagocytosis; a lysosome fuses w/the food vacuole and digests the molecules; afterward, it can fuse w/the plasma membrane and dump any materials that might be left inside
Lipases
A digestive enzyme that breaks down certain lipids