Chapter 6: A Tour Of The Cell Flashcards
Light Microscope
An optical instrument with lenses that refract visible light to magnify images of specimens
Electron Microscope
A microscope that uses magnets to focus an electron beam on or through a specimen, resulting in a practical resolution that is 100-fold greater than that of a light microscope using standard techniques
Transmission Electron Microscope
A microscope that passes an electron beam through very thin section stained with metal atoms and is primarily used to study the internal structure of cells.
Scanning electron microscope
A microscope that uses electron beam to scan the surface of a sample, coated with metal atoms, to study details of its topography
Cell fractionation
The disruption of a cell and separation of its parts by centrifugation at successively higher speeds
Plasma Membrane
the membrane at the boundary of every cell that acts as a selective barrier, regulating the cell’s chemical composition
Cytosol
the semifluid portion of the cytoplasm. Sub cellular components are suspended in the cytosol.
Eukaryotic cells
A type of cell with membrane enclosed Nucleus and membrane enclosed organelles
- DNA in Nucleus and has multiple linear chromosomes
- has internal membranes that divide the cell into compartments that provide local environments so incompatible processes can occur simultaneously in a single cell.
Prokaryotic cells
A type of cell lacking a membrane-enclose Nucleus and membrane enclose organelles
- DNA in concentrated in a region that is not membrane enclosed called the nucleoid
- Has a singular, circular chromosome.
Cell Wall
A protective layer external to the plasma membrane in the cells of plants. The cell wall is composed of cellulose. It protects the plant cell, maintains its shape, and prevents the excessive uptake of water
Plasmodesmata
An open channel through the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes, and some larger molecules to pass between cells
Organelles that plant cells have and animal cells do not
Chloroplast, Plastids, and a central vacuole
Extracellular matrix
The meshwork surrounding animal cells. Regulates cell behavior and communication through integrins
Integrin
A transmembrane receptor protein with two subs units that interconnect the extracellular matrix and the cytoskeleton
Tight Junction
Animal junction that forms a continuous seal around the cell
Desmosomes
Animal junction that functions like rivets, fastening cells into strong sheets
Gap Junctions
Animal cell junction that Provides Cytoplasmic channels from one cell to an adjacent cell
- creates pores which small molecules may pass through
- necessary for communication
Organelles that animal cell have and plant cells do not
Centrosomes and lysosome
Nucleus
The organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, which are made up of chromatin
Nuclear envelope
The double membrane that surrounds the nucleus, perforated with pores that regulate the traffic within the cytoplasm. The outer membrane is continuous with the ER
Nuclear Laminate
A netlike array of protein filaments that lines the inner surface of the nuclear envelope and helps maintain the shape of the nucleus
Chromosomes
A cellular structure consisting of one DNA molecule and associated protein molecules.
Chromatin
The complex of DNA and proteins that make up eukaryotic chromosomes. When the cell is not dividing chromatin exists in dispersed form, as a mass of very long, thin fibers.
- as the cell gets ready to divide the chromatin coils together and forms distinct chromosomes
Nucleolus
A specialized structure in the nucleus, consisting of chromosomal regions containing ribosomal RNA genes along with ribosomal proteins imported from the cytoplasm
Site of rRNA synthesis and ribosomal subunit assembly
Ribosome
A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm. Consists of a large and a small unit.
Not membrane bound
Free ribosomes
Ribosomes suspended in the cytosol. Most of the proteins made on free ribosomes function within the cytosol
Bound ribosomes
Attached to the outside of the ER or nuclear envelope. Make proteins that are destined for insertion into membranes, for packing within certain organelles, or for export from the cell. Cells that specialize in protein secretion have a high proportion of bound ribosomes
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.
Endoplasmic Reticulum
An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded and ribosome free regions
Smooth ER
The portion of the endoplasmic reticulum with no ribosomes attached
- Functions in the synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poison, and the storage of calcium ions
Rough ER
the portion of ER with ribosomes attached
- function
- ribosomes produce protein
- membrane factory for cells
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 endoplasmic reticulum and synthesize some products, notably non cellulose carbohydrates.
Products of the ER are modified stored, and sent to other destinations in the GA
Cis face is located near ER and trans face gives rise to vesicles that pinch off and travel to other sites
Lysosome
A membranous enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some protists
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.
Autophagy
Lysosomes recycle the cell’s own organic material
- a damaged organelle will be surrounded by a double membrane which will fuse with a lysosome.
Vacuole
A membrane bounded vesicle whose specialized function varies in different kinds of cells
Food vacuole
A membranous sac formed by the phagocytosis of microorganisms or particles to be used as food by the cell
Contractile Vacuole
A membranous sac that helps move excess water out of certain freshwater protists
Central Vacuole
In a mature plant cell, a large membranous sac with diverse roles in growth, storage, and sequestration of toxic substances
Mitochondria
An organelle in eukaryotic cells that serves as the site of cellular respiration
- uses oxygen to break down organic molecules and synthesize ATP
Chloroplast
An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water
Endosymbiont Theory
The theory that mitochondria and plastids originated as prokaryotic cells engulfed by a host cell. The engulfed cell and its host cell then evolved into a single organism
Mitochondria and chloroplast both contain their own ribosomes as well as circular DNA associated with their inner membranes. They are both autonomous organelles that grow and reproduce within the cell.
Cytoskeleton
A network of microtubules, microfilaments, and intermediate filaments that extends through the cytoplasm and serve a variety of mechanical, transport, and signaling functions
Motor Proteins
A protein that interacts with cytoskeletal elements and other components, producing movement of the whole cell or parts of the cell
Cell Motility
A protein that interacts with cytoskeletal elements and other components, producing movement of the whole cell or parts of the cell.
Function of the Cytoskeleton
Gives mechanical support to the cell, aids in maintaining its shape,
It can be quickly dismantled in one part of the cell and reassembled in a new location, changing the shape of the cell.
Microtubules
A hollow rod composed of tubulin proteins that make up part of the cytoskeleton and is found in cilia and flagella
Centrosome
A structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division
Has two centrioles
Flagella
A long cellular appendage specialized for locomotion
Composed of a core with nine outer doublet microtubules and two inner single microtubules ensheathed in an extension of the plasma membrane
Cilia
A short appendage containing microtubules
Can function in movement, sensory, or signaling
Basal Body
Organize the microtubule assembly of cilium or flagellum and is similar to a centriole
Dynein
In cilia and flagella, a large motor protein extending from one doublet to another. ATP hydrolysis drives changes in dynein shape that leads to the bending of cilia and flagella
Microfilaments
A cable composed of actin proteins in the cytoplasm, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction
Actin
A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other kinds of cells
Cortex
The outer region of cytoplasm in eukaryotic cells, lying just under the plasma membrane, that has a more gel-like consistency than the inner regions due to the presence of multiple microfilaments
Myosin
A type of motor protein that associated into filaments that interact with actin filaments to cause cell contraction
Cytoplasmic streaming
A circular flow of cytoplasm, involving interactions of myosin and actin filaments, that speeds up the distribution of materials within cells
Intermediate filaments
A component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments
Seems to function as the permanent framework of the entire cell
