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Biology Terms Test #2

The Important Terms for Test #2 for Biology
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Anchoring Junction
a junction which holds cells strongly together in tissue meant to stretch.
Cell Wall
the rigid extracellular structure that protects the cell and also provides skeletal support; only in plant cells.
Chloroplast
the photosynthesizing organelles of all photosynthetic eukaryotes
Chromatin
a complex of proteins and DNA which makes up the eukaryotic chromosomes.
Cilia
short, numerous appendages that propel protists (we have these in our windpipe)
Cistern
the flattened sacs of the Golgi body
Compound Light Microscope
works by passing visible light through a specimen; glass lenses in the microscope bend the light to magnify the image of the specimen and project the image into the viewer's eye (1,000 x mag.)
Cristae
the folds of the inner membrane of the Mitochondria.
Cytoplasm
the entire region between the nucleus and the plasma membrane.
Cytosol
the liquid component of the cytoplasm
Cytoskeleton
a network of protein fibers that extend through the cytoplasm of a cell, which provide not only structure for the cell, but also cell mobility.
Endosymbiosis Theory
Eukaryotes evolved as a larger prokaryotic cell engulfed a smaller prokaryotic cell which took on specific functions over time; this is involved with mitochondria and chloroplasts
Endoplasmic Reticulum
An interconnected system of tubes and flattened sacs that is involved in the transport, modification and addressing of substances. There are two types of these: smooth and rough.
Eukaryotic
compose all forms of life except for bacteria and archaea; have a nucleus
Flagellum
longer versions of cilia, which are a lot less numerous in the cell.
Gap Junction
a junction which provides direct connection between cytoplasm
Granum
the chloroplast's site where the green chlorophyll molecules trap energy.
Golgi body
a system of flattened sacs on top of each other; packages, further modifies and addresses the substances.
Intermediate Filament
the part of the cytoskeleton that is rigid for support and shape; Keratin is an example.
Lysosome
a vesicle containing hydrolytic enzymes for intracellular digestion; it breaks down food particles in the cell.
Matrix
(of a mitochondria); contains the mitochondrial DNA and ribosomes as well as many enzymes that catalyze some of the reactions of cellular respiration.
Microfilament
the part of the cytoskeleton that helps with muscle contractions, helps with cell shape and support, and helps with cell division (cytokinesis).
Microtubule
the part of the cytoskeleton that is the track for motor proteins (dynein and kinesin) it also makes up the Spindle Fibers that move chromosomes during mitosis/meiosis
Mitochondria
organelles that carry out cellular respiration in nearly all eukaryotic cells; they synthesize ATP
Nuclear Envelope
encloses the nucleus. It is a double membrane perforated with nuclear pores.
Nucleoid region
the dense region of DNA in a prokaryotic cell
Nucleolus
a prominent structure in the nucleus, where rRNA is synthesized according to instructions in the DNA
Nucleoplasm
similar to the cytosol of the cytoplasm, the nucleus contains this sappy liquid
Nucleus
contains most of the cell's DNA and controls the cell's activities by directing protein synthesis
Peroxisome
contains the enzyme catalase for breaking down and detoxifying certain chemicals
Plasmodesmata
gap junctions in the cell wall of plants so that the cells can communicate with each other
Plasma Membrane
the membrane that bounds all cells.
Prokaryotic
compose bacteria and archaea; have no nucleus
Ribosome
the site of protein synthesis; they are small and numerous in the cells. They can be suspended in the fluid of the cytoplasm (free ribosomes) or bound to the outside of the endoplasmic reticulum (bound ribosomes).
SEM (scanning electron microscope)
A microscope that uses an electron beam to scan the surface of a cell or group of cells that has been coated with metal; it emits electrons and the electrons are detected and projected onto a computer screen.
Stroma
the thick fluid composed of chloroplast DNA and ribosomes as well as enzymes. It is in the compartment within the inner membrane of a chloroplast.
Thylakoid
the interconnected sacs inside of the chloroplasts; many grana make this up
Transmitting Electron Microscope (TEM)
a microscope that works by transmitting an electron beam through a very small section of a specimen; the image is created by the pattern of transmitted electrons.
Tight Junction
a junction that prevents substances from passing in between cells
Vacuole
membranous sacs that have a variety of functions; essential for storage in the cell.
Vesicle
a membrane bound sphere that carries a specific substance throughout the cell.
Vesicle Transport
the process by which a substance is moved through the endomembrane system by a vesicle.
9 + 2 Microtubule
both flagella and cilia are composed of microtubules wrapped in an extension of the plasma membrane. A ring of nine microtubule doublets surrounds a central pair of microtubules. This arrangement is found in nearly all eukaryotic flagella and cilia.