Honors Biology - Chapter 4
Light Microscope (LM) - Optical instrument with lenses that refract (bend) visible light to magnify images and project them into the viewer's eye or onto photographic film. These can be used to study live specimens, but they only magnify about a thousand times.
Electron Microscope (EM) - A microscope that uses magnets to focus an electron beam on or through a specimen, resulting in resolving power a thousandfold greater than that of a light microscope. Achieves a hundredfold greater resolution than a light microscope.
Scanning Microscope (SEM) - A microscope that uses an electron beam to study the surface details of a cell or other specimens.
Transmission Electron Microscope (TEM) - A microscope that uses an electron beam to study the internal structure of thinly sectioned specimens.
cell theory - the idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells.
plasma membrane - The membrane at the boundary of every cell that acts as a selective barrier to the passage of ions and molecules into and out of the cell; consists of a phospholipid bilayer with embedded proteins (also referred to as cell membranes)
prokaryotic cells - Were the first to evolve, are simpler, and are usually smaller than eukaryotic cells (Earth's sole inhabitants for 1.5 billion years). Also a type of cell lacking a membrane-enclosed nucleus and other membrane-enclosed organelles; found only in the domains of BACTERIA and ARCHAEA
eukaryotic cells - A type of cell that has a membrane-enclosed nucleus and membrane-enclosed organelles. ALL organisms EXCEPT Bacteria and Archea are composed of this cell.
Cytosol - The semifluid portion of the cytoplasm
Cytoplasm - The contents of a eukaryotic cell between the plasma membrane and the nucleus; consists of a semifluid medium and organelles; can also refer to the interior of a PROKARYOTIC cell. In EUKARYOTIC cells this term refers ONLY to the region between the nucleus and plasma membrane
Chromosome - a gene-carrying structure found in the nucleus of a eukaryotic and most visible during mitosis and meiosis; also, the main gene-carrying structure of a prokaryotic cell. Consists of one very long DNA molecule and associated proteins.
Ribosome - A cell structure consisting of RNA and proteins organized into two subunits and functioning as the SITE of protein synthesis in the CYTOPLASM. In EUKARYOTIC cells, the ribosomal subunits are constructed in the NUCLEUS.
nucleoid
A non-membrane-bounded region in a prokaryotic cell where the DNA is concentrated
Flagellum - A long cellular appendage specialized for locomotion. The flagella of prokaryotes and eukaryotes DIFFER in both structure and function. Like cilia, eukaryotic flagella have a "9+2" arrangement of microtubules covered by cell plasma membrane
Cell (Surface-to-Volume) Ratio - Large cells have more surface area than small cells, but they have a much smaller surface area relative to their volume than small cells. (Efficiency in moving cells inside and out (also relevant to maintain temperature))
smooth endoplasmic reticulum (ER) - The portion of the endoplasmic reticulum that lacks ribosomes. Also storages calcium ions
rough endoplasmic reticulum (ER) - The portion of the endoplasmic reticulum with ribosomes attached that make membrane proteins and secretory proteins. Is also a membrane-making machine for the cell.
Glycoprotien - A protein with one or more short chains of sugar attached
transport vesicle - A small membranous sac in a eukaryotic cell's cytoplasm carrying molecules produced by the cell. The vesicle buds from the endoplasmic reticulum or Golgi and eventually fuses with another organelle or the plasma membrane, releasing its contents.
Organelles - A membrane-enclosed structure with a specialized function within a cell.
free ribosomes - Are suspended in cytosol, structurally identical to BOUND ribosomes and can function in either location, depending on the protein their making
bound ribosomes - Are attached to the outside of the endoplasmic reticulum or nucleus envelope
endomembrane system - A network of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles. The nuclear envelope, endoplasmic reticulum, Golgi Apparatus, vesicles, lysosomes, and vacuoles are all in the endomembrane system.
endoplasmic reticulum - An extensive membranous network in a eukaryotic cell, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.
Phospholipids - A lipid made up of glycerol joined to two fatty acids and a phosphate group, giving the molecule two non-polar hydrophobic tails and a polar hydrophilic head. Phospholipids form bilayers that function as biological membranes. Are made by the enzymes of the ROUGH ER
golgi appartus - An organelle in eukaryotic cells consisting of stacks of membranous sacs that modify, store, and ship products of the endoplasmic reticulum.
Serves:
- As a warehouse and processing station for ER products
golgi enzymes - Modify the carbohydrate portions of the glycoproteins made in ER
Lysosomes - A digestive organelle in eukaryotic cells; contains hydrolytic enzymes that digest engulfed food or damaged organelles.
Extra Info:
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* Lysosomes are derived from two Greek words meaning "breakdown body" - \
* Enzymes and membranes are made from Rough ER - \
* Have several digestive functions
Vacuole - A membrane-enclosed sac that is part of the endo-membrane system of a eukaryotic cell and has diverse functions in different kinds of cells.
Central Vacuole - In a plant cell, a large membranous sac with diverse roles in growth and the storage of chemicals and wastes.
Peroxisome - An organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen, producing and then degrading hydrogen peroxide. Some peroxisomes break down fatty acids to be used as cellular fuel. Also, in the liver they detoxify harmful compounds
Mitochondria - An organelle in eukaryotic cells where cellular respiration occurs. Enclosed by two membranes, it is where most of the cell's ATP is made. Also has two phospholipid bilayers
mitochondrial matrix - The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle.
Chloroplast - An organelle found in plants and algae that absorbs sunlight and uses it to drive the synthesis of organic compounds (sugars) from carbon dioxide and water.
Stroma - The dense fluid within the chloroplast that surrounds the thylakoid membrane. Sugars are made in the stroma by the enzymes of the Calvin cycle.
Thylakoid - A flattened membranous sac inside a chloroplast. Thylakoid membranes contain chlorophyll and the molecular complexes of the light reactions of photosynthesis. A stack of thylakoids is called a GRANUM.
thylakoid space - The compartments inside the thylakoids
endosymbiont theory - The theory that mitochondria and chloroplasts originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism.
Cytoskeleton - A network of protein fibers in the cytoplasm of a eukaryotic cell; includes microfilaments, intermediate filaments, and microtubules.
motor proteins - A protein that interacts with the cytoskeleton and other cell components, producing movement of the whole or parts of the cell
Microtubule - The thickest of the three main kinds of fibers making up the cytoskeleton of a eukaryotic cell; a hollow tube made of globular proteins called tubulins; found in cilia and flagella. Readily disassembled and their tubulin can be reused elsewhere in the cell
intermediate filaments - An intermediate-sized protein fiber that is one of the three main kinds of fibers making up the cytoskeleton of eukaryotic cells. Intermediate filaments are ropelike, made of fibrous proteins.
What it does:
- Reinforces cell shape and anchors some organelles. Also are more often permanent fixtures in the cell.
Microfilaments - The thinnest of the three main kinds of protein fibers making up the cytoskeleton of a eukaryotic cell; a solid, helical rod composed of the globular protein actin.
What it does:
- forms a three-dimensional network that helps support the cell's shape. Also involved in cell movement.
Centrosome - A structure found in animal cells from which microtubules originate and that is important during cell division. A centrosome has two centrioles.
Cilia - A type of protist that moves and feeds by means of cilia. Ciliates belong to the alveolate clade of the SAR supergroup. Cilia and FLAGELLA have common structures and mechanisms of movement.
primary cilium - Is important to embryonic development, sensory reception, and cell function
extracellular matrix (ECM) - The meshwork surrounding animal cells; consists of glycoproteins and polysaccharides synthesized and secreted by cells.
Integrin - A transmembrane protein that interconnects the extracellular matrix and the cytoskeleton in animal cells.
tight junctions - Tight junctions, the plasma membranes of neighboring cells are knit tightly together by proteins. Tight junctions prevent leakage of fluid across a layer of cells.
anchoring junctions - Anchoring junctions function like rivets, fastening cells together into strong sheets. Intermediate filaments made of sturdy proteins anchor these junctions in the cytoplasm. Anchoring junctions are common in tissues subject to stretching or mechanical stress, such as skin and muscle.
gap junctions - Gap junctions, also called communicating junctions, are channels that allow small molecules to flow through protein-lined pores between cells. The flow of ions through gap junctions in the cells of heart muscle coordinates their contraction. Gap junctions are common in embryos, where communication between cells is essential for development.
cell wall - A protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists; protects the cell and helps maintain its shape. Cell walls contain cellulose, polysaccharides, and proteins
Plasmodesma - An open channel in a plant cell wall that connects the cytoplasm of adjacent cells.
contractile vacuole - Controls the intracellular water balance by accumulating and expelling excess water out of the cell, allowing cells to survive under hypotonic stress as in pond water (specific to peroxisome).