Human Biology by Sylvia Mader CH 1, 2, 3,4
1. Actin Filament: Component of the cytoskeleton; plays a role in the movement of
the cell and its organelles; a protein filament in a sarcomere of a muscle, its
movement shortens the sarcomere, yielding muscle contraction
2. Bacillus: A rod-shaped bacterium; also a genus of bacteria
3. Capsule: A form of glycocalyx that consists of a gelatinous layer; found in blue-
green algae and certain bacteria
4. Cell: The smallest unit of life that displays all the properties of life; composed of
cytoplasm surrounded by a plasma membrane
5. Cell Envelope: In a prokaryotic cell, the portion composed of the plasma
membrane, the cell wall, and the glycocalyx
6. Cell Theory: One of the major theories of biology, which states that all organisms
are made up of cells; cells are capable of self-reproduction and come only from
preexisting cells
7. Cell Wall: Cellular structure that surrounds a plant, protistan, fungal, or bacterial
cell and maintains the cell's shape and rigidity; composed of polysaccarides
8. Central Vacuole: In a plant cell, a large, fluid-filled sac that stores metabolites.
During growth, it enlarges, forcing the primary cell wall to expand and the cell
surface-area-to-volume ration to increase
9. Centriole: Cell structure, existing in pairs, that occurs in the centrosome and
may help organize a mitotic spindle for chromosome movement during animal cell
division
10. Centrosome: Central microtubule organized center of cells. In animal cells, it
contains two centrioles.
11. Chloroplats: Membrane-bounded organelle in algae and plants with
chlorophyll-containing membranous thylakoids; where photosynthesis takes place
12. Chromatin: Network of DNA strands and associated proteins observed within
a nucleus of a cell
13. Chromoplast: Plastid in land plants responsible for orange, yellow, and red
color of plants, including the autumn colors in leaves
14. Chromosome: The structure that transmits the genetic material form one
generation to the next; composed of condensed chromatin; each species has a
particular number of chromosomes that is passed on to the next generation
15. Cilia (Sing., Cilium): Short, hairlike projections from the plasma membrane,
occurring usually in larger numbers
16. Cristae (Sing., Crista): Short, finger-like projections formed by the folding of
the inner membrane of the mitochondira
17. Cynobacterium (Pl., Cyanobaceria): Photosynthetic bacterium that contains
chlorophyll and releases oxygen; formerly called a blue-green alga
, .
18 Cytoplasm: Region of a cell between the nucleus, or the nucleoid region of a
bacterium, and the plasma membrane; contains the organelles of the cell
19. Cytoskeleton: Internal framework of the cell, consisting of microtubules, actin
filaments, and intermediate filaments
20. Endomembrane System: Cellular system that consists of the nuclear
envelope, endoplasmic reticulum, Golgi apparatus, and vesicles
21. Endoplasmic Reticulum (ER): System of membranous saccules and
channels in the cytoplasm, often with attached ribosomes
22. Eukaryotic Cell (Eukaryote): Type of cell that has a membrane-bounded
nucleus and membranous organelles; found in organisms with the domain Eukarya
23. Gene: Unit of heredity existing as alleles on the chromosomes; in diploid
organisms, typically to alleles are inherited-one from each parent
24. Glycocalyx: Gel-like coating outside the cell wall of a bacterium. If compact,
it is called a capsule; if diffused, it is called a slime layer
25. Golgi Apparatus: Organelle consisting of sacs and vesicles that processes,
packages, and distributes molecules about or from the cell
26. Granum (Pl., Grana): Stack of chlorophyll-containing thylakoids in a
chloroplast
27. Intermediate Filament: Rope-like assemblies of fibrous polpypeptides in the
cytoskeleton that provide support and strength to cells; so called because they are
intermediate in size between actin filaments and microtubules
28. Lysosome: Membrane-bounded vesicle that contains hydrolytic enzymes for
digesting macromolecules and bacteria; used to recycle worn-out cellular
organelles 29. Mesosome: In a bacterium, plasma membrane that folds into the
cytoplasm and increases surface area
30. Microtubule: Small, cylindrical organelle composed of tubulin protein around
an empty central core; present in the cytoplasm, centrioles, cilia, and flagella
31. Mitochondria (Sing., Mitochondrion): Memembrane-bounded organelle in
which ATP molecules are produced during the process of cellular respiration
32. Motor Molecule: Protein that moves along either actin filaments or
microtubules and translocates organelles
33. Nuclear Envelope: Double membrane that surrounds the nucleus in
eukaryotic cells and is connected to the endoplasmic reticulum; has pores that allow
substances to pass between the nucleus and the cytoplasm
34. Nuclear Pore: Opening in the nuclear envelope that permits the passage of
proteins into the nucleus and ribosomal sub-units out of the nucleus
35. Nucleoid: Region of prokaryotic cells where DNA is located; it is not bounded
by a nuclear envelope
, .
36. Nucleolus: Dark-staining, spherical body in the nucleus that produces
ribosomal subunits
37 Nucleoplasm: Semi-fluid medium of the nucleus containing chromatin
38. Organelle: Small, membranous structures in the cytoplasm having specific
structure and function
39. Peroxisome: Enzyme-filled vesicle in which fatty acids and amino acids are
metabolized to hydrogen peroxide that is broken down to harmless products
40. Plasma Membrane: Membrane surrounding the cytoplasm that consists of a
phospholipid bi-layer with embedded proteins; functions to regulate the entrance
and exit of molecules from cell
41. Plasmid: Extrachromosomal ring of accessory DNA in the cytoplasm of
prokaryotes
42. Plastid: Organelles of plants and algae that are bounded by a double
membrane and contain internal membranes and/or vesicles (i.e., chloroplasts,
chromoplasts, leucoplasts)
43. Prokaryotic Cell: Cells that generally lack a membrane-bounded nucleus and
organelles; and the cell type within the domains Bacteria and Archaea
44. Ribosome: Site of protein synthesis in a cell; composed of proteins and
ribosomal RNA (rRna)
45. Rough ER: Membranous system of tubules, vesticels, and sacs in cells; has
attached ribosomes
46. Smooth ER: Membranous system of tubules, vesicles, and sacs in eukaryotic
cells; site of lipid synthesis; lacks attached ribosomes
47. Spirochete: Long, rod-shaped bacterium that is twisted into a flexible spiral; if
the spiral is rigid rather than flexible, it is called a spirillum
48. Stroma: Region within a chloroplast that surrounds the grana; contains
enzymes involved int eh synthesis of carbohydrates during the Calvin cycle of
photosynthesis
49. Surface-Area-To-Volume-Ratio: Ration of a cell's outside area to its internal
volume; the relationship limits the maximum size of a cell
50. Thylakoid: Flattened sac within a granum of a chloroplast; membrane
contains chlorophyll, location where the light reactions of photosyntheis occur
51. Vacuole: Membranepbounded sac, larger than a vesicle; usually functions in
storage and can contain a variety of substances. In plants, a central one fills much
of the interior of the cell
52. Vesicle: Small, membrane-bounded sac that stores substances within a cell
53. Levels of Organization: atoms, molecules, cells, tissues, organs, organ
systems, populations, community, ecosystem, biosphere
