Chapter 5 | BIOL 1001 - GENERAL BIOLOGY, Quizzes of Biology

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Aerobic

using oxygen. TERM 2

Anaerobic

DEFINITION 2 not using oxygen. TERM 3

Basal Body

DEFINITION 3 a structure resembling a centriole that produces a cilium or flagellum and anchors this structure within the plasma membrane. TERM 4

Central Vacuole

DEFINITION 4 a large, fluid-filled vacuole occupying most of the volume of many plant cells; performs several functions, including maintaining turgor pressure. TERM 5

Centriole

DEFINITION 5 in animal cells, a short, barrel-shaped ring consisting of nine microtubule triplets; a microtubule-containing structure at the base of each cilium and flagellum; gives rise to the microtubules of cilia and flagella and is involved in spindle formation during cell division.

Chlorophyll

a pigment found in chloroplasts that captures light energy during photosynthesis; absorbs violet, blue, and red light but reflects green light. TERM 7

Chloroplast

DEFINITION 7 the organelle in plants and plantlike protists that is the site of photosynthesis; surrounded by a double membrane and containing an extensive internal membrane system that bears chlorophyll. TERM 8

Chromatin

DEFINITION 8 the complex of DNA and proteins that makes up eukaryotic chromosomes. TERM 9

Chromosome

DEFINITION 9 a single DNA double helix together with proteins that help to organize the DNA. TERM 10

Cilium

DEFINITION 10 a short, hairlike projection from the surface of certain eukaryotic cells that contains microtubules in a 9+ arrangement. The movement of cilia may propel cells through a fluid medium or move fluids over a stationary surface layer of cells.

Contractile Vacuole

a fluid-filled vacuole in certain protists that takes up water from the cytoplasm, contracts, and expels the water outside the cell through a pore in the plasma membrane. TERM 12

Cytoplasm

DEFINITION 12 the material contained within the plasma membrane of a cell, exclusive of the nucleus. TERM 13

Cytoskeleton

DEFINITION 13 a network of protein fibers in the cytoplasm that gives shape to a cell, holds and moves organelles, and is typically involved in cell movement. TERM 14

DNA

DEFINITION 14 a molecule composed of deoxyribose nucleotides; contains the genetic information of all living cells. TERM 15

Endoplasmic Reticulum

DEFINITION 15 a system of membranous tubes and channels within eukaryotic cells; the site of most protein and lipid syntheses.

endosymbiont hypothesis

the hypothesis that certain organelles, especially chloroplasts and mitochondria, arose as mutually beneficial associations between the ancestors of eukaryotic cells and captured bacteria that lived within the cytoplasm of the pre- eukaryotic cell. TERM 17

Eukaryotic

DEFINITION 17 referring to cells of organisms of the domain Eukarya (plants, animals, fungi, and protists). Eukaryotic cells have genetic material enclosed within a membrane-bound nucleus and contain other membrane-bound organelles. TERM 18

Flagellum

DEFINITION 18 a long, hairlike extension of the plasma membrane; in eukaryotic cells, it contains microtubules arranged in a pattern. The movement of flagella propel some cells through fluids. TERM 19

Food Vacuole

DEFINITION 19 a membranous sac, within a single cell, in which food is enclosed. Digestive enzymes are released into the vacuole, where intracellular digestion occurs. TERM 20

Golgi

Complex

DEFINITION 20 a stack of membranous sacs, found in most eukaryotic cells, that is the site of processing and separation of membrane components and secretory materials.

Intermediate Filament

part of the cytoskeleton of eukaryotic cells that probably functions mainly for support and is composed of several types of proteins. TERM 22

Lysosome

DEFINITION 22 a membrane-bound organelle containing intracellular digestive enzymes. TERM 23

Microfilament

DEFINITION 23 part of the cytoskeleton of eukaryotic cells that is composed of the proteins actin and (in some cases) myosin; functions in the movement of cell organelles and in locomotion by extension of the plasma membrane. TERM 24

Microtubule

DEFINITION 24 a hollow, cylindrical strand, found in eukaryotic cells, that is composed of the protein tubulin; part of the cytoskeleton used in the movement of organelles, cell growth, and the construction of cilia and flagella. TERM 25

Mitochondrion

DEFINITION 25 an organelle, bounded by two membranes, that is the site of the reactions of aerobic metabolism.

Nuclear Envelope

the double-membrane system surrounding the nucleus of eukaryotic cells; the outer membrane is typically continuous with the endoplasmic reticulum. TERM 27

Nucleiod

DEFINITION 27 the location of the genetic material in prokaryotic cells; not membrane-enclosed. TERM 28

Nucleolus

DEFINITION 28 the region of the eukaryotic nucleus that is engaged in ribosome synthesis; consists of the genes encoding ribosomal RNA, newly synthesized ribosomal RNA, and ribosomal proteins. TERM 29

Nucleus

DEFINITION 29 the membrane-bound organelle of eukaryotic cells that contains the cell's genetic material. TERM 30

Organelle

DEFINITION 30 a structure, found in the cytoplasm of eukaryotic cells, that performs a specific function; sometimes refers specifically to membrane-bound structures, such as the nucleus or endoplasmic reticulum.

Plastid

in plant cells, an organelle bounded by two membranes that may be involved in photosynthesis (chloroplasts), pigment storage, or food storage. TERM 32

Prokaryotic

DEFINITION 32 referring to cells of the domains Bacteria or Archaea. Prokaryotic cells have genetic material that is not enclosed in a membrane-bound nucleus; they lack other membrane- bound organelles. TERM 33

RNA

DEFINITION 33 a molecule composed of ribose nucleotides, each of which consists of a phosphate group, the sugar ribose, and one of the bases adenine, cytosine, guanine, or uracil; transfers hereditary instructions from the nucleus to the cytoplasm; also the genetic material of some viruses. TERM 34

Ribosome

DEFINITION 34 sequence of bases of messenger RNA is translated into the sequence of amino acids in a protein. TERM 35

Vacuole

DEFINITION 35 a vesicle that is typically large and consists of a single membrane enclosing a fluid-filled space.