Chapter 4 Flashcards
Plasma Membrane
Outer surface that regulates entrance and exit of molecules
Cytoskeleton
Maintains cell shape and assists movement of cell parts. Internal framework of the cell, consisting of microtubules, actin filaments, and intermediate filaments
Microtubules
Protein cylinders that move organelles
Intermediate Fillaments
Protein fibers that provide stability or shape
Actin Filaments
Protein fibers that play a role in cell division and shape
Centrioles
Short cylinders of microtubules. Not found in plant cells
Centrosome
Microtubule organizing center that contains a pair of centrioles
Vesicle
Small membrane bound sac that stores and transports substances
Lysosome
Vesicle that digests macromolecules and even cell parts. Not commonly found in plant cells
Golgi apparatus
Processes, packages, and secretes modified proteins
Mitochondrion
Organelle that carries out cellular respiration producing ATP molecules
Polyribosome
String of ribosomes simultaneously translating regions of the same mRNA strand during protein synthesis
Ribosome
Particles that carry out protein synthesis; composed of proteins and ribosomal RNA (rRNA)
Peroxisome
Vesicle that is involved in fatty acid metabolism
Smooth ER
Lacks ribosomes, synthesizes lipid molecules
Rough ER
Studded with ribosomes that synthesize proteins. Membranous system of tubules, vesicles, and sacs in cells.
Endoplasmic Reticulum (ER)
System of membraneous saccules and channels int the cytoplasm. Often with attached ribosomes. Protein and lipid metabolism
Nucleolus
Region that produces subunits of ribosomes. Dark- staining spherical body in the nucleus
Chromatin
Network of DNA strands and associated proteins observed within a nucleus of a cell. Diffuse threads containing DNA and protein
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
Nucleus
Command center of cell. Membrane-bound organelle within a eukaryotic cell that contains chromosomes and controls the structure and function of the cell
Cell theory
- all organisms are composed of cells
- cells are the basic unit of structure and function in organisms
- cells come only from preexisting cells because cells are self-reproducing
Prokaryotic Cells
Cells without a membrane-bound nucleus
Eukaryotic Cells
Cells that posses a nucleus.
Bacillus
Rod-shaped bacterium
Coccus
Spherical shaped bacterium
Spirillum
Long, rod-shaped bacterium twisted into a flexible spiral; if the spiral is rigid rather than flexible it is called a spirochete
Cell envelope
In a prokaryotic cell, the portion composed of the plasma membrane, the cell wall, and the glycalyx
Plasma membrane
Membrane surrounding the cytoplasm that consists of a phospholipid bilayer with embedded proteins; functions to regulate the entrance and exit of molecules from cell
Cell wall
Cellular structure that surrounds a plant, protistan, fungal, or bacterial cell and maintains the cells shape and rigidity; composed of polysaccharides
Glycocalyx
Gel-like coating outside the cell wall of a bacterium. If compact, it is called a capsule; if diffuse, it is called a slime layer. This coating helps protect the bacterium against drying out and evade the hosts immune system
Capsule
A form of glycocalyx that consists of a gelatinous layer found in blue-green algae and certain bacteria
Cytoplasm
Region of a cell between the nucleus, or the nucleotide region of a bacterium, and the plasma membrane. It is composed of a semi fluid solution composed of water and organic and inorganic materials
Nucleoid
Region of prokaryotic cells where DNA is located; it is not bound by a nuclear envelope
Plasmids
Extra chromosomal ring of accessory DNA in the cytoplasm of prokaryotes
Cyanobacteria
Photosynthetic bacterium that contains chlorophyll and releases oxygen; formerly called a blue-green alga
Thylakoid
Flattened sac within a granny of a chloroplast; membrane contains chlorophyll; location where the light reactions of photosynthesis occur
Flagella
Long, slender extension used for locomotion by some bacteria, protozoans, and sperm
Fimbria
Small, bristle-like fiber in the surface of a bacterial cell, which attaches bacteria to a surface
Conjugation Pili
In a bacterium, elongated, hollow appendage used to transfer DNA to other cells
Organelles
Small, membranous structure in the cytoplasm having a specific structure and function
Endosymbiotic Theory
Explanation of the evolution of eukaryotic organelles by phagocytosis of prokaryotes
Nucleoplasm
Semi fluid medium of the nucleus containing chromatin
Chromosomes
The structure that transmits the genetic material from 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.
Gene
Unit of heredity existing as alleles on the chromosome. In diploid organisms, typically two alleles are inherited-one from each parent.
Nuclear pores
Opening in the nuclear envelope that permits the passage of proteins into the nucleus and ribosomal subunits out of the nucleus
Autophagy
Breakdown of the internal structures of a eukaryotic cell by the lysosomes
Microbodies
Membrane bound vesicles that contain enzymes used for metabolic functions
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 ratio to increase
Chloroplasts
Membrane bound organelle in algae and plants with chlorophyll containing membranous thylakoids; where photosynthesis takes place
Mitochondria
Breaks down carbohydrate derived products to produce ATP
Storms
Semi fluid region enclosed by a double membrane
Plastid
Plant organelles that’s are surrounded by a double membrane and have varied functions
Cristae
Short, fingerling projections formed by the folding of the inner membrane of mitochondria
