The Cell Flashcards
(24 cards)
Four tenets of cell theory
(1) All living things are composed of cells
(2) The cell is the basic functional unit of life
(3) Cells arise only from preexisting cells
(4) Cells carry genetic information in the form of DNA which is passed on from parent to daughter cell
Eukaryotic vs Prokaryotic Cells
Eukaryotic cells contain a true nucleus enclosed in a membrane while prokaryotic cells have no nucleus
Eukaryotic cells also have mitochondria or chloroplasts and have chromosomal DNA
Nuclear pores
Found in the nuclear membrane; allows selective two-way exchange of material between the cytoplasm and the nucleus
Nucleolus
a section of the nucleus; takes up about 25% of the nucleus; the location of ribosomal RNA (rRNA) synthesis
Organization of DNA
Linear DNA is wound around organizing proteins known as histones and then further wound into strands called chromosomes
Structure of the Mitochondria
Outer membrane - barrier between teh cytosol and inner environment
Inner membrane - arranged into folds called cristae
Cristae - location of enzymes and molecules of the ETC
Inter-membrane space - space between inner and outer membrane
Matrix - space inside the inner membrane
Membrane-Bound Organelles
In eukaryotic cells, most organelles are membrane bound. This facilitates the compartmentalization of functions (i.e. separation of transcription and translation)
The Nucleus
The control center of the cell; contains all the genetic material needed for replication; surrounded by the nuclear membrane or envelope (double membrane)
Theory of the origin of mitochondria
Mitochondria are thought to have originated when teh engulfing of an aerobic prokaryote by an anaerobic prokaryote resulted in a symbiotic relationship
Apoptosis
Programmed cell death; caused by release of enzymes from the ETC (found in the mitochondria)
Lysosomes
Membrane-bound organelle containing hydrolytic enzymes to break things down.
Endosomes
Transport, package and sort cell material travelling to and from the membrane (moves material to the trans-golgi, cell membrane, or lysosomal pathway for degradation)
Autolysis
Release of lysosomal hydrolytic enzymes leads the the degradation of the cell
Endoplasmic Reticulum
A series of interconnected membranes that are contiguous with the nuclear envelope. The double membrane is folded into a complex structure with a central lumen.
Rough ER - has ribosomes to allow for protein synthesis
Smooth ER - no ribosomes; lipid synthesis, detoxification of certain toxins, transports proteins from RER to Golgi apparatus
Golgi Apparatus
Consists of stacked membrane bound sacs; materials come from RER in vesicles. The golgi apparatus modifies material by adding carbohydrates, phosphates, sulfates, and/or signal sequences to direct the delivery of modified material. Materials are repackaged into vesicles and sent to the correct location
Peroxisomes
contains hydrogen peroxide; functions: breakdown of long fatty acids via beta-oxidation, participates in synthesis of phospholipids, and contain some enzymes involved in the pentose phosphate pathway
Cytoskeleton
Provides structure and a conduit for transport of materials. Three components are microfilaments, microtubules and intermediate filaments
Microfilaments
Made of solid polymerized rods of actin
Resistant to compression and fracture
Can use ATP to interact with myosin and generate force for movement
Forms the cleavage furrow in cytokinesis; pinches off the connection between daughter cells
Cytokinesis
division of materials between daughter cells
Microtubules
Hollow polymers of tubulin proteins
Roadways for motor proteins like kinesin and dynein carry vesicles
Cilia and Flagella are examples of microtubule structures
9+2 structure
Found only in eukaryotic organelles of motility. 9 pairs of microtubules for an outer ring; 2 microtubles found in the center
Intermediate filaments
Diverse group of filamentous proteins
Can withstand a lot of tension
increases structural rigidity and anchors cells and organelles
Tissue (definition and types)
a collection of cells that work together; the cells may perform different functions to contribute to the main function of the tissue
Types: epithelial, connective, muscle, and nervous tissue
Epithelial Tissue
Cover the body and line body cavities
