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Cell Function
Term | Definition |
---|---|
Cells | Building blocks of human body. |
Cell Theory | Cells are the building blocks of all plants and animals, cells are the smallest functioning units of life, cells are produced through division of existing preexisting cells, each cell maintains homeostasis. |
Plasma Membrane/Cell Membrane | Separates cell contents from its watery surrounding environment. Very thin. Regulates exchange with the environment, entrance or ions and nutrients into cell, and waste. Structural support. Contains phospholipids. Only compounds not ions or water enter |
Cytoplasm | Cell contents |
Phospholipid Bilayer | Phospholipids lie in two distinct layers with hydrophobic tails on inside and hydrophilic heads on outside. |
Diffusion | Movement of molecules from an area of high concentration to low concentration (down concentration gradient). EX: by moving across a lipid portion of membrane or passing through a channel protein of membrane. |
Osmosis | Diffusion of water across a selectively permeable membrane. Occurs at section freely permeable to water not sollutes. |
Osmotic Pressure | An indication of the force of water movement into the solution, as a result of solute concentration. As solute concentration increases so does osmotic pressure. |
Hydrostatic Pressure | Fluid pressure. |
Isotonic | A solution that does not cause a new movement of water into or out the cell, and in these red blood cells do not chance apperence. |
Hypotonic | THe solution in a comparison with lower osmotic concentration. |
Hemolysis | Break down of red blood cells. |
Crenation | Shrinkage of cells or red blood cells due to osmotic movement of water out of cell. |
FIlteration | Hydrostatic pressure forces water accross membrane, no ATP. |
Carrier Mediated Transport | Membrane proteins bind specific ions or organic substances and carry them across the plasma membrane, through concentration gradient. |
Co-transport | The carrier transports two substrates in the same direction into or out of cell. |
Facilitated Diffusion | The molecule to be transported binds to a receptor site, the shape or the protein changes, which mves the molecule into plasma membrane, its then released into cytoplasm. NO ATP used. |
Active Transport | The high energy bond in ATP provides the energy needed to move ions or molecules across the membrane. Not dependant on concentration gradient. Can import or export materials regardless of their intracellular or extracellular concentrations. |
Vesicular Transport | Materials move into or out of the cell in vesicles, small membranes consumed 3 sodium ions ejected and two potassium ions are reclaimed by the cell. |
Ednocytosis | The packaging up of extracellular materials in a vesicle at the cell surface for import into the cell. all types require ATP. |
Receptor Mediated Endocytosis | Produces vesicles that contain high concentrations of specific target molecule. |
Pinocytosis | The formation of small vesicles filled with extracelular fluid. Not very selective. |
Phagocytosis | Cell eating, produces vesicles containing solid objects that may be as large as the cell itself. Only formed by specialized cells that protect tissues. Pinching off the cell membrane. |
Exocytosis | The functional reverse of endocytosi, a vesicle created inside the cell fuses with the plasma membrane and discharges its contents into the extra cellular environment. |
Cytoplasm | Material inside the cell, from plasma membrane to nucleus. Contains cytosol and oraganelles. |
Cytosol | Intracellular fluid, contains dissolved nutrients, ions, solluble and insoluble proteins. |
Organelle | Internal structures that perform specific functions essential to normal cell structures, maintanance, and metabolism. |
Organelles: inside membranes | Inside membrane: nucleus, mitochondria, endoplasmic reticulem, golgi apparatis, lysosomes, and perixosomes. |
Organelles: not inside membranes | Cytocskeleton, microvilli, centrioles, cilia, flagella, ribosomes, and proteasomes. |
Cytoskeleton | Protein framework that gives cytoplasm strength and flexibility. Ex: microfiliments, intermediate filaments, and microtubules. |
Microfilliments | The tiniest strands of cytoskeleton made of actin, a dense layer ouside plasma membrane, and attach it to underlying cytoplasm. |
Microtubulars | Hollow tubes made from tubulin and anchors organelles spindal apperatis in cell division. |
Microvilli | Small finger shaped projections of plasma membrane on exposed surface of cells, cells digestive tract. |
Centrioles | A cylindrical structure composed of triplets of microtubules, in a pair of perpendicular to each other, only in cells that divide. |
Cilia | Long, slender extensions of the plasma membrane, supported by microtubulars. movement requires ATP. Move fluid or secretions across the cell surface. |
Flagella | Much longer that cilia, move a cell through surrounding fluid in sex cells. |
Ribosomes | Organelles that manufacture protein, from information from DNA in nucleus. |
Free Ribosomes | Scattered through cytoplasm and proteins they make enter the cytosol. |
Fixed Ribosomes | Attached to endoplasmic reticulum. go through membran, enter endoplasmic reticulem whcih exports them. |
Proteasomes | Organelles that contain a bunch of protein breaking enzymes. Remove or recycle denatured proteins and break down abnormal proteins. |
Endoplasmic Reticulem | Membranes inside cell that connect to the surrounding envelope surrounding the nucleus. Responsible for; Synthesis, storage, transport, and detoxification. |
Smooth ER | No ribosomes, where carbs and lipids are produced and hormones in sex cells storage of glycerides. |
Rough ER | Fixed ribosomes, protein synthesis, sacs deliver proteins to golgi apperatis. |
Golgi Apparatus | Has 5 or 6 flat membraneous discs called cisternae. 1. modifies plasma membrane, 2. packages special enzymes |
Lysosomes | Vesicles with digestive enzymes. Clean up crew. Made in Golgi dude. |
Autolysis | When muscles break down without use. |
Peroxisomes | Larger than lysisomes, Form from growth and subdivision of existing peroxisomes. Absorbs and breaks down fatty acids. Is a free radical. |
Free Radical | Ions or molecules that contain unpaired electrons, highly reactant. |
Mitochondria | Organelle that provides energy to the cell. Double membraned, Outer membrane surrounds organelle, inner membrane has many folds called cristae. |
Matrix | Fluid contents. |
Aerobic Metabolism | Energy production in mitochondria. produces 95% of energy cells needs. |
Nucleus | Large, stores all information needed to control the making of over 100,000 different proteins. usually 1 nucleus in a cell. |
Nuclear Envelope | Double membrane around nucleus, which seperates fluid contents in nucleoplasm from cytosol. |
Nucleoplasm | Has ions, enzymes, RNA, DNA, nucleotides, proteins. |
Nuclear Pores | How nucleus and cytosol communicate. large enough for movements of ions and small molecule. Regulates transport of proteins and RNA. |
Chromosomes | Contain DNA in nuclues. 23 pairs in human body, 1 set from each parent. DNA strands wrapped and proteins called histones, DNA + Histones = nucleosomes. |
Genetic Code | The protein information stored as amino acids sequences in nucleus. Triplet code. A sequence of 3 nitrogenous bases. |
Gene | Has all the triplets needed to produce a protein. Before a gene can be activated, enzymes must temporarily break the bonds between its nitrogenous bases and remove the histone that guards the promotor segments. |
Promotor | The section of a gene that regulates activity (start here sign for enzymes). |
Transcription | Production of RNA from a single strand of DNA. Happens in nucleus. Forms mRNA. |
Messanger RNA | Communicates between nucleus and cytoplasm. A copy of information contained in the gene, the information is a sequence of nucleotides. |
Process of Transcription | 1. DNA polymerease binds to promotor of gene 2. At stop signal Enzyme and mRNA detach 3. 3 nitrogenous bases with a new mRNA strand that is complementing to the cooresponding triplet on gene 4. enters cytoplasm through nuclear pore. |
Translation | The making of proteins using the info by sequence of codons on the mRNA strand. |
Process of Translation | 1. mRNA has left nucleus and enters cytoplasm to bind to a ribosome 2. tRNA delivers amino acids that will be used by ribosome to assemble the protein 3. ribosomes enclose mRNA 4. second tRNA arrives 5. ribosome enzyes remove amino acid 1 from first tRNA |
Transport RNA | tRNA, contains a complementary triplet of nitrogenous bases (anticodon) that bind to specific codons on the mRNA. |
DNA Replication | The duplication of the cells genetic material. |
Mitosis | Nuclear division of somatic cells |
Meiosis | Production of sex cells |
Interphase | Where cells spend most of their time, time between cell division when they perform normal functions. |
Apoptosis | Controlled cell death. Helps homeostasis. |
S phase | Replicates DNA in nucleus every 6-8 hours. |
DNA replication process | 1. Complimentary strands separate and unwind 2. DNA polymerase binds to exposed nitrogenous bases 3. complementary nucleotides attach to nitrogenous base and form a pair of identicle DNA molecules 4. G2 phase protein synthesis |
Mitosis Phases | Interphase, Prophase, Metaphase, anaphase, telophase. |
Prophase | Early prophrase: a pair of centrioles are pulled by spinle fibers. Late prophase chromatids become attached to spindle fibers. |
Metaphase | ends when all chomosomes are alligned in the plane of the metaphase plate, and each chromosome has 2 chromatids |
Anaphase | when the centromere of each chromatid pair splits and the chromatids separate resulting in two daughter chromosomes which are now pulled to oppositeends of the cell ends when daughter chromosomes arrvce at centrioles at opposide ends of the cell. |
Telophase | Cell prepares to enter interphase again. nuclear membranes form nuclei enlarge, and DNA chromosomes gradually uncoil. nuclei reasemble |
Cytokinesis | The division that forms the daughter cells, begins in late anaphase. Constriction of cytoplasm when chromosomes near the ends of spindle fibers cleavage furrow. Marks end of cell division. |
Tumor | Mass swelling produced by abnormal cell growth and division. |
Benign | Cells usually remain in one place; in the epithelium tissue type, or connective tissue capsule. rarely life threatening, can be removed., |
Malignant | No longer responds to normal control mechanisms. Cells spread into surrounding tissues. |
Cancer | Resulting from malignant cells. The secondary tumors they form are very active and they stimulate growth of blood vessles into the area. this increased blood supply make the tumor grow faster. |
Differentiation | Switching off of genes to restrict cell functions. |
Phagocytosis | brings solid objects into the cell |
Major function of golgi apparatis | modify and package secretory products and lysosomal ezymes |
Codons | Thee nitrogenous base sequences on mRNA which are complementary to gene triplet. |
Which is the pulling apart phase in mitosis | Anaphase |
S Phase | Synthesis phase, of cell cycle is where DNA is replicated before cell divides. |
Which cell functions require ATP? | Active transport and endocytosis. |