The Cell - Wk3 PDF

TOPIC 2: THE CELL Prepared by: Heston Sial I. MICROSCOPY ▶ 1665 – Robert hook ▶ 1674 – Antoni van Leeuwenhoek (Visualized living cells) ▶ MICROSCOPE ▶ Magnification -Ratio of Objects image size to real size ▶ Resolution – Measure of Clarity of an Image ▶...

TOPIC 2: THE CELL Prepared by: Heston Sial I. MICROSCOPY ▶ 1665 – Robert hook ▶ 1674 – Antoni van Leeuwenhoek (Visualized living cells) ▶ MICROSCOPE ▶ Magnification -Ratio of Objects image size to real size ▶ Resolution – Measure of Clarity of an Image ▶ Contrast – visible difference in brightness between parts of the sample LIGHT MICROSCOPE FLOURESCENT MICROSCOPY CONFOCAL MICROSCOPE TRANSMISSION ELECTRON MICROSCOPE SCANNING ELECTRON MICROSCOPE Prokaryote -is a single celled organism that lacks a nucleus, and other membrane-bound organelles -cytoplasm is bound by plasma membrane -”before nucleus” Eukaryote - are organisms whose cells contain a nucleus and other membrane-bound organelles - larger and more complex than prokaryote 1. CELL MEMBRANE / PLASMA MEMBRANE STRUCTURE AND FUNCTION KEY TERMS: CELL MEMBRANE/PLASMA MEMBRANE: is a selective barrier that allows sufficient passage of Oxygen, nutrients, and waste to service the volume of every cell HYDROPHILIC: describes a substance or structure attracted to water HYDROPHOBIC: describes a substance or structure repelled by water SEMI-PERMEABLE: allowing certain substances to pass through it but not others, especially allowing the passage of a solvent but not of certain solutes PHOSPHOLIPID: phospholipid is a type of lipid molecule that is the main component of the cell membrane. MEMBRANE PROTEINS KEY TERMS: RECEPTOR: protein molecule that contains a binding site for another specific molecule (called a ligand) LIGAND: molecule that binds with specificity to a specific receptor molecule GLYCOPROTEIN: protein that has one or more carbohydrates attached GLYCOCALYX: coating of sugar molecules that surrounds the cell membrane PERIPHERAL PROTEIN: membrane-associated protein that does not span the width of the lipid bilayer, but is attached peripherally to integral proteins, membrane lipids, or other components of the membrane  TRANSPORT ACROSS THE CELL MEMBRANE DIFFUSION KEY TERMS: DIFFUSION: movement of a substance from an area of higher concentration to one of lower concentration CONCENTRATION GRADIENT: difference in the concentration of a substance between two regions FACILITATED DIFFUSION KEY TERMS: SELECTIVE PERMEABILITY: feature of any barrier that allows certain substances to cross but excludes others FACILITATED DIFFUSION: diffusion of a substance with the aid of a membrane protein ACTIVE TRANSPORT KEY TERMS: ACTIVE TRANSPORT: form of transport across the cell membrane that requires input of cellular energy PASSIVE TRANSPORT: form of transport across the cell membrane that does not require input of cellular energy SODIUM POTASSIUM PUMP CYCLE KEY TERMS: SODIUM-POTASSIUM PUMP: (also, Na+/K+ ATP-ase) membrane-embedded protein pump that uses ATP to move Na+ out of a cell and K+ into the cell OSMOSIS KEY TERMS: OSMOSIS: diffusion of water molecules down their concentration gradient across a selectively permeable membrane OSMOSIS PROCESS KEY TERMS: HYPERTONIC: describes a solution concentration that is higher than a reference concentration HYPOTONIC: describes a solution concentration that is lower than a reference concentration ISOTONIC: describes a solution concentration that is the same as a reference concentration ENDOCYTOSIS KEY TERMS: ENDOCYTOSIS: import of material into the cell by formation of a membrane-bound vesicle (into the cell) PINOCYTOSIS: endocytosis of fluid (Cell Drinking) PHAGOCYTOSIS: endocytosis of large particles (Cell Eating) RECEPTOR-MEDIATED ENDOCYTOSIS: endocytosis of ligands attached to membrane-bound receptors ELECTRICAL GRADIENT: difference in the electrical charge (potential) between two regions VESICLES: membrane-bound structure that contains materials within or outside of the cell EXOCYTOSIS KEY TERMS: EXOCYTOSIS: export of a substance out of a cell by formation of a membrane-bound vesicle (out of the cell) THE CYTOPLASM AND CELLULAR ORGANELLES ORGANELLES KEY TERMS: ORGANELLE (“little organ”): one of several different types of membrane-enclosed bodies in the cell, each performing a unique function. CYTOSOL: clear, semi-fluid medium of the cytoplasm, made up mostly of water CYTOPLASM: internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials EXTRACELLULAR FLUID KEY TERMS: EXTRA CELLULAR FLUID (ECF): extracellular fluid (ECF) fluid exterior to cells; includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body INTERSTITIAL FLUID (IF): fluid in the small spaces between cells not contained within blood vessels INTRACELLULAR FLUID (ICF): fluid in the cytosol of cells INTEGRINS: are the principal receptors used by animal cells to bind to the extracellular matrix NUCLEUS KEY TERMS: NUCLEUS: cell’s central organelle; contains the cell’s DNA ORGANELLE: any of several different types of membrane-enclosed specialized structures in the cell that perform specific functions for the cell CHROMATIN: substance consisting of DNA and associated proteins NUCLEOSOME: unit of chromatin consisting of a DNA strand wrapped around histone proteins NUCLEAR ENVELOPE: membrane that surrounds the nucleus; consisting of a double lipid-bilayer NUCLEAR POLE: one of the small, protein-lined openings found scattered throughout the nuclear envelope NUCLEOLUS: small region of the nucleus that functions in ribosome synthesis ORGANELLES OF THE ENDOMEMBRANE SYSTEM ENDOPLASMIC RETICULUM KEY TERMS: ENDOPLASMIC RETICULUM (ER): cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes RIBOSOME: cellular organelle that functions in protein synthesis RIBOSOMES KEY TERMS: RIBOSOME: cellular organelle that functions in protein synthesis RIBOSOMAL RNA (rRNA): RNA that makes up the subunits of a ribosome ENDOPLASMIC RETICULUM (ER): cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively) POLYRIBOSOME: simultaneous translation of a single mRNA transcript by multiple ribosomes GOLGI APPARATUS KEY TERMS: GOLGI APPARATUS: cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport LYSOSOMES KEY TERMS: LYSOSOME: is a membrane-bound cell organelle that contains digestive enzymes. AUTOPHAGY: lysosomal breakdown of a cell’s own components AUTOLYSIS: breakdown of cells by their own enzymatic action MITOCHONDRIA KEY TERMS: MITOCHONDRIA: one of the cellular organelles bound by a double lipid bilayer that function primarily in the production of cellular energy (ATP) PEROXISOMES KEY TERMS: PEROXISOME: membrane-bound organelle that contains enzymes primarily responsible for detoxifying harmful substances MUTATION: change in the nucleotide sequence in a gene within a cell’s DNA CYTOSKELETON KEY TERMS: CYTOSKELETON: “skeleton” of a cell; formed by rod-like proteins that support the cell’s shape and provide, among other functions, locomotive abilities MICROTUBULE: the thickest of the cytoskeletal filaments, composed of tubulin subunits that function in cellular movement and structural support MICROFILAMENT: the thinnest of the cytoskeletal filaments; composed of actin subunits that function in muscle contraction and cellular structural support ACTIN: a protein that forms chains, is the primary component of these microfilaments. Actin fibers, twisted chains of actin filaments, constitute a large component of muscle tissue and, along with the protein myosin, are responsible for muscle contraction. INTERMEDIATE FILAMENT: type of cytoskeletal filament made of keratin, characterized by an intermediate thickness, and playing a role in resisting cellular tension VACUOLES KEY TERMS: VACUOLE: A vacuole is a membrane-bound cell organelle. In animal cells, vacuoles are generally small and help sequester waste products. In plant cells, vacuoles help maintain water balance. Sometimes a single vacuole can take up most of the interior space of the plant cell CELL MOVEMENT KEY TERMS: FLAGELLUM: appendage on certain cells formed by microtubules and modified for movement CILIA: mall appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface VI. DNA THE STRUCTURE OF DNA THE STRUCTURE OF DNA QUIZ: 5’ AGGTCCG 3” 3’ ___________ 5’ RNA DNA REPLICATION KEYTERMS: DNA POLYMERASE: enzyme that unwinds DNA and then adds new nucleotides to a growing strand of RNA for the transcription phase of protein synthesis DNA to mRNA VI. CELL CYCLE CELL GROWTH AND DIVISION KEY TERMS: CELL CYCLE: life cycle of a single cell, from its birth until its division into two new daughter cells CELL DIVISION: is the process in which a Single parent Cell divides into two identical cells or four cells, each with half the number of chromosomes SOMATIC CELL: all cells of the body excluding gamete cells HOMOLOGOUS: describes two copies of the same chromosome (not identical), one inherited from each parent PHASES of the CELL CYCLE KEY TERMS: INTERPHASE: entire life cycle of a cell, excluding mitosis MITOSIS: division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed MITOTIC PHASE: phase of the cell cycle in which a cell undergoes mitosis CYTOKINESIS: final stage in cell division, where the cytoplasm divides to form two separate daughter cells METAPHASE: second stage of mitosis (and meiosis), characterized by the linear alignment of sister chromatids in the center of the cell MITOTIC SPINDLE: network of microtubules, originating from centrioles, that arranges and pulls apart chromosomes during mitosis STRUCTURE OF CHROMOSOMES KEY TERMS: CHROMOSOME: condensed version of chromatin CENTROMERE: region of attachment for two sister chromatids SISTER CHROMATID: one of a pair of identical chromosomes, formed during DNA replication CLASSIFICATION OF CHROMOSOMES CELLULAR DIFFERENTIATION END OF CHAPTER!