Biology

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cell theory

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-all cells come from previously existing cells

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plasma membrane

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each cells is surrounded by extremely thin, fluid membrane

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cytoplasm

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consists of all the fluid and structures that lie inside the plasma membrane, but outside of the nucleus

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cytoplasmic fluid

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fluid portion of the cytoplasm

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deoxyribonucleic acid (DNA)

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genetic material in cells

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ribonucleic acid (RNA)

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chemically related to DNA and comes in different forms that copy the blueprint of genes on DNA and help construct proteins based on this blueprint

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prokaryotic cells

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"before the nucleus" - form the bodies of bacteria and archaea (simplest form of life)

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eukaryotic cells

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"true nucleus" - more complex and comprise the bodies of animals, plants, fungi and protists.

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organelles

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membrane-enclosed structures that perform specific functions within the cell

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cytoskeleton

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a network of protein fibers, gives shape and organization to the cytoplasm of eukaryotic cells

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primary cell membrane

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plant cells secrete cellulose through their plasma membrane,forming this

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secondary cell membrane

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many plant cells, when they mature and stop enlarging, secrete more cellulose and other polysaccharides beneath the primary wall to form this

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middle lamella

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the primary cell walls of adjacent cells are joined by this, a layer made primarily of the polysaccharide pectin

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-microfilaments
-intermediate filaments
-microtubules

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--thin protein filaments
--medium sized
--thick

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functions of cytoskeleton

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cell shape, cell movement, organelle movement, cell division

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centrioles

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form the spindle that helps apportion the genetic material during animal cell division, composed of microtubules

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cilia & flagella

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slender extensions of the plasma membrane, supported internally with microtubules of the cytoskeleton

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basal body

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derived from a centriole

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nucleus

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sn organllese (usually the largest in the cell) consisting of 3 major parts: nuclear envelope, chromatic, nucleolus

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nuclear envelope

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isolates the nucleus from the rest of the body, consists of a double membrane

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nuclear pores

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tiny membrane-lined channel

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chromatin

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color substance

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chromosomes

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colored bodies

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nucleolus

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consists of ribosomal RNA, proteins, ribosomes in various stages of synthesis, and DNA

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ribosome

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a small particle composed of RNA and proteins that serves as a kind of "workbench" for the synthesis of proteins within the cell cytoplasm

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vesicles

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membrane sacs, ferry membranes and specialized contents among the separate regions of the membrane system

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endoplasmic reitculum (ER)

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a series of interconnected membrane-enclosed tubes and channels in the cytoplasm

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golgi apparatus

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main purpose is to modify, sort, and package proteins produced by the rough ER

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lysosomes

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function is digest food particles, which range from individual proteins to complete microorganisms, also digest excess cellular membranes and defective or malfunctioning organelles

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phagocytosis

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engulfing particles just outside the cell using extentions of the plasma membrane

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food vacuole

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plasma membrane with its enclosed food pinches off inside the cytosol and froms this

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vacuoles

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sacs of cell mebrane filled with fluid containing various molecules

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contract vacuoles

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composed of collectng ducts, a central reservoir and a tube learding to a pore in the plasma membrane

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central vacuole

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occupies 3/4 or more of the volume of many plant cells; involved in the cell's balance; provides a "dump site" for wastes

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turgor pressure

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the water pressure withing the vacuole..pushes the fluid portion of the cytoplasm up against the cell wall with cosiderable force

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mitochondria

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"powerhouse of the cell", convert energy to ATP

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chloroplasts

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captures energy directly from sunlight and store it in sugar molecules

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endosymbiosis

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"living together inside"

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cristae

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inner membrane forms deep folds called

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stroma

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inner membrane of chloroplast encloses a fluid called

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thylakoids; granum

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individual stacks of interconnected membranes;stack of sacs

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chlorophyll

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green pigment molecule

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plastids

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organlles found only in plants and photosynthetic protists;store foods

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nucleoid

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in the central region of prokaryotic cells, not separated from the cytoplasm by a membrane

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fluid mosaic model

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each membrane consists of a mosaic, or "patchwork" of diff proteins that constantly flow and shift within a viscous fluid formed by a double layer of phospholipids

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phospholipid bilayer

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double layer of phospholipid : hydrophilic heads and hydrophobic tails

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glycoproteins

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proteins in plasma membrane that have carb groups attached to the protein that is exposed on the outer membrane surface

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receptor proteins

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a hormone binds to the receptor, activates it and stimulates a response in the cell

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recognition proteins

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glycoproteins that serve as identification tags

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enzymes

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proteins that promote chemical rxn that synthesize or break apart biological molecules

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attachment proteins

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link the cytoskeleton inside the cell with the extracellular matrix outside; help maintain cell shape and move along aurfaces

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transport proteins

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regulate the movement of hydrophilic molecules through the plasma membrane

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channel proteins

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transport protein that forms channels whose central pores allow water molecules or specific ions to pass through the membrane along their concentraion gradients

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carrier proteins

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transport proteins that have binding sites that can temporarily attach to specific molecules on one side of the membrane

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fluid

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any substance whose molecules can flow past one another - no defined shape (gases/liquids)

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solute

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a substance that can be dissolved in a solvent

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solvent

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a fluid (liquid) capable of dissolving the solute
water = univeral

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concentration

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amount of solute in a given amount of solvent

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gradient

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a physical diff in properties of a particular substance in a fluid bw two adjoining regions of space

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concentration gradients

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cause molecules or ions to move form one region to the other in a manner that tends to equalize the difference

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diffusion

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movement from regions of high concentration to low concentrations, the higher the temperature the faster the rate

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selective permeable

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plasma membranes selectively allow only certain ions or molecules to pass through

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passive transport

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involves diffusion of substances across cell membranes down their concentration gradients

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energy-requiring transport

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requires that cell expend energy to move substances across membranes into or out of the cell

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simple diffusion

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diffusion of water through the phospholipid bilayer of a membrane

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facilitated diffusion

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diffusion of water through a membrane via a carries or channel protein

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osmosis

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diffusion of water from high [ ] to low [ ]

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endocytosis

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movemennt of particles or large molecules INTO a cell

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active transport

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movement of individual small molecules or ions against their [ ] gradients through membrane-spanning proteins

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exocytosis

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moent of particles or large molecules OUT of a cell

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aquaporins

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specialized water channel proteins; coupled with positivly charged amino acids

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isotonic

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solutions with equal [ ] of solute

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hypertonic;

hypotonic

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the solution that contains greater [ ] of solute;

lower [ ]