Basic Cell Structure
CellsBasic building blocks of lifeUnderstanding of cell structure is critical to the study of biotechnology
CellSmallest living unit of an organismGrow, reproduce, use energy, adapt, respond to their environment
CellMany cannot be seen with the naked eyeA cell may be an entire organism or it may be one of billions of cells that make up the organism
CellsDivided and classified in many waysOne common classification method is the presence or absence of a cell necleus
NucleusRelatively large structure with a cellDirects cell activitiesSome simple single celled organisms lack a nucleus
Common structuresOrganelles – smaller parts of the cell with specific funtionsCell membrane – acts as a gatekeeper
Cell membraneControls what enters and leaves the cellPlants, algae and bacteria typically have a tough outer structure known as a cell wall
Cell wallProvides additional structure and protects the cell from pressure caused by movement of waterAnimal cells do not have walls
CytoplasmOrganelles are surrounded by a jelly like substancePrimary component is water
NucleusLargest and most identifiable part of the cell
Other organellesRibosomesMitochondriaGolgi bodiesEndoplasmic reticulum
Other organellesLysosomesVacuolesChloroplasts in plants
NucleusBrain of the cellSite of much of the manipulation done in biotechnology
NucleusControls activity of the cellRound or oval structureTypically found in the middle of the cellAppears darker than surrounding material
NucleusSurrounded by a membrane that controls passage of materials in and out of the area
NucleusContains DNADNA is located on chromosomesMost organisms are diploid – have tow chromosomes for each trait
DiploidHumans – 23 pairGoldfish – 90 chrms, 45 pair
Cytoplasmic Organelles
Organelles are required for proper cell functionRibosome – make proteins for cellular use and communicationMay be attached to endoplasmic reticulum
Endoplasmic reticulum
Layered membraneous Make and transport proteins
VacuoleLarge organelle, without specific shapeStore waste or raw materials used in synthesis of proteins
Golgi BodiesGolgi apparatusSimilar to endo. Ret.Look like a thick elastic band that has been folded several times
Golgi BodiesAdds modifications to unfinished proteinsMakes lysosomes
LysosomeSmall roundStore enzymes that break down food into chemical compoundsDestroy cell organelles and the cell itself
MitochondriaEnergy factoriesRod shapedChange food into molecules that can be used for energy
MitochondriaContain DNACan replicate themselves
ChlorplastFound in plants and some other organismsContain chlorophyll
Cellular processesRespirationOsmosisDiffusionPhotosynthesis
RespirationCells break down carbohydrates and other molecules to produce energyOxidation of glucose is one of most common forms
RespirationBreaking down of sugar into water, carbon dioxide, and energyEnergy is used to do the work of the cell
Osmosis & DiffusionTransport of raw materials, wastes, and synthesized materials out of the cell
DiffusionMovement of molecules, especially gases and liquids from areas of high concentration to areas of low concentration
OsmosisSpecific type of diffusionMovement of water through a membrane from areas of high concentration to areas of low concentration
EquilibriumDiffusion and osmosis happen to enable a cell to reach equilibrium
Cellular reproductionThree waysFissionMitosisMeiosis
FissionProkaryotesCell grows larger and makes a second copy of its DNAAt some point the cell membrane divides the cell by the growth of a transverse septum
FissionTwo new cells are formed as the division grows inward from either side of the cellTwo cells now called “daughter cells”Sometimes known as “binary fission”
MitosisEukaryotesRequires 6 stagesInterphase, prophase, metaphase, anaphase, telophase, cytokinesis
MitosisCreates cells that are identical to the original cell.Have the entire compliment of chromosomes existing in pairs - diploid
MeiosisDivision of sex cellsStages of Meiosis I: Interphase I, prophase I, metaphase I, anaphase I, telophase I, cytokinesis I
MeiosisMeiosis IIInterphase II, prophase II, metaphase II, anaphase II, telophase II, cytokinesis II
MeiosisEach cell receives one chromosome from each pair randomlyResulting cells have half the normal number of Chromosomes - haploid