Biology STAAR EOC Review

Biology STAAR EOC Review(Adapted from Alief ISD Review)Reporting Category 1: Cell Structure and FunctionSTAAR -11 Questions STAAR M-9 Questions4 Readiness Stds5 Supporting StdsBiology is the study of life and living organisms.An organism is a complete, individual, living thing.All organisms are formed from the same basic building block – cells.TEKS(RS)- will betested (65%)(SS)- may betested (35%)Key IdeasCells are the smallest units of living thingsSimple cells are called prokaryotic; Complex cells are called eukaryoticCell Parts or OrganellesCell membraneCytoplasmNucleusMitochondriaEndoplasmic reticulum(smooth or rough)RibosomeGolgi body or complexLysosomevacuoleSurrounds the cell; controls what enters/leaves the cell; recognizes othercells; maintains homeostasisSuspends organelles in a eukaryotic cell; enclosed within the cell membraneControls the cell’s activities; contains chromosomes made of DNABreaks down food to release energyMoves substances within the cell (pipe-like structures)Makes proteins; round structures located in rough endoplasmic reticulumChanges and packages cell productsContains enzymes (proteins that speed up digestion and chemical reactions)Holds material like water; large in a plant cellPlant cells onlyCell wallchloroplastSurrounds the cell membrane; supports and protects plant cellContains chlorophyll (green pigment) for photosynthesis1

Cellular ProcessesI. Homeostasis is a process by which organisms keep internal conditions relatively stable regardless of changes in4BInvestigate andexplain rsions,transport ofmolecules, andsynthesis ofnew materials(RS)the external environment. It is important because the processes that keep the cell alive can only take place undercertain internal conditions. Balanced internal condition of cells Homeostasis is also called equilibrium Maintained by plasma membrane controlling what enters & leaves the cellPlasma or Cell MembraneThe cell membrane is flexible and allows a unicellular organism to moveWhen you transport something, you move it from one place to another. Cells transport materials across the cellmembrane.Functions (what they do) of Plasma or Cell Membrane Protective barrierRegulate transport in & out of cell (selectively permeable- only lets some things and out of the cell like aclub bouncer; Specifically, small molecules and larger hydrophobic molecules move through easily. e.g.O2, CO2, H2O; Ions, hydrophilic molecules larger than water, and large molecules such as proteins do notmove through the membrane on their own.Allow cell recognitionProvide anchoring sites for filaments of cytoskeletonProvide a binding site for enzymesInterlocking surfaces bind cells together (junctions)Contains the cytoplasm (fluid in cell)Structure of the Cell Membrane2

Cell Membrane Polar heads are hydrophilic “water loving”Nonpolar tails are hydrophobic “water fearing”Makes membrane “Selective” in what crosses - “Selectively permeable”II. Types of Transport Across Cell MembranesSimple DiffusionRequires NO energy; Molecules move from area of HIGH to LOW concentrationDIFFUSIONDiffusion is a PASSIVE process which means no energy is used to make the molecules move,they have a natural KINETIC ENERGYEx: Diffusion of LiquidsDiffusion through a MembraneSolute moves DOWN concentration gradient (HIGH to LOW)3

Osmosis- Diffusion of water across a membraneMoves from HIGH water potential (low solute) to LOW water potential (high solute)Diffusion of H2O Across A MembraneCells in Different Solutions (Think of a pimple)Isotonic (Balance flow)NO NET MOVEMENT OF H2O(equal amounts entering & leaving)Hypotonic SolutionCYTOLYSIS (Cell Swells)Hypertonic SolutionPLASMOLYSIS (Cell ---------------4

III. Energy ConversionsThree Forms of Transport Across the MembraneThree Forms of Transport Across the Membrane35A. Passive Diffusion- Simple DiffusionDoesn’t require energyMoves high to low concentrationExample: Oxygen or water diffusing into a cell and carbon dioxide diffusing out.B. Facilitated diffusionDoesn’t require energyUses transport proteins to move high to low concentrationExamples: Glucose or amino acids moving from blood into a cell.C. Active TransportRequires energy or ATPMoves materials from LOW to HIGH concentrationAGAINST concentration gradientExamples: Pumping Na (sodium ions) out and K (potassium ions) in against strong concentration gradients.Called Na -K -------------------------------------Proteins Are Critical to Membrane FunctionTypes of Transport Proteins Channel proteins are embedded in the cell membrane & have a pore for materials to cross5

Carrier proteins can change shape to move material from one side of the membrane to theotherFacilitated DiffusionMolecules will randomly move through the pores in Channel Proteins. Some Carrier proteins do not extend through the membrane.They bond and drag molecules through the lipid bilayer and release them on the opposite ---------------------------------------Carrier Proteins Other carrier proteins change shape to move materials across the cell is - moving things out of the cell Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.This is how many hormones are secreted and how nerve cells communicate with one anotherMoving the “Big Stuff” Out in the Cell6

Endocytosis- Large molecules move materials into the cell by one of three forms of endocytosis.Moving the “Big Stuff” in the cell3 Types of EndocytosisA. Pinocytosis- Most common form of endocytosis; Takes in dissolved molecules as a vesicleCell form an invagination*Materials dissolve in water to be brought into cellB. Phagocytosis-Used to engulf large particles such as food, bacteria, etc. into vesicles;Called “Cell Drinking”Phagocytosis about to occurC. Receptor-Mediated EndocytosisSome integral proteins have receptors on their surface to recognize & take in hormones, cholesterol, etc.7

Homeostasis Energy Conversions MoleculetransportationSummary of Cellular ProcessesRegulation of conditions (like pH or temperature) within a cell whichallows for stable, “normal” internal equilibrium (balance)During photosynthesis, plant cells use energy from the sun to makesugar called glucose; during aerobic cellular respiration, mitochondriarelease energy from molecules like glucoseMolecules move in and out of cells across the cell membrane byvarious means; active transport (like transport proteins) requiresenergy, but passive energy (like diffusion) does notCells can create new molecule from simpler molecules, like whenproteins are made from amino acids 4CCompare thestructures ofviruses to cells,describe viralreproduction,and describethe role ofviruses incausingdiseases suchas humanimmunodeficiency virus (HIV)and influenza(RS)Synthesis of NewMoleculesStructure of VirusesVirus StructureCapsidDNAor RNASPIKESENVELOPEOutside View of a VirusCAPSOMERESViruses and CellsCharacteristicStructureVirusDNA or RNA in capsid, some with envelopeReproductionOnly within a host cellGenetic CodeGrowth and DevelopmentDNA or RNANoObtain and use energyResponse to EnvironmentChange over timeNoNoYes CellCell membrane, cytoplasm,eukaryotes also contain nucleus andmany organellesIndependent cell division, eitherasexually or sexuallyDNAYes; in multicellular organisms, cellsincrease in number and differentiateYes—Eukaryotic ellYesYesA virus is a nonliving particle made up of proteins, nucleic acids, and sometimes lipids.8

Viruses can reproduce only by infecting living cells. A virus consists of a core of DNA or RNAsurrounded by a protein coat called a capsid.Unlike a cell, a virus lacks structures to take in food, break apart food for energy, or synthesize molecules.Because viruses are noncellular and cannot perform most functions of life, scientists classify viruses asnonliving particles. However, viruses are able to perform one life function- reproduction- with the aid ofa host organism.Hosts can be prokaryotes or eukaryotes.Viruses that use prokaryotes as host cells are called bacteriophages or phages.Viral ReproductionViruses reproduce by taking over the host cell. The process begins when a virus attaches to the outside of a cell. Thevirus then injects its genetic material into the cell. After the viral genetic material enters a host cell, one of twoprocesses may occur.A. Steps of Lytic Cycle and Lysogenic cycleStages of the Lytic CycleThe host cell starts making messenger RNA from the viralDNA.Stages of the Lysogenic CycleRole of Viruses in Causing Diseases Such as HIV and InfluenzaViruses can cause disease in humans through the lytic cycle such as HIV and Influenza.HIVandInfluenzaHIVInfluenza or the “flu”9

Human immunodeficiency Virus or HIVCauses AIDS or Acquired immunodeficiency Syndrome;currently there is no cure for AIDS because HIV mutatesand evolves rapidly;HIV infects and destroys immune system cells called helperT cells; Helper T cells play a role in keeping the body freefrom diseaseWhen HIV attacks a helper T cell, it binds to the cellmembrane and enters the cell. Once the virus is inside thecell, it uses the cell’s structures to make new viruses. Thenthe virus destroys the cell and the new viruses arereleased into the bloodstream. They travel throughout theblood, infecting and destroying other helper T cells.As an HIV infection progresses, more helper T cells aredestroyed. Doctors determine the number of helper Tcells in the blood of people with HIV infections to monitorhow far their infections have progressed. The fewer the Tcells in the blood, the more advanced the infection.As the immune system becomes increasingly compromisedby HIV, the body becomes more susceptible to diseasesthat seldom show up in people with a healthy immunesystem; People who have AIDS die from other diseasesbecause their immune system is too weak to fight offinfections (opportunistic diseases)5ADescribe thestages of thecell cycle,includingdeoxyribonucleic acidreplication andmitosis, andthe importanceof cell cycle tothe growth ofthe organism(ReadinessStandard)Influenza or the fluRNA virusInfects the respiratory tract of humans as well as otheranimalsThe death of the infected cells and a person’s immunesystem response causes inflammation which leads to sorethroat and mucus secretionsInfection causes mild to severe illness, including fever,cough, headache, and a general feeling of tirednessInfection lasts for 1 to 2 weeks and can cause a moresevere illnessThe Cell Cycle: Stages in growth & divisionG1 PhaseS PhaseG2 PhaseM Phase(Mitosis)CytokinesisFirst growth stageCopying of all ofDNA’s instructionsTime betweenDNA synthesis &mitosisCell growth & proteinproduction stop(Cell plate forming betweenthe two cells)Occurs after chromosomesseparateCell increases insizeChromosomesduplicatedCell continuesgrowingCell’s energy used tomake 2 daughter cellsForms two, identical daughtercellsNeeded proteinsproducedCalled mitosis orkaryokinesis(nuclear division)Cell prepares tocopy its DNA10