3rd Part Bio Exam PDF

B 2 3 1.. 2 3.. 2 , 2. 3. 3 2 3 4....

B 2 3 1.. 2 3.. 2 , 2. 3. 3 2 3 4. 2 3 5.. ,. , , CELLULAR DIFFERENTIATION - FERTILIZATION - the fusion of a male and female gamete to produce a single cell In multicellular organismsa cell devides repeatedly to generate an embryo of cells many mitosis - that the cells in all ensures an embryo are genetically identical In an early-stage embryo a cells are unspecialized -as an embryo grows I its develop along different pathways and become specialized for a specific action ~ allows each cell to carry its function more efficiently the cell develop the ideal structure with needed to out all the enzymes - can chemical reactions associated with its function - DIFFERENTIATION - the development of cells in different ways to carry out specific functions - In humans a 220 distinctively different higly specialized cell types - developted by differentiation - When a gene is being used in a cell , we say that the gene is being expressed The is switched and the information in it is used to make protein other gene gene - on a or product development of cell involves and but The a switching on expressing particular genes not others - Cell differentiation happens because a different sequence of genes is expressed in different cell types - In multicellular organisms - must be enough cells of each type and they must all be positions within in the the body - Gradients of signalling chemicals -> indicates cell's position in the embryo and determine which pathway of differentiation it follows these chemicals regulators of expression are gene - Stem cells have been intensively researched of their role in development - because and have potential therapeutic regenerative because they many or uses stem cells devide repeatedly - can - There is no limit to the number of times it can split into 2 cells Cell produced by division of a stem cell might remain as stem cells - or differentiatiate into a specific cett type - if they differentiate is they are longer stem cells no A stem cell is either undifferentiated on partially differentiated - > - they are always capable of differentiating along different path ways - Some stem cells remain in the adult body In present in human tissues Done many marrow, skin liver - , give them considerable and repair power of regeneration - STEM CELL NICHE - the precise location of stem cetes within a tissue - must provide microenvironment with conditions needed for the stem hair and done cell to remain inactive and undifferentiated over long periods of time, - marrow also for them to proliferate rapidly and differentiate when needed - In stricted (skeletal) muscle of there are stem cells that remain inactive unless ↓ there is muscle injury highly regenerative - Changes in the stem cells niche cause these after damaged cells to proliferate and differentate to replace damaged muscle tissue - Stem cells niche are of research interest as if they can de simulated outside the body for a particular stem cell type , it should be possible to generate human tissue in vitro (glass in laboratory) and use it in restorative surgery - Also , there are non-therapeutic uses for stem cells if appropriate microenvironments can be created ↓ only use : to produce large grantities of stricted muscle fibres for human consumption -early stage embryos are entirely composed of stem cells P TOTIPOTENT CELLS - TOTI POTENT CELLS T they can differentiate into any cell type potently replacement - very useful as in growth of whole heart kidney, or other organs cells gradually commit to particular pathways of differentiation during embryo - development > - involves series of points at which a a cell commits to develop along one pathway or another embryonic cell change from being totipotent to pluripotent - - PLURIPOTENT CELL-capable of differentiating into a range of cell types , but not every cell type MULTIPOTENT the that CELL stem cells remain in the adult body - - are more restricted in potential , but if they can differentiate into several types of mature cells a considered multipotent - Haematopoietic stem cells in Jone marrow are multipotent because they can generate different types of blood celts , but not other celt types - the size of a mature differentiated cell is one in which it is adapted to way perform its function the evidence in humans -  CELL DEVISION AND CANCER all organisms need to produce cells , for growth , maintenance and reproduction - new they do this by a cell devision a cell divides into I - MOTHER CELL - the cell that divides DAUGHTER the cells that produced from the mother cete - CELL - are the mother cell disappears entity in the unlike reproduction - a as an process by animal parents new cells are only produced by ever division of a pre-existing cell ↑ strong evidence for this theory a cell is for nuclear division by mitosis meiosis replicates all the DNA preparing or this ensures that each daughter cell produced receives a full complement of genes , allowing it to perform any required function earlier hypothesis falsified that single centromere held the chromatids - an now was a m allowing u , , anaphase together divided until chromatids separate , when it , the to -before replication , the DNA within the nucleus exists as long single molecules called chromosomes - after replication D there are pairs of identical DNA molecules COHESIN - loops of a protein complex ↓ still considered to be part of the DNA before replication = chromosome same chromosome and they are held b long single molecule together by cohesin - cohesin loops are not cut until the start of anaphase during mitosis on meiosis chromatics when DNA is in elongated state - Cohesinas > - a , & microtubules chromosomes are too narrow to be seen ↑ with light microscope containeule a r 2 chromadits - they become shorter and fatter during I chromosome IDNA IDNA early stages of mitosis or meiosis & then are visible - eventually each chromosome can be seen to have 2 strands , called chromatids  chromatid each contains single long DNA molecule produced by DNA - a very , replication from molecule an original 2 strands in chromosome are therefore known as sister chromatids genetically a identical -strands different chromatidsa not on chromosomes are non-sister genetically identical  D) 2 1 1.. , 2 1.. 2 , 2. 1. 3, 2 1.. 4 , 2. 1 5. , 1. 1 6. , 2 1.. 7 2. 1. S , CELL DEVISION AND CANCER CYTOKINESIS splitting of cytoplasm of a parent cell between daughter cells begins as soon chromosomes far enough apart as are CYTOKINESIS - animal cetts the plasma membrane is pulled inwands around the equator of the cell to form a cleavage furnow-using ring of a contractile proteins at the equator the proteins actin and similar to those that contraction myosin and - are are cause in muscle when the cleavage furrow reaches the centre the cell is pinched apart into ~ , two daughter cells CYTOKINESIS -D plant cells - microtubules are built into a scaffold on both sides of the equator - they assemble a layer of vesicles - the vesicles fuse together to form plateshaped structures - 2 complete layers of membrane are formed across the equator of the cell - the plasma membranes of the two daughter cells adjacent to the new dividing walls pectins and other substances brought in via vesicles - are and deposited by exocytosis between the two new membranes - formation of the middle lamella linking the new cell walls - both daughter cells bring celevlose to the equator and deposit it by exocytosis adjacent to the middle Camella-each cell builds its own cert wall across the equator  plant cell CYTOKINESIS can be equal and unequal - small cells produced by unequal division can survive and grow if they - nucleus and least receive a at one of each organelle that cannot be assembled from nuclear DNA and - e. g. budding in yeast oogenesis humans BUDDING IN YEAST -yeast cells reproduce asexually in a process called budding - the nucleus divides by mitosis - a small outgrowth of the mother cell is formed - it receives only a small share of the cytoplasm a dividing wall is constructed a the small cell splits away (leaving a scarl don't have yeast cells carry out this budding process repeatedly and to double in size between each division ANUCLEATE CELl-without nucleus - a cannot synthesize polypeptidesD they maintain themselves - cannot grow or have limited lifespans -  X you have more explanation in presentation i comment OOGENESIS IN HUMANS only one egg Coocyte) is cell produced at a time is with enough stored food to sustain the developing embryo unequal division of cytoplasm during oogenesis first and -the division produces one large cell with nearby all the cytoplasm a small polar body which does not develop further -only one large cell carries out the second division - unequal division of the cytoplasm - one large cell and one small polar Jody the large cell develops into mature oocyte that is ready - a for fertilization ROLES OF MITOSIS AND MELOSIS Mitosis - used to produce genetically identical cells a adiploidnume In - cells using mitosis have :x the same number of chromosomes as the parent cell , so the chromosomes number This that is maintained every cele ensures in a multicellular organism has all the genes that it needs. Also ensures that < have the same genes as the parent cell, the cells in a individual are genetically identical , Unumans mitosis maintains the preventing genome 23 tissue rejection. so problems such = as mitosis allows successful genome inherited without to be changes by - a offspring in a sexual reproduction ↑ division of a cell with only one nucleus produces anucleated nucleated one nucleated and one anucleate cell Meiosis - used to halve the chromosome number from diploid (2n) to haploid In and to generate genetic diversity - cells produced using meiosis have half as many chromosomes as the parent cell - division of a nucleus with 2 sets of chromosomes (diploid I results in nuclei with only one set Chaploid) D essential produce haploid to gametes from diploid germ cells in sexual life cycle -pains of genes in a diploid mother cell are dealt randomly to daughter cells , so there are an almost limitless numbers of possible combinations meiosis generates variation and genetic diversity allowing evolution by - , natural selection X DNA REPLICATION - a cell that is preparing for nuclear division mitosis by ar meiosis replicates all the DNA this ensures that each daughter - cell produced receives a full package of genes  CONDENSATION OF CHROMOSOMES - chromosomes are condensed by being made shorter. 1 by wrapping the double helix of DNA around histone protein to form nucleosomes C. linking the nucleosomes together - there are several more stages to condense the chromosomes , but they are not fully understood this is an active research field MOVEMENT OF CHROMOSOMES ???? pastavljajr se chromosomes moved using microtubules p - are -microtubule is a hallow cylinder of tudulin proteins that can be rapidly assembled or disassembled during interphase microtubules act as cytoskeleton disassembled in the early stages a - of mitosis and are reassembled by microtubule organizing centres MTOCs) at the poles of the cell , which link tubulin and form spindle-shaped molecules together a array kinetochones assembled the centromere of chromatid-some of each the growing - are on microtubules link up kinetochores and some attach to other microtubules from the opposite pole - the kinetochore removes the trarlin subunits from the attached ends of the microtubules putting them under tension as soon as the cohesin loops have been cut , sister chromatids to move to opposite poles in homologous meiosis , chromosomes are initially - held together by knot-like structures called chiasmata - when these have slid to the ends of the chromosomes movement to opposite poles can begin  PHASES OF MITOSIS mitosis requires precisely choreographed of D - actions phases a sequence PROPHASE - the starting phase with condensation of chromosomes protbefore METAPHASE the phase after condensation with released from nucleus - chromosomes the ANAPHASE Grief phase during which chromosomes moved up to poles from the equator - a the are TELOPHASE the final phase in which nuclei reform and chromosomes decondense - 1 U.. 2 5.. 3 6. Mitotic index = predroji neku fazu mitoze ↑ predroji ive faze ↑ i podjeli jedno s drugim B 2 1 1. 1 1. 12 2 1 10 , 2 1 4 2 1 9 1 1 7 ,........ , ,. ,. MEMBRANE STRUCTURE LIPIDS diverse group of substances in living organisms that dissolve in non-polar solvents hydrophobic not necessarily repelled by water but more attracted to non-polar substance fats melting point between 20 C and 37 % so they are solid % at room temperature and liquid at body temperature oils-melting point below 20 they solidify at low temperatures - so , waxes meeting point about 37 %, so they liquify at high temperatures - steroids molecules with a characteristic four-ring structure PHOSPHOLIPIDS SER synthesized by the smooth endoplasmic reticulum and transported as Svesicles to the cell membrane formed by a condensation reaction i one glycerol molecule links two fatty acid molecules and one phosphate group  hydrophilic - substances attracted to water hydrophobic substances not attracted to water amphipathic part of the molecule attracts polar substances hydrophilic part of a phospholipid is the phosphate group ↑ phosphate head · hydrophobic part consists of the 2 hydrocarbon chains - hydrocard on tails FORMATION OF PHOSPHOLIPIDS BILAYERS phospholipids form double layer phospholipid bilayer with the hydrophobic hydrocarbon tails facing inwards and the hydrophilic heads facing outwards to the water on either side they are stable structures and they form the basis of all cell membranes MEMBRANES-LIPID BILAYERS the plasma membrane forms the donder between a cell and its environment divide into compartments membranes the cytoplasm all biological membranes phospholipids bilayers - are made out of bilayer of phospholipids and other amphipathic molecules controls the passage of substances -  222 videoa presentation --- FLUID MOSAIC MODEL bilayer of phospholipids with proteins in variety of positions - a a -peripheral proteins are attached to the inner or outer surface integral proteins are embedded in the phospholipid bilayer phospholipid molecules are free to move laterally in each of the 2 layers of the bilayer so the proteins can also movea fluid mosaic model fatty acid tails on phospholipids can be saturated , monounsaturated and polyunsaturated this affects membrane fluidity. e g. Pump proteins is the plasma membranes of root cells in plants are oriented so that they pick up potassium ions from the soil and pump them into the root cell MEMBRANE PROTEINS Integral proteins at least partly hydrophobic embedded in the hydrocard on chains in the centre of the membrane & can extend across both bilayers transmembrane proteins extend ou many are they across the membrane , with hydrophilic parts projecting through the regions of phosphate on heads either side Peripheral proteins hydrophilic on their surface not embedded in the membrane most are attached to the surface of integral proteins and this attachment is often reversible some have a single hydrocarbon chain attached to them which is insented into the membrane , anchoring the protein to the membrane surface membranes all have an inner face and an outen face membrane proteins are oriented so that they can carry out their function - protein content is the membrane is variable membrane function varies  FUNCTIONS OF MEMBRANE PROTEINS used for of cells - DISPLAYING recognition by GLYCOPROTEINS conjugated proteins with carbohydrate as the non-polypeptide component a component of the plasma membrane of cells the protein part is embedded in membrane and part is out of cell the the carbohydrate projecting the GYCOLIPIDS glyco-with carbohydrate carbohydrates linked to lipids carbohydrate part a single monosaccharide on a short chain of between 2 or h sugar units lipid part 1 or 2 hydrocarbon chains , which naturally fit into the hydrophobic core of membranes gyclolipids occur in the - plasma membranes of all eukaryotic cells , with the attached carbohydrate projecting outwards into the extracellular environment of the cell prevents tissue from falling apart a GLYCOPROTEINS AND GLYCOLIPIDS form a carbohydrate-rich layen on the outer face of the plasma membrane of animal cells , with an aqueous solution in the gaps between the carbohydrates glycocalyx the glycocalyx of adjacent cells fuse-prevents the - can tissue from falling apart - both have roles in cell-to-cell recognition use glycolipids help the immune to system distinguish between self and non-self cells -  6) LYCOPROTEINS IN CELL-CELL RECOGNITION cells allow other cells by displaying distinctive glycoproteins to recognize them - , the glycoprotein the surface of on one cell is recognized by receptors on the surface of another cell cell-to-cell and allow recognition help with the organization of tissues also - can foreign cells or infected body cells to be identified and destroyed - e the ABO antigens in ned blood cells glycoproteins providing the.. g are means of cell-cell recognition ABO GLYCOPROTEINS blood ned cells have glycoproteins in their membranes that don't have a known function , but that affect blood transfusion any of 3 possible types of oligosaccharide be present the - can on A and glycoprotein , B two of these types of glycoprotein present in every person's blood - one or are never all 3 B 2 1 2 2 1 8 2 1 3 2 2 1 2 3 6.. ,.. ,.. ,. 1. 5,.. 6 ,. 1. 7 , 2.. , - Cell membrane is selectively permeable - Semi-permeable , party permeable the membrane core has low permeability to hydrophilic particles ions and polar molecules ; e.. g glucose ↑ molecule size - permeabilitya -simple diffusion facilitated diffusion and active transport - > - specific = selective SIMPLE DIFFUSION -diffusion is the spreading out of particles in liquids and gases net movement of particles from the higher to the lower concentration - a > - movement down the concentration gradient passive - - small polar molecules can diffuse at low rates OSMOSIS net movement of water molecules across the membrane due to the difference in concentrations of substances dissolved on opposite sides dissolution (dissolving of) formation of intermolecular bonds with water molecules - - > - osmotically active solutes - intramolecular bonds restrict movement-net movement of water from regions of lower solute concentration to regions with higher solute concentration - passive - concentration - the amount of solute per unit volume of solution - mot dm3 = mol dm - - hypotonic (b) hypertonic (4) and isotonic , () = cells change how rapidly osmosis the by changing permeability to - can occurs water of their plasma membrane more inside more outside Same in comparison to the cell :..... Water!n : : Just i hypotonic isotonic hypertonic  * G hypertonic isotonic solution - III - hypotonic * The sodium-potassium pump - video AQUAPORINS-water channels -greatly increase membrane permeability to HO FACILITATED DIFFUSION -diffusion with help of integral transmembrane channel proteins -size of of particle the pore ensures that only one type passes through Selection types of channel that synthesized and placed in plasma - - are the membrane channels temporary change in permeability by closing and opening -passivea don't need energy ACTIVE TRANSPORT - passing of particles through the membrane against the concentration gradient pump proteins use energy - - particles in direction - more one - have 2 conformations energy (ATP) used to change the protein from conformation (the more stable) to - - one the other (the less starte) the reverse change doesn't require - energy - allows the cell to control its contents SURFACE AREA TO VOLUME RATIOS - cell metabolism - all chemical reactions in a cell - the rate is proportional to the valume of the cell cell needs to take in reactants and waste products with reactions - remove to keep up the - the rate at which substance cross the membrane depends on its surface area surface area-to-volume nation = surface area mm2 volume (mm3  A 2 2 9.. Trend is a prevailing tendency a generalization Typical ,. does Discrepancy not fit the general trend variation from the trend - - a , Examples of discrepancies  A1 1. , D2 3. WATER solvent for polar substances The medium of life > - Y Cytoplasm In all SOLVENT biochemical organelles for Intercellularissue fluid reactions Permits transport of particles in and out of cells Provides a habitat Structure and polarity Polar covalent sands between axygen and hydrogen atoms the sharing of electrons is unequal the nucleus of atom is attractive to electrons that the nucleus of an oxygen more a hydrogen atom A hydrogen bond is the force that forms when a slightly positive hydrogen atom in one polar molecule is attracted to a slightly negative atom of another polar molecule · Cohesion water molecules stick together energy is required to break hydrogen bonds cohesion-molecules of the same type sticking together surface tension strong cohesive force due to the lack of upward pulling molecules ' habitat for some animal I allows the transport of water in plans water molecules are much more attracted to each other by hydrogen sanding than to air particles Adhesion hydrogen bonds that form between water and the surface of a solid composed of polar molecules cause water to stick to the surface of the solid capillary action movement of water through narrow glass tudes caused by adhesion D risings of underground water resource ↑ adhesion to celevlose in plants  some sea Physical properties -animal some find Solvent properties form shells around both charged and polar molecules prevents precipitating all substances that dissolve in water hydrophilic - are Metabolism Transport Hydrogen bonds individually weak , collectively strong continually breaking and reforming , - Solvation:1. the particles of a solute separate from each other 2. the water particles separate from each other 3. the separated solute and water particles combine to make a solution Solvation the combination of a solvent with the molecules or ions of a solute hydration lif solvent is HzO Water movement - osmosis-net movement of water across a membrane solutes are osmotically active if inter molecular attractions form between them and water sodium -e.. g , potassium , chloride ions and glucose cells can change the speed and direction of movement  BIOMOLECULES Carbon - carbon forms the Jasis of organic life due to its ability to form large and complex molecules - n electrons in the outer shell - Forms four covalent bonds in order to file its valence shell - covalent bond-a chemical linkage that arises from the sharing of an electron pair between two atoms Compound Diversity - it can for up to h single bonds with other atoms or multiple bonds with a single atom - it can produce molecules of various shape , including chains or rings 000000 o-i !, i ! :- o - ↑ 0 0 0 0 0 o d' o bonds straight Branched Multiple chains chains Rings Organic Compounds All organic compounds contain carson - almost all carbon compounds are organic exceptions included canbides (Ca(z) , carbonates (CO3) , cardon oxides (CO2) cyanides (CN) , there contribute cell types of organic compounds to four main that structure - are and function Nucleic Acids Carbohydrates Lipids Proteins > - , , ,  I - I Nucleic Acids - - nucleic acids consist of repeating subunits (called nucleotides) that contain a pentose sugar , a phosphate group and a nitrogenous based - Nucleic acids function as the genetic material of the cell-responsible for determining the inherited features of an organism - 2 main types of nucleic acids found in cells (or viruses) : · DNA functions as a master copy (the genetic blueprint of a cell) RNA is responsible for the assembly of proteins (gene expression * ATP is a modified nucleic acid Carbon hydrates -contain with a repeating typically