GENBIO a4 - Cell Cycle PDF
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This document provides notes on the cell cycle, including checkpoints, mitosis, meiosis, and cell division. It details the different phases of the cell cycle, such as interphase and the mitotic phase, highlighting key processes and regulators.
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Cell Cycle heckpoints (Cell Cycle Regulators) - It is a stage where...
Cell Cycle heckpoints (Cell Cycle Regulators) - It is a stage where C itosis –Cell Division (pagpaparami) M Interphase prokaryotic cell cycle where internal and external cues are 24-hour cell cycle Meiosis – Cell Reduction (pagbawas) / Reducing number of It is also called “non-dividing” stage because it is examined. They decide what will move forward and what will not. G1 - (6-12 hours) Chromosomes devoted tocell growth. S phase - (6-8 hours) Preparing itself for cell division 1 checkpoint (between G1 and S) G G2 - (3-4 hours) L ifebeginsasazygote-Itismadeupof46chromosomes.23 Cells grow and makes a copy or replicate its DNA to Green - positive regulators -Stimulating Proteins M phase (1 hour) from each prepare for cell division Growth factors parent. Cyclin and cyclin-dependent kinases (CDK) - It G2 checkpoint (between G2 and M phase) First Gap Phase (G1 Phase) canonlyphosphorylatedownstreamproteinswhenitis Ensures that all DNA are completely and correctly Little change is visible (cells increases in size) bound with its partner cyclins. A lone CDK is replicated. The cell here is quite active at biochemical level. inactive,butthebindingofacyclinactivatesit,making Damages to replicated DNA are checked. It accumulates sufficient energy reserves to complete itafunctionalenzymeandallowingittomodifytarget Cell proceeds toMPhaseifcellsizeandnutrientsare task of replicating each chromosome in the nucleus. proteins. sufficient. Metabolically active, period of growth, and cells ○ It will not work if walang nakadikit na Stimulating protein - Cyclin and cyclin-dependent increases in size and in volume. Cyclin. kinases It produces CLEP Inhibiting proteins-p53 protein CLEP Red - negative regulators -Inhibiting Proteins Carbohydrates P53 protein (tumor-protein 53) (Guardian of the Inactive Stage/ Gap 0 (G0) phase Lipids genome) - The TP53 gene provides instructions for Gap0Phaseisalsoreferredtoasthe"restingphase". Enzymes making aproteincalledtumorprotein53.Thisprotein Itisbecauseitisinthisphasewhenthecellfollowing Proteins actsasatumorsupressorinwhichthatitregulates celldivisionentersarestingperiod.Thecellisinactive ell Cycle- The cell cycle is the series of C cell division by keeping the cells from growing and inawaythatitexitsthecellcycleandisnotpreparing events that occurs in a cell from one division to the next. Synthesis of DNA (S) Phase dividing. itself to undergo cell division. It is the phase in which DNA is replicated occurring ○ Proliferation - Nagpaparami ng abnormal Mitotic (M) Phase Important tasks between G1 Phase and G2 Phase. cells Cell division It must grow Replicates a single chromatid into a full chromosome. ○ thisproteinplaysacriticalroleindetermining Cells separate DNA into two sets and divide its It must copy its own genetic material Chromatid - Half of chromosome whether the DNA will be repaired or the cytoplasm, forming new cells It must physically split up into two new daughter cells damaged cell will self-destruct (undergo Mitosis involves four phases, based on the physical apoptosis). If the DNA can be repaired, p53 stateofthechromosomesandspindle.Thesephases Importance of the cell cycle activatesothergenestofixthedamage.Ifthe are prophase, metaphase, anaphase, and It is essential in forming new plants DNAcannotberepaired,thisproteinprevents telophase. It is vital in the process of healing and tissue repair thecellfromdividingandsignalsittoundergo It makes new life possible apoptosis. Centrosomes - Chromatin - Chromatids - Sister Retinoblastomaprotein(Rb)-arareformofcancer chromatids - Homologous Chromosomes 2 Major Phases of Cell Cycle that rapidly develops from the immature cells of a Interphase Centrosomes Second gap phase (G2) retina ○ First gap phase (G1 phase) You cannot call it centrosomes without microtubules The cellreplenishesits stored energy ○ Synthesis of DNA (S phase) ote: Cell cycle checkpoints “ensure N and centrioles Synthesizes proteins necessary for chromosomal ○ Second gap phase (G2 phase) ordered progression through the cell It is a cellular structure that organizes microtubules manipulation. Mitotic (M) Phase and centrioles. It is present in the cell division. Some cell organelles are duplicated and the ○ Karyokinesis yclins-ItwasdiscoveredbyTimothyHunt,LelandH.Hartwell C ○ Microtubules cytoskeleton is dismantled toprovideresourceforthe Prophase and Paul Nurse. tubulins (proteins) mitotic phase. Metaphase They found that the concentration of each cyclin was (Cytoskeleton) Anaphase S ynthesizes proteins, duplicates some organelles, cells different at each stage and changed in a cyclical Hollow rods Telophase continues to increase in size, final preparations fashion. Fibrous ○ Cytokinesis TheywonaNobelprizein2001fortheircontributionto Function primarily to help support excells–Humangametes(eggandspermcells)arehaploid, S Physiology and Medicine. and shape the cell containing 22 autosomes and one sex Cyclins are among the most important core cell ○ Centrioles chromosome. cycle regulators. Multiple microtubules It contains 23 chromosomes. Cyclins are a group ofrelatedproteinsthatundergoa A cylindrical structure that are In the human body, we have 46 chromosomes cycleofsynthesisanddegradationineachroundofthe composed of groupings of (23 from each parent). cell cycle. microtubules They help in the regulation of the cell cycle. A rranged in a 9+3 pattern (9 na E ach chromosome contains two identical chromatids T he sister chromatids break down and separate at the dikit-dikit, bawat dikit-dikit may called "sister chromatids" connected at the centromere and move away from each other. Cell Cycle in Plant Cell tatlong microtubules) centromere. When they separate, eachchromatid still has Thenuclear envelopebreaks down. centromeresattached to them. Each chromatid is now a chromosome. The centrosomesmigrate to opposite poles. The chromatid lengthens, thuselongating the cell. Thespindle fibersbegin to form. The nuclear envelope also means the nuclear membrane Spindle Fibers - Aggregates that move the chromosome in cell division(Microtubules) W hen plant cells undergo cell division, theydo not physically separate, aCell plateforms to separate the two new cells. Plant cells cannot separate since their cell walls are Chromatin rigid Yarn or thread-like When plant cells produce a cell plate,they will return It is themass of a genetic material to the G1 phaseand repeat the process. Telophase Contains your DNA and Protein Thecleavage f urrow Beforeitturnsintochromatids,itcondenseswiththe Haploid and Diploid Cells forms in the center of help ofHistones the cell. Youtube Notes The Haploid Diploid chromosomes o nce again ne set of chromosomes O 2 sets of chromosomes decondense to become Symbol n Symbol 2n thin threads of chromatin. Sex cells (Gametes) Zygote (return to previous to Every gamete has 1 set of 46 chromosomes prepare for the next cell Metaphase 23 chromosomes Each cell has 1 set of division) Metaphase = Middle Produced byMEIOSIS chromosome from the Each chromatid c lusters at Sister chromatids align at the center/equator of the mother and another from opposite poles. Chromatids cell (imaginary line), attached to spindle fibers atthe the father. (These pair are The nuclear One of the two identical copies of a replicated kinetochores. called homologous membrane reappears chromosome chromosomes) The equator is calledtheequatorialormetaphase and spindle fibers disassemble. Histones- Specialized type of protein Dalwa na yung nucleus Undergo cell division many plate. times Centromeres Cytokinesis All body cells (somatic Connects two chromatids cells) are diploid It is a division of cytoplasm. Other organisms have The cell has acontractile ring somatic cells with Sister chromatids Also termed cell splitting different diploid numbers Sister chromatids are identical copies of a of chromosomes, the half chromosome that are held together duringreplication of this is the gamete and remainattacheduntiltheyareseparatedduring haploid. mitosis. Reproduce byMITOSIS Homologous vs Sister Chromatids S ister chromatids aregeneticallyidentical.Theyhavethesame Metaphase (Spindle) checkpoint genesandthesamealleles.Whilethehomologouschromosomes Occurs during metaphase come from the two parents, the one from the motherandone The attachment of spindle fibers to kinetochores is from the father, they have the same genes but only different checked. Stimulating protein -Anaphase-promoting alleles Lecture Notes c omplex/cyclosome(A CP/C) -Allows the cell to Cell Cycle in Animal Cell aploid and Diploid arethetermsusedtodescribethenumberof H Prophase proceed to Anaphase chromosomes in a cell It is thelongest phase I nhibiting Protein-Mitotic Arrest Deficient (MAD) Haploid Diploid Proteins. The chromatin condenses and becomes O nly reproduced through R eproduced only be chromosomes. meiosis(reduction Mitosis Anaphase Anaphase = Apart/Away division) All body cells(except Gametes (sex cells) gametes) R epresented by n 2 n=46 ○ A ftertheDNAinthechromatinreplicates, C ○ entrioles migrate to the two opposite poles ○ C rossing over -aphysicalexchange n=23 Consist of2 SETSof it condenses into the more familiar ○ Spindle fibersform of information occurs at a Consist of1 SETof chromosomes (1 set from x-shaped chromosomes. corresponding position ofhomologous chromosomes each parent) ○ The replicated DNA is the same in the Metaphase II chromosomes. NoHomologous Contain pairs of identical sister chromatids of each ○ Chromosomes line up at the ○ Genetic Recombination - new Chromosomes Homologous chromosome equatorial/metaphase plate combinations of allele are created by chromosomes ○ In a process called Synapsis, each crossing over. chromosome binds to and pairs up its Anaphase II Diplonema - The 2 pairs of sister corresponding homologous chromosome ○ Sister chromatids of each chromosome chromatids begin to separate from each forming atetrad. separate and move to opposite poles. other ○ Tetrad - is the group of four sister ○ Once Sister chromatids separate, they are ○ Chiasma - area of contact between chromatids paired in homologous called and turn to chromosomes non-sister chromatids. It is the chromosomes. evidence of crossing over. Telophase II ○ Chromosomes - containgeneticinformation Diakinesis - chromosomes continue to ○ Spindle fibers disappear called genes, thesegenesareinheritedfrom condense andTetradsare clearly visible. ○ Nuclear membranes reappear each parent. Metaphase I Cytokinesis occurs in both cell Metaphase = Middle Homologous Chromosomes Sister Chromatids ○ Allele- different versions of the same gene Meiosis II ends with 4 genetically different haploid Tetradsalignatthecenter/equatorofthe Carrysame genetic arrysame genetic C ○ In a process called Crossing Over daughter cells. cell (imaginary line) attached to spindle type/material type/material (Recombination), chromatids from each Same Size Same Size homologous chromosomes exchange fibers at the centromeres L ecture Notes The equator is called theequatorialor Same Shape Same Shape segments of alleles 2 major phases of Meiosis metaphase plate Differentversion of SAMEversion ofAlleles This explains why every gamete is Interphase Alleles geneticallydifferentfromeveryother ○ First Gap Phase (G1 Phase) Anaphase I gamete. ○ Synthesis of DNA Phase (S Phase) The separation of tetrads at the excells–Humangametes(eggandspermcells)arehaploid, S Causesvarietyinoffspring,that’swhy ○ Second Gap Phase (G2 Phase) centromere and moves towards the containing 22 autosomesand one sex siblingscanhavedifferenttraitsfrom Meiosis poles. chromosome. their biological parents ○ First Meiotic Division (Meiosis I) Anaphase = Apart It contains 23 chromosomes. ○ Nuclear membranedisappears Prophase I(LaZyPaDiDi) -Longestphaseof Telophase I In the human body, we have 46 chromosomes ○ Centriolemoves to theopposite poles meiosis The Cleavage furrow forms in the (23 from each parent). ○ Spindle Fiber forms Leptonema - The chromatin condenses, center of the cell Autosomes - Any chromosome that is not a sex Metaphase I ○ Homologous chromosomes line up at the becomes chromosomes. The nuclear membrane reappearsand chromosome ○ Replicated chromosomes have coiled spindle fibers disassemble equatorial/metaphase plate Meiosis Anaphase I and are already visible. Cytokinesis Y outube Notes ○ Spindle fibers pull the chromosomes, ○ The number of chromosomes present Also termed as “cell splitting” Meiosis (R eduction Division)- The type of cell division that separating them fromeachtetradandpulling arestillthesame(46chromosomes)as 2newhaploidcellsareformed,with1 produces gametes. them from opposite cell poles. the number in the diploid cell. set of each chromosome Meiosis I Telophase I Zygonema - Homologous chromosomes The division of the cytoplasm is ○ Prophase I ○ One chromosome from each homologous find each other and synapse. completed. ○ Metaphase I chromosome at opposite poles ○ Homologous chromosomes begin to ○ Second Meiotic Division (Meiosis II) ○ Anaphase I ○ Sister chromatids are nolongeridenticaldue pair and twistsaroundeachotherina ○ Replication does not occur again before ○ Telophase I to DNA recombination (exchange of alleles) highly specified manner. Meiosis II Meiosis II ○ Spindle fibers disappear ○ The pairing iscalled“Synapsis” -the ○ Daughter cells from Meiosis I stays as haploid ○ Prophase II ○ Nuclear membrane reforms around the joining of homologous chromosomes. ○ Meiosis happens in both daughter cells ○ Metaphase II chromosomes ○ Synaptonemal Complex - precisely ○ ○ Anaphase II Cytokinesis occurs aligned homologous chromosomes, Prophase II ○ Telophase II match by base pairs. Nuclear membrane disappears Meiosis I eiosis 1 endswithtwogeneticallydifferenthaploiddaughter M Pachynema - Chromosomes become Spindle fibers appears from opposite Prophase I cells. much shorter and thicker. poles in the centrioles ○ Starts with aDiploid cell ○ Homologous chromosomes exchange Metaphase II ○ Its chromatin contains two uncoiled Meiosis II genetic information by “crossing Thechromosomesineachcelllineup spread-out sets of chromosomes from Prophase II over” - the parts of the homologous attheequatorandattachedtospindle each parent ○ NO DNA REPLICATION chromosomesarerecombined(genetic fibers from both poles ○ Nuclear membranedisappears information) Anaphase II T he sister chromatids of each T risomies and Monosomies are two types of Small Jaw ○ nable to conceive naturally U chromosome separate and move into chromosomal abnormalities. ○ Low set of ears Heart concerns the opposite poles. Once sister ○ Trisomy - when a person has three of a ○ Smallmouth Kidney abnormalities chromatids separates, they are now particular chromosome, instead of the usual ○ Receding chin Life Expectancy: Individuals with Turner called chromosomes. two. ○ Difficulty feeding syndromecanlivehealthyliveswithappropriate Telophase II ○ Monosomy - when they just have one ○ Delayed motor and cognitive skills medical care and management of associated The spindle fibers disappear and chromosome, instead of the usual two. ○ High Mortality rate health issues. nuclear membranes reform. 1. Patau Syndrome (Trisomy 13) ○ Life expectancy: reduced Cytokinesis 3. Down Syndrome (Trisomy-21) - the presence ofan aryotyping - the process of pairing or ordering the K Meiosis II ends with 4 genetically extra copy of chromosome number 21 chromosomes of an organism. differenthaploidcellscontainingonly 1 set of chromosomes (23) aryotype – a visual representation of the complete set of K UMMARY: S chromosomes in a cell. First Meiotic Division (Meiosis I) Male XY Prophase I (LaZyPaDiDi) Female XX ○ Leptonema- Since the female is XX, each of her eggs has a single X ○ Zygonema chromosome. The male, being XY, can generate two types of ○ Pachynema sperm: half bear the X chromosome, and half the Y. ○ Diplonema ○ Diakinesis Transport Mechanisms It is ageneticdisorderthatiscausedbythepresence Metaphase I If there is no cell membrane Anaphase I of an extra copy of chromosomes 13 in cells. 1. The cellDies Telophase I Range of physical and intellectual disability 2. There will be no boundary that separates the inside ○ Cytokinesis Experience severe medical complication Features and outside of the cell Second Meiotic Division (Meiosis II) Features ○ Almond-shaped eyes Prophase II ○ Cleft lip and palate The cell membrane is compared to amosaic ○ Flat facial profile Metaphase II ○ Extra fingers or toes(Polydactyly) Thereareproteinsscattered in the phospholipid layers ○ Small nose Anaphase II ○ Heart defects and other organ malfunctions Lipids ○ Low Muscle tone (hypotonia) Telophase II ○ Eye and ear abnormalities Group of organic compounds that are insoluble in water ○ Wide range of cognitive abilities, but a little Cytokinesis ○ Small head(Microcephaly) ○ Examples include fats, waxes, oils, and bit of developmental delays in speech and ○ Sloping Forehead hormones (or steroids) motor skills. ○ Severe intellectual disability ○ Proneto:congenitalheartdefects,respiratory ○ Developed mental delays in motor and Fluid Mosaic Model infections, gastrointestinal cognitive skills Seymour Jonathan Singer and Garth Nicolson in ○ Life Expectancy: With improved medical ○ High Mortality rate (not surviving past 1970. care and support people with Down infancy) syndrome are now living longer. ○ Heart and kidney problems (Increased) ○ Difficulty to thrive and eat 4. Turner’sSyndrome(MonosomyX) -onlyhappensin ○ Life expectancy: reduced females (XX) 2. E dward’s Syndrome (Trisomy-18) - problem with chromosome number 18 Diseases from Cell Malfunctions Complete or partial absence of one of the X chromosome Short Delayed or absent puberty E xtra copy of chromosome 18 Webbed neck Severe developmental abnormalities and medical Low set of ears conditions Characteristics of a phospholipid Broad chest Aneuploidy -Abnormalities that occur in a chromosome. Features Ovarian Dysfunction leads to infertility 1. Amphipathic - characteristic of being hydrophobic ○ Clenched fist and hydrophilic 2. S emi-permeable - Allowsonlycertainsubstancesbut not everything. 3. Pliable- Flexible, fluid able to flow Oligosaccharide- 5 or more sugar units embrane Transport - It refers to the movement of M roteins -These biomolecules are made up of P particlesacross or through a membranous barrier. hat are the factors that can affect membrane W building blocks calledamino acidsjoined bypeptide bonds. Transport of substances is one of the important transport? Peripheral - Proteins that stays on the perimeter functions of thecell membrane 1. Membrane Permeability (side)of the membrane (Gilid) Why there is membrane transport? 2. Size and charge of the solute Monoprotic - Proteins that attachedtoonlyoneside ○ Absorptionof nutrients during digestion 3. Transmembrane solute concentration gradient or layer of the membrane. ○ Dischargeof waste materials. 4. Heat the Ph Polytropic/transmembrane - Proteins that span acrossthe membrane. holesterol-Itisatypeoflipid,awaxysubstancefoundin C cells.Itisessentialsintheproductionofotherbiomoleculeslike hormones, steroids, and Vitamin D. Saturated- Solid at room temp Unsaturated- liquid at room temp groups being transported by cell - Categorized by 4 Functions of Protein permeability Small Hydrophobic Molecules Receptor: It can transmit signals between the cells ○ Oxygen, Carbon Dioxide, Nitrogen internal and external environment. ○ It is membrane-permeable Channel:Theyallowthefacilitateddiffusionofcertain Small, uncharged polar molecules materials across a concentration. ○ Water, urea, glycerol Transmembranetransport:Itismuchmorecomplex. ○ Mostly permeable Molecules that transport proteins requires use of Two types of Membrane Transport ○ Pass by diffusion or osmosis energy. Passive-Does not require energy Large, uncharged polar molecules Adhesion:Proteins serves as binding with other cells. ○ Glucose, sucrose Cell recognition: Proteins enables the cell to ○ Mostly impermeable recognize their cells, or they can recognize other ○ Requires transport proteins substances bacteria and viruses. Ions Enzymatic function:Involves in activities of enzymes. ○ Sodium, Potassium, Chloride, Calcium ○ Completely impermeable arbohydrates - It is a biomolecule made up of carbon, C
