Mitosis Cell Cycle PDF

CELL CYCLE AND MITOSIS kinds of cell division 1. Binary fission (priečne delenie) - in prokaryotic cells 2. Mitosis (Mitóza) in euraryotic cells 3. Meiosis (Meióza) 1. binary fission ◦ the simplest and fastest form of reproduction ◦ in...

CELL CYCLE AND MITOSIS kinds of cell division 1. Binary fission (priečne delenie) - in prokaryotic cells 2. Mitosis (Mitóza) in euraryotic cells 3. Meiosis (Meióza) 1. binary fission ◦ the simplest and fastest form of reproduction ◦ in prokaryotic cells ◦ the parent cell (materská bunka) divides into two ◦ daughter cells (dcérske bunky) that are about equal ◦ steps: ⁃ the DNA replicates (makes a copy) ⁃ the cell elongates ⁃ a cell wall for,s between two chromosomes ⁃ the cell splits into two new cells division in eukaryotic cells cell cycle (bunkový cyklus) ◦ cells are not dividing all the time ◦ division is only a short part of a cell cycle ◦ cell cycle = is the repeating set of events that make up the life of a cell ◦ cell cycle lasts from the time the cell is first formed ("birth”) until its own division into two cells ◦ cell cycle is divided into: 1. Interphase (90%) 2. Mitosis/Meiosis (10%) 1. INTERPHASE (interfáza) ◦ the time between two cell divisions ◦ growth, DNA replications, cell functions ◦ interphase: G1 phase, S phase, G2 phase S phase one chromosome sister chromosome chromosome (unduplicated) (duplicated) ◦ a chromosome is a structure made up of a single molecule of deoxyribonucleic acid (DNA) coiled around proteins ◦ in S phase, the DNA in each chromosome is replicated. The two identical copies that result from this DNA replication are referred to as 'sister chromatids (sesterské chromatídy), and are joined to each chromosomes: 1 chromosomes: 2 other by a region of the DNA molecules: 1 DNA molecules: 2 chromosome called the centromere (centroméra).  2. MITOSIS ◦ chromosomal "dance" with some fancy choreography ◦ is a process where a single cell divides into two identical daughter cells ◦ when mitosis is done, body cells are produced ◦ the major purpose of mitosis is for growth and repair of damage 1. prophase (profáza) 2. methaphase (metafáza) prophase 4. telophase (telofáza) during prophase the double chromosomes coil into rod-shaped chromosomes (condense, skracujú sa) in animal cells, centrosomes (centrioles) 3. anaphase (anafáza) move toward the opposite ends, or poles, of the cell the microtubules of centrosomes form a football-shaped structure called the spindle (deliace vretienko) spindle fibers attach to the centromere of chromosomes the nuclear membrane breaks down and disappears into the cytoplasm nucleolus breaks down Chromatin - before mitosis Condensed chromosome - Mitosis Centrioles divide early prophase Chromatin begins Condensed to condense chromosomes before mitosis prophase centrioles late prophase  metaphase ◦ during metaphase spindle fibers move the chromosome to the centre of the cell- equatorial plane (ekvalitórna rovina) anaphase ◦ in anaphase, the chromatids of each chromosome separate (get apart) ◦ each chromatid now becomes its own chromosome ◦ the microtubules of the spindle shorten drawing the chromosomes to opposite poles of the cell ◦ as a result, one complete set of chromosomes goes to one pole while the other identical set goes to the other pole ◦ unatached microtubules elongate and push apart, making the cell longer telophase ◦ during telophase, the chromosomes uncoil, getting longer, and slowly take on the threadlike (vláknitý) appearance of chromatin (decondense) ◦ the spindle disappears ◦ the nucleoli reappear ◦ the nuclear membrane forms around each daughter nucleus ◦ the cytoplasm divides by a process called cytokinesis (cytokinéza) cytokinesis: ◦ In animal cell, microfilaments form a structure called cleavage furrow (deliaca brázda, kontraktilný prstenec) which pinches the cell into two (zaškrtí bunku). ◦ In plant cell, a cell plate (platnička) forms along the middle of the dividing cell. It is basically a new cell wall which splits the cell into daughter cells.