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Published byStanley Boyd Modified over 9 years ago
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The life process by which an organism produces new individuals of the same kind. This is essential for the survival of the species
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Asexual Reproduction Involves ________ parent and results in one or more offspring that are genetically _________ to that parent. Cells reproduce by Mitosis one identical
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A process where a cell divides and creates two daughter cells which are identical to the parent Cell Division happens by series of phases ▪ Interphase, prophase, metaphase,anaphase, and telophase (cytokinesis) ▪ I.P.M.A.T.(C).
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interphaseprophase metaphaseanaphasetelophase cytokinesis I.P.M.A.T.C. P lease M ake A nother T wo C ells
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nucleus cell DNA in chromosomes nucleus cell duplicated chromosomes chromosomes in cell 4 single-stranded chromosomes duplicated chromosomes 4 double-stranded chromosomes
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Stage 1: cell copies DNA nucleus cell DNA Copy DNA! INTERPHASE
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Stage 2: DNA winds into chromosomes Nuclear membrane disappears Spindle Fibers/ Centrioles appear nucleus cell duplicated chromosomes Wind up! PROPHASE
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double-stranded human chromosomes ready for mitosis
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Stage 3: Chromosomes line up in middle attached to protein “cables” that will help them move duplicated chromosomes lined up in middle of cell Line up! METAPHASE
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Stage 4: Chromosomes separate start moving to opposite ends chromosomes split & move to opposite ends Separate! ANAPHASE
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Stage 5: Cell starts to divide Two nuclei Chromosomes unwind Divide! TELOPHASE
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Stage 6: DNA unwinds again cells separate completely (cleavage furrow) now they can do their every day jobs Bye Bye! CYTOKINESIS
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Biology is the only subject in which multiplication is the same thing as division…
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Binary Fission The cell splits into two identical cells, each containing an exact copy of the original cell's DNA. Nucleus and Cytoplasm divide EQUALLY!
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Budding- where the daughter cell grows out of the parent and gradually increases in size. Yeast cells Hydra Nucleus divides equally Cytoplasm divides unequally
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Spores Reproductive cell that contains a nucleus and a small amount of cytoplasm Spores are highly resistant to heat Spores are capable of growing into a new organism when conditions allow Produced by bread mold, mushrooms, mosses and ferns
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Regeneration Development of a new organism from part of a parent Whole organisms are produced – Starfish! Replacement of lost body part
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Vegetative Propagation Part of a plant (root, stem, leaves) grows into a new plant Seedless fruits & vegetables Commonly used by farmers = quick, easy & successful!
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Offspring receive half of their genes from one parent and half from the other parent The genes are carried on chromosomes in sex cells known as gametes Male gamete is the sperm cell Female gamete is the ovum (egg)
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Joining of 2 sex cells (egg & sperm) Do we make egg & sperm by mitosis? 46 + 92 eggspermzygote What if we did, then…. Doesn’t work! No!
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Gametes are formed by Meiosis Meiosis (reduction division) In series of divisions the number of chromosomes is reduced by half
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46 chromosomes to 23 chromosomes half the number of chromosomes 23 46 egg sperm 46 meiosis haploiddiploid
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Fertilization Two gametes (Ovum and Sperm) join to create an offspring Variation Each offspring gets a unique combination of genes, therefore they are not identical to their parents or siblings.
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Meiosis (reduction division) Spermatogenesis: Creates 4 sperm cells Oogenesis: Creates 1 ovum and 3 polar bodies
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mitosis zygote 23 46 egg sperm 46 meiosis 46 23 fertilization mitosis & development meiosis fertilization mitosis + development 46 gametes
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Meiosis to make gametes sperm & egg Mitosis to make copies of cells growth repair Development replacement
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Consistency over time meiosis keeps chromosome number same from generation to generation from Mom from Dad offspring DadMom
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Change over time meiosis introduces genetic variation ▪ gametes of offspring do not have same genes as gametes from parents ▪ new combinations of traits from Mom from Dad new gametes made by offspring offspring We ’ re mixing things up here! variation
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Crossing Over – Trading DNA! During prophase 1, sister chromatids intertwine homologous pairs swap pieces of chromosome ▪ DNA breaks & re-attaches tetrad prophase 1
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Sexual reproduction allows us to maintain both genetic similarity & differences. Baldwin brothers Jonas Brothers Martin & Charlie Sheen, Emilio Estevez
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The nucleus is taken from parent with a complete set of genetic information Injected into an egg cell which has had its nucleus removed
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The egg is implanted in a surrogate mother Result is an organism which is 100% genetically identical to parent
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Many more to come… Too many to list…
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