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TYPES OF REPRODUCTION AND MEIOSIS

TYPES OF REPRODUCTION AND MEIOSIS. UNIT 5: Chapter 11. TYPES OF REPRODUCTION. Asexual Reproduction does not include joining of gametes. SPORES are asexual because they do not have to fuse to another cell. BUD becomes new individual.

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TYPES OF REPRODUCTION AND MEIOSIS

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  1. TYPES OF REPRODUCTION AND MEIOSIS UNIT 5: Chapter 11

  2. TYPES OF REPRODUCTION

  3. Asexual Reproduction does not include joining of gametes SPORES are asexual because they do not have to fuse to another cell. BUD becomes new individual FRAGMENTATION: Pieces of organism develop into a new whole organism (Starfish and planarian are examples) Hydra BINARY FISSION: Individual divides to produce new offspring PARTHENOGENESIS:unfertilized eggs develop into individuals (some fish, several insects, few species of frogs and lizards) Bacteria

  4. Sexual Reproduction Process of sexual reproduction in which male and female gametes join to form a new cell (zygote). Gametes are called sex cells.

  5. Sexual versus Asexual Reproduction Asexual • NO FUSION of gametes • Very little GENETIC variation • MANY OFFSPRING in short time without having to find mate • LESS genetic variation causes LESS ability to ADAPT to changing environment Sexual GAMETES fuse to form zygote VARIED GENES are produced Genetic VARIATION allows for greater ADAPTATION in changing environment

  6. Meiosis gametes When gametes (egg and sperm) unite during fertilization, each gamete contributes one allele.

  7. DRAW AND LABEL A CHROMOSOME Identical chromatids centromere chromatid

  8. Chromosome Identical Chromatids Centromere chromatid • DNA strands coiled around proteins • Formed during cell division • Contains specific genes on each chromosome • Found only in nucleus of cell • Diploid organisms have 2 of each chromosome, one from each parent • Haploid organisms have one of each chromosome • Somatic chromosomes are in different sizes and shapes • Number if chromosomes are different for each species • Humans: 46 (23 pairs) • Sex chromosomes ore either X or Y. • Females receive XX • males receive XY

  9. What is a chromosome?

  10. Formation of chromosome Tightly coiled strands form chromosome DNA/Protein strands coil tightly DNA strands wrap around proteins DNA = twisted ladder of nucleotides

  11. Where are chromosomes found? • Chromosomes are found in the nucleus of our eukaryotic cells. • Many organisms have a different numbers of chromosomes in their cells • Fruit fly 4 chromosomes • human 46 chromosomes

  12. What are gametes? • Also known as a sex cell. • 23 chromosomes in sperm (male gamete). • 23 chromosomes in egg (female gamete). • Gametes are a product of meiosis. • Meiosis is the process which the number of chromosomes cell is cut in half through the separation of homologous chromosomes. • 2 part process. • Process results in 4 gametes. \

  13. MEIOSIS

  14. Meiosis Meiosis- The process of cell division in sexually reproducing organisms that reduces the number of chromosomes in reproductive cells from diploid to haploid, leading to the production of gametes in animals and spores in plants.

  15. Meiosis • Two phases of cell division (Meiosis 1 and 2) • Produces cells with half the number of chromosomes (Haploid) • Haploid cells have one of each chromosome • Haploid cells (sperm and egg) join to form zygote • Meiosis allows genetic variation • Joining of gametes makes new combinations of genes for each new individual

  16. Meiosis

  17. Law of independent assortment PpTt meiosis pT PT Pt pt 4 haploid gametes: one of each chromosome Alleles of different genes separate independently of one another

  18. Meiosis summary: Produces 4 haploid cells

  19. Homologous chromosomes • Same shape • Same size • Same type of genes • One from each parent One chromosome from each parent

  20. Crossing over occurs during Prophase I New genetic combination • creates new combination of genes • occurs between two homologous chromosomes

  21. Gametogenesis: Process of making gametes Most of cytoplasm from three cells is combined into one egg cell

  22. When Meiosis Goes Bad….. http://www.infertilityivfhouston.com/images/Sperm-morphology.jpg

  23. Dangers of gametes without 23 chromosomes….

  24. Mitosis vs. meiosis

  25. What is a karyotype? A karyotype is a set of photographed chromosomes grouped by pairs.

  26. CHROMOSOME PAIR ARE CALLED SEX CHROMOSOMES: IF XX= FEMALE IF XY= MALE AUTOSOMES Chromosomes #1-22 are called How is sex determined? Video HUMAN MALE KAROTYPE HUMAN FEMALE KARYOTYPE

  27. What happens if there are 3 chromosomes on your 21 chromosome? ANSWER: DOWN SYNDROME

  28. Down Syndrome

  29. Homologous chromosomes • Same shape • Same size • Same type of genes • One from each parent One chromosome from each parent

  30. Which letter is an example of meiosis?Which letter is an example of fertilization? Letter A is an example of meiosis. Letter B is an example of fertilization.

  31. DNA/Chromosomal Mutations

  32.  Chromosomal Mutations Section 12-4 Deletion Duplication Inversion Translocation

  33. Genetic Mutation?

  34. Genetic Mutation?

  35. IS albinism caused by a genetic mutation? • Albinism (from Latinalbus, meaning "white") is a lack of pigmentation in the eyes, skin and hair. It is an inherited condition resulting from the combination of recessive genes passed from both parents of an individual. This condition is known to affect mammals, fish, birds, reptiles, and amphibians.

  36. Caused by a genetic mutation? World’s Largest Feline

  37. Is the caused by a genetic mutation? • A clubfoot is a common birth defect.

  38. Down Syndrome • Defect (extra chromo) on the 21st chromosome.

  39. If someone has a defect or disease, there is something wrong with chromosomes in nucleus.

  40. DISEASES Can be caused by 2 things: • The environment that surrounds you. • Your inherited genes . http://www.youtube.com/watch?v=kBfWybm0218&feature=related (vytorin commercial)

  41. What disorders are sex-linked? Baldness Hemophilia (free bleeder) Duchenne Muscular Dystrophy (Progressive loss of muscle) Red-green colorblindness These disorders are only found on the 23rd (sex) chromosomes.

  42. Colorblindness • Are you color blind?

  43. What disorders are autosomal? Recall, alleles are different forms of genes. • Disorders caused by recessive alleles: albinism, cystic fibrosis, galactosemia, phenylketonuria(PKU), Tay-Sachs disease • Disorders caused by dominant alleles: achondroplasia, huntington’s disease, hyperchlesterolemia • Disorders caused by codominant genes: sickle cell anemia

  44. Recessive Disorders Sickle Cell anemia (abnormal hemoglobin molecules Results in poor blood circulation Tay-Sachs Disease (defective form of a brain enzyme) Results in deterioration of nervous system in infants- early death Cystic Fibrosis (Defective chloride-ion transport protein) Excessive mucous accumulation in organs, especially lungs- die young

  45. Environmental Influences on Traits Hydrangea flower color is due to amount of acid in soil Temperature affects changes in fox color from winter to summer Darker parts of Siamese cat are a lower temperature, e.g., ears, nose, paws and tail Height in humans is influenced by temperature, such as internal environmental condition.

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