1 / 24

Exploring Cell Theory and Genetics: The Basis of Life

Discover the Cell Theory origins by Schwann and Schleiden in 1838, cell structure's essence, DNA's role, chromosome traits, genetic inheritance, and disorders. Unravel the mysteries of mitosis, meiosis, and cell replication.

misha
Download Presentation

Exploring Cell Theory and Genetics: The Basis of Life

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cells and Genes

  2. Cell Theory In 1838, two German Scientists Theodor Schwann and Mattias Jakob Schleiden put forward a theory on the structure of living organisms. This theory had a number of observations, including: • The cell is the unit of structure, physiology, and organization in living things. • The cell retains a dual existence as a distinct entity and a building block in the construction of organisms. • These observations have become parts of what is known as the Cell Theory

  3. Cells • Cells are the smallest living subunits of an organism • Some organisms are unicellular, meaning that they are comprised of only one cell • Ex bacteria, amoebas, etc

  4. Cells • Other organisms are multicellular, meaning that they are comprised of many cells • Ex animals, birds, insects, human beings • Human beings are said to contain about 200 different types of cells – each adapted to a specific task

  5. Cytology • The study of the formation, structure, and function of cells • Focus on different aspects including: • Chromosomes • DNA • Genetics • Cytology = cyt/o(cell), -logy (study of)

  6. Cell Structure

  7. DNA • DNA stands for deoxyribonucleic acid • Has two strands that twist together to form a double helix • DNA is read to create the proteins encoded in our more than 20,000 genes

  8. Chromosomes • Chromosomes are pieces of DNA found within the nucleus of a cell • Normally cannot be seen individually • When a cell is preparingto divide, the DNA condenses into dense rod-like structures that are copied before division occurs

  9. Chromosomes • Human body (somatic) cells normally have 46chromosomes arranged into 23 pairs • Sex cells or gametes contain 23 single chromosomes • Chromosomes contain regions called genes, that can be “read” to give the cell instructions,or to produce a necessarysubstance

  10. Karyotype • A karyotypeimage is a map of the number and appearance of chromosomes within a human cell • The chromosomes are treated with chemicals so that characteristic bands of light and dark areas can be seen • It may be requested if there is any suspicion of genetic disorder

  11. Genetics • Genetics is the study of how genes are transferred from generation to generation • Genesis means producing or origin • Geneticists study not only how genes function in normal conditions, but also how they function to create disease

  12. Genetic Inheritance • Humans normally receive two copies (alleles) of every gene – one from their mother, and one from their father • Gametes have one copy of each chromosome • When a male gamete (sperm) fertilizes a female gamete (ovum), the DNA mingles • The resulting fetus develops with this mix of maternal and paternal DNA

  13. Inheritance • Dominant alleles will cause their trait to be displayed even if only one copy of the gene is received

  14. Inheritance • Recessive alleles will only cause their trait to be displayed if two copies of the gene are received

  15. Genetic Disorders • Genetic disorders are usually due to a genetic mutation • Inherited • Acquired • Mutations can be due to: • Deletions • Substitutions • Additions

  16. Trisomy 21 (Down Syndrome)

  17. Kleinfelter Syndrome

  18. Genetic Disorders • Down Syndrome (trisomy 21) • Cystic Fibrosis (recessive) • Hemophilia (X-linked recessive) • Huntington Disease (dominant) • Phenylketonuria (recessive) • Tay-Sachs Disease (recessive) • OsteogenesisImperfecta (dominant)

  19. Cell Division • Mitosis • Normal Cell replication • One cell with a diploid number of chromosomes (46) divides into two cells, each with the diploid number of chromosomes • Produces identical cells • Used to replace cells in the body • Mitosis Animation

  20. Cell Division • Meiosis • Cell replication to form gametes • Gametes are sex cells – the ovum and the spermatozoon • Each gamete contains half of the usual number of chromosomes (23)

  21. Cell Replication • Meiosis has two parts: • Meiosis I – begins when the chromosomes duplicate • The chromosomes group together so that all chromosomes of one type are joined together (at this point the copies of the chromosomes can exchange information) • The chromosomes then separate in a process similar to Mitosis • Meiosis II – the process occurs again, without the chromosomes replicating to create the gametes • Mitosis results in 2 daughter cells, Meiosis results in 4 daughter cells

More Related