1 / 8

Continuing Life

Continuing Life. Cells must divide to continue life Asexual reproduction occurs when an organism simply buds or divides to make another copy of itself (binary fission) The division of body (somatic) cells is called mitosis .

betha
Télécharger la présentation

Continuing 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. Continuing Life • Cells must divide to continue life • Asexual reproduction occurs when an organism simply buds or divides to make another copy of itself (binary fission) • The division of body (somatic) cells is called mitosis

  2. Organisms that reproduce asexually: hydra, bacteria, some molds, plants, a species of lizard • Other organisms reproduce sexually: Two cells combine to form a new organism human male karyotype • Meiosis reduces the number of chromosomes in sex cells to half the norm…so human sex cells have 23 (half of 46!).

  3. DNA • Code of Life • All living things (except some viruses) use DNA to carry their genetic info.

  4. Structure • 4 bases: adenine, thymine, cytosine, guanine • Rosalind Franklin took X-ray pictures of DNA and saw it was a double helix • James Watson and Francis Crick figured out the structure of DNA (1953)

  5. Chromosomes contain DNA (deoxyribonucleic acid) which contains genes. • Genes “code” for what you look like, how you develop, etc. There are different versions of genes called alleles.

  6. Dominant and Recessive • Some traits are determined by only one set of genes (pairs). • If one gene in the pair is dominant, it covers up the recessive one. EXAMPLE: in pea plants, tall is dominant over short. So, a plant with a tall gene and a short gene will be tall. Which plants will be short?

  7. Cloning-A How-to Guide • Cloning- can be used to produce offspring that are genetically identical to their parent. • Uses cells from a donor organism. The cell’s DNA is then inserted into an empty egg. The egg is then given a mild shock or chemical “bath”. The egg may then begin dividing and can be implanted into a female to carry.

  8. Cloning-Is it ethical? • Scientific ethics- “the study of the impact of technology and science on society” • As the debate continues about whether humans or anything should be cloned, think about your own opinion on the subject. Do we really need to be able to clone humans? What about farm animals? Why is cloning NOT the answer to the endangered species problem?

More Related