Haploid= half the genetic content (n) Diploid = genetic equal to the parent. Full genetic content (2n)
The process that produces gametes (eggs and sperm) with half the number of chromosomes as body cells occurs in the sex cells. mQS_FZ0&safety_mode=true&persist_safety_mode=1 mQS_FZ0&safety_mode=true&persist_safety_mode=1
DNA replication occurs only once in the process. Meiosis I: the result is two daughter cells. Meiosis II: the result is four haploid cells, each with half the number of chromosomes.
Prophase I: homologous chromosomes pair up. Metaphase I: homologous chromosomes line up in the middle of the cell.
Anaphase I: homologous chromosomes separate and are pulled to opposite sides. Telophase I: one chromosome from each pair is at each pole of the cell.
Prophase II: one chromosome of the homologous pair in each cell. Metaphase II: the x-shaped chromosomes form a single line across the middle.
Anaphase II: sister chromatids move to opposite poles of the cell. Telophase II: a nuclear membrane forms around the chromosomes. 1&safety_mode=true&persist_safety_mode=1 1&safety_mode=true&persist_safety_mode=1
Mitosis Meiosis In body cells Two daughter cells Same number of chromosomes as parent cell Asexual reproduction In sex organs to produce sex cells Four daughter cells Half the number of chromosomes as the parent cell. Sexual reproduction
1. Mosses: External fertilization Water allows the egg and sperm cells to meet Reproduces both sexually and asexually
2. Flowering plants Pollination Transfer of male gametes in structures called pollen from the male structure to the female structure of the plant.
1.Pollinators such as bees and other insects, fruit bats 2.Wind 3.Water Pollen can be transported by:
After fertilization, seeds are often protected in fruit or cones. Seeds contain the plant embryos.
In many insects, the male deposits a package of sperm inside the female. Insects often change a great deal between hatching and adulthood
This change in form is called metamorphosis. Metamorphosis can be incomplete or complete
Incomplete Three stages: Egg Nymph Adult The adult and the nymph resemble one another Ex. grasshopper
Complete Four stages: Egg Larvae Pupa Adult The adult and the larva look completely different Ex. Butterfly
Asexual Sexual 1 parent cells No gametes; cell divides Little variation in offspring Little energy required Less parental care Two parent cells 2 sex cells unite to form a zygote Greater variation in offspring Greater energy required Greater parental care
Gregor Mendel Mid-1800s Experimented with inherited traits in pea plants.
Francis Crick & James Watson (1953) Described the structure of DNA and how it replicates.
The Human Genome Project Genome: consists of the full set of genetic material that makes up an organism. Made a map to identify genes
This information may be used to check for particular diseases. ◦ Ex. Allderdice syndrome where part of one chromosome is reversed. Identified in Sandy Point NL.
A special “picture” of a person showing all their chromosomes arranged in a particular order called a karyotype is studied.
Can help to determine if there is any abnormalities in the chromosomes. Can identify syndromes such as Down’s Syndrome (extra 21 st chromosome).
Can be used to save the genetic information from endangered plants and animals or to mass- produce an organism with a desired trait.
Reproductive cloning: Also called DNA cloning Purpose is to produce a genetic duplicate of an existing organism with desirable qualities.
Therapeutic cloning Used to correct health problems. Stem cells and embryonic stem cells are able to become many different types of cells.