PPT-14.1 Human Chromosomes

Karyotypes To find what makes us uniquely human we have to explore the human genome A genome is the full set of genetic information that an organism carries in its DNA A study of any genome starts with chromosomes the bundles of DNA and protein found in the nuclei of eukaryotic cells . CELL DIVISION. TOPIC . 2 - 2015. CHROMOSOMES . & CELL DIVISION. Things to cover. Chromosomes. Karyotypes. inc. . chromosomal. . disorders. Cell. division:. Mitosis. Meiosis. & fertilisation. Chromosome theory of inheritance. Genes located on chromosomes = gene locus. Thomas Hunt Morgan, Columbia Univ. “Fly room”. Drosophila. 100s of offspring. 2n = 8. 3 . prs. autosomes. X and Y sex chromosomes. Essential idea: Chromosomes carry genes in a linear sequence that is shared by members of a species.. The . asian. rice (. Oryza. sativa. ) genome can be seen illustrated . above. . Rice possesses up 63,000 genes divided up between 12 chromosomes. The Chromosome Theory of Heredity. Mutations. Regulation of Gene Expression. Objectives. State the chromosome theory of heredity. Explain how gene linkage affects inherited traits. Describe the process of crossing-over and explain how it increases genetic variety. Phases of Mitosis and Meiosis. Unit 2. glossary. Chromatin - diffuse, long fibers of DNA with proteins attached . Single chromosomes - a chromosome which has not been duplicated (like ½ of an x). Duplicated chromosomes - a chromosome which has been duplicated (a complete X). in Chimps and Humans. are Horrendously Different. Paul Giem. Loma Linda, CA. Y Chromosomes in Chimps and Humans. The common chimp (Pan troglodytes) and human Y chromosomes are "horrendously different from each other", says David Page of the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts. diploid. Sex cells (gametes/germ cells) have only one set of chromosomes . . = . haploid. . That means when fertilization . occurs, the new individual will. have the correct number of chromosomes.. Chromosomes carry genetic information. Chromosomes are wound up DNA. Diploid – Every body cell has 2 sets of chromosomes . n = number of chromosomes. Normal body cells have 2n (2 x n) chromosomes. .. DNA . in cells is usually spread out so transcription can take place.. During . cell division, . chromosomes. form. .. Chromosomes are . DNA. and protein (. histones. ) coiled into a rod.. After DNA replicates, two . Human Genes and Chromosomes. Chromosomes 21 and 22 are the smallest human autosomes. Chromosome 22 has about 43 million DNA base pairs. Chromosome 21 has about 32 million base pairs. . Chromosome 22 has about 545 different genes. Genetic disorders tat occur on chromosome 22 are leukemia and neurofibromatosis (a tumor causing disease). There is also a long stretch of repeating DNA that does not code for proteins. . Ms. Diana and Ms. Su’ad. Karyotype Studies. The study of genetic material does not only involve the study of genes. It also involves whole chromosomes by using images of chromosomes stained during metaphase. . 22 pairs of autosomes. 1 pair of sex chromosomes. XX = Female, XY = Male. Karyotype - chromosomes are arranged according to shape and size. AN EXTRA COPY OF CHROMOSOME 21 CAUSES DOWN SYNDROME. This condition is called . They are also called as mega chromosomes. . These chromosomes are very long and thick in appearance during metaphase than normal chromosomes.. Hence they are called as Giant chromosomes.. The Giant chromosomes are of two types-. Important. Notes. For revision only. Objectives: . Describe the number, structure, and classification of human chromosomes . Explain what a Karyotype is and how it is obtained. . Describe chromosomal banding and explain its use. .