PPT-Figure 4.1 Human chromosomes

Figure 42 Development of the male and female reproductive tracts Figure 42 Development of the male and female reproductive tracts Figure 43 Development of the male and female external genitalia. CELL DIVISION. TOPIC . 2 - 2015. CHROMOSOMES . & CELL DIVISION. Things to cover. Chromosomes. Karyotypes. inc. . chromosomal. . disorders. Cell. division:. Mitosis. Meiosis. & fertilisation. 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. Chromosomes carry genes in a linear sequence that is shared by members of a species.. Understandings:. Prokaryotes have one chromosome consisting of a circular DNA molecule. . Some prokaryotes also have plasmids but eukaryotes do not. .. 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. 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. GENES. DNA. DNA. :  the chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms. . The material inside the nucleus of cells that carries genetic information.. .. 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. . Week’s Number. Lecture. 1. Introduction of human chromosomes. 2. Linkage, crossing over . 3. Chromosome mapping. 4. Sex determination systems and sex-linked inheritance . 5. Pedigree Analysis . 6. Pedigree Analysis . Chromosomal Disorders. Chromosome abnormalities occur as a result of chromosome . mutations. brought on by . mutagens. (like radiation) or problems that occur during cell division.. . The defects are classified as abnormalities of . 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 . Introduction . The human genome consists of at least 20,000 genes on 23 pairs of chromosomes. Of these pairs, 22 are autosomes, and the other pair consists of sex chromosomes (X, Y). Linked genes are located on the same chromosome; sex-linked genes are located on a sex chromosome. The frequency of crossing-over between genes is used to construct linkage maps, which show the locations of genes on chromosomes.. 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. .