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Chromosomes. Mrs. MacWilliams Academic Biology. Chromosomes “ chromo ” =colored; “ soma ” = body. A. Formation of New Cells 1. Human body makes 2 trillion cells per day! B. TYPES OF CELLS : 1. Gametes - reproductive cells (eggs & sperm)
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Chromosomes Mrs. MacWilliams Academic Biology
Chromosomes“chromo”=colored; “soma”= body A. Formation of New Cells 1. Human body makes 2 trillion cells per day! B. TYPES OF CELLS: 1. Gametes- reproductive cells (eggs & sperm) 2. Somatic Cell-“body cell” (not reproductive)
C. Eukaryotic Reproduction 1. Gene- segment of DNA that codes for a protein or RNA molecule 2. Chromosomes -Chromatin- DNA + proteins that make up eukaryotic chromosomes -Chromatids- two exact copies of DNA that make up each chromosome. “Sister Chromatids” -Centromere- point at which 2 chromotids attach to form chromosome
One chromosome 2 chromatids One centromere
D. Sets of Chromosomes **Humans have 23 PAIRS (2 sets) of chromosomes (46 chromosomes total) 1. Homologous chromosomes- (homo=same; logous=location) PAIR that are SAME size, shape, and genetic content 2. Diploid- (di=two) somatic cells have two SETS chromosomes (46) 3. Haploid- (hap=half) gametes have one SETof chromosomes (23) (sperm & egg) 4. Zygote- (zygo=union) fertilized egg - egg 23 (haploid) + sperm 23 (haploid) = 46 diploid
E. Types of Chromosome 1. Autosomes-(auto=self; soma=body) CHROMOSOMEnot directly involved with determining GENDER 2. Sex chromosomes- determine gender (humans have X and Y) XX = FEMALE= XY = MALE= http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/index.shtml
F. Change in Chromosomes 1. change in number/structure of chromosomes = genetic abnormality 2. Karyotype- (karyo=nucleus) picture of the chromosomes in a dividing cell (aids in finding genetic defects)
Male karyotype Female karyotype
Karyotype of a Haploid Gamete (Sex Cell) **This cell would either have ONE X chromosome or ONE Y