Chromosomes Copy all notes and draw all diagrams

Chromosomes **Copy all notes and draw all diagrams unless directed otherwise Mrs. Mac. Williams Academic Biology

I. 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 n 2 chromatids n One centromere n Draw this diagram with labels

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 SET of chromosomes (23) (sperm & egg) 4. Zygote- (zygo=union) fertilized egg - egg 23 (haploid) + sperm 23 (haploid) = 46 diploid

Draw this diagram with labels

E. Types of Chromosome 1. Autosomes-(auto=self; soma=body) CHROMOSOME not directly involved with determining GENDER 2. Sex chromosomes- determine gender (humans have X and Y) XX = FEMALE= XY = MALE= The link below shows genes on all of the 23 pairs of chromosomes. Click on the X chromosome and Y chromosome. Notice the size differences. http: //www. ornl. gov/sci/techresources/Human_Genome/posters/c hromosome/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) **Note: You must be able to analyze a karyotype and determine if it is from a somatic cell or gamete AND whether the cell is from a male or female. REALLY STUDY NEXT 2 SLIDES.

Male karyotype (XY) Female karyotype (XX) **You do not need to the copy these pictures… BUT YOU MUST KNOW HOW TO IDENTIFY WHICH IS MALE AND WHICH IS FEMALE!

You do not need to draw this… but you must be able to tell whether the karyotype is from a somatic/body cell (46 chromosomes) or from a gamete/sex cell (23 chromosomes) Karyotype of a Haploid Gamete (Sex Cell) **YOU KNOW IT IS A SEX CELL BECAUSE THERE ARE ONLY 23 CHROMOSOMES HERE NOTE: This cell would either have ONE X chromosome or ONE Y (NOT BOTH like shown here)

CHROMOSOME NUMBERS IN EUKARYOTIC ORGANISMS DO NOT NEED TO COPY… JUST INTERESTING FACTS SCIENTIFIC NAME DIPLOID ORGANISMS ANIMALS Homo sapiens Pan troglodytes Aquinus caballus Ros taurus Canis familiaris Felis domesticatus Oryctolagus cuniculus Rattus norvegicus Mus musculus Meleagris gallopavo Xenopus laevis Caenorhabditis elagans Musca domestica Drosophila melanogaster PLANTS Pinus ponderosa Ptsum sativum Solanum tuberosum Nicotiana tabacum Iriticum aestivum Zea mays Vicia faba HAPLOID ORGANISMS Chlamydomaonas reinhardi Neurospora crassa Aspergillus nidulans Saccharomyces cerevisiae COMMON NAME NUMBER OF CHROMOSOMES Human Chimpanzee Horse Cattle Dog Cat Rabbit Rat House mouse Turkey Toad Nematode Housefly Fruit fly Ponderosa pine Garden pea Potato Tobacco Bread wheat Corn Broad bean A unicellular algae Orange bread mold A green bread mold Brewer's yeast 46 48 64 60 78 38 44 42 40 82 36 11 male/ 12 female 12 8 24 14 48 48 42 20 12 16 7 8 16

QUESTIONS? ? ? n WRITE DOWN ANY QUESTIONS YOU HAVE ABOUT THE NOTES. n WRITE DOWN COMMENTS ABOUT THINGS YOU DON’T UNDERSTAND. n ASK MRS. MACWILLIAMS NEXT CLASS TO CLARIFY!