ChromosomesChromosomes

Mrs. MacWilliams

Academic Biology

I.I. ChromosomesChromosomes““chromochromo””=colored; =colored; ““somasoma””= body= body

A. Formation of New CellsA. Formation of New Cells

1. Human body makes 2 trillion cells per 1. Human body makes 2 trillion cells per day!day!

B. B. TYPES OF TYPES OF CELLSCELLS::

1. 1. GametesGametes- reproductive - reproductive cellscells (eggs (eggs & sperm)& sperm)

2. 2. Somatic CellSomatic Cell-- ““body body cellcell”” (not (not reproductive)reproductive)

C. Eukaryotic ReproductionC. Eukaryotic Reproduction

1. 1. GeneGene- segment of DNA that codes for - segment of DNA that codes for a protein or RNA moleculea protein or RNA molecule

2. 2. ChromosomesChromosomes

--ChromatinChromatin- DNA + proteins that - DNA + proteins that make up make up eukaryotic chromosomeseukaryotic chromosomes

--ChromatidsChromatids- two exact copies of - two exact copies of DNA that DNA that make up each chromosome. make up each chromosome. “Sister “Sister Chromatids”Chromatids”

--CentromereCentromere- point at which 2 - point at which 2 chromotids attach to form chromosome chromotids attach to form chromosome

One chromosomeOne chromosome 2 chromatids2 chromatids One centromereOne centromere

D. Sets of ChromosomesD. Sets of Chromosomes**Humans have 23 PAIRS (2 sets) of **Humans have 23 PAIRS (2 sets) of

chromosomes (46 chromosomes total)chromosomes (46 chromosomes total)1. 1. Homologous chromosomesHomologous chromosomes- (- (homo=same; homo=same; logous=location)logous=location)PAIR that are PAIR that are SAMESAME size, shape, and genetic size, shape, and genetic contentcontent

2. 2. DiploidDiploid- (- (di=two) di=two) somatic cells have two somatic cells have two SETSSETS chromosomes (46)chromosomes (46)

3. 3. Haploid Haploid- (- (hap=half) hap=half) gametes have one gametes have one SETSET of of chromosomes (23) (sperm & egg)chromosomes (23) (sperm & egg)

4. 4. ZygoteZygote- (- (zygo=union) zygo=union) fertilized eggfertilized egg- egg 23 (haploid) + sperm 23 (haploid) = 46 diploid- egg 23 (haploid) + sperm 23 (haploid) = 46 diploid

CHROMOSOME NUMBERS IN EUKARYOTIC ORGANISMSCHROMOSOME NUMBERS IN EUKARYOTIC ORGANISMS

SCIENTIFIC NAME COMMON NAME NUMBER OF

CHROMOSOMES DIPLOID ORGANISMSANIMALSHomo sapiens Human 46Pan troglodytes Chimpanzee 48Aquinus caballus Horse 64Ros taurus Cattle 60Canis familiaris Dog 78Felis domesticatus Cat 38Oryctolagus cuniculus Rabbit 44Rattus norvegicus Rat 42Mus musculus House mouse 40Meleagris gallopavo Turkey 82Xenopus laevis Toad 36Caenorhabditis elagans Nematode 11 male/ 12 femaleMusca domestica Housefly 12Drosophila melanogaster Fruit fly 8PLANTS    Pinus ponderosa Ponderosa pine 24Ptsum sativum Garden pea 14Solanum tuberosum Potato 48Nicotiana tabacum Tobacco 48Iriticum aestivum Bread wheat 42Zea mays Corn 20Vicia faba Broad bean 12HAPLOID ORGANISMS    Chlamydomaonas reinhardi A unicellular algae 16Neurospora crassa Orange bread mold 7Aspergillus nidulans A green bread mold 8Saccharomyces cerevisiae Brewer's yeast 16

Oliver the HumanzeeClick on “Oliver the Humanzee” for ” for

videovideo

E. Types of ChromosomeE. Types of Chromosome

1. 1. AutosomesAutosomes-(-(auto=self; soma=bodyauto=self; soma=body) )

CHROMOSOMECHROMOSOME not directly involved not directly involved with determining with determining GENDERGENDER

2. 2. Sex Sex chromosomeschromosomes-- determine determine gender (humans have X and Y)gender (humans have X and Y)

XX = FEMALE=XX = FEMALE=

XY = MALE=XY = MALE=

http://www.ornl.gov/sci/techresources/http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/Human_Genome/posters/chromosome/index.shtmlindex.shtml

F. Change in ChromosomesF. Change in Chromosomes

1. change in number/structure of 1. change in number/structure of chromosomes = genetic chromosomes = genetic abnormalityabnormality

2. 2. KaryotypeKaryotype- (- (karyo=nucleuskaryo=nucleus))

picture of the chromosomes in a picture of the chromosomes in a dividing cell (aids in finding genetic dividing cell (aids in finding genetic defects)defects)

Male karyotype Female karyotype

Karyotype of a Haploid Gamete (Sex Cell)**This cell would either have ONE X chromosome or ONE Y