1. The Human Genome Chapter 14 Section 1

2. karyotype (KAR-ee-uh-typ). photograph cells in mitosis, when the chromosomes are fully condensed and easy to see. The biologists then cut out the chromosomes from the photographs Then group them together in pairs.

4. Two of 46 chromosomes in humans are known as sex chromosomes, because they determine an individual's sex. To distinguish them from the sex chromosomes, the remaining 44 chromosomes are known as autosomal chromosomes, or autosomes

5. From Gene to Molecule In both cystic fibrosis and sickle cell disease, a small change in the DNA of a single gene affects the structure of a protein, causing a serious genetic disorder. (test question)

6. In a population, approximately half of the zygotes are XX (female) and half are XY (male).

7. X and Y chromosomes Females have two X chromosomes, but males have only one. If just one X chromosome is enough for cells in males, how does the cell “adjust” to the extra X chromosome in female cells? In female cells, one X chromosome is randomly switched off. That turned-off chromosome forms a dense region in the nucleus known as a Barr body.

8. pedigree chart pedigree chart example

9. Fun Fact about Cats a gene that controls the color of coat spots is located on the X chromosome. One X chromosome may have an allele for orange spots and the other may have an allele for black spots. In cells in some parts of the body, one X chromosome is switched off. In other parts of the body, the other X chromosome is switched off. As a result, the cat's fur will have a mixture of orange and black spots. Male cats, which have just one X chromosome, can have spots of only one color.

10. Calicos are female

11. Human Chromosomes A human diploid cell contains more than 6 billion base pairs of DNA. All of this DNA is neatly packed into the 46 chromosomes present in every diploid human cell. only about 2 percent of the DNA in your chromosomes functions as genes—that is, is transcribed into RNA Genes are scattered among long segments of DNA that do not code for RNA.

12. Sex-Linked Genes Males have just one X chromosome. Thus, all X-linked alleles are expressed in males, even if they are recessive. color blind Colorblindness Hemophilia Duchenne Muscular Dystrophy

13. assignment Page 348 1-2 Page 354 1-3