SCIENTIFIC THINKING Each scientist works as part of a broader community of scientists, building on the work of others. Scientific advances often depend on the application of new technologies and/or on new techniques applied to an existing problem. What improvements to existing cloning methods did Wilmut make that allowed him to successfully clone Dolly the sheep from an adult cell?

A cell that begins mitosis with 46 chromosomes produces daughter cells with chromosomes.a. 13;b. 23;c. 46;d. 92

Which of the following is not a function of mitosis in humans?a. repair of woundsb. growthc. production of gametes from diploid cellsd. replacement of lost or damaged cells

Mitosis .a. occurs only in cancerous cells;b. occurs only in skin cells;c. produces daughter cells that are exact genetic copies of the parent cell;d. results in the production of three different cells

It took three sheep to create the clone Dolly: A blackface sheep donated the egg, a whiteface sheep donated the mammary cells from which the nucleus was taken, and a blackface sheep served as surrogate. Assuming face color is genetically determined, what color face did Dolly have?

Red blood cells, which carry oxygen to body tissues, live for only about 120 days. Replacement cells are produced by cell division in bone marrow. How many cell divisions must occur each second in your bone marrow just to replace red blood cells? Here is some information to use in calculating your answer: There are about 5 million red blood cells per cubic millimeter (mm3) of blood. An average adult has about 5 L (5,000 cm3) of blood. (Hint: What is the total number of red blood cells in the body? What fraction of them must be replaced each day if all are replaced in 120 days?)