HUMAN BIOLOGY

CeLL reprOduCtIOn 355 What are the tWo types of chromosomes? A cell’s DNA is organized into autosomes and sex chromosomes. In h ...

356 Chapter 18 n Mitosis occurs during the “lifetime” of a somatic cell, called the cell cycle. Meiosis occurs solely in germ ...

CeLL reprOduCtIOn 357 a chromosome undergoes changes in preparation for cell division As already mentioned, a chromosome consist ...

358 Chapter 18 What are the stages of mitosis? Mitosis occurs in consecutive stages, called prophase, metaphase, anaphase, and ...

CeLL reprOduCtIOn 359 Early prophase Mitosis begins. In the nucleus, the DNA begins to condense. The centrosome gets duplicated. ...

360 Chapter 18 What is cytokinesis? Cytokinesis completes cell division following mitosis. It divides the parent cell’s cytopla ...

CeLL reProDuCTIoN 361 epithelial cells of the skin and intestinal lining, and red blood cells, among other cell types. The resul ...

362 Chapter 18 Meiosis: the beginnings of eggs and sperm n Meiosis divides the nuclei of germ cells in a way that halves the num ...

CeLL reprOduCtIOn 363 What does meiosis do? Meiosis is the first step in the formation of gametes—sperm and eggs—for sexual rep ...

364 Chapter 18 the stages of Meiosis Pairs of centrioles are positioned at the opposite sides of the nucleus as the nuclear enve ...

CeLL reprOduCtIOn 365 What are the key events of meiosis? In meiosis the nucleus of a diploid germ cell divides twice. Ultimate ...

366 Chapter 18 how Meiosis produces new Combinations of genes are rearranged. Remember that germ cells contain sets of homologou ...

CeLL reprOduCtIOn 367 hoW does meiosis create variation in the chromosomes gametes receive? Meiosis moves maternal and paternal ...

368 Chapter 18 Anaphase Sister chromatids sepa- rate and move toward opposite spindle poles. Metaphase Chromosomes align midw ...

CeLL reprOduCtIOn 369 Anaphase Sister chromatids sepa- rate and move toward opposite spindle poles. Metaphase Chromosomes ali ...

370 Chapter 18 expLoreon your oWn suMMary section 18.1 In reproduction, a parent cell produces a new generation of cells, or par ...

CeLL reprOduCtIOn 371 section 18.8 Meiosis contributes to genetic variation. Crossing over during prophase I creates new combina ...

372 Chapter 18 CritiCaL thinKing Normally you can’t inherit both copies of a homologous chromosome from the same parent. Why? A ...

This chapter fleshes out the concept of inheritance intro- duced at the beginning of this textbook (1.1). You will also draw on ...

How many genes for a trait does a person inHerit? Each of us inherits two copies of each gene, one on each member of a pair of ...