BIOL211#14and#15

BIOL211#14and#15 - Chapter 15 The Eukaryotic Cell Cycle The...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chapter 15 The Eukaryotic Cell Cycle The Eukaryotic Cell Cycle The ability to reproduce their own kind is the one characteristic that distinguishes living things from nonliving matter The continuity of life is based on the reproduction of cells (cell division) “Omnis cellula e cellula” – “Every cell from a cell” Unicellular organisms – Division of one cell reproduces an entire organism Paramecium Multicellular organisms – Enables development from a fertilized egg – Renews or repairs cells that die from normal wear and tear or accidents The cell division process is an integral part of the cell cycle Cytogenetics – The field of genetics that involves the microscopic examination of chromosomes and cell division
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Karyotype Each human somatic cell has 46 chromosomes arranged in pairs – Chromosomes in a pair have the same length, centromere position, and staining pattern and are known as homologous chromosomes (homologues) – Both chromosomes in a pair carry genes that control the same inherited characters Sex chromosomes are an exception – Females have a homologous pair of X chromosomes (XX) – Males have an X and a Y chromosome (XY) The term autosome refers to all chromosomes other than the sex chromosomes We inherit one chromosome of each homologous pair from each parent – A maternal set of 23 chromosomes – A paternal set of 23 chromosomes The number of chromosomes in a single set is represented by n When the cells carry two sets of chromosomes it is referred to as a diploid cell (2 n ) All human somatic cells are diploid Gametes have one set of chromosomes – Eggs: 22 autosomes and an X – Sperm: 22 autosomes and an X or Y A gamete with a single chromosome set is called a haploid cell ( n )
Background image of page 2
3 The human life cycle begins when a haploid sperm fuses with a haploid egg – When the cells fuse it results in fertilization – The resulting fertilized egg (zygote) is now diploid As a human develops into a sexually mature adult, mitosis generates all the somatic cells of the body Gametes are not produced by mitosis Gametes are produced by meiosis Fertilization and meiosis alternate in all sexual life cycles
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 13

BIOL211#14and#15 - Chapter 15 The Eukaryotic Cell Cycle The...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online