Homologous chromosome

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Mendelian inheritance

Genetic recombination

Sex linkage

The Chromosomal Basis of Inheritance Locating Genes Along Chromosomes ( 15.1) * Mendel?s ?hereditary factors? were purely abstract when first proposed * Today, we can show that the factors?genes?are located on chromosomes * The location of a particular gene can be seen by tagging isolated chromosomes with a fluorescent dye that highlights the gene * Cytologists worked out the process of mitosis in 1875 and meiosis in the 1890s using improved techniques of microscopy * Biologists began to see parallels between the behavior of Mendel?s proposed hereditary factors and chromosomes * Around 1902, Sutton and Boveri and others independently noted these parallels and began to develop the chromosome theory of inheritance 15.2

AP Bio_genetic_variation

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Ploidy

Sex

Genetic variation produced in sexual life cycles contributes to evolution * Mutations (changes in an organism?s DNA) are the original source of genetic diversity * Mutations create different versions of genes called alleles * Reshuffling of alleles during sexual reproduction produces genetic variation Origins of Genetic Variation Among Offspring * The behavior of chromosomes during meiosis and fertilization is responsible for most of the variation that arises in each generation * Three mechanisms contribute to genetic variation: ? Independent assortment of chromosomes ? Crossing over ? Random fertilization Independent Assortment of Chromosomes * Homologous pairs of chromosomes orient randomly at metaphase I of meiosis

AP Bio_Meiosis

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Mitosis

Cohesin

Cell division

Concept 13.3: Meiosis reduces the number of chromosome sets from diploid to haploid * Like mitosis, meiosis is preceded by the replication of chromosomes * Meiosis takes place in two consecutive cell divisions, called meiosis I and meiosis II * The two cell divisions result in four daughter cells, rather than the two daughter cells in mitosis * Each daughter cell has only half as many chromosomes as the parent cell The Stages of Meiosis * Chromosomes duplicate before meiosis * The resulting sister chromatids are closely associated along their lengths * This is called sister chromatid cohesion * The chromatids are sorted into four haploid daughter cells * Division in meiosis I occurs in four phases: Prophase I

Living Environment - Genetics Review

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Genetics

Gene

Introduction to genetics

Mutation

DNA

Mendelian inheritance

The Living Environment The study of organisms and their interactions with the environment. Topics Unit 1: Ecology Unit 2: The Cell Unit 3: Genetics Unit 4: History of Biological Diversity Unit 5: The Human Body GENETICS The science of heredity and the study of how traits are passed on from generation to generation. Mendelian Genetics: How Genetics Began Commonly referred to as the ?father of modern genetics? Gregor Mendel, born in 1822 in what is now the Czech Republic, published the first known findings of heredity in 1866. His primary findings were based on the study of pea plants during his 14 year tenure as an Austrian monk in charge of the monastery garden. Mendelian Genetics

Ch 13 Study Guide

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Chromatid

Cell division

Copyright ? 2011 Pearson Education, Inc. -1- Name__________________________Period___________ Chapter 13: Meiosis and Sexual Life Cycles Concept 13.1 Offspring acquire genes from parents by inheriting chromosomes 1. Let?s begin with a review of several terms that you may already know. Define: gene: A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses) locus: A specific place along the length of a chromosome where a given gene is located gamete: A haploid reproductive cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote. male gamete: Sperm female gamete: Eggs

Biology: Mitosis vs Meiosis

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Ploidy

Chromosome

Meiosis v. Mitosis Ploidy Non disjunction Definitions Mitosis - the way normal body cells divide, reproduce, and grow...and meisosis extends it one step further. In meiosis the cell grows larger. THey both divide into 2 seperate cells but in meiosis, the steps continue - the resulting cells divide further into meiosis. WHen cells undergo meiosis, the result is the creation of gametes, sex-cells. It involves one replication of chromosones and 2 successive cell divisions. Mitosis - starts our all diploid and then it splits into Haploid. Non disjunction - chromosomes fail to separate correctly.

chromosomes and human heredity

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Technology

2/21/13 2:31 PM Scientists don?t just study genes, they also study whole chromosomes by using images of chromosomes stained during metaphase Karyotype- pairs of homologous chromosomes arranged in decreasing size to produce a micrograph Telomeres Telomeres- chromosome s end in protective caps, these caps consist of DNA associated with protiens The telomere also might be involved with aging and caner Nondisjunction Cell division during which sister chromatids fail to separate properly, this can take place during meiosis I or meiosis II One form two kinds of gametes result One has an extra one and one is missing one Organisms with an extra chromosome can survive but those lacking one usually do not Monosomy- lacking a chromosome in humans don?t usually survive

Meiosis Outline

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Genetics

Cytogenetics

Classical genetics

Chromosome

Ploidy

meiosis and sexual life cycle

Sex

Gamete

Centromere

Gene

Health

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1/22/13 2:17 PM Chromosome and chromosome number Genes- the DNA on chromosomes is arranged in segments Chromosomes determine you genes which are passed on determining the color of your hair and eyes Homologous Chromosome Homologous Chromosome- One chromosome from each parent Have same length and same centromere position and carry genes which determine the inherited traits Haploid and diploid cells Gametes- sex cells that have half the number of chromosomes Haploid- A cell with n number of chromosomes in a gamete Fertilization- the process by which one haploid gamete combines with another haploid gamete Diploid- After fertilization the cell has 2n chromosomes Meiosis Meiosis- Type of cell division that reduces the amount of chromosomes

AP Biology Essay

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Genetics

Cytogenetics

Classical genetics