Cytogenetics

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Chromosomal abnormalities

Cytogenetics

Chromosomes

Chromosomal translocation

Alterations of chromosome number or structure cause some genetic disorders * Large-scale chromosomal alterations in humans and other mammals often lead to spontaneous abortions (miscarriages) or cause a variety of developmental disorders * Plants tolerate such genetic changes better than animals do Abnormal Chromosome Number * In nondisjunction, pairs of homologous chromosomes do not separate normally during meiosis * As a result, one gamete receives 2 of the same type of chromosome, and another gamete receives no copy * Aneuploidy results from the fertilization of gametes in which nondisjunction occurred * Offspring with this condition have an abnormal number of a particular chromosome * A monosomic zygote has only 1 copy of a particular chromosome

AP Bio_chromosomal_basis_of_inheritance

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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_Cell division

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Developmental biology

Alternation of generations

Gamete

Sex

Meiosis and Sexual Life Cycles Variations on a Theme * Offspring resemble their parents more than they do unrelated individuals * Heredity is the transmission of traits from one generation to the next * Variation is demonstrated by the differences in appearance that offspring show from parents and siblings * Genetics is the scientific study of heredity and variation Concept 13.1: Offspring acquire genes from parents by inheriting chromosomes * In a literal sense, children do not inherit particular physical traits from their parents * It is genes that are actually inherited Inheritance of Genes * Genes are the units of heredity and are made up of segments of DNA * Genes are passed to the next generation via reproductive cells called gametes (sperm and eggs)

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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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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Cytogenetics

Classical genetics

Chromosome

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

Bio Notes Genetics

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Philosophy of biology

Health

Sex Linked genes -The X and Y chromosomes determine the sex of an individual and contain genes related to female and maleness. All other genes on these chromosomes are called sex linked genes -The X chromosome has the most genes but in some species (fruit fly), genes are found on the Y chromosome as well. genes on the Y chromosome are only passed from father to son -Sex linked gene inheritance (x linked) can be studied using fruit flies. The gene for eye color is located on the X chromosome. R-Red eyes are dominant to r white eyes. -Alleles carried on the X chromosome are shown as X^R, and X^r, Females have 2 alleles (X^R X^R, X^R X^r, or X^r X^r) while males only have one (X^R Y, or X^r Y) The male?s phenotype results from one X allele plll. Sex Linked Disorders In Humans

AP Biology Essay

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Cytogenetics

Classical genetics

Mendelian inheritance

Health

Genetics An organism is heterozygous at two genetic loci on different chromosomes. Explain how these alleles are transmitted by the process of mitosis to daughter cells. Explain how these alleles are distributed by the process of meiosis to gametes. Explain how the behavior of these two pairs of homologous chromosomes during meiosis provides the physical basis for Mendel?s two laws of inheritance. Labeled diagrams that are explained in your answer may be useful.

Biology vocab

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