Unit 4

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Unit 4 Plant Reproduction Lesson Lesson 8
Chromosomes and Genetics

• Colorado Agriscience Curriculum

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Chromosomes and Genetics

• What do I know about chromosomes?
• What do I think I know about chromosomes?
• What dont I know about chromosomes?

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Objectives

• 1. Identify the anatomy of chromosomes.
• 2. Understand how chromosomes determine
  gender.
• 3. Identify chromosome structure and identify
  chromosome mutations.

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I. Chromosome Terminology

• A) Self Replicating genetic structure of cells
  containing DNA that bears genes
• B) Chromatids
• 2 exact copies of DNA that makes up a chromosome
  
• C) Centromere
• Place where chromatids are attached to form a
  chromosome

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I. Chromosome Terminology

• D) Homologous Chromosome
• Chromosomes that are similar in size, shape, and
  genetic content
• E) Genes
• 1. Fundamental physical and functional unit of
  heredity
• 2. Found on chromosomes
• F) Gametes
• 1. Organisms reproductive cells (sperm/egg)
• G) Somatic cells
• 1. All cells besides sex cells

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I. Chromosome Terminology

• H) Diploid
• A cell that contains two sets of like chromosomes
  
• I) Haploid
• A cell that contains one set of like chromosomes
• J) Zygote
• A fertilized ovum

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E - Moment

• Hieroglyphic Moment

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II. Gender

• A) Autosomes
• 1. Chromosomes that are not involved in
  determining the gender of an individual
• B) Sex Chromosomes
• 1. One pair of chromosomes that determine gender
• A. X chromosome FM XX
• B. Y chromosome M XY

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III. Number of Chromosomes

• Humans 46
• Cattle 60
• Sheep 54
• Swine 38
• Horses 64
• Corn 20

• 2 chromosomes are sex chromosomes
• 1/2 of the total of chromosomes is contributed
  by the male and 1/2 by the female

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V. Chromosome Structure

• Down load or scan picture

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VI Chromosome Mutations

• A) change in an organisms chromosome structure
• 1. Deletion
• A. piece of a chromosome breaks off (often fatal)
• 2. Duplication
• A. fragment of a chromosome attaches to its
  homologue
• 3. Inversion
• Fragment reattaches to its chrom. ???? Is placed
  their backwards

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IV. Genetic Disorders

• A. Usually caused by mutations
• 1. Fainting Goats
• a. defect in muscle tissue that causes temporary
  tetanus when under stress
• 2. www.faintinggoat.com
• Research history of the breed to decide if all
  genetic mutations are bad.