Chromosomes, Genes & DNA

Life Science - Middle School

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www.newpathlearning.com © Copyright NewPath Learning. All Rights Reserved. 94-4640 Chromosomes, Genes & DNA A A A C C C C G G G G T T T chromosome pair gene A B c D e F G h i J a b C d E f g H I j Chromosomes are made up of DNA. DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. The hereditary information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T). The order, or sequence, of these bases, determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences. DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each chromosome contains thousands of genes. A gene is a section of a DNA strand that is made up of a series of bases which contains the information for cells to make one specific protein. DNA strand genes proteins chromosomes centromere nucleolus nucleus cell Human Karyotype A karyotype is a picture of the complete set of chromosomes in a cell. Scientists examine a karyotype to identify and evaluate the size, shape and number of chromosomes in a human cell. Extra, missing or abnormal positions of chromosome pieces can cause problems with a person's growth, development and body functions. A normal human male karyotype is represented as 46, XY and a normal female karyotype is represented as 46, XX. Individuals with chromosomal disorders include Down Syndrome (47, XY, +21) and Turner’s Syndrome (45, X) among others. 5 4 3 2 1 6 13 14 19 20 21 22 20 15 16 18 17 7 8 9 10 11 12 XX (female) XY (male) Chromosome Spread Identifying Chromosomes 1-3 Very long; centromere in the center 4-5 Very long; centromere not in the center 6-12 Long; centromere not in the center 13-15 Medium; centromere above the center 16-18 Medium; centromere at or close to center 19-20 Short; centromere at or close to center 21-22 Short; centromere not in the center Sex chromosomes X is long; centromere in the center Y is short; centromere above the center Chromosome Characteristics or Karyotype images courtesy of Joana Costa, Genetics Department, Liverpool Women's Hospital
A A A C C C C G G G G T T T J Chromosomes, Genes and DNA ___________________ are made up of DNA. DNA, or __________________________, is the __________________________ in humans and almost all other organisms. The hereditary information in DNA is stored as a code made up of four chemical bases: ________________, ________________, ________________ and ________________. The order, or sequence, of these bases, determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences. DNA bases pair up with each other, ___ with T and C with ___, to form units called _______________________. Each chromosome contains thousands of _________________. A ________________ is a section of a DNA strand that is made up of a series of bases which contains the information for cells to make one specific ________________. DNA strand nucleolus nucleus cell gene A B c D e F G h i a b C d E f g H I www.newpathlearning.com © Copyright NewPath Learning. All Rights Reserved. 94-4640 Chromosomes, Genes & DNA Chromosome Spread Identifying Chromosomes 1-3 4-5 6-12 13-15 16-18 19-20 21-22 Sex chromosomes Chromosome Characteristics 1 2 3 6 7 8 9 10 11 12 13 14 19 20 21 22 XX (female) XY (male) 15 16 17 18 4 5 or A _________________ is a picture of the complete set of ___________________ in a cell. Scientists examine a karyotype to identify and evaluate the size, shape and number of chromosomes in a human cell. Extra, missing or abnormal positions of chromosome pieces can cause problems with a person's growth, development and body functions. A normal human male karyotype is represented as _______________ and a normal female karyotype is represented __________________. Individuals with chromosomal disorders include ________________________________ (47, XY, +21) and ________________________________ (45, X) among others. Key Vocabulary Terms Adenine DNA base pairs hereditary material centromere gene chemical base Guanine chromosome karyotype chromosome spread protein Cytosine Thymine 5 4 3 2 1 6 13 14 19 20 21 22 20 15 16 18 17 7 8 9 10 11 12 XX (female) XY (male) or Human Karyotype \|xiBAHBDy01748mzV