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Chapter 61225

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Biology 1225
Michael Butler

Chapter 6 DNA Structure and Function 6.2 Chromosomes pg. 101 centromere – Of a duplicated eukaryotic chromosome, constricted region where sister chromatids attach to each other chromosome a structure that consists of DNA and associated proteins; carries part of all of the cell’s genetic information chromosome number – the sum of all chromosomes n a cell of a given species clone – genetically identical copy of an organism histone – type of protein that structurally organizes eukaryotic chromosomes sister chromatid – one of two attached members of a duplicated eukaryotic chromosome 1. the DNA of eukaryotes is divided among a characteristic number of chromosomes that differ in length and shape 2. histone proteins that associate with eukaryotic DNA help it pack into a nucleus 3. When duplicated, a eukaryotic chromosome consists of two sister chromatids attached at a centromere. 4. Diploid cells have two of each type of chromosome 5. Chromosome number is the sum of all chromosomes in a cell of a given species. For example the chromosome number of oak trees is 12, so the nucleus of a cell from an oak tree has 12 chromosomes. The number of human body cells is 46, so human body cells have chromosomes. 6. Members of a pair of sex chromosomes differ among males and females 7. All other are autosomes. Autosomes of a pair have the same length, shape and centromere location. 8. A karyotype reveals an individual’s complement of chromosomes 1 Take Home Message What are chromosomes?? 1. In cells, DNA and associated proteins are organized as chromosomes. 2. A eukaryotic cell’s DNA is divided among some characteristic number of chromosomes, which differ in length and shape 3. Members of a pair of sex chromosomes differ between males and females. Chromosomes that are the same in males and females are called autosomes. 2 6.3 Fame, Glory and DNA structure pg 102 autosome – any chromosome other than a sex chromosome diploid – having two of each type of chromosome characteristic of the species karyotype – image of an individual’s complement of chromosomes arranged by size, length, shape and centromere location sex chromosome – member of a pair of chromosomes that differs between males and females 1. A DNA molecule consists of two chains of nucleotides coiled into a double helix 2. A DNA nucleotide has a five carbons sugar, three phosphate groups and on of four bases after which the nucleotide is named; 1. Adenine, 2. Thymine, 3. Guanine or 4. Cytosine 3. Bases of the two DNA strands in a double helix pair in a consistent way; adenine with thymine(A-T), and guanine with cytosine (G-C) 4. The order of the bases (the DNA sequence) varies among species and among individuals Take home message What is the Structure of DNA 1. A DNA molecule consists of two nucleotide chains(strands) running in opposite d
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