DNA Deoxyribonucleic Acid Objectives Learn the location shape

DNA Deoxyribonucleic Acid

Objectives Learn the location, shape, and material of DNA. Understand that traits are controlled by genes on chromosomes.

Vocabulary Focus Allele DNA Chromosomes Gene Map Genetics Heredity Homologous Karyotype Trait

Habit of the Mind Applying Past Knowledge to New Situations Responding with Wonderment and Awe

Titan Creed Focus Titans take ownership of and find joy in learning.

Question to Ponder How are DNA, chromosomes, and genes related?

Genetics - the field of biology devoted to studying heredity Heredity the passing on of traits from parents to offspring

Deoxyribonucleic Acid DNA dee OK see RY boh noo KLEE ik) Hereditary “code of life” Possesses information that determines an organism’s traits/characteristics Transmitted (passed down) from one generation to the next Contains the genetic blue print of all the directions that control the functions of the organism Has all the information needed to build, control, and maintain a living organism Image acquired from http: //www. sciencedaily. com/releases/2008/05/080526155300. htm

DNA Location Cell’s nucleus DNA organized into chromosomes Chro mosomes coiled DNA Image acquired fromhttp: //www. riversideonline. com/health_reference/Tools/DS 00549. cfm? Render. For. Print=1

Rosalind Franklin 1951 discovered the double helix shape of DNA like a miniature ladder 2 sides and rungs connecting the sides Sides twist around each other like a spiral staircase 10 rungs for each turn Image acquired from http: //www. bu. edu/today/2009/genomes have bumps/

DNA Model 1953 James Watson/Francis Crick Made a model of the DNA molecule Has changed very little Ladder sides made up of … Phosphates (P) Joined with deoxyribose sugar (D) Units alternate to form the two strands Pairs of bases connect the two strands. Each base pair forms a rung on the ladder. A single DNA molecule, or ladder, can have thousands of steps. The number of steps and how they are ar ranged form a genetic code. The genetic code determines the different kinds of inherited traits.

DNA - Bases Hereditary characteristics of living organisms determined by the information encoded in DNA. Particular sequences of the four nitrogenous bases comprise a code that specifies the traits of living things. Four nitrogen bases in DNA: adenine (A) cytosine (C) guanine (G) thymine (T)

DNA - Bases Four bases pair up in an orderly manner creating a code Ad enine (A) pairs only with thymine (T) Cytosine (C) only pairs with guanine (G)

DNA - Bases What other types of codes can you think of? Morse code a set of dots and dashes that correspond to letters of the alphabet. Musical notes a code that determines the melody and harmony of songs. Any of these codes can be arranged in a variety of ways to give different outcomes. The same is true with the DNA code. Different arrangements of base pair sequences result in different instructions for creating living things. Sequences of specific instructions called genes. Video The Double Helix (HHMI) Video DNA Basics

Activity Creating a Model of DNA

DNA = Chromosome DNA organized into chromosomes Chro mosomes coiled DNA Image acquired fromhttp: //www. riversideonline. com/health_reference/Tools/DS 00549. cfm? Render. For. Print=1

Chromosomes Coiled DNA Thread like structures that carry the hereditary information of living organisms

Chromosome Numbers Characteristic of a species A normal human body cell 46 22 matured pairs autosomes 2 sex chromosomes (X and Y) Females – 2 X chromosomes Males 1 X / 1 Y chromosome Chromosome number varies widely from species to species Garden pea 14 Potato 48 Crayfish – 200 Dogs – 78 Silkworms 56 Larger organisms do not always have more chromosomes.

Karyotype Definition: the chromosomes of a cell, usually displayed as a systematized arrangement of chromosome pairs in descending order of size How do scientists read chromosomes? Size Banding pattern Centromere position Make a karyotype Using karyotypes to diagnose genetic disorders

Chromosomes and Genes Chromosomes are made up of many genes joined together like beads on a string Each pair of chromosomes has the same genes. Homologous having the same alleles or genes in the same order of arrangement Genes lined up same order from one end of the chromosomes to the other Alleles might be different A variation of a gene (i. e. eye color) Video: What is a Chromosome?

Gene Map A diagram showing the relative locations of each known gene on a particular chromosome.

Genes determine specific traits Trait - a characteristic feature/quality distinguishing a particular person or thing Functional segment of DNA or sequence of DNA that determines a trait Video Gene Basics Image acquired from http: //www. accessexcellence. org/RC/VL/GG/genes. php

How are DNA, chromosomes, and genes related?

Exploration – Web Links • • • DNA Extraction Virtual Lab (University of Utah) Tour of Basic Genetics (University of Utah) Characteristics of Inheritance (University of Utah) Molecules of Inheritance DNA/Genes (University of Utah) Chromosomes and Inheritance (University of Utah)