12 12 Chromosomes and DNA 12 2 Chromosomes

12– 1&2 Chromosomes and DNA 12 -2 Chromosomes and DNA Replication Slide 1 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication Vocabulary words • DNA • Nucleotide • Purine • Pyramidine • Chargaff's Rules • Double Helix • Hydrogen Bonds • Histone • Nucleosome • Chromosome • Gene Copyright Pearson Prentice Hall Slide 2 of 21 End Show

12– 2 Chromosomes and DNA Replication • Outline – DNA • structure • Chargaff’s rule – Chromosomes • Structure • Pairing Slide 3 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication • Deoxyribonucleic acid (DNA) - a molecule that encodes the genetic instructions used in all living organisms and many viruses. • Gene – single unit of heredity Slide 4 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes The Components and Structure of DNA Replication There are four kinds of bases in in DNA: • adenine • guanine • cytosine • thymine Slide 5 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes The Components and Structure of DNA Replication Chargaff's Rules Erwin Chargaff discovered that: • The percentages of guanine [G] and cytosine [C] bases are almost equal in any sample of DNA. • The percentages of adenine [A] and thymine [T] bases are almost equal in any sample of DNA. Slide 6 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication The Components and Structure of DNA Double Helix Slide 7 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication DNA and Chromosomes In prokaryotic cells, DNA is located in the cytoplasm. Most prokaryotes have a single DNA molecule containing nearly all of the cell’s genetic information. Slide 8 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication DNA and Chromosomes Eukaryotic DNA is located in the cell nucleus inside chromosomes. Many eukaryotes have 1000 times the amount of DNA as prokaryotes. Slide 9 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication • Nucleus – Control center of the cell. Contains DNA Slide 10 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication • Nucleus Envelope - double lipid bilayer which surrounds the DNA and nucleolus • Chromatin - the combination of DNA and proteins that make up the contents of the nucleus of a cell. (makes chromosomes) • Nucleolus – dark dense center of the nucleus. Where ribosome are made Slide 11 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication DNA and Chromosomes Chromosome Structure Both Prokaryotes and Eukaryotes have the same structure of DNA Eukaryotic cells contain chromosomes which are molecules that contain DNA and protein, tightly packed together. . Slide 12 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication • Chromosome - is an organized structure of DNA, protein, found in cells. It is a single piece of coiled DNA containing many genes. . Centromere – center of chromosome Chromatid - is one copy of a duplicated chromosome Slide 13 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication DNA and Chromosomes Eukaryotic Chromosome Structure Chromosome Nucleosome DNA double helix Coils Supercoils Histones Slide 14 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication • Histone – Protein that packages and orders DNA into structural units called nucleosomes • Nucleosome - DNA wound around histone protein cores Slide 15 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication DNA and Chromosomes Eukaryotic Chromosome Structure Chromosome Nucleosome DNA double helix Coils Supercoils Histones Slide 16 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Chromosomes and DNA Replication • Humans have 46 pairs of chromosomes – 23 from your mom – 23 from your dad • Last 2 chromosomes pairs determine sex of child – XX Girl – XY Boy • The number of chromosomes varies from one species to the next. Slide 17 of 21 Copyright Pearson Prentice Hall End Show

12– 2 Click to Launch: Continue to: - or - Slide 18 of 21 End Show Copyright Pearson Prentice Hall

12– 2 In prokaryotic cells, DNA is found in the a. cytoplasm. b. nucleus. c. ribosome. d. cell membrane. Slide 19 of 21 End Show Copyright Pearson Prentice Hall

12– 2 A DNA molecule separates, and the sequence GCGAATTCG occurs in one strand. What is the base sequence on the other strand? a. GCGAATTCG b. CGCTTAAGC c. TATCCGGAT d. GATGGCCAG Slide 20 of 21 End Show Copyright Pearson Prentice Hall

Slide 21 of 21 End Show Copyright Pearson Prentice Hall

Slide 22 of 21 End Show Copyright Pearson Prentice Hall

12– 2 Slide 23 of 21 End Show Copyright Pearson Prentice Hall

Next class • Homework: Glue QR codes to notes and watch the video on the QR code for next class (the cell cycle). • Possible quiz on vocabulary next class –matching Slide 24 of 21 End Show Copyright Pearson Prentice Hall

END OF SECTION