DNA Replication Cell Division Cells in order for

DNA Replication

Cell Division • Cells __________ in order for an organism to grow, reproduce, and repair itself

Kinds of Cells • ___________ (Sex) Cells • ___________ (Body) Cells • Both contain DNA • DNA stored in __________

Chromatin • Long _____________ of ___________ • Associated with proteins • How DNA is stored when the cell is not dividing

Chromosomes Cell ready to divide Chromatin _________ and _____________ Chromosomes form Reproductive Cells Single set __________ number (n) Humans _________ Somatic Cells Two sets ___________ number (2 n) Humans _________

DNA Replication • Copy DNA • Double strands of DNA helix ________________ • Become _______________individual strands • New DNA strands assembled from ___________________________________in cell’s nucleus • DNA ______________________ collects the nucleotide bases and matches them to their complementary pair

DNA is semi conservative • Every DNA molecule is half ______ and half ______________ new

DNA Replication • Strands separate • __________________ use each strand as a template to assemble new strands A A Nucleotides Parental molecule of DNA Both parental strands serve as templates Two identical daughter molecules of DNA

Enzymes involved in replication • _________________ • Unwind two strands • _________________ • Attaches complementary nucleotides • _________________ • Fills in gaps to form continuous strand

5 end 3 end P P P P • Strands oriented in ____________ direction • Strands only assembled in 5’ to 3’ direction • One ________ group of sugar exposed P 3 end 5 end

DNA polymerase molecule 5 end Daughter strand synthesized continuously Parental DNA 5 3 Daughter strand synthesized in pieces 3 5 P 5 3 3 5 P DNA ligase Overall direction of replication

DNA Repair • ______________________ can occur • DNA ___________________ – proofreads • DNA ______________Ligase – repairs mistakes