1. 12-2: CHROMOSOMES AND DNA REPLICATION
Biology 2

2. Prokaryotes lack a nucleus and organelles DNA is located in cytoplasm
and Chromosomes
Prokaryotes lack a nucleus and organelles
DNA is located in cytoplasm
Most have single circular DNA
Eukaryotes are more complex
DNA is located in nucleus, as chromosomes
Number of chromosomes varies between species

3. EUKARYOTE DNA
PROKARYOTE DNA

4. DNA is wrapped tightly around histones (forms chromatin)
and Chromosomes
DNA is wrapped tightly around histones (forms chromatin)
CHROMATIN: granular material visible within the nucleus; consists of DNA tightly coiled around proteins
Chromatin is wrapped up tightly to form loops and coils
As it wraps tighter and tighter, it forms the X structure of chromosomes

5. HOW IS DNA PACKAGED

6. CHROMOSOME ORGANIZATION

7. Before a cell divides it creates a “copy” of DNA during replication
REPLICATION: copying process by which a cell duplicates its DNA
DNA separates into 2 strands, and “copies” the pattern to create another strand
Must use base pairing rules (A=T, C=G) to make new strand
Goal of replication is to have 2 complete sets of DNA for cells
DNA Replication

8. DNA REPLICATION

9. Section Assessment
Prokaryotes lack a __________ and __________ , DNA is located in __________
Eukaryotes are more __________ , DNA is located in __________ , as __________
Goal of replication is to have ______________ of DNA for cells

10. Bill Nye – Genes and Chromosomes