1. Unit 6: Cell Growth and Development 6
Unit 6: Cell Growth and Development 6.1 Chromosomes and Cell Reproduction

2. Why do cells reproduce?
Growth
Development
Repair

3. Cell Division and Reproduction
Growing cells divide to form two daughter cells.
Cell copies DNA prior to dividing
Cell Division and Reproduction

4. Asexual Reproduction Production of genetically identical offspring
Examples: bacteria (binary fission), some fungi, some plants, and even some animals!
Asexual Reproduction

5. Offspring with genetic information from each parent
Examples: most plants and animals
Sexual Reproduction

6. There are advantages and disadvantages to each reproductive strategy!

7. Genetic information (DNA) bundled into packages
Chromosomes

8. Prokaryotic Chromosomes
No nucleus; DNA molecules found in the cytoplasm
Most contain a single, circular DNA chromosome
Prokaryotic Chromosomes

9. Eukaryotic Chromosomes
Contain multiple chromosomes in a nucleus
Chromatin: complex of chromosomes and protein (histones)
DNA tightly coils around histones, forming bead-like structures (nucleosomes), which pack together to form chromosomes
Eukaryotic Chromosomes

10. Chromosomes make it possible to separate DNA precisely during cell division

11. Homologous Chromosomes
Chromosomes in female parent have corresponding chromosomes in male parent
Similar but not identical
Each carries the same genes in the same order, but have different alleles for each trait.
Homologous Chromosomes

13. Diploid “Two sets”- contain both sets of homologous chromosomes
In humans: 23 from mom and 23 from dad for a total of 46.
Symbol 2n
Somatic cells: cells that are NOT used in reproduction
Diploid

14. Haploid “One-set”- contains only a single set of chromosomes Symbol: n
Gametes: cells used in reproduction
Haploid