1. Ch. 8 Cell Reproduction Ch 8.1 Chromosomes

2. How is DNA organized? Usually in a cell, DNA is wrapped around ________ proteins in long strands called chromatin. Usually in a cell, DNA is wrapped around ________ proteins in long strands called chromatin. During cell division, the chromatin __________ into chromosomes. During cell division, the chromatin __________ into chromosomes. The chromosome is made of two identical DNA structures, called chromatids, that are joined together at the _____________. The chromosome is made of two identical DNA structures, called chromatids, that are joined together at the _____________. histone condenses centromere

3. nucleus Chromatin and Condensed Chromosome Structure chromatin DNA helix histones chromosome centromere chromatid

4. Each species has a specific _______ of chromosomes. Each species has a specific _______ of chromosomes. Each different chromosome contains information for different ________. Each different chromosome contains information for different ________. number traits

5. Types of Chromosomes Sex chromosomes: In humans, chromosome __ and __, determine the sex of a person. Sex chromosomes: In humans, chromosome __ and __, determine the sex of a person. –Females have two X, and males have X and Y. All other chromosomes are called _____________. All other chromosomes are called _____________. X Y autosomes

6. Most human cells normally contain ____ sets of each chromosome. Most human cells normally contain ____ sets of each chromosome. These are called _______ cells and is abbreviated as ____. These are called _______ cells and is abbreviated as ____. How many chromosomes are in a cell? two diploid 2n

7. Reproductive cells, sperm and egg cells, are _______. Reproductive cells, sperm and egg cells, are _______. Haploid cells contain only ___ set of chromosomes. This is abbreviated as ___. Haploid cells contain only ___ set of chromosomes. This is abbreviated as ___. haploid one n

8. Karyotype An organized profile of an organism’s complete set of chromosomes. An organized profile of an organism’s complete set of chromosomes. Scientist pair together homologous chromosomes based on their size, banding pattern, and position of their centromere. Scientist pair together homologous chromosomes based on their size, banding pattern, and position of their centromere. Then they arrange them by size from largest to smallest. Then they arrange them by size from largest to smallest.

9. Human male karyotype

11. Cell Division Asexual vs. Sexual Reproduction

12. Asexual Reproduction Requires only one parent. Requires only one parent. Resulting offspring are genetically identical. Resulting offspring are genetically identical. The only source of genetic variation comes from mutations. The only source of genetic variation comes from mutations.

13. Budding Parent produces an outgrowth that pinches off, forming a new organism Parent produces an outgrowth that pinches off, forming a new organism Occurs in yeast, hydra, sponges. Occurs in yeast, hydra, sponges.

14. http://www.waycross.edu/faculty/bmajdi/hydra%20budding.jpg

16. Spore formation Single or multi-celled spores are produced and grow into a new organism. Single or multi-celled spores are produced and grow into a new organism. Occurs in algae, fungi, protists, and plants Occurs in algae, fungi, protists, and plants

18. Binary Fission DNA replicates and one cell divides into two DNA replicates and one cell divides into two Occurs in bacteria, protozoa, and algae. Occurs in bacteria, protozoa, and algae.

20. Sexual reproduction Requires two gametes (sex cells) : egg and sperm. Requires two gametes (sex cells) : egg and sperm. The egg and sperm join to form an entirely new organism The egg and sperm join to form an entirely new organism The offspring is genetically different from the parent organism The offspring is genetically different from the parent organism

21. Why do cells reproduce? Produce more offspring (new organisms). Produce more offspring (new organisms). Organism needs to grow or repair Organism needs to grow or repair

22. Prokaryotes Prokaryotic cells divide by ________ ___________. Prokaryotic cells divide by ________ ___________. They have circular chromosomes without any proteins and cell division occurs very quickly. They have circular chromosomes without any proteins and cell division occurs very quickly. binary fission

23. Eukaryotes Eukaryotes divide by mitosis Eukaryotes divide by mitosis Cells spend only a small percentage of their time dividing. Cells spend only a small percentage of their time dividing. The set of events in the life of a cell is called the cell cycle. The set of events in the life of a cell is called the cell cycle. A cell spends most of its life in interphase. A cell spends most of its life in interphase.

24. G1 Phase Cell grows to mature size Cell grows to mature size

25. S Phase DNA replicates. DNA replicates.

26. G2 Cell grows and prepares to divide. Cell grows and prepares to divide.

27. What is cancer? Cancer occurs when cells do not stop growing. Cancer occurs when cells do not stop growing. Healthy cells regulate when and how often they continue in the cell cycle. Healthy cells regulate when and how often they continue in the cell cycle. Cancer cells continuously go through the cell cycle without stopping, which leads to a tumor. Cancer cells continuously go through the cell cycle without stopping, which leads to a tumor.