Biology STAAR Review

1. Biology STAAR Review Session #4 Cell Differentiation/specialization Cell Cycle Mitosis vs. Meiosis

2. Things to Know DNA If they all have the same DNA, why do they have different functions? Some segments of DNA (genes) are turned off so only certain functions are performed. Cells have specialized jobs because of the genes that are turned on and being used. Often these specialized jobs require specialized structures like: Chloroplasts, cilia/flagella, dendrite/axon ALL the cells of an organism have the exact same ________

4. Stem cells Unspecialized cells are called ____________, and they become specialized due to internal and external factors. Internal Factors • Production of enzymes, hormones, or other chemical signals • Proteins binding to segments of DNA to activate or deactivate genes. External Factors • Temperature changes • Supply of oxygen • Available nutrients • Pollution • Climate factors (ex. length of day)

5. Gene Regulation/Expression means: Transcription Translation DNA Trait Protein Questions?

6. Cell Cycle • Interphase • G1-Growth, Normal cell function/job • S-DNA replication • G2- Double check DNA & organelles to prepare for division • **G0- Cell is not growing, still performs normal function/job Cells that are not regulated by the cell cycle will divide uncontrollably and can lead to _________________ Cancer

7. Growth & DNA Replication occurs Chromosomes line up in middle of cell Chromatin condenses into chromosomes Chromosomes pull apart (And Cytokinesis) Cell and chromosomes divide into two separate cells Questions?

8. Somatic cellsare BODY cells made by MITOSIS • Gametes are SEX cells (egg or sperm) made by MEIOSIS • Diploid cellshave TWO COPIES of each chromosome (complete set) and are made by MITOSIS • Haploid cellshave ONE COPY of each chromosome (half set) and are made by MEIOSIS

9. Crossing over • Happens in MEIOSIS (Metaphase 1) when TETRADS form • INCREASES genetic variation

10. Process B Meiosis Mitosis Process A

11. Comparing Mitosis & Meiosis                 

12. The table lists and describes three types of cells from prepared slides that students observed with a microscope. Which of these sets of slides could students have used for their observations? C) Squamous cell: cheek cell Erythrocyte: red blood cell Gamete: sperm cell A) Squamous cell: cheek cell Erythrocyte: skin cell Gamete: ovum X B) Squamous cell: red blood cell Erythrocyte: white blood cell Gamete: sperm cell D) Squamous cell: ovum Erythrocyte: white blood cell Gamete: skin cell X

13. The model represents the change in the DNA content of a cell during the cell cycle. Which part of the model represents the S phase? • I • II • III • IV

14. When cells leave the cell cycle, they exit during G1 phase and then enter G0phase, a resting period. Most normal cells can leave G0 phase and reenter G1 phase before entering S phase. Cancer cells are different because they cannot enter G0 phase and are likely to do which of the following? • Fail to complete S phase • Mutate during G1 phase • Repeat the cell cycle continuously • Die after completing mitosis

15. Sexual reproduction in animals depends on the production of gametes. Which of these processes produces gametes in animals? Mitosis Fertilization Meiosis Binary fission

16. You are going to ROCK the STAAR!!!

17. Cell Cycle, Mitosis vs. Meiosis, & Cell Differentiation 5A Describe the stages of the cell cycle including DNA replication and mitosis and the importance of the cell cycle to the growth of organisms. 5BExamine specialized cells, including roots, stems, and leaves of plants; and animal cells such as blood, muscle, and epithelium 5CDescribe the roles of DNA, ribonucleic acid (RNA), and environmental factors in cell differentiation. 5DRecognize that disruptions of the cell cycle lead to diseases such as cancer 6D Recognize that gene expression is a regulated process; 6G Recognize the significance of meiosis to sexual reproduction.