Describe the action of the lysosomes in various “unique” situations, such as the destruction of specific cells during embryonic development, or the part they play in the shedding of the endometrium of the uterus during the menstrual cycle

During cell division cycle, cells need to monitor the process of DNA replication and segregation of replicated DNA so that these processes are error-free. Some potential errors that could occur include incomplete DNA replication, DNA damage in genome, and uneven separation of replicated genome. These mechanisms that cells used to monitor these processes are referred as the "cell cycle checkpoint, which can control specific Cdk activity to regulate the progression of cell cycle. For the following checkpoint mechanisms, indicate which Cdk activity is attenuated? Also indicate one of the key proteins or protein complexes involved in the following checkpoints. a) DNA damage checkpoint during S-phase b) Mitotic checkpoint during M-phase

A 42-year-old woman comes to the physician for a follow-up examination after two separate Pap smears have shown dysplastic epithelial cells. Results of a molecular diagnostic test show DNA that encodes high-risk versions of the human papillomavirus E6 and E7 proteins. The viral E6 protein binds to the cellular p53 tumor suppressor gene, causing it to be degraded. Which of the following best describes the mechanism by which the E6 protein causes cervical cancer? (A) Arrests the cell cycle (B) Enhances tissue invasion and metastasis (C) Inhibits telomerase expression (D) Prevents apoptosis (E) Sustains angiogenesis

A classical experiment studying the fate determination of stem cells in the developing embryo uses the transplantation of somites from one organism to another. In such an experiment, a scientist transplanted somites 20, 21, and 22 from the right side of the neural tube from five-day-old developing quail embryos into chick embryos. The transplantation was performed in two orientations so that the order of the somites was sometimes reversed.   Use the passage to answer the question. Observations of the developing chick embryo reveal that skeletal muscles develop from the transplanted somites even though motor neurons innervating those muscles arise from chick neural crest cells. Based on these observations, what is MOST likely true?   A. Neural crest cells differentiate into somites.   B. Neural crest cells fuse with developing somite cells.   C. Neural crest cells develop from migrating somite cells.   D. Neural crest cells send projections into developing…