Mitosis
What is prophase?
This is the stage where chromosomes become visible and the nuclear envelope breaks down. The spindle fibers start to form as the cell prepares for division.
Discuss the role of meiosis in genetic variation.
Meiosis plays a crucial role in generating genetic diversity, which is fundamental for the evolution of species. This diversity is achieved through two main mechanisms: crossing over and independent assortment.
This is the starting cell in spermatogenesis, which undergoes mitosis to produce primary spermatocytes.
spermatogonium
Describe the process of cancer development, starting from a normal cell.
Cancer begins when a normal cell undergoes mutations in its DNA, leading to uncontrolled cell division. Over time, the abnormal cells form a tumor, which can invade surrounding tissues and, in some cases, metastasize to other parts of the body.
The primary constriction in the center of a chromosome that attaches chromatids or spindle fibers. The centromere also separates the chromosome into a short arm (p) and a long arm (q).
Centromere
What is metaphase?
During this phase, chromosomes line up at the cell’s equator, and spindle fibers attach to the centromeres of the chromosomes.
Describe the process of meiosis and its stages.
Meiosis is a two-part cell division process that reduces the chromosome number by half, creating four genetically unique haploid cells through the stages of meiosis I (homologous chromosomes separate) and meiosis II (sister chromatids separate).
This is the process by which the female gametes, or ova, are produced.
Oogenesis
Explain the difference between benign and malignant tumors.
Benign tumors are non-cancerous growths that remain localized and do not spread to other tissues. In contrast, malignant tumors are cancerous, capable of invading nearby tissues and spreading throughout the body via the bloodstream or lymphatic system (metastasis).
The shorter arm of a chromosome, located above the centromere.
P - arm
What is anaphase? Explain the process of chromatid separation in anaphase and why accurate separation is crucial for healthy cell division.
The sister chromatids are pulled apart and move toward opposite poles of the cell.
Crossing over during prophase I allows homologous chromosomes to exchange genetic material, creating new allele combinations and increasing genetic diversity among offspring.
Analyze the importance of crossing over during meiosis.
This is the large cell produced during oogenesis, while the smaller, non-functional cells are called polar bodies.
secondary oocyte
Analyze the impact of environmental factors on cancer risk.
Environmental factors such as tobacco smoke, ultraviolet (UV) radiation, and exposure to certain chemicals increase cancer risk by causing DNA damage. For example, smoking is strongly linked to lung cancer, while excessive sun exposure can lead to skin cancer. The body's ability to repair DNA damage varies among individuals, influencing their susceptibility to cancer.
The longer arm of the chromosome, located below the centromere
q - arm
What is telophase and cytokinesis? Describe the events that occur during telophase and cytokinesis and their role in completing mitosis.
This final stage involves the reformation of the nuclear envelope around separated chromosomes, followed by the division of the cytoplasm.
Explain the significance of chromosome reduction in meiosis.
Chromosome reduction is essential in meiosis to produce haploid gametes, ensuring that the chromosome number remains stable when fertilization restores the diploid state in the offspring.
During oogenesis, this structure forms and contains the genetic material discarded during cell divisions.
Polar bodies
Discuss the role of genetic mutations in the development of cancer, with a focus on apoptosis and cell cycle checkpoints.
Genetic mutations can disrupt the normal mechanisms of apoptosis (programmed cell death) and cell cycle checkpoints, leading to cancer.
A single strand of a chromosome that contains a double helix of DNA. Chromatids are the result of DNA replication, and each chromosome consists of two identical chromatids joined together by the centromere.
Sister Chromatids
Why is mitosis important?
This is why mitosis is essential for growth and repair in multicellular organisms.
Compare and contrast meiosis and mitosis.
The key similarities include DNA replication before division and the use of spindle fibers for chromosome separation. However, meiosis involves processes like crossing over and independent assortment, which do not occur in mitosis. These processes contribute to genetic diversity, whereas mitosis maintains genetic consistency.
The number of viable gametes produced from one primary spermatocyte.
four
Evaluate the impact of lifestyle choices on cancer risk and provide examples of modifiable risk factors.
Lifestyle choices significantly affect cancer risk, with smoking, poor diet, lack of physical activity, and excessive alcohol consumption being key modifiable factors. For example, smoking is linked to lung cancer due to the carcinogenic chemicals in tobacco smoke, while a diet high in processed foods may increase the risk of colorectal cancer. Adopting a healthy lifestyle can reduce exposure to these risk factors, lowering the likelihood of developing cancer.
I am always hungry, I must always be fed. The finger I touch, Will soon turn red. What am I?
Fire