Chapter 3 - (Pt.3) Flashcards
cell division and cancer
Q: What is cell division?
A: Cell division is the process by which a cell reproduces itself, consisting of nuclear division (mitosis) and cytoplasmic division (cytokinesis). It includes somatic and reproductive cell division.
Q: What are somatic cells?
A: Somatic cells are all body cells except those involved in reproduction. They undergo somatic cell division.
Q: What occurs during somatic cell division?
A: mitosis and cytokinesis, which create two identical cells with the same chromosomes as the original. This process replaces dead or injured cells and supports tissue growth
Q: What are germ cells?
A: Germ cells include gametes (sperm and oocytes) and precursor cells that develop into gametes.
Q: What happens during reproductive cell division?
A: Meiosis produces gametes by halving the chromosome number, preparing for sexual reproduction to ensure the next generation has the correct chromosome count.
Q: What is a somatic cell in the human body?
A: It is any cell of the human body besides a germ cell involved in reproduction.
Q: What process do somatic cells undergo for division?
A: Somatic cell division consists of mitosis and cytokinesis.
Q: What are reproductive cells responsible for producing?
A: They produce gametes, which are sperm and oocytes.
Q: What is the process of reproductive cell division called?
A: Reproductive cell division is called meiosis.
Q: What is the cell cycle?
A: It is the growth and division of a single cell into two identical cells, consisting of interphase and the mitotic phase.
Q: How many pairs of chromosomes do human somatic cells have?
A: Human somatic cells have 23 pairs of chromosomes, totaling 46.
Q: What are homologous chromosomes?
A: They are two chromosomes that belong to a pair, containing similar genes in similar arrangements (also called homologs).
Q: What is distinct about sex chromosomes in humans?
A: Females have two X chromosomes, while males have one X and one smaller Y chromosome.
Q: What does it mean for a cell to be diploid?
A: A diploid cell (2n) has two sets of chromosomes.
Q: What occurs during interphase?
A: The cell is not dividing but prepares for division by replicating DNA, producing additional organelles, and synthesizing cytosolic components.
Q: What happens in the G1 phase of interphase?
A: The cell grows and performs normal functions without DNA replication.
Q: What occurs during the S phase of interphase?
A: DNA is synthesized and replicated.
Q: Describe the G2 phase of interphase.
A: The cell continues to grow and prepares for division after DNA replication.
Q: What happens in the mitotic phase of the cell cycle?
A: The cell divides to form two new identical cells.
Q: What happens during the G1 phase of interphase?
A: The cell is metabolically active, duplicates organelles and cytosolic components, and centrosome replication begins.
Q: What occurs during the S phase of interphase?
A: DNA is replicated.
Q: What happens in the G2 phase of interphase?
A: Cell growth continues, and enzymes and other proteins are synthesized; centrosome replication is completed.
Q: What is the G0 phase?
A: It is the phase where the cell exits the cell cycle and is non-dividing.
Q: How long does the S phase typically last?
A: About 8 hours.
Q: During which phase are cells not actively dividing?
A: G0 phase.
Q: What follows interphase in the cell cycle?
A: The mitotic (M) phase.
Q: What are the stages of the mitotic phase?
A: Prophase, Metaphase, Anaphase, and Telophase.
Q: In which phase of the cell cycle does centrosome replication begin?
A: Centrosome replication begins during the G1 phase.
Q: What happens to DNA strands during replication?
A: The two strands of the double helix separate by breaking the hydrogen bonds between nucleotides.
Q: What phase follows the S phase in the cell cycle?
A: The G2 phase follows the S phase.
Q: How long does the G1 phase typically last?
A: The G1 phase generally lasts 8 to 10 hours but can be shorter in embryonic or cancer cells.
Q: What occurs during the G2 phase of interphase?
A: The cell continues to grow, synthesize proteins, and complete centrosome replication in preparation for division.
Q: What is the G0 phase?
A: It is a phase where cells that do not divide may enter, such as most nerve cells.
Q: How long does mitosis typically take to complete?
A: Mitosis takes about 1-2 hours.
Q: What is the main result of mitosis?
A: The distribution of 2 sets of chromosomes into 2 separate nuclei.
Q: What are the four stages of mitosis?
A: Prophase, Metaphase, Anaphase, and Telophase.
Q: During the Mitotic (M) Phase, what two types of cell division occur?
A: Nuclear division (mitosis) and cytoplasmic division (cytokinesis).
Q: What critical process is ensured by mitosis?
A: Exact genetic partitioning into two daughter cells.
Q: What is the first stage of mitosis called?
Prophase
Q: What happens to chromatin during prophase?
A: It condenses into visible, compact structures called chromosomes
Q: What are the identical halves of a chromosome called, and where are they joined?
A: Chromatids, joined at the centromere
Q: What happens to the nuclear envelope during prophase?
A: It breaks down, and the nucleolus disappears
Q: What structure helps in separating the chromosomes during mitosis, and how is it formed?
A: The mitotic spindle, formed by centrosomes assembling microtubules
Q: What critical process does prophase prepare for by organizing genetic material?
A: The division of genetic material, by organizing it into discrete chromosomes
Q: What stage of mitosis is characterized by chromosomes lining up in the middle of the cell?
A: Metaphase
Q: What is the middle area of the cell where chromosomes line up during metaphase called?
A: The metaphase plate
Q: What structures attach to the centromeres of each chromosome during metaphase?
A: Spindle fibers (made of microtubules)
Q: Why is the arrangement of chromosomes during metaphase important for mitosis?
A: It ensures that chromosomes are ready to be evenly divided in the next stage .
Q: What is the main purpose of metaphase in mitosis?
A: To organize chromosomes in a neat line to prepare for their separation
Q: What happens to sister chromatids during anaphase?
A: They separate and move to opposite ends of the cell
Q: What role do spindle fibers play during anaphase?
A: They help pull the sister chromatids apart
Q: What begins to occur during anaphase besides chromatid separation?
A: Cytokinesis, the process of dividing the cell’s cytoplasm, begins
Q: Why is the separation of sister chromatids important in anaphase?
A: It ensures each end of the cell will have an identical set of chromosomes
Q: What does anaphase set the stage for in the cell cycle?
A: For the cell to eventually split into two new cells, each with its own complete set of chromosomes .
Q: What happens to the mitotic spindle during telophase?
A: It dissolves and disappears
Q: How do chromosomes change during telophase?
A: They start to uncoil and return to their loose, thread-like form called chromatin
Q: What forms around each set of chromatin during telophase?
A: A new nuclear membrane forms, creating two separate nuclei
Q: What is the main role of telophase in the process of cell division?
A: To re-establish normal nuclear structures, preparing the cell for the final step of splitting into two separate cells .
Q: What is cytokinesis?
A: The process where a cell’s cytoplasm and organelles are divided into two identical cells
Q: When does cytokinesis begin and end?
A: It begins in late anaphase with the formation of a cleavage furrow and is completed after telophase
Q: What is a cleavage furrow and what role does it play in cytokinesis?
A: It is an indentation in the plasma membrane that forms midway between centrosomes, eventually pinching the cell into two
Q: What is the contractile ring, and what does it do during cytokinesis?
A: Made of actin microfilaments, it pulls the membrane inward like a belt to divide the cell
Q: How is the orientation of the cleavage furrow significant?
A: It is perpendicular to the mitotic spindle, ensuring the two sets of chromosomes are separated into different cells
Q: What happens to the cell cycle once cytokinesis is finished?
A: The cell cycle restarts with interphase
Q: What are the three possible fates of a cell?
A:
Remain alive and function
grow and divide
die through processes such as apoptosis.
hint: RGD
Q: Why is homeostasis important in cell growth and death?
A: Maintaining a balance is crucial for healthy functioning, with signals regulating whether a cell should stop dividing, continue cycling, or undergo cell death
Q: What key process occurs during Meiosis I?
A: Homologous pairs of chromosomes split
Q: What key process occurs during Meiosis II?
A: Sister chromatids separate
Q: How are cell sizes measured, and what is the typical unit?
A: Cell sizes are measured in micrometers (µm), where 1 µm is one-millionth of a meter.
Q: What is the largest cell in the human body, and what is its size?
A: The largest cell is the ovum, measuring about 140 µm.
Q: What is the approximate diameter of a red blood cell?
A: A red blood cell is about 8 µm in diameter.
Q: How is a red blood cell’s shape related to its function?
A: Its disc shape maximizes surface area, enhancing oxygen transport.
Q: What shape are nerve cells, and why are they shaped that way?
A: Nerve cells have long extensions to conduct impulses over large distances.
Q: Why are intestinal cells equipped with microvilli?
A: Microvilli increase surface area, speeding up food absorption.
Q: How many different cell types are there typically in an adult human?
A: About 200 different cell types exist in an adult human body.
Q: What enables cells to form complex tissues and organs?
A: Cellular diversity allows cells to fulfill distinct roles.
Q: Why do smooth muscle cells have a spindle shape?
A: Their shape aids in contraction, thereby controlling blood flow by changing the shape of blood vessels.
Q: What is the significance of cell shape in relation to function?
A: Cells are shaped to contribute specifically to their function.
Q: Which types of cells typically do not continue to divide?
A: Muscle and nerve cells typically do not continue to divide.
Q: Why is it significant that certain cells like muscle and nerve cells do not divide continuously?
A: This means that damage to these cells can be more difficult to repair, which is why injuries to muscle and nerve tissues can be particularly severe.
Q: What is an example of cells that do continuously divide in the body?
A: Skin cells and epithelial cells are examples of cells that continuously divide to replace old or damaged cells.
Q: What are telomeres?
A: Telomeres consist of repetitive DNA sequences that cap the ends of chromosomes; regulate how many times a cell can divide
Q: Where are telomeres located?
A: At the ends of all human chromosomes, protecting genetic data during cell division.
Q: What is the primary function of telomeres?
A: They act as protective buffers to prevent chromosomes from deteriorating or fusing with each other.
How do telomeres contribute to the replication process?
They ensure the entire length of the chromosome is copied during DNA replication, preserving genetic information for cellular function.
What happens to telomeres during aging?
A: They progressively shorten with each cell division, eventually leading to cell senescence or apoptosis.
Q: Why is telomere shortening significant in aging?
A: Shortening contributes to the decline in cellular function and regeneration, a natural part of aging.
Q: How do stress and lifestyle factors affect telomeres?
A: They can accelerate telomere shortening, linking stress and environmental factors to biological aging.
Q: What state do cells enter when telomeres become too short?
A: Cells enter a state called senescence or undergo apoptosis, stopping further division.
Q: What is cancer?
A: An abnormal and uncontrolled multiplication of cells that can lead to death.
Q: How can cancer cells spread to other parts of the body?
A: Via the bloodstream or lymphatic system.
Q: What is a tumor?
A: A mass of tissue that serves no physiological purpose.
Q: What differentiates a benign tumor from a malignant tumor?
A: A benign tumor is enclosed in a membrane that prevents penetration of other tissues, while a malignant tumor can invade surrounding tissues.
Q: How does every case of cancer begin?
A: As a change in a cell that allows it to grow and divide when it should not.
Q: What initiates the beginning of a tumor development?
A: It begins when a genetic mutation allows a cell to divide when it normally would not.
Q: What are genetically altered cells associated with in the development of a tumor?
A: The initial stage where a mutation allows abnormal cell division.
Q: What is hyperplasia in the context of tumor development?
A: The stage where the altered cells and their descendants continue to look normal but reproduce excessively.
Q: What is the significance of dysplasia in tumor development?
A: Descendants of altered cells look abnormal in shape and structure, indicating further progression towards cancer.
Q: What happens during the in situ cancer stage?
A: The affected cells remain within their original tissue and form a mass, which can eventually turn into invasive cancer if not controlled.
Q: What characterizes invasive cancer as depicted?
A: It occurs when genetic changes allow the tumor to invade other tissues, spreading through the blood or lymph system.
Q: What is metastasis in the context of cancer?
A: The process by which cancer cells spread from the original site to other parts of the body.
Q: How do cancer cells travel during metastasis?
A: Through the bloodstream and lymphatic system.
Q: What happens when cancer cells reach a new site in the body?
A: They can invade and form new tumors at that location.
Q: Why is metastasis considered a critical aspect of cancer progression?
A: It allows cancer to spread beyond its original site, making it more challenging to treat.
Q: How are malignant tumors classified?
A: According to the types of cells that give rise to them.
Q: Where do carcinomas originate, and what are some common sites?
A: Carcinomas start in the epithelium, covering body surfaces or lining internal organs; common sites include skin (melanoma), breast, uterus, prostate, lungs, and gastrointestinal tract.
Q: What tissues do sarcomas form in?
A: Supporting or connective tissues of the body, such as bones, muscles, and blood vessels.
Q: What is leukemia, and where does it begin?
A: Leukemia is a type of cancer that begins in blood-forming tissues, such as the bone marrow, lymph nodes, and spleen.
Q: Where do lymphomas arise, and what system is involved?
A: Lymphomas arise in the cells of the lymphatic system (lymph nodes), which is part of the body’s infection-fighting system.
