Chapter 3 - (Pt.3) Flashcards

cell division and cancer

1
Q

Q: What is cell division?

A

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.

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2
Q

Q: What are somatic cells?

A

A: Somatic cells are all body cells except those involved in reproduction. They undergo somatic cell division.

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3
Q

Q: What occurs during somatic cell division?

A

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

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4
Q

Q: What are germ cells?

A

A: Germ cells include gametes (sperm and oocytes) and precursor cells that develop into gametes.

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5
Q

Q: What happens during reproductive cell division?

A

A: Meiosis produces gametes by halving the chromosome number, preparing for sexual reproduction to ensure the next generation has the correct chromosome count.

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6
Q

Q: What is a somatic cell in the human body?

A

A: It is any cell of the human body besides a germ cell involved in reproduction.

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7
Q

Q: What process do somatic cells undergo for division?

A

A: Somatic cell division consists of mitosis and cytokinesis.

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8
Q

Q: What are reproductive cells responsible for producing?

A

A: They produce gametes, which are sperm and oocytes.

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9
Q

Q: What is the process of reproductive cell division called?

A

A: Reproductive cell division is called meiosis.

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10
Q

Q: What is the cell cycle?

A

A: It is the growth and division of a single cell into two identical cells, consisting of interphase and the mitotic phase.

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11
Q

Q: How many pairs of chromosomes do human somatic cells have?

A

A: Human somatic cells have 23 pairs of chromosomes, totaling 46.

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12
Q

Q: What are homologous chromosomes?

A

A: They are two chromosomes that belong to a pair, containing similar genes in similar arrangements (also called homologs).

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13
Q

Q: What is distinct about sex chromosomes in humans?

A

A: Females have two X chromosomes, while males have one X and one smaller Y chromosome.

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14
Q

Q: What does it mean for a cell to be diploid?

A

A: A diploid cell (2n) has two sets of chromosomes.

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15
Q

Q: What occurs during interphase?

A

A: The cell is not dividing but prepares for division by replicating DNA, producing additional organelles, and synthesizing cytosolic components.

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16
Q

Q: What happens in the G1 phase of interphase?

A

A: The cell grows and performs normal functions without DNA replication.

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17
Q

Q: What occurs during the S phase of interphase?

A

A: DNA is synthesized and replicated.

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18
Q

Q: Describe the G2 phase of interphase.

A

A: The cell continues to grow and prepares for division after DNA replication.

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19
Q

Q: What happens in the mitotic phase of the cell cycle?

A

A: The cell divides to form two new identical cells.

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20
Q

Q: What happens during the G1 phase of interphase?

A

A: The cell is metabolically active, duplicates organelles and cytosolic components, and centrosome replication begins.

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21
Q

Q: What occurs during the S phase of interphase?

A

A: DNA is replicated.

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22
Q

Q: What happens in the G2 phase of interphase?

A

A: Cell growth continues, and enzymes and other proteins are synthesized; centrosome replication is completed.

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23
Q

Q: What is the G0 phase?

A

A: It is the phase where the cell exits the cell cycle and is non-dividing.

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24
Q

Q: How long does the S phase typically last?

A

A: About 8 hours.

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25
Q

Q: During which phase are cells not actively dividing?

A

A: G0 phase.

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26
Q

Q: What follows interphase in the cell cycle?

A

A: The mitotic (M) phase.

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27
Q

Q: What are the stages of the mitotic phase?

A

A: Prophase, Metaphase, Anaphase, and Telophase.

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28
Q

Q: In which phase of the cell cycle does centrosome replication begin?

A

A: Centrosome replication begins during the G1 phase.

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29
Q

Q: What happens to DNA strands during replication?

A

A: The two strands of the double helix separate by breaking the hydrogen bonds between nucleotides.

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30
Q

Q: What phase follows the S phase in the cell cycle?

A

A: The G2 phase follows the S phase.

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31
Q

Q: How long does the G1 phase typically last?

A

A: The G1 phase generally lasts 8 to 10 hours but can be shorter in embryonic or cancer cells.

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32
Q

Q: What occurs during the G2 phase of interphase?

A

A: The cell continues to grow, synthesize proteins, and complete centrosome replication in preparation for division.

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33
Q

Q: What is the G0 phase?

A

A: It is a phase where cells that do not divide may enter, such as most nerve cells.

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34
Q

Q: How long does mitosis typically take to complete?

A

A: Mitosis takes about 1-2 hours.

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35
Q

Q: What is the main result of mitosis?

A

A: The distribution of 2 sets of chromosomes into 2 separate nuclei.

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35
Q

Q: What are the four stages of mitosis?

A

A: Prophase, Metaphase, Anaphase, and Telophase.

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36
Q

Q: During the Mitotic (M) Phase, what two types of cell division occur?

A

A: Nuclear division (mitosis) and cytoplasmic division (cytokinesis).

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37
Q

Q: What critical process is ensured by mitosis?

A

A: Exact genetic partitioning into two daughter cells.

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38
Q

Q: What is the first stage of mitosis called?

A

Prophase

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39
Q

Q: What happens to chromatin during prophase?

A

A: It condenses into visible, compact structures called chromosomes

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40
Q

Q: What are the identical halves of a chromosome called, and where are they joined?

A

A: Chromatids, joined at the centromere

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41
Q

Q: What happens to the nuclear envelope during prophase?

A

A: It breaks down, and the nucleolus disappears

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42
Q

Q: What structure helps in separating the chromosomes during mitosis, and how is it formed?

A

A: The mitotic spindle, formed by centrosomes assembling microtubules

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43
Q

Q: What critical process does prophase prepare for by organizing genetic material?

A

A: The division of genetic material, by organizing it into discrete chromosomes

44
Q

Q: What stage of mitosis is characterized by chromosomes lining up in the middle of the cell?

A

A: Metaphase

45
Q

Q: What is the middle area of the cell where chromosomes line up during metaphase called?

A

A: The metaphase plate

46
Q

Q: What structures attach to the centromeres of each chromosome during metaphase?

A

A: Spindle fibers (made of microtubules)

47
Q

Q: Why is the arrangement of chromosomes during metaphase important for mitosis?

A

A: It ensures that chromosomes are ready to be evenly divided in the next stage .

48
Q

Q: What is the main purpose of metaphase in mitosis?

A

A: To organize chromosomes in a neat line to prepare for their separation

49
Q

Q: What happens to sister chromatids during anaphase?

A

A: They separate and move to opposite ends of the cell

50
Q

Q: What role do spindle fibers play during anaphase?

A

A: They help pull the sister chromatids apart

51
Q

Q: What begins to occur during anaphase besides chromatid separation?

A

A: Cytokinesis, the process of dividing the cell’s cytoplasm, begins

52
Q

Q: Why is the separation of sister chromatids important in anaphase?

A

A: It ensures each end of the cell will have an identical set of chromosomes

53
Q

Q: What does anaphase set the stage for in the cell cycle?

A

A: For the cell to eventually split into two new cells, each with its own complete set of chromosomes .

54
Q

Q: What happens to the mitotic spindle during telophase?

A

A: It dissolves and disappears

55
Q

Q: How do chromosomes change during telophase?

A

A: They start to uncoil and return to their loose, thread-like form called chromatin

56
Q

Q: What forms around each set of chromatin during telophase?

A

A: A new nuclear membrane forms, creating two separate nuclei

57
Q

Q: What is the main role of telophase in the process of cell division?

A

A: To re-establish normal nuclear structures, preparing the cell for the final step of splitting into two separate cells .

58
Q

Q: What is cytokinesis?

A

A: The process where a cell’s cytoplasm and organelles are divided into two identical cells

59
Q

Q: When does cytokinesis begin and end?

A

A: It begins in late anaphase with the formation of a cleavage furrow and is completed after telophase

60
Q

Q: What is a cleavage furrow and what role does it play in cytokinesis?

A

A: It is an indentation in the plasma membrane that forms midway between centrosomes, eventually pinching the cell into two

61
Q

Q: What is the contractile ring, and what does it do during cytokinesis?

A

A: Made of actin microfilaments, it pulls the membrane inward like a belt to divide the cell

62
Q

Q: How is the orientation of the cleavage furrow significant?

A

A: It is perpendicular to the mitotic spindle, ensuring the two sets of chromosomes are separated into different cells

63
Q

Q: What happens to the cell cycle once cytokinesis is finished?

A

A: The cell cycle restarts with interphase

64
Q

Q: What are the three possible fates of a cell?

A

A:
Remain alive and function
grow and divide
die through processes such as apoptosis.

hint: RGD

65
Q

Q: Why is homeostasis important in cell growth and death?

A

A: Maintaining a balance is crucial for healthy functioning, with signals regulating whether a cell should stop dividing, continue cycling, or undergo cell death

66
Q

Q: What key process occurs during Meiosis I?

A

A: Homologous pairs of chromosomes split

67
Q

Q: What key process occurs during Meiosis II?

A

A: Sister chromatids separate

68
Q

Q: How are cell sizes measured, and what is the typical unit?

A

A: Cell sizes are measured in micrometers (µm), where 1 µm is one-millionth of a meter.

69
Q

Q: What is the largest cell in the human body, and what is its size?

A

A: The largest cell is the ovum, measuring about 140 µm.

70
Q

Q: What is the approximate diameter of a red blood cell?

A

A: A red blood cell is about 8 µm in diameter.

71
Q

Q: How is a red blood cell’s shape related to its function?

A

A: Its disc shape maximizes surface area, enhancing oxygen transport.

72
Q

Q: What shape are nerve cells, and why are they shaped that way?

A

A: Nerve cells have long extensions to conduct impulses over large distances.

73
Q

Q: Why are intestinal cells equipped with microvilli?

A

A: Microvilli increase surface area, speeding up food absorption.

74
Q

Q: How many different cell types are there typically in an adult human?

A

A: About 200 different cell types exist in an adult human body.

75
Q

Q: What enables cells to form complex tissues and organs?

A

A: Cellular diversity allows cells to fulfill distinct roles.

76
Q

Q: Why do smooth muscle cells have a spindle shape?

A

A: Their shape aids in contraction, thereby controlling blood flow by changing the shape of blood vessels.

77
Q

Q: What is the significance of cell shape in relation to function?

A

A: Cells are shaped to contribute specifically to their function.

78
Q

Q: Which types of cells typically do not continue to divide?

A

A: Muscle and nerve cells typically do not continue to divide.

79
Q

Q: Why is it significant that certain cells like muscle and nerve cells do not divide continuously?

A

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.

80
Q

Q: What is an example of cells that do continuously divide in the body?

A

A: Skin cells and epithelial cells are examples of cells that continuously divide to replace old or damaged cells.

81
Q

Q: What are telomeres?

A

A: Telomeres consist of repetitive DNA sequences that cap the ends of chromosomes; regulate how many times a cell can divide

82
Q

Q: Where are telomeres located?

A

A: At the ends of all human chromosomes, protecting genetic data during cell division.

83
Q

Q: What is the primary function of telomeres?

A

A: They act as protective buffers to prevent chromosomes from deteriorating or fusing with each other.

84
Q

How do telomeres contribute to the replication process?

A

They ensure the entire length of the chromosome is copied during DNA replication, preserving genetic information for cellular function.

85
Q

What happens to telomeres during aging?

A

A: They progressively shorten with each cell division, eventually leading to cell senescence or apoptosis.

86
Q

Q: Why is telomere shortening significant in aging?

A

A: Shortening contributes to the decline in cellular function and regeneration, a natural part of aging.

87
Q

Q: How do stress and lifestyle factors affect telomeres?

A

A: They can accelerate telomere shortening, linking stress and environmental factors to biological aging.

88
Q

Q: What state do cells enter when telomeres become too short?

A

A: Cells enter a state called senescence or undergo apoptosis, stopping further division.

89
Q

Q: What is cancer?

A

A: An abnormal and uncontrolled multiplication of cells that can lead to death.

90
Q

Q: How can cancer cells spread to other parts of the body?

A

A: Via the bloodstream or lymphatic system.

91
Q

Q: What is a tumor?

A

A: A mass of tissue that serves no physiological purpose.

92
Q

Q: What differentiates a benign tumor from a malignant tumor?

A

A: A benign tumor is enclosed in a membrane that prevents penetration of other tissues, while a malignant tumor can invade surrounding tissues.

93
Q

Q: How does every case of cancer begin?

A

A: As a change in a cell that allows it to grow and divide when it should not.

94
Q

Q: What initiates the beginning of a tumor development?

A

A: It begins when a genetic mutation allows a cell to divide when it normally would not.

95
Q

Q: What are genetically altered cells associated with in the development of a tumor?

A

A: The initial stage where a mutation allows abnormal cell division.

96
Q

Q: What is hyperplasia in the context of tumor development?

A

A: The stage where the altered cells and their descendants continue to look normal but reproduce excessively.

97
Q

Q: What is the significance of dysplasia in tumor development?

A

A: Descendants of altered cells look abnormal in shape and structure, indicating further progression towards cancer.

98
Q

Q: What happens during the in situ cancer stage?

A

A: The affected cells remain within their original tissue and form a mass, which can eventually turn into invasive cancer if not controlled.

99
Q

Q: What characterizes invasive cancer as depicted?

A

A: It occurs when genetic changes allow the tumor to invade other tissues, spreading through the blood or lymph system.

100
Q

Q: What is metastasis in the context of cancer?

A

A: The process by which cancer cells spread from the original site to other parts of the body.

101
Q

Q: How do cancer cells travel during metastasis?

A

A: Through the bloodstream and lymphatic system.

102
Q

Q: What happens when cancer cells reach a new site in the body?

A

A: They can invade and form new tumors at that location.

103
Q

Q: Why is metastasis considered a critical aspect of cancer progression?

A

A: It allows cancer to spread beyond its original site, making it more challenging to treat.

104
Q

Q: How are malignant tumors classified?

A

A: According to the types of cells that give rise to them.

105
Q

Q: Where do carcinomas originate, and what are some common sites?

A

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.

106
Q

Q: What tissues do sarcomas form in?

A

A: Supporting or connective tissues of the body, such as bones, muscles, and blood vessels.

107
Q

Q: What is leukemia, and where does it begin?

A

A: Leukemia is a type of cancer that begins in blood-forming tissues, such as the bone marrow, lymph nodes, and spleen.

108
Q

Q: Where do lymphomas arise, and what system is involved?

A

A: Lymphomas arise in the cells of the lymphatic system (lymph nodes), which is part of the body’s infection-fighting system.