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Bio oct 30th chapter 8

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  • What is cell division?

    Cell division is the splitting of one parent cell into two genetically identical daughter cells, enabling cellular reproduction.

  • What is Asexual reproduction?

    Asexual reproduction is cell division resulting in reproduction of a whole organism that produces clones (genetically identical individuals), common in single-celled and SOME multicellular organisms.

  • What characterizes sexual reproduction?

    Sexual reproduction requires fusion of gametes (egg and sperm), involves a special cell division that ONLY OCCURS in reproductive organs, and produces genetically unique offspring. (not identical to parents/other offspring).

  • Role of cell division in multicellular organisms?

    Cell division allows a zygote to develop into an embryo and then a mature organism, and supports renewal and repair of tissues.

  • How do prokaryotes divide?

    Prokaryotes divide by binary fission, splitting in half their single circular DNA molecule (prokaryotic chromosome). *SHORTER THEN EUKARYOTIC CHROMOSOME.

  • Difference between mitosis and meiosis in eukaryotes?

    Mitosis supports growth/maintenance and asexual reproduction (multicellular organisms)

    Meiosis produces gametes (egg/sperm) in testes and ovaries for sexual reproduction.

  • What is a Eukaryotic chromosome?

    A chromosome is a single DNA strand with hundreds or thousands of genes, associated with proteins that maintain structure and regulate gene expression.

  • Describe chromatin.

    Chromatin is the structure of DNA and it's proteins in a diffuse form of long thin fibers during most of the cell cycle; it coils into distinct chromosomes when the cell prepares to divide.

    *EACH CHROMOSOMES CAN BE SEEN W/ A LIGHT MICROSCOPE.

  • What are sister chromatids?

    Sister chromatids are two identical copies of a chromosome attached by proteins at the centromere, separating during cell division.

  • What is the cell cycle?

    The cell cycle is the ordered sequence from cell formation to division into 2 daughter cells, includes: interphase (growth, high metabolic activity, 90% of cell cycle) and mitotic phase (cell division).

  • Phases of interphase?

    Interphase includes G1 1ST GAP (normal functions happen), S SYTHESIS PHASE (DNA replication), and G2 2ND GAP (normal functions and preparation for division).

  • What happens during mitotic phase?

    The mitotic phase includes mitosis (nucleus division) and cytokinesis (cytoplasm division/separation of 2 daughter cells), producing two identical daughter cells.

  • Describe prophase in mitosis.

    Chromatin coils into chromosomes; mitotic spindle forms from centrosomes; spindle fibers begin to organize.

  • What occurs during prometaphase?

    Nuclear envelope breaks down; spindle fibers attach to kinetochores on sister chromatids; chromosomes begin moving toward cell center.

  • Key event in metaphase?

    Chromosomes align at the metaphase plate with kinetochores attached to spindle fibers from opposite poles.

  • What happens in anaphase?

    Sister chromatids separate as centromeres split; motor proteins pull chromatids to opposite poles(ATP powered); spindle fibers shorten and cell elongates.

  • Describe telophase.

    Daughter nuclei form at poles; nuclear envelopes reassemble; chromosomes uncoil; mitosis is finished.

  • What is cytokinesis in animal cells?

    A cleavage furrow (groove in cell surface) forms as actin and myosin filaments contract, furrow pinches the parent cell into two daughter cells.

  • How does cytokinesis occur in plant cells?

    Vesicles form a cell plate at the center, which grows and fuses with the plasma membrane, creating two daughter cells with new cell walls.

  • What is anchorage dependence?

    Anchorage dependence means cells must be in contact w/ a solid surface to divide, common in most animal cells.

  • Explain density-dependent inhibition.

    Density-dependent inhibition is when crowded cells stop dividing, preventing overgrowth.

  • what is chemical and growth factors?

    Chemical factors: Cells need certain nutrients to grow.

    Growth factors: Certain proteins needed to proceed with division.

  • What causes cancer in terms of cell division?

    Cancer is the disease of the CELL CYCLE and results from cells not recognizing signals that regulate cell cycle.

  • Difference between benign and malignant tumors?

    Benign tumors abnormal cells stay in original location.

    malignant tumors abnormally produces cells that spread into other tissues in other parts of body.

  • What is metastasis?

    Metastasis is the spread of cancer cells beyond original place by entering bloodstream from blood vessels that grow TOWARDS the tumor.

  • How many eukaryotic chromosomes does humans, dogs, and hedgehogs have?

    Humans = 46

    Dogs = 78

    Hedgehogs = 90