2023-12-21T03:46:21+03:00[Europe/Moscow] en true <p>The cell cycle involves what? (2)</p>, <p>For Unicellular organisms, such as bacteria or yeast: each cell cycle gives rise to how many organisms? and what about multicellular organisms?</p>, <p>Picture outlining the phases of the cell cycle:</p>, <p>Many cells in our body are in what phase? Elaborate</p>, <p>What is the G1,S,G2 and M phases? (short answers)</p>, <p>Mitosis consists of what steps?</p>, <p>What is Prophase?</p>, <p>What is Prometaphase?</p>, <p>What is Metaphase?</p>, <p>What is Anaphase?</p>, <p>What is Telophase?</p>, <p>What is Cytokinesis?</p>, <p>State some information about the mitotic spindle-The microtubule machine</p>, <p>What is the centrosome?</p>, <p>State some information about the Centrosome cycle:</p>, <p>Cell organelles cannot spontaneously regenerate, so must be present in.....?</p>, <p>State some information about Meiosis:</p>, <p>What are the differences of Mitosis and Meiosis?</p>, <p>When meiosis goes wrong, nondisjunction occurs; What is nondisjunction?</p>, <p>What is an autosome? When nondisjunction occurs, is it fatal? (name at least one exception)</p>, <p>List some examples of Sex chromosomes that can have non-disjunction events</p>, <p>How is the cell cycle generally regulated?</p>, <p>What are the 2 cell cycle regulators? Elaborate on them slightly:</p>, <p>Picture outlining cell cycle control in yeast:</p>, <p>Picture outlining cell cycle control in humans:</p>, <p>What are the 5 basic principles of cell cycle control?</p>, <p>What is Neoplasia? Elaborate on this:</p> flashcards

The Cell Cycle (The Living Cell)

Learning Outcomes At the end of this session students should be able to: Describe the phases of the cell cycle Describe the key events occurring during M phase Understand mitotic versus meiotic cell division Understand how the cell cycle is controlled in yeast compared to higher eukaryotes

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  • The cell cycle involves what? (2)

    • Duplication of cell contents: DNA,organelles, cytoplasm• Division into two new daughter cells

  • For Unicellular organisms, such as bacteria or yeast: each cell cycle gives rise to how many organisms? and what about multicellular organisms?

    Unicellular organisms:

    2

    Multicellular organisms, such as humans:-single-celled zygote must undergo many rounds of the cell cycle tomake a new fully grown organism-must also constantly replace any cells that die during the lifetime of the organism

  • Picture outlining the phases of the cell cycle:

    G0-Resting phase. No cell division is taking place

    G0-Resting phase. No cell division is taking place

  • Many cells in our body are in what phase? Elaborate

    G0As a result, not all can re-enter the cell cycle• For some cells.....Cell cycle re-entry not possible, e.g. nerve cells• Some cells are..... Maintained in Go unless stimulated to divide, e.g. hepatocytes• Some cells are.... Constantly in the cell cycle, e.g. epithelial cells of the gut

    G0

    As a result, not all can re-enter the cell cycle

    • For some cells.....Cell cycle re-entry not possible, e.g. nerve cells

    • Some cells are..... Maintained in Go unless stimulated to divide, e.g. hepatocytes

    • Some cells are.... Constantly in the cell cycle, e.g. epithelial cells of the gut

  • What is the G1,S,G2 and M phases? (short answers)

    • G1= Gap 1 phase: growth and preparation for S phase• S = Synthesis phase: chromosome duplication• G2= Gap 2 phase: growth and preparation for M phase• M = Mitotic phase: mitosis and cytokinesis

    • G1= Gap 1 phase: growth and preparation for S phase• S = Synthesis phase: chromosome duplication• G2= Gap 2 phase: growth and preparation for M phase• M = Mitotic phase: mitosis and cytokinesis

  • Mitosis consists of what steps?

    • Prophase• Prometaphase• Metaphase• Anaphase• Telophase• Cytokinesis

    • Prophase• Prometaphase• Metaphase• Anaphase• Telophase• Cytokinesis

  • What is Prophase?

    Prophase: chromosomes condense, centrosomes move to opposite poles, mitotic spindle forms

    Prophase: chromosomes condense, centrosomes move to opposite poles, mitotic spindle forms

  • What is Prometaphase?

    Prometaphase: breakdown of nuclear envelope, chromosomes attach to mitotic spindle

    Prometaphase: breakdown of nuclear envelope, chromosomes attach to mitotic spindle

  • What is Metaphase?

    Metaphase: centrosome are at opposite poles, chromosome are at their most condensed and line up at the equator of the mitotic spindle

    Metaphase: centrosome are at opposite poles, chromosome are at their most condensed and line up at the equator of the mitotic spindle

  • What is Anaphase?

    Anaphase: sister chromatids separate synchronously, each new daughter chromosome moving to the opposite spindle pole

    Anaphase: sister chromatids separate synchronously, each new daughter chromosome moving to the opposite spindle pole

  • What is Telophase?

    Telophase: chromosome arrives at the spindle poles, chromosomes decondense, nuclear envelope reforms

    Telophase: chromosome arrives at the spindle poles, chromosomes decondense, nuclear envelope reforms

  • What is Cytokinesis?

    Cytokinesis: cytoplasm divides at the position of the metaphase plate. Contractile ring of actin and myosin II constrict the cell into two new cells via cleavage furrow

    Cytokinesis: cytoplasm divides at the position of the metaphase plate. Contractile ring of actin and myosin II constrict the cell into two new cells via cleavage furrow

  • State some information about the mitotic spindle-The microtubule machine

    • Starts to assemble during prophase from the centrosomes• Function: separate the duplicated chromosomes• Constructed from microtubules• 3 types of spindle microtubules+ astral microtubules+ kinetochore microtubules+ interpolar microtubules• Chromosomes attach to the spindlevia the kinetochore –(a proteincomplex assembled on thecentromere)

    • Starts to assemble during prophase from the centrosomes• Function: separate the duplicated chromosomes• Constructed from microtubules

    • 3 types of spindle microtubules+ astral microtubules+ kinetochore microtubules+ interpolar microtubules

    • Chromosomes attach to the spindlevia the kinetochore –(a proteincomplex assembled on thecentromere)

  • What is the centrosome?

    -An organelle near the nucleus of a cell which contains the centrioles (in animal cells) and from which the spindle fibres develop in cell division.

    -An organelle near the nucleus of a cell which contains the centrioles (in animal cells) and from which the spindle fibres develop in cell division.

  • State some information about the Centrosome cycle:

    • microtubule-organizing centre in animal cells• centrosome consists of a pair of centrioles surrounded by pericentriolar material• duplicated during interphase• migrate to opposite poles in preparation for M phase

    • microtubule-organizing centre in animal cells• centrosome consists of a pair of centrioles surrounded by pericentriolar material• duplicated during interphase• migrate to opposite poles in preparation for M phase

  • Cell organelles cannot spontaneously regenerate, so must be present in.....?

    The new daughter cells

  • State some information about Meiosis:

    • Meiosis is a specialised cell division that starts with one diploid cells and ends with 4 haploid cells• Purpose is to produce gametes: sperm and egg• One round of DNA replication during S phase and two rounds ofcell division- in meiosis I homologous chromosomes line up on the spindle and separate to opposite spindle poles- in meiosis II, sister chromatids line up on the spindle andseparate to opposite spindle pole• Recombination occurs between homologous chromosomes

    • Meiosis is a specialised cell division that starts with one diploid cells and ends with 4 haploid cells• Purpose is to produce gametes: sperm and egg

    • One round of DNA replication during S phase and two rounds ofcell division- in meiosis I homologous chromosomes line up on the spindle and separate to opposite spindle poles- in meiosis II, sister chromatids line up on the spindle andseparate to opposite spindle pole

    • Recombination occurs between homologous chromosomes

  • What are the differences of Mitosis and Meiosis?

    Mitosis:• two cells• one round of cell division• diploid• no recombination

    Meiosis:• four cells• Two rounds of cell division• haploid• recombination

  • When meiosis goes wrong, nondisjunction occurs; What is nondisjunction?

    • nondisjunction- failure of homologues to separate from one another, either at meiotic division I or meiotic division II

  • What is an autosome? When nondisjunction occurs, is it fatal? (name at least one exception)

    An autosome is one of the numbered chromosomes, as opposed to the sex chromosomes.• autosomes-usually fatal, exceptions are:• trisomy 21 Down’s Syndrome• trisomy 18 Edward’s syndrome• trisomy 13 Patau Syndrome-no viable autosomal monosomies

    An autosome is one of the numbered chromosomes, as opposed to the sex chromosomes.

    • autosomes-usually fatal, exceptions are:

    • trisomy 21 Down’s Syndrome

    • trisomy 18 Edward’s syndrome

    • trisomy 13 Patau Syndrome

    -no viable autosomal monosomies

  • List some examples of Sex chromosomes that can have non-disjunction events

    • sex chromosomes:• XO Turner's syndrome• XXX Triple X• XXY Klinefelter's syndrome

    • sex chromosomes:• XO Turner's syndrome• XXX Triple X• XXY Klinefelter's syndrome

  • How is the cell cycle generally regulated?

    • Entry into the cell cycle must be strictly controlled• Each phase must occur only once per cell cycle• Phases must be in the correct order• G1-S-G2-M• Phases must be non-overlapping

    • Entry into the cell cycle must be strictly controlled• Each phase must occur only once per cell cycle

    • Phases must be in the correct order• G1-S-G2-M• Phases must be non-overlapping

  • What are the 2 cell cycle regulators? Elaborate on them slightly:

    -Cyclin dependent kinases (Cdks)o active when bound to a cyclino phosphorylates target proteins-Cyclinso different cyclins produced ateach phase of the cell cycle

    -Cyclin dependent kinases (Cdks)

    o active when bound to a cyclino phosphorylates target proteins

    -Cyclins

    o different cyclins produced ateach phase of the cell cycle

  • Picture outlining cell cycle control in yeast:

  • Picture outlining cell cycle control in humans:

  • What are the 5 basic principles of cell cycle control?

    • Cdk levels, fairly stable throughout the cell cycle

    • Cyclin levels vary as part of the cell cycle

    • Cdk bound to cyclin is active and can phosphorylate target protein

    • Cdk activation triggers the next step in the cell cycle such as entry into S phase, M phase

    • Cyclin degradation terminates Cdk activity

  • What is Neoplasia? Elaborate on this:

    Neoplasia-is the uncontrolled, abnormal growth of cells or tissues in the body• Cells escape normal cell cycle regulation - no barriers to prevent uncontrolled progression through the cell cycle• Many genes mutated in human cancers are regulators of the cellcycle such as p53 and pRB, known as tumour suppressor genes

    Neoplasia-is the uncontrolled, abnormal growth of cells or tissues in the body

    • Cells escape normal cell cycle regulation - no barriers to prevent uncontrolled progression through the cell cycle

    • Many genes mutated in human cancers are regulators of the cellcycle such as p53 and pRB, known as tumour suppressor genes