All flashcards
Flashcard 1: What must occur at kinetochores before anaphase begins?
Answer: Each sister chromatid must be attached to opposite spindle poles. Ensures equal chromosome distribution through bipolar attachment.
Flashcard 2: What happens to the nuclear envelope during prometaphase?
Answer: It breaks down. Nuclear barrier dissolves to allow spindle access to chromosomes.
Flashcard 3: What is mitosis?
Answer: Nuclear division that produces two genetically identical nuclei. Ensures genetic material is equally distributed to daughter cells.
Flashcard 4: What is the correct order of mitosis stages (excluding interphase and cytokinesis)?
Answer: Prophase, metaphase, anaphase, telophase. Standard sequence of nuclear division stages.
Flashcard 5: What is the main event of prophase in mitosis?
Answer: Chromatin condenses into visible chromosomes. DNA-protein complex becomes compact and visible under microscope.
Flashcard 6: What happens to the nucleolus during prophase?
Answer: It disappears. Ribosome assembly site dissolves as nuclear organization changes.
Flashcard 7: What happens to the nuclear envelope during prometaphase?
Answer: It breaks down. Nuclear barrier dissolves to allow spindle access to chromosomes.
Flashcard 8: What is prometaphase?
Answer: Stage when nuclear envelope breaks and spindle attaches to kinetochores. Transition phase between prophase and metaphase.
Flashcard 9: What structure forms the mitotic spindle?
Answer: Microtubules. Protein filaments that move chromosomes during division.
Flashcard 10: What is a centrosome in animal cells during mitosis?
Answer: Microtubule-organizing center that forms spindle poles. Contains centrioles that organize spindle formation.
Flashcard 11: Where do centrosomes move during prophase?
Answer: To opposite poles of the cell. Establishes bipolar spindle apparatus for chromosome separation.
Flashcard 12: What is a kinetochore?
Answer: Protein complex on a centromere where spindle microtubules attach. Connection point between chromosome and spindle apparatus.
Flashcard 13: What is the centromere?
Answer: Chromosome region that holds sister chromatids together. Attachment site for spindle fibers during chromosome movement.
Flashcard 14: What are sister chromatids?
Answer: Two identical copies of a replicated chromosome joined at a centromere. Result of DNA replication in S phase of cell cycle.
Flashcard 15: What is the defining event of metaphase?
Answer: Chromosomes align at the metaphase plate. Chromosomes position for equal distribution to daughter cells.
Flashcard 16: What is the metaphase plate?
Answer: Imaginary plane at the cell equator where chromosomes line up. Equatorial alignment ensures balanced chromosome distribution.
Flashcard 17: Which mitosis stage has chromosomes most condensed and easiest to count?
Answer: Metaphase. Maximum condensation makes chromosomes clearly visible and countable.
Flashcard 18: What must occur at kinetochores before anaphase begins?
Answer: Each sister chromatid must be attached to opposite spindle poles. Ensures equal chromosome distribution through bipolar attachment.
Flashcard 19: What is the defining event of anaphase?
Answer: Sister chromatids separate and move to opposite poles. Chromosome copies move to create two identical nuclei.
Flashcard 20: During anaphase, what does each separated sister chromatid become called?
Answer: A daughter chromosome. Individual chromatid becomes independent chromosome after separation.
Flashcard 21: What happens to kinetochore microtubules during anaphase?
Answer: They shorten to pull chromosomes toward the poles. Depolymerization creates pulling force on attached chromosomes.
Flashcard 22: What happens to non-kinetochore microtubules during anaphase?
Answer: They lengthen and push spindle poles apart. Elongation separates spindle poles and stretches the cell.
Flashcard 23: What is the defining event of telophase?
Answer: Nuclear envelopes reform around each set of chromosomes. Chromosomes are enclosed in separate nuclear compartments.
Flashcard 24: What happens to chromosomes during telophase?
Answer: They decondense back into chromatin. Chromosomes return to extended form for gene expression.
Flashcard 25: What happens to the nucleolus during telophase?
Answer: It reappears. Ribosome assembly site reforms in new nuclei.
Flashcard 26: What is cytokinesis?
Answer: Division of the cytoplasm to form two separate daughter cells. Physical separation creates two independent cells.
Flashcard 27: In animal cells, what structure forms to begin cytokinesis?
Answer: A cleavage furrow. Pinching inward divides animal cell cytoplasm.
Flashcard 28: What forms the contractile ring that creates the cleavage furrow in animal cells?
Answer: Actin and myosin filaments. Contractile proteins create constricting force for cell division.
Flashcard 29: In plant cells, what structure forms during cytokinesis?
Answer: A cell plate. Plant cells build wall rather than pinch to divide.
Flashcard 30: What does the plant cell plate develop into after cytokinesis?
Answer: A new cell wall between the daughter cells. Creates permanent barrier between daughter plant cells.