Chapter 8 (cycle of the Cell) Flashcards
Q: How do unicellular organisms reproduce?
Q: What process do multicellular organisms depend on for growth and repair?
A: Cell division.
Q: What are the two main processes of eukaryotic cell division?
A: Mitosis (division of the nucleus) and cytokinesis (division of the cytoplasm).
Q: What are chromosomes made of?
A: Chromatin, a complex of DNA and protein.
Q: What is binary fission?
A: It’s a type of cell division in bacteria, different from mitosis in eukaryotes.
Q: How do organisms reproduce asexually?
A: By producing genetically identical offspring through cell division.
Q: Why does sexual reproduction create more genetic variation than asexual reproduction?
A: Offspring inherit a unique combination of genes from two parents.
Q: How many chromosomes do human somatic cells have?
A: 46 chromosomes (two sets of 23).
Q: What type of cells are created by meiosis?
A: Haploid gametes (eggs and sperm) with 23 chromosomes each.
Q: What are the stages of the mitotic phase of the cell cycle?
A: Mitosis and cytokinesis.
Q: What are the phases of mitosis?
A: Prophase, prometaphase, metaphase, anaphase, and telophase.
Q: What happens during interphase?
A: The cell grows, and DNA is replicated during the S phase.
Q: What is the mitotic spindle?
A: A structure of microtubules that controls chromosome movement during mitosis.
What structure helps separate sister chromatids in anaphase?
A : The kinetochores move along shortening microtubules.
Q: What are the key roles of cell division?
A: Reproduction, growth, and repair.
Q: How does cytokinesis differ in animal and plant cells?
A: Animal cells form cleavage furrows, while plant cells form cell plates.
Q: What happens during fertilization?
A: An egg and sperm combine to form a diploid zygote with 46 chromosomes.
Q: What alternates in all sexual life cycles?
A: Diploid and haploid stages.
Q: What is found in the cytoplasm of a cell in late interphase?
A: Two centrosomes, each possibly containing a pair of centrioles.
Q: What is found in the nucleus during late interphase?
A: Chromosomes are replicated and dispersed as chromatin, with one or more nucleoli present.
Q: What happens to nucleoli and chromatin during prophase?
A: Nucleoli disappear, and chromatin coils to form chromosomes with two sister chromatids.
Q: What happens at the metaphase stage?
A: Chromosomes align at the metaphase plate, and the mitotic spindle is fully formed.
Q: What occurs during anaphase?
A: Sister chromatids separate into daughter chromosomes and move toward opposite poles.
Q: What changes occur in the cell during telophase?
A: Nuclear envelopes form, chromosomes uncoil, and nucleoli reappear in each new nucleus.
Q: How does cytokinesis differ in animal and plant cells?
A: Animal cells form a cleavage furrow, while plant cells form a cell plate.
Q: How does binary fission differ from mitosis?
A: Binary fission occurs in bacteria and involves an unknown mechanism for chromosome separation.
Q: What drives the cell cycle?
A: A molecular control system involving cyclin-dependent kinases (Cdks) and cyclins.
Q: What are cyclins?
A: Proteins whose levels rise and fall with the cell cycle stages, including G1, S-phase, and mitotic cyclins.
Q: What are cyclin-dependent kinases (Cdks)?
A: Proteins that must bind with cyclins to be active and add phosphate groups to control the cell cycle.
Q: What are examples of specific Cdks?
A: G1 Cdk (Cdk4), S-phase Cdk (Cdk2), and M-phase Cdk (Cdk1).
Q: What does the anaphase-promoting complex (APC) do?
A: It triggers sister chromatid separation and degrades mitotic cyclins
Q: What does G1-cyclin do in the cell cycle?
A: G1-cyclin binds to Cdks to prepare chromosomes for replication.