Cell Cycle & Mitosis Quiz

Cell Cycle & Mitosis

• Prokaryotic cell division is simpler than eukaryotic cell division, and involves binary fission.
• Eukaryotic cell division is more complex, involving multiple phases and the process of mitosis.
• Cell cycle phases: G1, S, G2, and M/C, with G0 as a resting phase.
• G1 phase: Cell growth and preparation for DNA replication.
• S phase: DNA replication occurs, resulting in duplicated chromosomes.
• G2 phase: Further cell growth and preparation for mitosis.
• M/C phase: Mitosis (nuclear division) and Cytokinesis (cytoplasmic division) occur.
• Cyclins and cyclin-dependent kinases (CDKs): Protein complexes that regulate the cell cycle, controlling transitions between phases.
• Cell cycle checkpoints: G1/S and G2/M checkpoints ensure accurate DNA replication and proper chromosome alignment.
• G1/S checkpoint: Monitors for DNA damage and adequate resources for replication.
• G2/M checkpoint: Monitors for completion of DNA replication and proper chromosome structure.
• Tumour suppressor network: Proteins like p21 and p53 prevent uncontrolled cell growth and division, contributing to cell cycle control.
• Mitosis phases: Prophase, Prometaphase, Metaphase, Anaphase, and Telophase.
• Prophase: Chromosomes condense, nuclear envelope breaks down, and spindle formation begins.
• Prometaphase: Microtubules attach to kinetochores on chromosomes.
• Metaphase: Chromosomes align at the metaphase plate.
• Anaphase: Sister chromatids separate and move towards opposite poles.
• Telophase: Nuclear envelopes re-form around daughter chromosomes, and chromosomes decondense.
• Cytokinesis follows mitosis: The cytoplasm divides, resulting in two daughter cells.
• Cell cycle errors: Can lead to uncontrolled cell growth and development of diseases like cancer.
• Research techniques: Microscopy, fluorescent probes, flow cytometry are used to study mitosis and the cell cycle.

DNA Structure and Replication

• Genetic material: Deoxyribonucleic acid (DNA), a double-stranded helix.
• DNA structure: Made up of nucleotides, each consisting of a sugar, phosphate, and nitrogenous base (adenine, guanine, cytosine, thymine).
• DNA replication: The process of copying DNA before cell division.
• DNA replication initiation: Begins at specific origins of replication, where DNA unwinds and separates.
• DNA replication process: Involves enzymes like DNA polymerase, helicase, and topoisomerase.
• Chromosome structure: DNA packaged into compact structures by wrapping around histone proteins.
• Prokaryotic genome: Typically circular and located in a nucleoid region.
• Eukaryotic genome: Linear and organized within a nucleus.
• Eukaryotic genome organisation: Chromosomes are organized into genes, which contain coding regions (exons) and non-coding regions (introns).

Transcription

• Transcription: The process of copying DNA into RNA.
• Prokaryotic transcription: Occurs in the cytoplasm, with a single RNA polymerase.
• Eukaryotic transcription: Occurs in the nucleus, with multiple RNA polymerases (I, II, and III).
• Transcription steps: Initiation, elongation, and termination.
• Eukaryotic transcriptional modifications: 5' capping, 3' polyadenylation, and splicing.
• Central dogma of molecular biology: DNA → RNA → Protein.
• Exceptions: Reverse transcription (RNA → DNA).
• Gene expression regulation: Mechanisms controlling the production of specific proteins from genes.
• Alternate splicing: Process that generates multiple protein isoforms from a single gene.

Protein Synthesis

• Protein synthesis: The process of translating genetic information from mRNA into proteins.
• Translation steps: Initiation, elongation, and termination.
• Requirements for translation: mRNA, ribosomes, tRNAs, and amino acids.
• tRNA function: Carries specific amino acids to the ribosome, guided by its anticodon.
• Ribosome function: Site of protein synthesis, facilitating mRNA binding and tRNA interactions.
• Protein folding: Amino acid sequence determines the three-dimensional structure of a protein.
• Post-translational modifications: Modifications that occur after protein synthesis, influencing protein function.
• Phosphorylation: Addition of a phosphate group, can activate or deactivate a protein.
• Ubiquitination: Addition of a ubiquitin tag, can target a protein for degradation.

Meiosis

• Meiosis: A specialized cell division that produces gametes (sperm and egg cells) with half the number of chromosomes.
• Meiosis phases: Meiosis I and Meiosis II, each with prophase, metaphase, anaphase, and telophase.
• Meiosis I: Homologous chromosomes pair up, exchange genetic material (crossing over), and separate.
• Meiosis II: Sister chromatids separate, resulting in four haploid daughter cells.
• Significance of meiosis: Genetic diversity, maintaining the chromosome number in sexually reproducing organisms.

Test your knowledge on the cell cycle and mitosis with this quiz. Explore the phases of the cell cycle, the differences between prokaryotic and eukaryotic cell division, and the regulatory mechanisms involved. Perfect for biology students looking to reinforce their understanding of cellular processes.