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Questions and Answers
In what form is DNA loose non-condensed and condensed and organized?
In what form is DNA loose non-condensed and condensed and organized?
non-condensed=chromatin; condensed=chromosome
2 gametes combine to form a _____. What are the 2 gametes?
2 gametes combine to form a _____. What are the 2 gametes?
zygote; sperm and egg
What occurs during anaphase?
What occurs during anaphase?
sister chromatids separate
What happens when a cell undergoes mitosis but not cytokinesis?
What happens when a cell undergoes mitosis but not cytokinesis?
Following (but not including) which phase of the cell cycle do we have 2 sister chromatids?
Following (but not including) which phase of the cell cycle do we have 2 sister chromatids?
What is the protein involved in passing cell cycle checkpoints that cycles in concentration?
What is the protein involved in passing cell cycle checkpoints that cycles in concentration?
What occurs during the S phase?
What occurs during the S phase?
Mitosis produces what kinds of daughter cells?
Mitosis produces what kinds of daughter cells?
Which checkpoint in the cell cycle is considered the restriction point?
Which checkpoint in the cell cycle is considered the restriction point?
When do chromosomes first become visible in mitosis?
When do chromosomes first become visible in mitosis?
In both mitosis and meiosis, sister chromatids separate during anaphase, but there are ___ haploid daughter nuclei produced by meiosis compared to ____ diploid nuclei by mitosis.
In both mitosis and meiosis, sister chromatids separate during anaphase, but there are ___ haploid daughter nuclei produced by meiosis compared to ____ diploid nuclei by mitosis.
What is the period in the cell cycle between divisions?
What is the period in the cell cycle between divisions?
When does the nuclear envelope disappear in mitosis?
When does the nuclear envelope disappear in mitosis?
Meiosis reduces _____. Fertilization restores _____.
Meiosis reduces _____. Fertilization restores _____.
Once mitosis is complete what is the next step?
Once mitosis is complete what is the next step?
When does crossing over occur in meiosis?
When does crossing over occur in meiosis?
What is a protein that aids in adding a phosphate?
What is a protein that aids in adding a phosphate?
Tetrads of chromosomes are lined up at the equator during which stage of meiosis?
Tetrads of chromosomes are lined up at the equator during which stage of meiosis?
Where do chromosomes become visible in meiosis?
Where do chromosomes become visible in meiosis?
At what stage do chromatids separate in meiosis?
At what stage do chromatids separate in meiosis?
What kinds of cells are typically in G0?
What kinds of cells are typically in G0?
What is PDGF? What is its purpose?
What is PDGF? What is its purpose?
What connects sister chromatids together?
What connects sister chromatids together?
How long is the cell cycle of an embryo?
How long is the cell cycle of an embryo?
If a cell has 40 chromatids at metaphase, how many chromosomes will each daughter cell have after cytokinesis?
If a cell has 40 chromatids at metaphase, how many chromosomes will each daughter cell have after cytokinesis?
How long is the cell cycle for skin cells?
How long is the cell cycle for skin cells?
In mitosis, which stage do we separate out sister chromatids?
In mitosis, which stage do we separate out sister chromatids?
If there are 30 chromatids in a cell, how many centromeres will there be?
If there are 30 chromatids in a cell, how many centromeres will there be?
What is density dependent inhibition?
What is density dependent inhibition?
What protein is maintained at constant levels and interacts with cyclin?
What protein is maintained at constant levels and interacts with cyclin?
What are proto-oncogenes?
What are proto-oncogenes?
Non-dividing cells are in which stage of the cell cycle?
Non-dividing cells are in which stage of the cell cycle?
What happens during a synapse in meiosis?
What happens during a synapse in meiosis?
What is anchorage dependence?
What is anchorage dependence?
Interphase is composed of which stages of the cell cycle?
Interphase is composed of which stages of the cell cycle?
What is p53? Name one specific role of this gene.
What is p53? Name one specific role of this gene.
What is the goal of meiosis II? To separate what?
What is the goal of meiosis II? To separate what?
What is the difference between cytokinesis of animals vs. plant cells?
What is the difference between cytokinesis of animals vs. plant cells?
Study Notes
Cell Structure and Function
- DNA exists in two forms: chromatin (non-condensed) and chromosomes (condensed).
- Sister chromatids are connected by a centromere.
Gamete Formation
- Two gametes (sperm and egg) unite to create a zygote.
Cell Cycle Phases
- Anaphase involves the separation of sister chromatids.
- Mitosis without cytokinesis results in a cell with two nuclei.
- The S phase is when DNA synthesis occurs, producing two sister chromatids.
- Following the S phase, the cell has two sister chromatids.
- Interphase is the period between cell divisions, consisting of G1, S, and G2 phases.
Mitosis and Meiosis Comparisons
- Mitosis results in two genetically identical diploid daughter cells (46 chromosomes).
- Meiosis yields four haploid daughter nuclei, reducing chromosome number.
- Crossing over, a key process in meiosis, occurs during Prophase I.
- Tetrads align at the equator during Metaphase I of meiosis.
Cellular Checkpoints and Proteins
- The G1 checkpoint is referred to as the restriction point in the cell cycle.
- Cyclin regulates cell cycle checkpoints, varying in concentration based on cell cycle stages.
- Cyclin-dependent kinases maintain constant levels and work alongside cyclins.
- p53 is a tumor suppressor gene that recruits repair enzymes, triggers apoptosis, and holds cells in the G0 phase.
Mitosis and Meiosis Processes
- Chromosomes first become visible during prophase (mitosis and meiosis).
- Cytokinesis follows mitosis, completing the cell division process.
- Anaphase is the stage where chromatids separate during both mitosis and meiosis (specifically Anaphase II in meiosis).
Special Cell Conditions
- Non-dividing cells are found in G0 phase, often including nerve, muscle, and liver cells.
- Density-dependent inhibition stops cell division when cell overcrowding occurs.
- Anchorage dependence requires cells to be anchored for division to occur.
Time Frames in Cell Division
- The cell cycle duration for embryos is approximately 20 minutes.
- Skin cell cycles last between 12-24 hours.
- If a cell has 40 chromatids at metaphase, each daughter cell will possess 20 chromosomes.
- For a cell with 30 chromatids, there will be 15 centromeres.
Genetic Concepts
- Proto-oncogenes normally regulate cell division but can become oncogenes (cancerous) when mutated.
- During synapsis in meiosis, homologous chromosomes come together for genetic recombination.
- Meiosis I's objective is to separate homologous chromosomes, while Meiosis II's goal is to separate sister chromatids.
Cytokinesis Differences
- In animal cells, cytokinesis forms a cleavage furrow, while in plant cells, a cell plate is established.
Studying That Suits You
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Description
Test your knowledge with these flashcards on AP Biology Unit 4. This quiz covers key concepts like DNA structure, gamete formation, and stages of mitosis. Perfect for reviewing before exams and reinforcing your understanding of core biological principles.
