뒤로General Biology II Unit 3 Practice Assessment Study Guidance
스터디 가이드 - 스마트 노트
자료에 맞춘 맞춤형 노트, 핵심 정의, 예시, 맥락을 확장해 제공합니다.
Q36. What phase of meiosis is seen in the figure to the right?
Background
Topic: Meiosis Phases
This question tests your ability to identify the specific stage of meiosis based on the arrangement and movement of chromosomes within the cell.
Key Terms:
Meiosis: A type of cell division that reduces the chromosome number by half, producing four gamete cells.
Anaphase: The stage where chromosomes are pulled apart toward opposite poles.
Metaphase: The stage where chromosomes align at the cell's equator.
Sister chromatids: Identical copies of a chromosome connected by a centromere.
Step-by-Step Guidance
Observe the image: Chromosomes are being pulled toward opposite poles of the cell.
Recall the phases of meiosis: Metaphase (chromosomes align), Anaphase (chromosomes separate).
Determine if the chromosomes being separated are homologous pairs or sister chromatids. In Anaphase I, homologous chromosomes separate; in Anaphase II, sister chromatids separate.
Look for clues in the chromosome structure: Are the chromosomes still X-shaped (replicated) or single (unreplicated)?
Use these observations to decide which phase is depicted, but stop before stating the final answer.
Try solving on your own before revealing the answer!
Final Answer: D) Anaphase II
The image shows sister chromatids being pulled apart to opposite poles, which is characteristic of Anaphase II in meiosis.
In Anaphase II, the centromeres divide and the sister chromatids (now individual chromosomes) move toward opposite ends of the cell.
Q48. Fill in the model below showing what the cell would look like throughout meiosis. Make sure that you accurately represent whether chromosomes are unreplicated or replicated, cell ploidy level.
Background
Topic: Chromosome Behavior in Meiosis
This question tests your understanding of chromosome number, replication status, and ploidy changes during the stages of meiosis.
Key Terms:
Chromosome: A DNA molecule with part or all of the genetic material of an organism.
Replicated chromosome: Two sister chromatids joined at the centromere.
Unreplicated chromosome: A single chromatid.
Diploid (2n): Two sets of chromosomes.
Haploid (n): One set of chromosomes.
Step-by-Step Guidance
Starting cell: Count the number of chromosomes and note if they are replicated (X-shaped) or unreplicated (single line).
Determine the ploidy: Is the cell diploid (2n) or haploid (n)? At the start, cells are typically diploid.
End of Meiosis I: After homologous chromosomes separate, count the chromosomes in each cell and note their replication status.
Determine ploidy after Meiosis I: Cells are now haploid, but chromosomes are still replicated.
End of Meiosis II: After sister chromatids separate, count chromosomes and note if they are unreplicated. Confirm ploidy.
Try solving on your own before revealing the answer!
Final Answer:
Starting cell: 4 chromosomes, replicated, diploid.
End of Meiosis I: 2 chromosomes per cell, replicated, haploid.
End of Meiosis II: 2 chromosomes per cell, unreplicated, haploid.
Meiosis reduces chromosome number by half and separates sister chromatids in the second division.
