BiologyChapter 13: Chromosome and DNA
MITOSIS vs MEIOSIS
Mitosis: growth, repair, asexual; two 2n clones (ignore mutation); one division; chromosomes line once.
Learning objectives
- Explain mitosis vs meiosis in clear biological language.
- Distinguish 1. mitosis from 2. meiosis.
- Use the key terms to answer a short Federal Board exam question.
Definition
Mitosis: growth, repair, asexual; two 2n clones (ignore mutation); one division; chromosomes line once. Meiosis: gametes; four n cells; two divisions; homologous pairs then sisters; crossing over in prophase I named; independent assortment at metaphase I. Reduction is why 2n parents make n gametes. Cancer: mitosis out of control (named), not a method. Chromosomes carry genes in a linear order. Homologous pairs carry the same genes but possibly different alleles. Karyotypes show chromosome number and major abnormalities.
Important terms
- MITOSIS vs MEIOSIS
- Mitosis: growth, repair, asexual; two 2n clones (ignore mutation); one division; chromosomes line once.
- 1. MITOSIS
- PMAT.
- 2. MEIOSIS
- Homologues pair (bivalent/tetrad).
Relationship
- mitosis = clone 2n
- meiosis = n and mix
Overview
One division vs two:
Mitosis
PMAT. Equator. Spindle. Cytokinesis. Plant: cell plate. Same chromosome number. Skin, meristem. Human: 2n = 46 (23 pairs). Autosomes 1–22; sex chromosomes XX or XY. Gametes: n = 23. Down syndrome: trisomy 21 (three copies of chromosome 21).
Examples Two cells · Identical school · No pairing of homologues
Meiosis
Homologues pair (bivalent/tetrad). Chiasma named. Meiosis I reduces. Meiosis II splits sisters. Male: four sperm. Female: one egg + polar bodies (school). Two divisions: meiosis I (homologues separate) and II (sister chromatids separate). Four n gametes. Crossing over in prophase I creates new allele combinations.
Examples Four cells (male school) · Variation: CO + assortment · Nondisjunction risk named
WHAT — MITOSIS vs MEIOSIS
Mitosis: growth, repair, asexual; two 2n clones (ignore mutation); one division; chromosomes line once. Meiosis: gametes; four n cells; two divisions; homologous pairs then sisters; crossing over in prophase I named; independent assortment at metaphase I. Reduction is why 2n parents make n gametes. Cancer: mitosis out of control (named), not a method. Chromosomes carry genes in a linear order. Homologous pairs carry the same genes but possibly different alleles. Karyotypes show chromosome number and major abnormalities.
WHY — Why this topic matters
MITOSIS vs MEIOSIS is an independent FBISE learning unit because students must connect its structures and processes with their biological functions and examples.
HOW — How it works
MITOSIS: PMAT. Equator. Spindle. Cytokinesis. Plant: cell plate. Same chromosome number. Skin, meristem. Human: 2n = 46 (23 pairs). Autosomes 1–22; sex chromosomes XX or XY. Gametes: n = 23. Down syndrome: trisomy 21 (three copies of chromosome 21). Examples: Two cells; Identical school; No pairing of homologues. MEIOSIS: Homologues pair (bivalent/tetrad). Chiasma named. Meiosis I reduces. Meiosis II splits sisters. Male: four sperm. Female: one egg + polar bodies (school). Two divisions: meiosis I (homologues separate) and II (sister chromatids separate). Four n gametes. Crossing over in prophase I creates new allele combinations. Examples: Four cells (male school); Variation: CO + assortment; Nondisjunction risk named. Exam tell-apart: Mitosis: one division two clones. Meiosis: two divisions four n cells. Crossing over is meiosis I.
In simple words
Division names. No cell-culture method.
Key points
- mitosis = clone 2n
- meiosis = n and mix
- 2n -> 2n
- 2n -> n
Exam preparation
Exam Focus
Quick revision
Revision Zone
Review the key facts, formulas and checks before you move on.MITOSIS vs MEIOSIS
Sticky Notes · Quick Revision
Core Idea
- Mitosis: growth, repair, asexual; two 2n clones (ignore mutation); one division; chromosomes line once. Meiosis: gametes; four n cells; two divisions; homologous pairs then sisters; crossing over in prophase I named; independent assortment at metaphase I. Reduction is why 2n parents make n gametes. Cancer: mitosis out of control (named), not a method. Chromosomes carry genes in a linear order. Homologous pairs carry the same genes but possibly different alleles. Karyotypes show chromosome number and major abnormalities.
1. MITOSIS
- PMAT. Equator. Spindle. Cytokinesis. Plant: cell plate. Same chromosome number. Skin, meristem. Human: 2n = 46 (23 pairs). Autosomes 1–22; sex chromosomes XX or XY. Gametes: n = 23. Down syndrome: trisomy 21 (three copies of chromosome 21).
2. MEIOSIS
- Homologues pair (bivalent/tetrad). Chiasma named. Meiosis I reduces. Meiosis II splits sisters. Male: four sperm. Female: one egg + polar bodies (school). Two divisions: meiosis I (homologues separate) and II (sister chromatids separate). Four n gametes. Crossing over in prophase I creates new allele combinations.
Exam Example
- Exam tell-apart:
- Mitosis: one division
- two clones.
- Meiosis: two divisions
- four n cells.
- Crossing over is meiosis I.
Common Misconception
- Do not treat 1. MITOSIS and 2. MEIOSIS as the same idea; each explains a different part of the topic.
FBISE Exam Check
- Define mitosis vs meiosis, explain the two key parts, and use the correct biological terms.
- Exam reminder: Exam tell-apart: Mitosis: one division two clones. Meiosis: two divisions four n cells. Crossing over is meiosis I.
60-second revision
- Mitosis: growth, repair, asexual; two 2n clones (ignore mutation); one division; chromosomes line once.
- 1. MITOSIS: PMAT.
- 2. MEIOSIS: Homologues pair (bivalent/tetrad).
- Exam reminder: Exam tell-apart: Mitosis: one division two clones. Meiosis: two divisions four n cells. Crossing over is meiosis I.
Did you understand this topic?
Your answer is saved with your learning record. It does not mark the topic as mastered.