2.2.1
Mitosis
Cell Division
Cell Division
Viruses require a host cell to divide. Cells that have the ability to divide have a cell cycle. The eukaryotic cell cycle is outlined here.
The cell cycle
The cell cycle
- Cells on the path to cell division proceed through a series of precisely timed and carefully regulated stages of growth, DNA replication, and division.
- This is called the cell cycle.
Phases of the cell cycle
Phases of the cell cycle
- The cell cycle has two major phases: interphase and the mitotic phase.
- During interphase, the cell grows and DNA is replicated.
- During the mitotic phase, the replicated DNA and cytoplasmic contents are separated, and the cell divides.
- There are two types of cell division in eukaryotes: mitosis and meiosis.
Interphase
Interphase
- Interphase is subdivided into three growth stages called G1, S and G2 stage.
- In G1, the cell grows.
- In S, DNA synthesis happens.
- In G2, the cell grows some more before the mitotic phases begins.
The mitotic phase
The mitotic phase
- Mitosis is the part of the cell cycle in which a eukaryotic cell divides to produce two daughter cells, each with the identical copies of DNA produced by the parent cell during DNA replication.
- Multicellular organisms go through mitosis to grow and repair damaged tissues.
Stages of Mitosis
Stages of Mitosis
In mitosis, chromosomes go through prophase, metaphase, anaphase and telophase. Interphase happens just before mitosis.
Interphase
Interphase
- The cell prepares to divide.
- DNA is replicated by semi-conservative replication. There are now two copies of every chromosome.
- The organelles are also replicated.
- More ATP is produced to be used in cell division.
Prophase
Prophase
- The nuclear envelope breaks down and the nucleolus disappears. Chromosomes are left floating in the cytoplasm.
- The chromosomes coil more tightly and become shorter and fatter. They can be seen under a light microscope.
- Small protein bundles called centrioles move to opposite poles of the cell.
- Microtubules form the mitotic spindle between the centrioles.
Metaphase
Metaphase
- The chromosomes line up along the mid-line of the cell.
- In metaphase, the chromosomes are maximally condensed.
- They are attached to the spindle by the centromere.
Anaphase
Anaphase
- The chromosomes break into two chromatids. The sister chromatids separate at the centromere.
- The spindles contract and pull the chromatids to each pole of the cell.
Telophase
Telophase
- The chromatids reach the opposite poles and begin to decondense (unravel), becoming chromosomes again.
- Nuclear envelopes form around the chromosomes so there are now two nuclei.
- The cytoplasm splits and two daughter cells are formed. The daughter cells are identical to the original cell and to each other.
- The cell cycle starts again.
Way to remember the stages:
Way to remember the stages:
- I (interphase).
- Picked (prophase).
- My (metaphase).
- Apples (anaphase).
- Today (telophase).
1Biological Molecules
1.1Monomers & Polymers
1.2Carbohydrates
1.3Lipids
1.4Proteins
1.4.1The Peptide Chain
1.4.2Investigating Proteins
1.4.3Primary & Secondary Protein Structure
1.4.4Tertiary & Quaternary Protein Structure
1.4.5Enzymes
1.4.6Factors Affecting Enzyme Activity
1.4.7Enzyme-Controlled Reactions
1.4.8End of Topic Test - Lipids & Proteins
1.4.9A-A* (AO3/4) - Enzymes
1.4.10A-A* (AO3/4) - Proteins
1.5Nucleic Acids
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
4Genetic Information & Variation
4.1DNA, Genes & Chromosomes
4.2DNA & Protein Synthesis
4.3Mutations & Meiosis
4.4Genetic Diversity & Adaptation
4.5Species & Taxonomy
4.6Biodiversity Within a Community
4.7Investigating Diversity
5Energy Transfers (A2 only)
5.1Photosynthesis
5.2Respiration
5.3Energy & Ecosystems
6Responding to Change (A2 only)
6.1Nervous Communication
6.2Nervous Coordination
6.3Muscle Contraction
6.4Homeostasis
6.4.1Overview of Homeostasis
6.4.2Blood Glucose Concentration
6.4.3Controlling Blood Glucose Concentration
6.4.4End of Topic Test - Blood Glucose
6.4.5Primary & Secondary Messengers
6.4.6Diabetes Mellitus
6.4.7Measuring Glucose Concentration
6.4.8Osmoregulation
6.4.9Controlling Blood Water Potential
6.4.10ADH
6.4.11End of Topic Test - Diabetes & Osmoregulation
6.4.12A-A* (AO3/4) - Homeostasis
7Genetics & Ecosystems (A2 only)
7.1Genetics
7.2Populations
7.3Evolution
7.3.1Variation
7.3.2Natural Selection & Evolution
7.3.3End of Topic Test - Populations & Evolution
7.3.4Types of Selection
7.3.5Types of Selection Summary
7.3.6Overview of Speciation
7.3.7Causes of Speciation
7.3.8Diversity
7.3.9End of Topic Test - Selection & Speciation
7.3.10A-A* (AO3/4) - Populations & Evolution
8The Control of Gene Expression (A2 only)
8.2Gene Expression
8.2.1Stem Cells
8.2.2Stem Cells in Disease
8.2.3End of Topic Test - Mutation & Gene Epression
8.2.4A-A* (AO3/4) - Mutation & Stem Cells
8.2.5Regulating Transcription
8.2.6Epigenetics
8.2.7Epigenetics & Disease
8.2.8Regulating Translation
8.2.9Experimental Data
8.2.10End of Topic Test - Transcription & Translation
8.2.11Tumours
8.2.12Correlations & Causes
8.2.13Prevention & Treatment
8.2.14End of Topic Test - Cancer
8.2.15A-A* (AO3/4) - Gene Expression & Cancer
8.3Genome Projects
Jump to other topics
1Biological Molecules
1.1Monomers & Polymers
1.2Carbohydrates
1.3Lipids
1.4Proteins
1.4.1The Peptide Chain
1.4.2Investigating Proteins
1.4.3Primary & Secondary Protein Structure
1.4.4Tertiary & Quaternary Protein Structure
1.4.5Enzymes
1.4.6Factors Affecting Enzyme Activity
1.4.7Enzyme-Controlled Reactions
1.4.8End of Topic Test - Lipids & Proteins
1.4.9A-A* (AO3/4) - Enzymes
1.4.10A-A* (AO3/4) - Proteins
1.5Nucleic Acids
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
4Genetic Information & Variation
4.1DNA, Genes & Chromosomes
4.2DNA & Protein Synthesis
4.3Mutations & Meiosis
4.4Genetic Diversity & Adaptation
4.5Species & Taxonomy
4.6Biodiversity Within a Community
4.7Investigating Diversity
5Energy Transfers (A2 only)
5.1Photosynthesis
5.2Respiration
5.3Energy & Ecosystems
6Responding to Change (A2 only)
6.1Nervous Communication
6.2Nervous Coordination
6.3Muscle Contraction
6.4Homeostasis
6.4.1Overview of Homeostasis
6.4.2Blood Glucose Concentration
6.4.3Controlling Blood Glucose Concentration
6.4.4End of Topic Test - Blood Glucose
6.4.5Primary & Secondary Messengers
6.4.6Diabetes Mellitus
6.4.7Measuring Glucose Concentration
6.4.8Osmoregulation
6.4.9Controlling Blood Water Potential
6.4.10ADH
6.4.11End of Topic Test - Diabetes & Osmoregulation
6.4.12A-A* (AO3/4) - Homeostasis
7Genetics & Ecosystems (A2 only)
7.1Genetics
7.2Populations
7.3Evolution
7.3.1Variation
7.3.2Natural Selection & Evolution
7.3.3End of Topic Test - Populations & Evolution
7.3.4Types of Selection
7.3.5Types of Selection Summary
7.3.6Overview of Speciation
7.3.7Causes of Speciation
7.3.8Diversity
7.3.9End of Topic Test - Selection & Speciation
7.3.10A-A* (AO3/4) - Populations & Evolution
8The Control of Gene Expression (A2 only)
8.2Gene Expression
8.2.1Stem Cells
8.2.2Stem Cells in Disease
8.2.3End of Topic Test - Mutation & Gene Epression
8.2.4A-A* (AO3/4) - Mutation & Stem Cells
8.2.5Regulating Transcription
8.2.6Epigenetics
8.2.7Epigenetics & Disease
8.2.8Regulating Translation
8.2.9Experimental Data
8.2.10End of Topic Test - Transcription & Translation
8.2.11Tumours
8.2.12Correlations & Causes
8.2.13Prevention & Treatment
8.2.14End of Topic Test - Cancer
8.2.15A-A* (AO3/4) - Gene Expression & Cancer
8.3Genome Projects
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