8.2.11
Tumours
Types of Tumour
Types of Tumour
Tumours are a cluster of cells that are growing uncontrollably. In some cases, tumours can cause cancer. There are two types of tumour:


Benign tumours
Benign tumours
- Benign tumours are NOT cancerous.
- Benign tumours consist of cells that are dividing uncontrollably but the cells cannot spread and invade other tissues.
- Benign tumours can develop into malignant tumours.


Malignant tumours
Malignant tumours
- Malignant tumours are cancerous.
- Malignant tumours consist of cells that are dividing uncontrollably and spread into other tissues and around the body.
- Malignant tumours can be life-threatening and can grow rapidly.
Development of Tumours
Development of Tumours
Tumours can develop when gene expression is not regulated correctly. The development of tumours can happen in the following ways:


Tumour suppressor genes
Tumour suppressor genes
- Tumour suppressor genes are genes found in all cells.
- These genes inhibit cell division to regulate the rate at which cells divide.
- Increased methylation of a tumour suppressor gene inhibits this gene.
- When tumour suppressor genes are not expressed, cell division is not inhibited. This causes the cells to divide uncontrollably.


Oncogenes
Oncogenes
- Oncogenes are mutations in a gene called a proto-oncogene. Oncogenes are capable of transforming a cell into a cancerous cell because they cause excessive cell division.
- Proto-oncogenes normally stimulate cell division.
- Decreased methylation of a proto-oncogene causes proto-oncogenes to be over-expressed.
- Over-expression of proto-oncogenes stimulates cell division.


Oestrogen
Oestrogen
- Oestrogen is a hormone that can bind to receptors on transcription factors in the cytoplasm.
- Oestrogen can increase the expression of genes.
- When genes are over-expressed, a tumour may develop.
- High levels of oestrogen have been detected in some breast cancers.
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
1.4.11Diagnostic Misconceptions - Enzyme Inhibitors
1.5Nucleic Acids
1.6ATP
1.7Water
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
2.4Cell Recognition & the Immune System
2.4.1Immune System
2.4.2Phagocytosis
2.4.3T Lymphocytes
2.4.4B Lymphocytes
2.4.5Antibodies
2.4.6Primary & Secondary Response
2.4.7Vaccines
2.4.8HIV
2.4.9Ethical Issues
2.4.10End of Topic Test - Immune System
2.4.11Exam-Style Question - Immune System
2.4.12A-A* (AO3/4) - Immune System
2.4.13Diagnostic Misconceptions - Humoral vs Cellular
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
3.4Mass Transport
3.4.1Haemoglobin
3.4.2Oxygen Transport
3.4.3The Circulatory System
3.4.4The Heart
3.4.5Blood Vessels
3.4.6Cardiovascular Disease
3.4.7Heart Dissection
3.4.8Xylem
3.4.9Phloem
3.4.10Investigating Plant Transport
3.4.11End of Topic Test - Mass Transport
3.4.12A-A* (AO3/4) - Mass Transport
3.4.13Diagnostic Misconceptions - Concentration Gradient
3.4.14Diagnostic Misconceptions - Cardiac Cycle
3.4.15Diagnostic Misconceptions - Carrying Capacity
3.4.16Diagnostic Misconceptions - Translocation
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
5.1.1Overview of Photosynthesis
5.1.2Photoionisation of Chlorophyll
5.1.3Production of ATP & Reduced NADP
5.1.4Cyclic Photophosphorylation
5.1.5Light-Independent Reaction
5.1.6A-A* (AO3/4) - Photosynthesis Reactions
5.1.7Limiting Factors
5.1.8Photosynthesis Experiments
5.1.9End of Topic Test - Photosynthesis
5.1.10A-A* (AO3/4) - Photosynthesis
5.2Respiration
5.2.1Overview of Respiration
5.2.2Anaerobic Respiration
5.2.3A-A* (AO3/4) - Anaerobic Respiration
5.2.4The Link Reaction
5.2.5The Krebs Cycle
5.2.6Oxidative Phosphorylation
5.2.7Respiration Experiments
5.2.8End of Topic Test - Respiration
5.2.9A-A* (AO3/4) - Respiration
5.2.10Diagnostic Misconceptions - Aerobic vs Anaerobic
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
6.4.13Diagnostic Misconceptions - Effect of ADH
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
7.3.11Diagnostic Misconceptions - Types of Speciation
8The Control of Gene Expression (A2 only)
8.1Mutation
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
1.4.11Diagnostic Misconceptions - Enzyme Inhibitors
1.5Nucleic Acids
1.6ATP
1.7Water
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
2.4Cell Recognition & the Immune System
2.4.1Immune System
2.4.2Phagocytosis
2.4.3T Lymphocytes
2.4.4B Lymphocytes
2.4.5Antibodies
2.4.6Primary & Secondary Response
2.4.7Vaccines
2.4.8HIV
2.4.9Ethical Issues
2.4.10End of Topic Test - Immune System
2.4.11Exam-Style Question - Immune System
2.4.12A-A* (AO3/4) - Immune System
2.4.13Diagnostic Misconceptions - Humoral vs Cellular
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
3.4Mass Transport
3.4.1Haemoglobin
3.4.2Oxygen Transport
3.4.3The Circulatory System
3.4.4The Heart
3.4.5Blood Vessels
3.4.6Cardiovascular Disease
3.4.7Heart Dissection
3.4.8Xylem
3.4.9Phloem
3.4.10Investigating Plant Transport
3.4.11End of Topic Test - Mass Transport
3.4.12A-A* (AO3/4) - Mass Transport
3.4.13Diagnostic Misconceptions - Concentration Gradient
3.4.14Diagnostic Misconceptions - Cardiac Cycle
3.4.15Diagnostic Misconceptions - Carrying Capacity
3.4.16Diagnostic Misconceptions - Translocation
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
5.1.1Overview of Photosynthesis
5.1.2Photoionisation of Chlorophyll
5.1.3Production of ATP & Reduced NADP
5.1.4Cyclic Photophosphorylation
5.1.5Light-Independent Reaction
5.1.6A-A* (AO3/4) - Photosynthesis Reactions
5.1.7Limiting Factors
5.1.8Photosynthesis Experiments
5.1.9End of Topic Test - Photosynthesis
5.1.10A-A* (AO3/4) - Photosynthesis
5.2Respiration
5.2.1Overview of Respiration
5.2.2Anaerobic Respiration
5.2.3A-A* (AO3/4) - Anaerobic Respiration
5.2.4The Link Reaction
5.2.5The Krebs Cycle
5.2.6Oxidative Phosphorylation
5.2.7Respiration Experiments
5.2.8End of Topic Test - Respiration
5.2.9A-A* (AO3/4) - Respiration
5.2.10Diagnostic Misconceptions - Aerobic vs Anaerobic
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
6.4.13Diagnostic Misconceptions - Effect of ADH
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
7.3.11Diagnostic Misconceptions - Types of Speciation
8The Control of Gene Expression (A2 only)
8.1Mutation
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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