3.1.2
Viruses
Viruses
Viruses
Viruses are tiny, non-living (do not have cells) particles that can reproduce rapidly within the body.
![Illustrative background for Invasion](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/toy-1551383_1280%20-%20Edited-min,h_400,q_80,w_640.jpg)
![Illustrative background for Invasion ?? "content](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/toy-1551383_1280%20-%20Edited-min,h_400,q_80,w_640.jpg)
Invasion
Invasion
- To survive and replicate, they invade host cells (animals or plant cells).
![Illustrative background for Replication](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/toy-1551383_640-min,h_400,q_80,w_640.jpg)
![Illustrative background for Replication ?? "content](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/toy-1551383_640-min,h_400,q_80,w_640.jpg)
Replication
Replication
- The virus particle inserts its own DNA into the host cell’s DNA, which is then copied and used to make more viruses.
![Illustrative background for Invaded cells burst](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/explosion-600477_640-min,h_400,q_80,w_640.jpg)
![Illustrative background for Invaded cells burst ?? "content](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/explosion-600477_640-min,h_400,q_80,w_640.jpg)
Invaded cells burst
Invaded cells burst
- Once the new virus particles have been synthesised (made), they cause the cell to burst.
- This releases the new viruses to invade more cells.
![Illustrative background for Illness](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/illness,h_400,q_80,w_640.jpg)
![Illustrative background for Illness ?? "content](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/illness,h_400,q_80,w_640.jpg)
Illness
Illness
- This cell damage makes us feel ill.
Virus Examples
Virus Examples
Many diseases are caused by viruses. Some examples are:
![Illustrative background for Measles](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/measles-min,h_400,q_80,w_640.jpg)
![Illustrative background for Measles ?? "content](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/measles-min,h_400,q_80,w_640.jpg)
Measles
Measles
- Symptoms include a fever and red skin rash.
- Measles is a virus that can be fatal if complications arise.
- For this reason, most young children are vaccinated against measles.
- The measles virus is spread by breathing in (inhaling) droplets from sneezes and coughs.
![Illustrative background for HIV (Human immunodeficiency virus)](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/injecting-519389_640-min,h_400,q_80,w_640.jpg)
![Illustrative background for HIV (Human immunodeficiency virus) ?? "content](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/injecting-519389_640-min,h_400,q_80,w_640.jpg)
HIV (Human immunodeficiency virus)
HIV (Human immunodeficiency virus)
- HIV is spread by sexual contact or the exchange of body fluids (e.g blood from sharing needles).
- Initially, HIV causes a flu-like illness. However, unless antiretroviral drugs are used successfully, the HIV virus enters the lymph nodes and attacks the body’s own immune cells.
- AIDS is caused by HIV. It is the name given to the life-threatening infections that can happen when a person’s immune system has been badly damaged by HIV.
![Illustrative background for TMV (Tobacco mosaic virus)](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/mosaic,h_400,q_80,w_640.jpg)
![Illustrative background for TMV (Tobacco mosaic virus) ?? "content](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/3.1.1%20-%20Pathogens/mosaic,h_400,q_80,w_640.jpg)
TMV (Tobacco mosaic virus)
TMV (Tobacco mosaic virus)
- Tobacco mosaic virus (TMV) is a pathogen that affects plants, such as tomatoes.
- The unique ‘mosaic’ pattern of the discolouration of the plant stunts the growth of the affected plant, because photosynthesis cannot take place.
1Cell Biology
1.1What's in Cells?
1.1.1Types of Cells
1.1.2Properties of Prokaryotes
1.1.3Standard Form
1.1.4Standard Form - Calculations
1.1.5Addition in Standard Form - Calculations
1.1.6Subtraction in Standard Form - Calculations
1.1.7Multiplication in Standard Form - Calculations
1.1.8Division in Standard Form - Calculations
1.1.9Animal Cells
1.1.10Plant Cells
1.1.11Differences Between Animal & Plant Cells
1.1.12Bacterial Cells
1.1.13Types of Cells HyperLearning
1.1.14Cell Specialisation in Animals
1.1.15Sperm Cells
1.1.16Nerve Cells
1.1.17Muscle Cells
1.1.18Cell Specialisation in Plants
1.1.19Microscopy
1.1.20Developments in Microscopy
1.1.21Microscope Practical
1.1.22Microscopy - Calculations
1.1.23Culturing Microorganisms
1.1.24Contamination
1.1.25Avoiding Contamination
1.1.26Calculating Bacteria
1.1.27Calculating Bacteria - Calculations
1.1.28End of Topic Test - What's in Cells?
1.1.29Exam-Style Questions - Cell Structure & Microscopy
1.2Cell Division
1.3Transport in Cells
1.3.1Diffusion
1.3.2Factors Affecting Diffusion
1.3.3Surface Area : Volume
1.3.4Surface Area : Volume - Calculations
1.3.5Exchange Surfaces
1.3.6Examples of Exchange Surfaces
1.3.7Osmosis
1.3.8Osmosis Practical
1.3.9Active Transport
1.3.10Transport in Cells
1.3.11End of Topic Test - Cell Division & Transport
1.3.12Grade 9 - Cell Transport
2Organisation
2.1Principles of Organisation
2.2Enzymes
2.2.1Enzymes
2.2.2Enzymes HyperFlashcards
2.2.3Rate of Reaction
2.2.4Calculating Rate of Reaction
2.2.5Rate of Reaction - Calculations
2.2.6Digestion
2.2.7Bile
2.2.8Examples of Digestive Enzymes - Amylase
2.2.9Examples of Digestive Enzymes - Protease
2.2.10Examples of Digestive Enzymes - Lipase
2.2.11Testing for Biological Molecules
2.2.12End of Topic Test - Organisation & Enzymes
2.2.13Grade 9 - Enzymes
2.2.14Exam-Style Questions - Enzymes
2.3Circulatory System
2.3.1Types of Blood Vessel
2.3.2Blood Vessels - Arteries
2.3.3Blood Vessels - Capillaries
2.3.4Blood Vessels - Veins
2.3.5The Heart - Structure
2.3.6The Heart - Function
2.3.7Important Blood Vessels
2.3.8Double Circulatory System
2.3.9Gas Exchange
2.3.10Gas exchange - Calculations
2.3.11Alveoli
2.3.12Blood Components
2.3.13Platelets
2.3.14Red Blood Cells
2.3.15White Blood Cells
2.3.16End of Topic Test - Circulatory System
2.4Non-Communicable Diseases
2.4.1Health Issues
2.4.2Disease Interactions
2.4.3Sampling
2.4.4Sampling - Calculations
2.4.5Risk Factors
2.4.6Examples of Risk Factors
2.4.7Risk Factor Graphs
2.4.8Coronary Heart Disease
2.4.9Heart Valve Disease
2.4.10Heart Failure
2.4.11Treating Heart Disease
2.4.12Cancer
2.4.13Cancer Risk Factors
2.4.14End of Topic Test - Non-Communicable Diseases
2.4.15Exam-Style Questions - Coronary Heart Disease
2.5Plant Tissues, Organs & Systems
3Infection & Response
3.1Communicable Disease
3.1.1Spreading Disease
3.1.2Viruses
3.1.3Other Pathogens
3.1.4Human Defence Systems
3.1.5Human Defence Systems 2
3.1.6Grade 9 - Immune System
3.1.7Antibiotics
3.1.8Drug Development
3.1.9Drug Testing
3.1.10Drug Testing / Efficacy - Calculations
3.1.11End of Topic Test - Communicable Diseases
3.1.12Exam-Style Questions - Microorganisms & Disease
3.2Monoclonal Antibodies
4Bioenergetics
4.1Photosynthesis
5Homeostasis & Response
5.1Homeostasis
5.2The Human Nervous System
5.2.1The Nervous System
5.2.2The Nervous System HyperFlashcards
5.2.3Synapses
5.2.4Reflexes
5.2.5Exam-Style Questions - Nervous System
5.2.6The Brain
5.2.7Eye Anatomy
5.2.8Eye Function
5.2.9Control of Body Temperature
5.2.10Warming Up & Cooling Down
5.2.11Body Temperature HyperLearning
5.2.12End of Topic Test - Human Nervous System
5.3Hormonal Coordination in Humans
5.3.1Endocrine System
5.3.2Thyroxine & Adrenaline
5.3.3Blood Glucose
5.3.4Diabetes
5.3.5Control of Water Balance
5.3.6Urine
5.3.7Dialysis
5.3.8Transplants
5.3.9Puberty
5.3.10Menstruation
5.3.11Contraception
5.3.12Contraception 2
5.3.13Hormones for Infertility
5.3.14End of Topic Test - Homeostasis & Hormones
5.3.15Grade 9 - Hormonal Coordination
5.3.16Exam-Style Questions - Hormones & Contraception
6Inheritance, Variation & Evolution
6.1Reproduction
6.1.1Reproduction
6.1.2Reproduction 2
6.1.3Genome
6.1.4DNA
6.1.5Protein Synthesis
6.1.6Genetic Inheritance
6.1.7Genetic Crosses
6.1.8Inherited Disorders
6.1.9Inherited Disorders 2
6.1.10Genetic Crosses - Calculations
6.1.11Genome Screening & Sex Determination
6.1.12End of Topic Test - Reproduction
6.1.13Exam-Style Questions - DNA & Genetics
6.2Variation & Evolution
6.3Genetics & Evolution
7Ecology
7.1Adaptations & Interdependence
7.2Organisation of Ecosystems
7.3Biodiversity
7.4Trophic Levels
Jump to other topics
1Cell Biology
1.1What's in Cells?
1.1.1Types of Cells
1.1.2Properties of Prokaryotes
1.1.3Standard Form
1.1.4Standard Form - Calculations
1.1.5Addition in Standard Form - Calculations
1.1.6Subtraction in Standard Form - Calculations
1.1.7Multiplication in Standard Form - Calculations
1.1.8Division in Standard Form - Calculations
1.1.9Animal Cells
1.1.10Plant Cells
1.1.11Differences Between Animal & Plant Cells
1.1.12Bacterial Cells
1.1.13Types of Cells HyperLearning
1.1.14Cell Specialisation in Animals
1.1.15Sperm Cells
1.1.16Nerve Cells
1.1.17Muscle Cells
1.1.18Cell Specialisation in Plants
1.1.19Microscopy
1.1.20Developments in Microscopy
1.1.21Microscope Practical
1.1.22Microscopy - Calculations
1.1.23Culturing Microorganisms
1.1.24Contamination
1.1.25Avoiding Contamination
1.1.26Calculating Bacteria
1.1.27Calculating Bacteria - Calculations
1.1.28End of Topic Test - What's in Cells?
1.1.29Exam-Style Questions - Cell Structure & Microscopy
1.2Cell Division
1.3Transport in Cells
1.3.1Diffusion
1.3.2Factors Affecting Diffusion
1.3.3Surface Area : Volume
1.3.4Surface Area : Volume - Calculations
1.3.5Exchange Surfaces
1.3.6Examples of Exchange Surfaces
1.3.7Osmosis
1.3.8Osmosis Practical
1.3.9Active Transport
1.3.10Transport in Cells
1.3.11End of Topic Test - Cell Division & Transport
1.3.12Grade 9 - Cell Transport
2Organisation
2.1Principles of Organisation
2.2Enzymes
2.2.1Enzymes
2.2.2Enzymes HyperFlashcards
2.2.3Rate of Reaction
2.2.4Calculating Rate of Reaction
2.2.5Rate of Reaction - Calculations
2.2.6Digestion
2.2.7Bile
2.2.8Examples of Digestive Enzymes - Amylase
2.2.9Examples of Digestive Enzymes - Protease
2.2.10Examples of Digestive Enzymes - Lipase
2.2.11Testing for Biological Molecules
2.2.12End of Topic Test - Organisation & Enzymes
2.2.13Grade 9 - Enzymes
2.2.14Exam-Style Questions - Enzymes
2.3Circulatory System
2.3.1Types of Blood Vessel
2.3.2Blood Vessels - Arteries
2.3.3Blood Vessels - Capillaries
2.3.4Blood Vessels - Veins
2.3.5The Heart - Structure
2.3.6The Heart - Function
2.3.7Important Blood Vessels
2.3.8Double Circulatory System
2.3.9Gas Exchange
2.3.10Gas exchange - Calculations
2.3.11Alveoli
2.3.12Blood Components
2.3.13Platelets
2.3.14Red Blood Cells
2.3.15White Blood Cells
2.3.16End of Topic Test - Circulatory System
2.4Non-Communicable Diseases
2.4.1Health Issues
2.4.2Disease Interactions
2.4.3Sampling
2.4.4Sampling - Calculations
2.4.5Risk Factors
2.4.6Examples of Risk Factors
2.4.7Risk Factor Graphs
2.4.8Coronary Heart Disease
2.4.9Heart Valve Disease
2.4.10Heart Failure
2.4.11Treating Heart Disease
2.4.12Cancer
2.4.13Cancer Risk Factors
2.4.14End of Topic Test - Non-Communicable Diseases
2.4.15Exam-Style Questions - Coronary Heart Disease
2.5Plant Tissues, Organs & Systems
3Infection & Response
3.1Communicable Disease
3.1.1Spreading Disease
3.1.2Viruses
3.1.3Other Pathogens
3.1.4Human Defence Systems
3.1.5Human Defence Systems 2
3.1.6Grade 9 - Immune System
3.1.7Antibiotics
3.1.8Drug Development
3.1.9Drug Testing
3.1.10Drug Testing / Efficacy - Calculations
3.1.11End of Topic Test - Communicable Diseases
3.1.12Exam-Style Questions - Microorganisms & Disease
3.2Monoclonal Antibodies
4Bioenergetics
4.1Photosynthesis
5Homeostasis & Response
5.1Homeostasis
5.2The Human Nervous System
5.2.1The Nervous System
5.2.2The Nervous System HyperFlashcards
5.2.3Synapses
5.2.4Reflexes
5.2.5Exam-Style Questions - Nervous System
5.2.6The Brain
5.2.7Eye Anatomy
5.2.8Eye Function
5.2.9Control of Body Temperature
5.2.10Warming Up & Cooling Down
5.2.11Body Temperature HyperLearning
5.2.12End of Topic Test - Human Nervous System
5.3Hormonal Coordination in Humans
5.3.1Endocrine System
5.3.2Thyroxine & Adrenaline
5.3.3Blood Glucose
5.3.4Diabetes
5.3.5Control of Water Balance
5.3.6Urine
5.3.7Dialysis
5.3.8Transplants
5.3.9Puberty
5.3.10Menstruation
5.3.11Contraception
5.3.12Contraception 2
5.3.13Hormones for Infertility
5.3.14End of Topic Test - Homeostasis & Hormones
5.3.15Grade 9 - Hormonal Coordination
5.3.16Exam-Style Questions - Hormones & Contraception
6Inheritance, Variation & Evolution
6.1Reproduction
6.1.1Reproduction
6.1.2Reproduction 2
6.1.3Genome
6.1.4DNA
6.1.5Protein Synthesis
6.1.6Genetic Inheritance
6.1.7Genetic Crosses
6.1.8Inherited Disorders
6.1.9Inherited Disorders 2
6.1.10Genetic Crosses - Calculations
6.1.11Genome Screening & Sex Determination
6.1.12End of Topic Test - Reproduction
6.1.13Exam-Style Questions - DNA & Genetics
6.2Variation & Evolution
6.3Genetics & Evolution
7Ecology
7.1Adaptations & Interdependence
7.2Organisation of Ecosystems
7.3Biodiversity
7.4Trophic Levels
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