Name the virus that causes smallpox and state the tissue in which its most obvious effects appear.

Smallpox is caused by the variola virus, and although it is inhaled into the respiratory tract its most obvious effects are the fluid-filled pustules it produces in the skin.

How is smallpox spread from person to person?

It is spread by inhaling droplets breathed out by an infected person, and by direct contact with the fluid or scabs from the pustules or with contaminated bedding and clothing.

Which tissue does the influenza virus infect?

It infects the ciliated epithelium lining the respiratory tract, destroying the cells and leaving the airways open to secondary infection.

Name the two surface antigens of the influenza virus that define its antigenic types.

The two surface antigens are haemagglutinin and neuraminidase, which give subtypes their names such as H1N1 and H3N2.

Eduqas A-Level Biology A400QS

Biological Molecules

Topic overview Inorganic ions and the properties of water Monosaccharides and disaccharides Polysaccharides, storage and structure Lipids, triglycerides and phospholipids Amino acids and protein structure Condensation, hydrolysis and the food tests

Cell Structure and Organisation

Topic overview The nucleus and the endomembrane system Mitochondria, chloroplasts and other organelles Prokaryotic cells and viruses Cell theory, microscopy and measuring cells Comparing cells and the levels of organisation

Cell Membranes and Transport

Topic overview The fluid-mosaic model Factors affecting membrane permeability Diffusion and facilitated diffusion Osmosis and water potential Active transport and bulk transport Determining water potential in practice

Enzymes

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Nucleic Acids and Their Functions

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Importance of ATP

Topic overview ATP synthetase and the synthesis of ATP Chemiosmosis and the electrochemical gradient Proton pumps and the electron transport chain Membranes of mitochondria and chloroplasts compared Investigating dehydrogenase activity

Photosynthesis

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Respiration

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Microbiology

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Population Size and Ecosystems

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Sexual Reproduction in Plants

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Inheritance

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Variation and Evolution

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Application of Reproduction and Genetics

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Adaptations for Gas Exchange

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Topic overview Vascular systems compared across animal groups The mammalian heart and blood vessels The cardiac cycle and its control Blood, haemoglobin and dissociation curves The Bohr effect, chloride shift and tissue fluid The root and the uptake of water The endodermis and the entry to the xylem Xylem, transpiration and cohesion-tension The potometer and xerophytes and hydrophytes Phloem and translocation

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Homeostasis and the Kidney

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The Nervous System

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Immunology and Disease: Disease and Its TransmissionImmunology

Topic overview The language of infection and disease The human body as a host Cholera and tuberculosis Smallpox, influenza and viral pathogenicity Malaria and its transmission

Immunology and Disease: AntibioticsImmunology

Topic overview Bacteriostatic and bactericidal antibiotics Broad and narrow spectrum antibiotics Penicillin and the bacterial cell wall Tetracycline and the Gram negative barrier The spread of antibiotic resistance

Immunology and Disease: The Immune ResponseImmunology

Topic overview Natural barriers to infection Inflammation, clotting and phagocytosis Antigens, B lymphocytes and the humoral response Cell-mediated immunity and T lymphocytes Active and passive immunity Vaccination programmes and their ethics

Human Musculoskeletal Anatomy: Skeletal TissuesMusculoskeletal

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Human Musculoskeletal Anatomy: Structure and Function of the SkeletonMusculoskeletal

Topic overview The axial and appendicular skeleton The girdles and the bones of the limbs The vertebral column and its vertebrae Fractures and postural deformities The functions of the skeleton

Human Musculoskeletal Anatomy: JointsMusculoskeletal

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Neurobiology and Behaviour: The BrainNeurobiology

Topic overview The structure of the human brain The functions of the cerebrum, cerebellum and medulla oblongata The hypothalamus and the control of the endocrine system The sympathetic and parasympathetic nervous systems Sensory and motor areas, the homunculus and language

Neurobiology and Behaviour: NeuroscienceNeurobiology

Topic overview Non-invasive study of the brain: CT and MRI Functional imaging: fMRI, PET and EEG Brain development and critical periods Neuroplasticity Gene expression, brain development and mental illness

Neurobiology and Behaviour: BehaviourNeurobiology

Topic overview Innate behaviour: escape reflexes, kineses and taxes Habituation and imprinting Classical and operant conditioning Primate societies and the costs and benefits of group living Insect castes, dominance hierarchies, territory and courtship

Immunology and Disease: Disease and Its Transmission

Smallpox, influenza and viral pathogenicity

3 things to know
Component 3

Overview

Antigenic drift in the influenza virus, antigenic shift and how the lytic cycle of a virus damages its host.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Explain how the lytic cycle of a virus damages its host.

Numbers

In what year was smallpox declared eradicated, and by which organisation?

Key term

Give four features of smallpox that made worldwide eradication possible.

Questions from this subtopic

Each one with the model answer underneath.

1
Name the virus that causes smallpox and state the tissue in which its most obvious effects appear.
Model answer
Smallpox is caused by the variola virus, and although it is inhaled into the respiratory tract its most obvious effects are the fluid-filled pustules it produces in the skin.
2
How is smallpox spread from person to person?
Model answer
It is spread by inhaling droplets breathed out by an infected person, and by direct contact with the fluid or scabs from the pustules or with contaminated bedding and clothing.
3
In what year was smallpox declared eradicated, and by which organisation?
Model answer
Smallpox was declared eradicated by the World Health Organization in 1980.
4
Give four features of smallpox that made worldwide eradication possible.
Model answer
There was no animal reservoir and no long-term carrier state, the rash made every case easy to identify, the virus had one stable antigenic type so a single vaccine kept working, and a heat-stable vaccine could be delivered by ring vaccination around each case.
5
Which tissue does the influenza virus infect?
Model answer
It infects the ciliated epithelium lining the respiratory tract, destroying the cells and leaving the airways open to secondary infection.
6
Name the two surface antigens of the influenza virus that define its antigenic types.
Model answer
The two surface antigens are haemagglutinin and neuraminidase, which give subtypes their names such as H1N1 and H3N2.

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