Unit4InfluenzaNonADAedit cpatterson copy

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• Unit Title: Unit 04: Influenza A

• Publisher: McGraw Hill LLC

• Content Trust: All rights reserved. No reproduction or distribution without prior consent.

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• Unit Focus: Exploring the biology and evolution of Influenza A.

• Visual Aid: Figure illustrating influenza.

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Unit Objectives

• Understand the nature and naming of influenza viruses.

• Explain viral reproduction.

• Describe flu impact on the respiratory system.

• Discuss flu vaccine contents and production.

• Relate evolution to biological studies.

• Understand natural selection as a mechanism of evolution.

• Summarize evidence of population evolution.

• Explain influenza virus evolutionary processes.

• Describe the immune system's role against pathogens.

• Discuss immune response to influenza.

• Review treatments for influenza.

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Introduction Topics

• Overview of Influenza.

• Connection between evolution and influenza.

• Immune response to influenza infection.

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Understanding Influenza

• Focus on causes and impacts of influenza virus.

• Visual Aid: Diagram pertaining to influenza.

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Media Content

• Animated representation related to influenza.

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Characteristics of the Flu

• Names of the Flu: Bird flu, swine flu, H1N1, etc.

• Virus Type: All caused by the influenza virus.

• Topics Covered:

  • Virus structure

  • Reproduction

  • Body effects

  • Vaccine production

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Virus Definition

• Nature of Viruses: Obligate parasites needing host cells.

• Components:

  • Genetic material (DNA or RNA)

  • Capsid (protein coat)

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Virus Examples

• Adenovirus: DNA virus with polyhedral capsid.

• Bacteriophage: DNA virus with helical tail.

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Influenza Structure

• Influenza Virus: RNA virus with spherical capsid and envelope with spikes.

• Function of Envelope:

  • Helps in host cell attachment and entry.

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Naming Influenza Viruses

• Types: Influenza A, B, C, D.

• Common Types: A and B infect humans most often.

• WHO Naming Convention:

  • Host (if not human), type (A or B), strain, location, and year isolated.

• Example: H1N1.

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Recent Flu Vaccines

• 2020–2021 Trivalent Vaccine Components:

  • A/Hawaii/70/2019 (H1N1)-like

  • A/HongKong/45/2019 (H3N2)-like

  • B/Washington/02/2019 (B/Victoria lineage)

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Viral Glycoproteins

• Viral Spikes: Glycoproteins facilitating host recognition.

• Types:

  • H spikes (hemagglutinin)

  • N spikes (neuraminidase)

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H and N Spikes Functions

• H Spikes: Attach to host cell receptors.

• N Spikes: Breakdown mucous for viral entry.

• Variability: 17 forms of H spikes and 10 forms of N spikes.

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Characteristics of Life

• Biological Criteria:

  • Energy processing, homeostasis, response to stimuli, reproduction, adaptation.

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Living Status of Viruses

• Viruses: Typically not classified as living; challenged by giant viruses.

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Giant Viruses

• Characteristics: Larger than typical, some can produce proteins.

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Quick Check 1

Questions

1. A virus identified as H7N9 belongs to which class?

2. Select the components of a virus. (DNA/RNA, capsid, etc.)

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Viral Reproduction

• Efficiency: Viruses hijack host cells to produce numerous new viruses.

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Genetic Material of Viruses

• Types: DNA and RNA viruses.

• Human Examples: DNA viruses (smallpox), RNA viruses (influenza).

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Virus Specificity

• Infection Targeting: Proteins on the virus capsid determine cell targeting.

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Media Content

• Animation related to virus entry into host.

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Virus Life Cycle

• Two Cycles:

  • Lytic: Immediate replication and host cell destruction.

  • Lysogenic: Viral DNA integrates into host DNA, remains inactive.

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Lytic Cycle Stages

1. Attachment

2. Penetration

3. Biosynthesis

4. Maturation

5. Release

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Lysogenic Cycle Process

• Integration into Host DNA: Viral DNA replicated passively until activation.

• Examples: HIV retains a latent phase in the host.

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RNA Virus Challenges

• Need for enzymes to convert RNA to DNA or mRNA for protein synthesis.

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Quick Check 2

Questions

1. Which enzyme does influenza use?

2. Identify true statements about the influenza virus.

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Effects of the Flu

• Understanding respiratory interaction and related symptoms.

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Target Cells of Influenza

• Primary Targets: Epithelial cells in the respiratory system.

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Virus Entry

• Pathway: Through mouth/nose, moving rapidly to the lungs.

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Cytokines and the Immune System

• Function: Alert body systems to pathogen presence.

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Body System Effects of Cytokines

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Quick Check 3

Questions

1. What types of cells do influenza viruses target?

2. What system reacts to chills and fever?

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Components of a Flu Vaccine 1

• General concerns regarding flu shot ingredients.

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Contents of a Flu Shot

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Types of Vaccines

• Trivalent vaccine (3 viruses)

• Quadrivalent vaccine (4 strains).

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Vaccine Selection Process

• Involves global monitoring and prediction of pandemic potential.

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Common Production Method

• Chicken Egg Method: Effective but time-consuming.

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Recombinant Vaccine Production

• New method using H spikes in insect cells for rapid production, allowing for egg-free alternatives.

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Quick Check 4

Questions

1. Identify the ingredient that helps the immune system recognize the flu virus.

2. Which method of production does not require the full virus?

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Evolution and Influenza

• Understanding evolutionary methods aids in better treatment design.

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Definition of Evolution

• Evidence of life change recognized by scientists.

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Evolution in Biology

• Contributes to the unifying theory of biology.

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Evolution of Influenza Virus

• Evolution from animal hosts leading to human infections.

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Quick Check 5

Questions

1. True statements about evolution.

2. Statements about influenza and evolution.

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Natural Selection Overview

• Concept introduced by Darwin and Wallace as an evolutionary process.

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Early Contributors to Evolution Understanding

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Natural Selection Observations

• Examples from Darwin's research in the Galápagos.

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Natural Selection Mechanism

• Key Concepts: Variation, struggle for existence, fitness, adaptation over generations.

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Evolution and Adaptation

• Natural selection forms populations to become well-adapted over time.

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Variations in Natural Selection

• Selection Types:

  • Stabilizing

  • Directional

  • Disruptive

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Natural Selection Visuals

• Diagrams illustrating selection forms.

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Genetic Material Changes

• Structure of DNA and mutations affecting traits.

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Protein Information Flow

• Amino acids define protein functions based on combinations.

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Mutation Effects

• Changes in nucleotide sequences altering protein characteristics.

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Quick Check 6

Questions

1. Normal information flow direction in a cell.

2. Processes producing genetic changes.

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Evidence of Evolution

• Examining fossils and genetic data to understand evolution.

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Fossil Record

• Definition and significance of fossils in showing life history.

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Comparative Anatomy

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Embryonic Development Evidence

• Homologous structures observed in animal embryonic stages.

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Genetic Evidence

• Similarities in genetic material across different organisms.

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Quick Check 7

Questions

1. Forms of evidence supporting evolution.

2. Tiktaalik and Archaeopteryx evidence type.

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Impact of Influenza Evolution

• Millions affected yearly, historical significance of the 1918 flu pandemic.

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Mechanisms of Viral Evolution

• Antigenic Drift: Small changes in spikes.

• Antigenic Shift: Significant genetic changes from co-infection.

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Evolution Mechanisms in Animals

• Antigenic shift as a major evasion strategy for the immune system.

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Quick Check 8

Questions

1. Characteristics of antigenic drift.

2. Antigenic shift specifics.

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Immune System Overview

• Function: Protects against pathogens, closely linked to the lymphatic system.

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Immune System Components

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Immune System Cell Types

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Self vs Non-self Recognition

• MHC markers identify self-cells in the body.

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Glycoproteins as Identification Tags

• MHC-I and MHC-II markers differentiate between cell types.

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Antigen Definition

• Any substance triggering specific immune response.

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Quick Check 9

Questions

1. Producing immune system cells.

2. Identifying markers present in body cells.

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Immune System Functions

• Multiple defense levels against pathogens.

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Innate Defense Mechanisms

• General defenses against pathogens.

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Physical Barrier Defenses

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Chemical Signals in Immune Response

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Inflammatory Response Stages

1. Histamine release post-damage.

2. Macrophages attack pathogens at the wound.

3. Neutrophils clean debris.

4. Clotting occurs to seal the wound.

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Adaptive Immunity

• Targeting Pathogens: Specific responses against pathogens and memory function.

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Cell-mediated Immunity

• Targeting Infected Cells: T lymphocytes activated to recognize and kill infected cells.

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Recognition of Antigens

• Antigen Presentation: Infected cells signal T cells via MHC-I markers.

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B Lymphocyte Action

• Produces antibodies against free antigens.

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Immunological Memory

• Adaptive response retains memory T/B cells for faster future responses.

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Flu Vaccine Mechanism

• Activates the immune system to prevent infection upon exposure.

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Advances in Flu Vaccines

• Research for universal vaccine and antiviral agents against virus adaptability.

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Quick Check 10

Questions

1. Identify antibody-producing cells.

2. Histamine role in the immune response.

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Future Directions in Flu Vaccination

• Ongoing research for effective strategies against flu virus evolution.

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Evolutionary Adaptability of Influenza

• Recognizing evolution methods in increasing flu virus resilience.

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Targeting Viral Life Cycle

• Antiviral Strategies:

  • Attachment

  • Uncoating

  • Release

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New Vaccine Development

• Core proteins as stable targets for vaccines offering broader protection.

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Quick Check 11

Questions

1. Viral life cycle targeting strategies.

2. Specific antiviral targeting by Tamiflu.

Unit Title: Unit 04: Influenza APublisher: McGraw Hill LLCUnit Focus: Biology and evolution of Influenza A.

Objectives:

• Understand influenza virus naming and viral reproduction.

• Describe vaccine components, production, and immune response to influenza.

• Explore evolution and natural selection concepts.

• Review treatments and flu's impact on the respiratory system.

Key Topics:

• Overview of influenza causes and impacts.

• Characteristics: Different types of flu, virus structure, and reproduction.

• Types of viruses: Influenza A, B, C, D.

• Vaccine components and production methods.

• Evolution: Mechanisms, evidence, and significance of influenza evolution.

• Immune response and functions: Identification of pathogens and defense mechanisms.

Challenges of RNA viruses:Need for enzymes for protein synthesis; unique reproductive cycles (lytic and lysogenic).

Flu's historical significance:Millions affected yearly; understanding ensures better treatment strategies and vaccine development strategies against evolving strains.