Mod 4 Flashcards
(30 cards)
Differences Between Bacteria and Viruses
Bacteria are prokaryotic cells without membrane-bound organelles.
Viruses consist solely of nucleic acid and a protein coat.
Bacteria can survive independently, while viruses need a host to survive.
Viruses are smaller than bacteria.
Bacteria have structures like cell membranes and organelles, unlike viruses
Understanding Tuberculosis (TB): Causes and Effects
Tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis.
The initial infection is symptomless and the bacteria remain dormant in tubercles.
Tubercles are formed as a result of the inflammatory response in the lungs.
When the immune system weakens, TB bacteria can become active and damage lung tissue.
Symptoms include coughing, weight loss, fever, and it can be fatal if untreated.
Understanding Viral Infections: HIV and Influenza
HIV is a viral infection that leads to AIDS.
Initial symptoms of HIV include fever, fatigue, and headaches.
After a few weeks, HIV antibodies develop, indicating positivity.
Symptoms may disappear until the immune system weakens, resulting in AIDS.
Influenza infects the respiratory epithelial cells and has various strains.
Diseases Caused by Organisms: Human and Plant Impact
Athlete’s foot is caused by a fungus and spreads through direct contact.
Malaria is transmitted indirectly by female Anopheles mosquitoes.
Plants can also be infected by diseases, impacting agriculture.
Tobacco mosaic virus affects tobacco plants, a key global crop.
Blight and Black Sigatoka are fungal diseases that impact potatoes and bananas, respectively.
Plant Defenses Against Pathogens
Plants have evolved physical and chemical against pathogens.
Physical barriers include cellulose cell walls, lignin layers, and waxy cuticles.
Old vascular tissue is blocked to stop pathogen spread within the plant.
Upon detecting pathogens, plants close stomata and thicken cell walls with cellulose.
Necrosis occurs to kill infected cells, with canker being a specific type affecting woody tissue
Chemical Defenses in Plants
Menthols from mint are terpenoids with antibacterial properties.
Phenols like tannin disrupt digestion, deterring insect attacks.
Alkaloids such as caffeine and morphine have bitter flavors to prevent herbivory.
Defensins are proteins that inhibit transport channels in invaders.
Hydrolytic enzymes like chitinases break down the cell walls of invading organisms.
Key Physical Barriers to Infection
Skin acts as a tough barrier made of keratin.
Stomach acid effectively kills bacteria.
Gut flora competes with pathogens for resources.
Skin flora provides a natural defense against infections.
These barriers work together to prevent pathogen entry.
Body’s Defense Mechanisms Against Infection
Inflammation increases blood flow and vessel permeability to combat infection.
Lysozyme, found in tears and mucus, destroys bacterial cell walls.
Interferons inhibit virus spread by blocking protein synthesis in infected cells.
Phagocytosis involves white blood cells engulfing and destroying pathogens.
Blood clotting minimizes blood loss and prevents pathogen entry.
Understanding Immune Response: Antigen Presentation
Phagocytes engulf and destroy pathogens, presenting antigens on their surface.
Antigen presenting cells activate other immune cells when antigens are recognized as foreign.
The specific immune response targets one pathogen type specifically.
B cells, which mature in the bone marrow, contribute to the humoral immune response.
T cells mature in the thymus gland and are involved in the cell-mediated immune response.
Understanding Memory and Immune Cells
Memory cells replicate when encountering a pathogen.
They remain in lymph nodes to facilitate quick immune responses.
B effector/plasma cells produce antibodies.
T helper cells stimulate the division of B and T killer cells.
T killer cells are responsible for destroying infected cells.
Cell Mediated Response
Foreign microbe with antigens has it’s antigens ingested by a macrophage.
They are processed and presented to the T-cell
The T-Cell produces clones:
T-killer cell: directly destroys antigens
T-helper cell: stimulates T and B cells
T-suppressor cell: inhibits T and B cells
T-Memory cell: Remembers antigens for future encounters
Humoral response
A B-cell is triggered when it encounters its matching antigen.
The b-cell engulfs the antigen and digests it, it displays antigen fragments bound to its unique MHC molecules
This combination of antigen and MHC attracts the help of a mature matching T-cell
Cytokines secreted by T-cell help the B-cell to multiply and mature into antibody producing plasma cells
Released into blood, antibodies lock into matching antigens.
The antigen-antibody complexes are cleared by the complement cascade OR the liver and spleen
Understanding Antibodies and Their Function
Antibodies are produced by lymphocytes.
They have a specific shape that complements specific antigens.
Antibodies inhibit the action of antigens through neutralisation.
Methods of neutralisation include phagocyte binding and agglutination.
Antibodies also neutralise toxins released by pathogens.
Understanding Antibody Structure and Function
Antibodies consist of four polypeptide chains connected by disulphide bridges.
They have a constant region that aids in phagocyte interaction and phagocytosis.
Each antibody features a unique variable region for specificity against specific antigens.
Hinge regions provide flexibility, allowing binding to multiple pathogens.
The variation in amino acid sequences in the variable region determines antibody specificity.
Understanding Active and Passive Immunity
Immunity is classified as active or passive.
Active immunity involves the immune system producing antibodies against antigens.
Passive immunity is gained through antibodies from another source, such as a person or animal.
Natural immunity comes from disease exposure or maternal antibodies, while artificial immunity is gained through vaccinations or antibody injections.
There are two subtypes of each category: natural and artificial, affecting how immunity is developed.
Understanding Antibiotics: Types and Functions
Antibiotics combat infections by killing or inhibiting bacteria.
Bactericidal antibiotics destroy bacteria by targeting their cell walls.
Bacteriostatic antibiotics prevent bacterial growth by halting protein synthesis.
Both types are crucial in treating bacterial infections.
Choosing the right type depends on the specific infection.
Combating Antibiotic Resistance in Hospitals
Bacteria can develop resistance to antibiotics through natural selection.
Antibiotic-resistant strains, such as MRSA, pose significant risks in healthcare settings.
Hospitals screen and isolate new patients to control the spread of resistant infections.
Judicious use of antibiotics and completing prescribed courses helps minimize resistance development.
Strict hygiene practices among healthcare staff are essential in preventing transmission of resistant bacteria.
Understanding Species Richness and Sampling Methods
Species richness refers to the variety of different species in a community.
Random sampling is a key method for obtaining representative species data.
Systematic sampling, like transects, follows a specific pattern during data collection.
Opportunistic sampling relies on collecting samples based on ease of access.
Stratified sampling divides populations into strata for proportional random sampling.
Understanding Species Evenness and Genetic Diversity
Species evenness assesses the abundance distribution among different species in a habitat.
Genetic diversity refers to the variation of genes within a species.
It is quantified by the number of alleles present in a gene pool.
The heterozygosity index (H) measures genetic diversity.
A higher heterozygosity index indicates greater genetic diversity in a population.
What is the biodiversity index equation?
D= N(N-1) / {n(n-1)
N = total number of organisms
n = total number of organisms of each species
The Importance of Biodiversity Conservation
Biodiversity is crucial for ecological balance and economic stability.
It helps in preserving landscapes and enhancing aesthetic value.
In situ conservation methods include marine conservation zones and wildlife reserves.
Ex situ methods involve zoos, seed banks, and botanic gardens.
Both approaches are essential for effective biodiversity protection.
Conservation Efforts by Zoos
Zoos conduct scientific research to improve animal breeding and health.
Captive breeding programs enhance genetic diversity of endangered species.
Reintroduction programs aim to return captive-bred animals to their natural habitats.
Zoos engage in habitat restoration to support wildlife.
Educational initiatives raise awareness about biodiversity and illegal animal trade.
The Role of Seed Banks in Conservation
Seed Banks conserve genetic diversity and prevent plant extinction.
They store seeds which is more efficient than keeping whole plants.
Storing seeds requires less space and is cost-effective.
Seeds are kept in cool, dry conditions to prolong their viability.
Periodic testing ensures the seeds remain viable for future planting.
The Importance of Global Cooperation in Biodiversity Conservation
Biodiversity conservation requires international collaboration.
Historic agreements like CITES focus on protecting endangered species.
The Rio Convention on Biological Diversity (CBD) addresses global biodiversity issues.
The Countryside Stewardship Scheme (CSS) supports conservation efforts in rural areas.
Effective conservation strategies depend on shared global commitments.
