6.3-6.4 Flashcards
Bacteria
Prokaryote (no real nucleous), divides by binary fission.
Cause: eye/ear infections, cholera.
Viruses
Acellular (needs a host cell to carry out functions of life)
Can have DNA or RNA
Mutate, evolve, and recombine quickly.
Cause: Flu, HIV/AIDS, herpes.
Fungi
Eukaryotes (reproduce by spores)
Cause: mold, ringworm.
Protozoa
Simple parasites
Cause: malaria, toxoplasmosis
Transmission of pathogens
Inhaled droplets
Direct contact
Bodily fluids
Animal vectors
Blood contact
Ingested
Primary defence against the pathogens
Skin and mucous membrane
Mucuous membrane
Nose, mouth, pelvic area
Sticky mucus traps invadors
Ph not favourable to pathogens
Lysozome,, enzymes that breakdown pathogens.
Natural organisms, competitive exclusion
Skin
Continuous, hard to find opening
Many layers
Dry
Ph not favourable to pathogens
Lysozomes
Natural organisms
Cuts and blood clotting
Opening which pathogens can enter
Platelets and damaged tissue release clotting factors
Blood clots at the wound site prevent excessive blood loss.
Clotting factors from platelets
Clotting factors release series of reactions
Fibrin fibres form a mesh across the wound site
Fibre fibres capture blood cells and platelets forming a clot.
Presence of air clot dires and forms scab with healing shields under
Cascade results in rapid conversion of fibrinogen to fibrin by thrombin.
Atherosclerosis
Degenerative disease
Artery wall damaged
Macrophages release growth factors -> growth of fibrous tissue
Cholesterol builds up in damaged areas
Forms plaque and artery wall loses elasticity
Coronary Thrombosis
Build up of cholesterol and plaque
Lumen narrows
Blood can’t flow
If plaque ruptures, blood clotting is triggered (Thrombosis)
Coronary Heart Disease
clots in coronary arteries
Vessels are damaged by cholesterol deposition
Deposits reduce vessel diameter and increase blood pressure
The stress damages arterial walls
The vessels wall loses elasticity and forms atheroschelortic plaques
If plaque ruptures, blood clotting occurs forming thrombus.
If thrombus blocks blood flow, myocardial infarction results.
White blood cells
Leukocytes
Cells of the immune system defending the body against infectious diseases and foreign materials.
Types exist
All produced and derived from a multipotent cell in the bone marrow (hematopoietic stem cell).
Found throughout the body, including blood and lymphatic system.
Ingestion of pathogens by phagocytic white blood cells gives non-specific immunity to diseases
If pathogen enters body, first line of defence are phagocytic leukocytes.
Phagocytic Leukocytes
Chemotaxis attracts the phagocytes to the area of invasion
Response to proteins produce by pathogen
Phospholipids released by damaged cells
Phagocyte attaches to the pathogen’s cell surface proteins and then engulfs it. The fluid nature of the plasma membrane allows this.
Phagosome forms.
Vesicle that contains the pathogen.
Lysosomes deposit the enzymes into the phagosome.
Digestive enzymes break down the pathogen and waste products are expelled by exocytosis.
Phagocytosis
Involves phagocyte
Detecting foreign material and moving towards it by chemotaxis
F.M is ingested by endocytosis
Lysosomes attach to the ingested vesicle and release enzymes into it
Digest and breakdown F.M
Remains are expelled
Production of antibodies by lymphocytes in response to particular pathogens gives specific immunity
Antigen is substance or molecule found on a cell or virus surface that causes antibody formation.
Antibody is a globulare protein that recognises a specific antigen and binds to it as part of an immune response. Specific to certain antigens
Clonal selection
Each type of lymphocyte recognises one specific antigen. When invaded the corresponding lymphocycte responds.
It makes many clones of itself to produce antibodies to the pathogen.
Some cloned cells remain as memory cells.
Antibiotics blocking processes that occur in prokaryotic cells
Antibiotics are designed to disrupt structures or metabolic pathways in bacteria and fungi:
cell walls and membranes
protein synthesis
DNA/RNA synthesis
Viruses and antibiotics
Viruses have a different structure to prokaryotes. They lack metabolism and cannot be treated with antibiotics
Antibiotic resistance
Example of evolution by natural selection
Bacteria mutate and resistance naturally arises
Bacteria divide rapidly
Over time strains of bacteria can become resistant to multiple strains of bacteria.
Effects of HIV on immune system and methods of transmission
HIV attacks the immune system. Individuals affected find it harder to fight off infections and diseases.
AIDS is a syndrome caused by HIB. Develops when the HIV is advanced. Last stage of HIV where body can no longer defend it self.
No cure yet.
HIV
Retrovirus
Inserts own RNA into host cell
Attacks T-helper cells
HIV RNA is inserted into the marcophage genome
Transcription now includes the HIV’s code.
