To fully understand many of the important issues affecting our society, you must understand the science behind it. Science is the systematic study of natural phenomena- explains how electrons travel Technology is the application of scientific insight to practical life- developed devices that use electricity Coronavirus Covid-19 Infectious disease caused by SAR-CoV-2 virus, spread through close contact via resp. droplets from coughing/sneezing New human virus – no immunity, but now a level of immunity exists with vaccines Coronavirus Infects both animals and humans Known strains: 7 (SAR-CoV-2 is 7th) Strains result from virus jumping species, through close contact of people w infected animals 2002- SARS-CoV horseshoe bats to civet cat to human 2012- MERS-CoV dromedary camels to human (Saudi arabia) 2019- SAR-CoV-2 bat to pangolin to human (china) (proposed route of infection) Next pandemic More animal only strains of coronavirus 1. New transfer to humans will occur 2. No one knows when 3. Slow/prevent by removing animal + human interactions, stopping/limiting trade in exotic and wild animals Virus v. Bacteria Virus 1. Not alive (not able to replicate, cannot self-reproduce) 2. Infect a cell and direct cell to make copies of the virus (host cell) 3. New virus affects new cells 4. Doesn’t need “food” to survive 5. Errors can occur when copies made- makes new mutations/strains Bacteria 1. Microscopic, single celled organism 2. Most harmless, many are good for us Good bacteria in digestive system Breast milk has bacteria to feed bacteria in newborns digestive system 3. Killed by antibiotics – viruses can’t be killed by antibiotics 4. Overuse of antibiotics leads to drug-resistant bacteria Cellular Organization Cells < tissue < organ < organ systems < organism Microscopes and Cells Discovery made by invention of microscopes - Anton van Leeuwenhoek (1600’s) - Robert Hooke (1653-1703) first used compound microscope to view thinkly sliced cork cells. First to use the term cell Cell Theory All living things are composed of cells Cells are the basic unit of structure and function of living things All cells are produced from other cells 2 Basic Cell Types ( EXPAND page 13) - Prokaryote 1. Lacks internal comparents, has no true nucleus, most are unicellular organisms such as bacteria - Eukaryote 1. Has internal structures (organelles) and a true nucleus, can be either unicellular or multicellular Yeast is unicellular Plants and animals are multicellular Cell Anatomy - Cell wall (only in plants and bacteria/ and protus and fungi), rigid layer of nonliving material provides protection and support - Plasma membrane (outer layer of animal cells, found inside cell wall if its present), controls what enters and leaves the cell/ keeps cell together, important for cells to communicate - Nucleus (single membrane, directs cell activities, contains DNA), materials pass in and out through nuclear membrane, easiest part of cell to see usually 1. Nucleolus Primary role is synthesis of ribosomes 2. Chromatin Packages DNA into smaller volume Reinforces DNA macromolecules Prevents DNA damage Control gene expression/DNA replication 3. Chromosomes Packages of DNA - - - Mitochondria- rod shaped, double membrane, create energy for cell from food), has its own DNA (37 genes, needed for mitochondrial fxn, inherited from mom) so some scientists believe it was originally a separate entity from cells Chloroplast- turn suns energy into food thru photosynthesis, converts energy does not make energy (can’t make or destroy energy) Endoplasmic reticulum- single membrane from nucleus 1. Smooth ER many uses incl. carb synthesis, move fluid in cells, detoxify compounds, synthesize M/F hormones 2. Rough ER makes membranes and ribosomes (make proteins), antibodies, insulin Many proteins are synthesized on the rough ER surface Ribosome- found on ER or in cytoplasm, produces proteins within the cell Golgi body- single membrane, flattened sacs -> receive proteins+materials to package and ship out Vacuole- stores food water and materials, small in animal cells and large in plant cells, provides structural support in large plants by storing water and keeping plants upright Lysosome- cell waste disposal system (material from inside and outside the cell), contains enzymes that function in digestion of food and dead cell parts (can break down almost all biomolecules), surrounded by a membrane w/ internal PH ~4.5-5 like our stomachs Animal Vs. Plant 1. Plant cells has chloroplast 2. Plant cells have a cell wall 3. Plant cells have a large central vacuole 4. Animal cells have more lysosomes Specialized Cells (page 25 of slide #1) - Muscle cells (skeletal muscle, smooth muscle, cardiac muscle) - Red blood cells - Nerve cells (neurons) Virus Entering Cells thru 3 mechanisms (page 26 of slide #1) - Direct endocytosis 1. Releases viral nucleic acid into the cytoplasm through a membrane pore - Receptor-mediated endocytosis 1. Endosomal enzymes can aid in virus uncoating - Direct fusion 1. Fusion of the viral envelope with host cell plasma membrane Body’s reaction to virus -Immune response triggered when foreign item enters body (starts to fight foreign item) - Body releases proteins to start to fight the foreign material (makes you feel slightly ill, headache, aches etc) -if harmless, it’ll go away. If not, the release continues until you develop antibodies. (this is why we feel ill after vax or massage) Antibodies -used to neutralize pathogens including bad bacteria and viruses -infected body takes time to figure out how to neutralize/ make correct antibody. Before this time the person may get more ill and die before antibodies are developed -body remembers all previously made antibodies, provides immunity or quicker response time when exposed to same or similar pathogen -Survivors of Spanish Flu 1918 pandemic are still protected against virus (H1N1 2008) Antibodies- mode of action (page 30 slide #1) 1. Antibodies and pathogens are free in blood 2. Antibodies bind to pathogens a. Opsonization: bind to the pathogen b. Neutralization: surround the pathogen c. Agglutination: combine a few pathogens together x. this allows body’s phagocyte cells to recognize and destroy pathogen 3. phagocyte cell recognize the pathogen/antibody material 4. phagocyte cell surround and destroys pathogen Herd Immunity -Achieved naturally or thru vaccines -Naturally lets people get infected to achieve H.I. but people could die and overwhelms global healthcare systems Vaccine - inactive or weakened form of a pathogen injected into body to trigger immune response Produces antibodies, same ones that body would produce to fight actual infection Reduces/removes time it takes for body to develop antibodies. Body can fight/destroy pathogen before you feel sick or only have mild illness - Cannot get the illness from the vaccine - No medication or anything put into our body is 100% safe w/ no side-effects with at least one person of the population - Have reduced/greatly eliminated the appearance of illness 1. Small pox is first disease to be completely eradicated except samples in gov care - Dropping vax rate has resulted in returing illnesses and deaths due to return 1. WHO: global measles outbreaks increasing due to decreased vaccines against it 2. Monkeypox: small pox vaccine no longer routine/required, SP vax protected against MP - - Feeling ill after vax? 1. Your body assumes vax is a pathogen and attacks it (feel sick bc of this). 2. Within 24hrs body realizes it’s safe and stops the attack (feel better) COVID 1. Initial body immune response is too aggressive and body attacks healthy cells 2. SAR-CoV-2 virus attacks healthy lung cell, triggering cell death, swelling and pneumonia (can lead to death of patient, newer variants have strong focus on upper resp tract)
