Bacterial Membranes and Carbohydrates

• Review the first handout to understand the second material package, especially concepts of negativity.

Bacteria Membrane Structure

• Bacteria share a similar membrane structure to ours, mainly phospholipids.
• Phospholipids self-assemble into a bilayer, crucial for cell growth, division, and repair after damage.
• Phospholipids spontaneously form this bilayer because their hydrophilic heads interact with water, while hydrophobic tails exclude water and coalesce.

Soaps Disrupt Phospholipid Bilayers

• Soaps disrupt phospholipid bilayers due to their amphipathic nature, possessing both hydrophilic and hydrophobic components, leading to dissociation.
• Model the zone with hydrocarbons like phospholipids but with a simpler, single-tail system.

Carbohydrates

• Bacteria share a similar metabolism to humans, utilizing sugars like glucose for energy and carbon, but can metabolize more carbohydrate types than humans.
• E. coli cannot break down cellulose, but other bacteria can.
• Cellulose and starch are both glucose polymers but have different bonds, digestible by bacteria (starch) but not humans (cellulose).
• Cellulose is vital for movement of material through the digestive system.

Protein and Nucleic Acid Structures

• Focus on gene expression models related to protein and DNA structure/function.
• Use the gene expression process covered.

Gene Expression Model

• Genes are represented as arrows on chromosomes.
• A promoter is required for gene expression/activation.
• An enzyme binds to the promoter, creating an mRNA molecule longer than the gene.
• mRNA then binds to ribosomes (small and large subunits).
• Ribosomes then create a polypeptide product with amino acids.
• After release from the ribosome, the polypeptide folds up into a 3D structure, sometimes creating an enzyme with an active site.
• Transcription converts DNA to mRNA, and translation converts mRNA to a polypeptide product.

Operons and Gene Expression Regulation

• Bacteria organize genes into operons in functional units controlled by a single promoter for efficiency.
• Most (over 90%) of bacteria DNA codes.
• Gene expression is regulated by proteins that turn the promoter on/off.

Plasmids and Gene Expression

• Gene expression is distinct from DNA replication.
• Signals to bacterial cells, such as touching plant cells, can trigger gene expression.
• DNA replication involves using the double-stranded DNA as a template to build new strands.
• Cells replicate DNA to make more copies, but also express genes to produce proteins needed for cellular activities.
• Messenger RNA (mRNA) carries DNA information to the ribosomes

DNA Replication

• DNA replication involves separating the two strands using energy to make new daughter strands.
• Hydrogen bonds form and break spontaneously between the strands.
• Hydrogen bonds, formed spontaneously without chemical reactions, hold the two DNA strands together

Horizontal Gene Transfer

• Genes can move between different cells.
• Genes clustered together, like those for the botulinum toxin in Clostridium botulinum, form pathogenicity islands which can move to other bacteria.
• Plasmids also facilitate information transfer between cells.
• Transformation occurs when bacteria pick up free DNA and incorporate it into their genome.

Translation Process

• Translation involves using an mRNA sequence and a codon table to create a protein product.
• Be able to use a codon table to translate mRNA to protein.

Codon Table

• The codon table is universal. All organisms use the same table.
• Viruses utilize the same codon table.

Taxonomy

• Taxonomy is the study of classifying and naming organisms.
• Latin names are used to specify the organisms
• Know the difference between genus and species.

Scientific Names

• Every species has its unique name to avoid errors in communication across languages.
• Genus and species are used by all organisms
• Genus is capitalized, whereas the species is written in lowercase.
• C. botulinum is the proper notation
• The genus can by abbreviated (C. botulinum)
• E. coli (Escherichia)

Cell Types

• Eukaryotic cells are larger, have membrane-bound organelles (like a nucleus), and are often multicellular.
• Prokaryotic cells lack membrane-bound organelles are are unicellular.
• Eukaryotes are multicellular (often)
• Eukaryotes can cause diseases known as parasites.
• Bacteria are referred to as pathogens.
• Prokaryotic are are unicellular (always) and can form colonies and communicate.
• Biofilms are example are such colonies.
• Quorum sensing is the cell signalling to attach and cause disease.

Week 4: Viruses and Prions

Viruses

• Viruses are small (nanometers)
• Need specialized tools to study them, such as electron microscope.
• Viruses and prions was the covered material that the class needs to cover.
• Can have DNA or RNA genomes (double or single-stranded)
• Can be enveloped (lipid bilayer with host and viral components) or non-enveloped.
• Genome Structure
  • Double strand DNA
  • Single strand DNA
  • Double strand RNA
  • Single strand RNA
    • Positive strand RNA
    • Negative strand RNA

Viral Envelopes

• Envelopes impact stability and infectivity.
• Enveloped viruses are less stable and more susceptible to disruption by soaps.
• Viruses attach to host cells via viral proteins (ligands) binding to host cell receptors. Has a specificity.
• Specificity determines which species and tissue/cell types a virus can infect.
• The lipid bilayer is removed with soap to prevent transmission to the next host.
• Non-enveloped viruses have receptors as part of their capsid coat.

Virus Transmission

• If a potential new carrier is exposed to the virus, and the viral particals are able to make it to the cuts/abrasions on the new hosts skin, then the virus could be transmitted that way.
• Another way is food.

DNA and Horizontal Transfer

• horizontal transfer and DNA is a great example of DNA, and viruses ability to work as delivery mechanism
• Non stable/living viruses hang out with living things
• Spores are living and metabolically inert

Spores

• Spores are metabolically inert with a thick wall.
• Bacterial Spores: Metabolically Inert with a thick wall that can also be dormant.
  • Living cells
  • Gram positive
• It can become metabolically active again.
• Spores germination factors: temperatures high enough to stimulate.

Radiation Exposure

• Spores are particularly vulnerabe to radiation exposure.
• Can with stand uv radiation so can autoclaving techniques

Germination

• Clostridium will express when exposed to moisture, like waking up plant seeds
• Bacillius can go back to a happy self.

Clostridium botulinum

• It can survive even if they are exposed to UV light
• Forms spores when exposed to oxygen and lacks superoxide dismutase (SOD-) and catalase to break down reactive oxygen species.
• Impacts human health.

Canned Goods

• The way that it impacts human heath in particular, is with canned good products - and oil packed goods.
• If you open a can and it sounds "poofy" do not risk cooking it.

Oil Packed Goods

• Oxygen forces Clostridium to create spores to keep it alive
• Spores are created even if you take oil pack peppers and mushrooms and just pack them in oil for a good and anaerobic environment
• Will still grow in the fridge - spores are a bit slow to get there but they still will
• If you are making flavored olls, you need to dry goods completely because it needs a "water source"

Pathogenicity

-Pathogenicity depends on species. Non-enveloped or vice versa depends.

• The level of toxin that is in the material is key.

Viral reproductive cycles

• Genome structure impacts envelopes and significances
• Know pandemic and epidemic

Evolution and adaptation

• Virus can be categorized by how they change or evolve and adapt with humans
  • Shift can happen as a fast evolutionary tactict
  • Drift is a slow burn method with random mutations

Viral Structure

• The fact that there are three pieces, means that humans will need to be exposed to create the three pieces for infection.
• Each has their own chromosome makeup

Prions

• There will be a prion question
• A prion, does not have a genome with a simple protein structure and that causes protein in an infected pastral protein.

Pathogens With Out A Genome

• The thing that separates pathogens without out a genome, is that specific proteins continue to be absorbed, and it causes nerve tissue for a patient that shows balding.
• Can create plaques for CMS.
• Cooking can easily destroy it with cooking or boiling from those things. By adding heat, the protein will start to denature. When people eat infected mean and pick up the protein, all this is still absorbed.

Disease Terminology

• Mad cow disease is not that nervous
• Can takes 10 years to see symptoms

Cell surface structure

• In addition to all this, some concept matching terms like "Strap and step" may be relevant. It is critical to know for a articulated biopsy

Capsules

• Important for attachment between bacteria, viruses and proteins.
• Take away the capsule protein, infection is no longer possible.

Explore bacterial membrane structure, focusing on phospholipids and their bilayer formation. Understand how soaps disrupt these bilayers and compare bacterial carbohydrate metabolism to humans. Learn about bacterial ability to metabolize diverse carbohydrate types.