Prokaryotes: Archaea and Eubacteria

Prokaryotes

• Prokaryotic cells are simpler structurally and organizationally compared to eukaryotic cells.
• They have fewer membrane folds and generally lack membrane-bound organelles.

Cellular Components

• Cytosol and ribosomes are found in prokaryotic cells.
• Genetic material exists as a single, circular DNA molecule in an unbound region called the nucleoid.
• Nucleoid isn't considered a true nucleus by some.
• Prokaryotes include bacteria, cyanobacteria, and archaea.

Five-Kingdom Classification

• The Monera kingdom consists of unicellular prokaryotes split into Archaebacteria (archaea) and Eubacteria (bacteria/cyanobacteria).

Three-Domain System

• Prokaryotes are divided into the Bacteria domain (eubacteria) and the Archaea domain.
• The Eukarya domain contains eukaryotic organisms.

Archaea

• Archaea represents a small group of prokaryotes with low species diversity
• Their RNA structure and membrane/cell wall components differ from eubacteria and share traits with eukaryotes.
• They thrive in extreme conditions like high salinity, temperature, or pH, however some appear in milder conditions.
• They can be methanogens (methane producers), thermophiles (high-temperature survival), halophiles (high-salinity tolerance), or acidophiles (low-pH survival).

Eubacteria

• Eubacteria or true bacteria make up the largest and most diverse bacterial group
• They are adaptable to varied environments including the human body
• Cyanobacteria, previously named cyanophytes (blue-green algae), are in this group.

Bacterial Cell Structure

• Bacteria have a basic cell structureconsisting of:
• Cell wall containing peptidoglycans for protection.
• Lipoprotein-based plasma membrane enclosing the cytoplasm.
• Ribosomes for protein synthesis.
• Nucleoid with a singular, circular DNA chromosome.
• The mesosome is an infolding of the plasma membrane, which is the DNA attachment site
• Plasmids are circular DNA molecules separate from the chromosome, allowing independent reproduction

Bacteria: Forms and Associations

• Bacteria have varied shapes based on their cell wall, and may exist freely or in colonies.
• Many have flagella for movement.
• Cocci are spherical bacteria, which are classified as:
• Diplococci when paired.
• Streptococci when chained.
• Staphylococci when clustered.
• Spirilla are spiral-shaped
• Bacilli are rod-shaped
• Streptobacilli are bacilli organized into chains.
• Vibriões are comma-shaped

Gram Staining Technique

• Gram staining identifies bacteria based on cell wall composition by using violet dye.
• Gram-positive bacteria retain the dye and appear blue-purple.
• Gram-negative bacteria do not and appear pink.

Gram-Positive Bacteria

• Gram-positive bacteria have a thick, simple cell wall made of exposed peptidoglycans
• They readily absorb the dye and stain blue.

Gram-Negative Bacteria

• Gram-negative bacteria have a complex, multi-layered cell wall.
• It contains a thin peptidoglycan layer and an outer membrane with phospholipids and proteins
• It repels most dyes, unless colorized in a lab.
• Since it repels color, its called gram-negative

Characteristics Gram-Negative Bacteria

• Lipopolysaccharides (LPS) in the outer membrane act as endotoxins
• This endotoxin increases pathogenicity and trigger inflammation
• Gram-negative bacteria are considered more virulent than Gram-positive ones.

Bacterial Nutrition

• Most bacteria don't produce their own food, so they are heterotrophic
• Many act as decomposers (saprophages) and eat dead organic matter which recycles matter in nature
• Some act as parasites and harm plants, animals, and humans
• Some use relationships like commensalism, protocooperation, and mutualism, etc

Autotrophic Bacteria

• Some bacteria are autotrophic, like photosynthetic, photo-reducing, or chemosynthetic bacteria

Bacterial Respiration

• Bacteria can be aerobic or anaerobic
• Aerobic bacteria use O2 in the respiratory chain.
• Anaerobic bacteria use an alternative electron acceptor or fermentation.
• Obligate anaerobes die with O2, facultative anaerobes prefer O2 but can survive without it.
• Facultative anaerobes ferment producing energy, and ingredients for making yogurt, vinegar, and alcohol

Bacterial Reproduction

• Bacteria reproduce mainly by binary fission where on bacteria creates 2 equal bacteria
• Bacteria can divide every 20 mins
• This process is not mitosis, as it lacks the nuclear division seen in mitosis involving dissolution and reconstitution of the karyotype.

Recombination

• Bacteria can also undergo genetic exchange
• This is referred to as sexual reproduction by certain researchers

Bacterial Conjugation

• Bacteria can exchange plasmids through conjugation.
• It occurs when compatible bacteria bind using pili that establish cytoplasmic bridges.
• Plasmids are transferred from donor (F+) to recipient (F-) bacteria

Bacterial Transformation

• A bacterium can absorb DNA fragments in it's surrounding environment
• As DNA is absorbed, DNA are introduced that increment its DNA structure

Bacterial Transduction

• A virus transfers DNA from one bacteria to another
• It transits by bacteriophages invading bacteria
• This results in genetic recombination, and this trait can be passed on to future offspring

Bacterial Sporulation

• Some bacteria, like Bacillus and Clostridium, can sporulate with specific chemical or environmental catalysts
• These resistance cells are called spores that formulate through hydration
• The bacteria resume its vegetal form once in favorable environmental conditions

Introduction to Botany

• Over 250,000 plant species exist in diverse forms regarding size, shape, and morphology.
• Botany studies the plant kingdom (Plantae, Metaphyta, or Vegetal) across 12 phyla.

Plant Traits

• Plants are autotrophic photosynthesizers, generating energy from light and inorganic compounds
• This includes plants with eukaryotic units, protein-based cytoskeleton, and larger organelles connected to membranes
• Photosynthetic units have the presence of chlorophyll-rich chloroplasts containing chlorophyll a and b, along with auxiliary pigments like carotenes and xanthophylls
• The plant's DNA is safeguarded by cell walls of cellulose connected by the many cell interconnections
• Plants are composed of large number of pluricellular organisms which results in complex diversity

Phylogenetic Relations

• DNA sequencing shows algae and plants differ.
• Plants are categorized as embryophytes because multicellular development goes through the embryo stage.
• Plants develop multicellular embryos without internal cavities linked to maternal organisms.
• Algae and plants with life cycles that alternates between haploid and diploid.
• These life cycles result in generations in haploid and diploid traits, with haploids creating diploid zygotes leading to diploid embryos

Multicellularity

• Within each generation, gametophytes produce haploid gametes via mitosis.
• During sexual reproduction, diploid zygotes become embryos that evolve into sporophytes.
• Once mature, sporophytes have cells that encounter meiosis that is referred to as sporic meisosis
• Resulting cells yield haploid organisms that are grown, through mitosis to give off haploid organisms
• Every plants show both sporophytic diploids and gametophytic haploids

Reproductive Structure

• All gametophytes present all gametangia(n), structures resulting in gametes, while all sporophytes all possess spirangia
• Plant kingdom displays trends resulting in prominent sporophytes.

Vascular and Avascular Plants

• Plants that lack true tissues and transportive traits have prevailing gametophytic traits and identified to be acascular.
• Vascular tissue that transports substances via channels may contain fluids and minerals absorbed via environment labeled seiva.
• Plants display traits that are developed referred to as tracheophytes Traqueophytes possess vessels that contains seiva The vessels also provides the plant the ability to have enhanced, efficient environmental benefits

Traqueófitas

• Tracheophytes divide based on their ability to yield the seeds and secure their embryos.
• Pteridophytas are traqueophytas produce no seeds Spermatophytas Traqueophytas may produce the seeds

Anglosperms and Gimnosperms

• The spermatophytas have have exposed seeds in reproductive traits.
• The spermatophytas traits display seeds kept inside the fruit which results in angiosperms

Plant reproduction

• Plant life display a trait to reproduce assexually and sexually by seed creation
• Plants may link development to plant source by linking reproduction to the embryo

Gametes

• The female gamete, oosfera displays retention on gametangio
• Male gamete must obtain the female gamete to procreate in plants

Cryptogams

• Briófitas and Pteridófitas are referred to as cryptogams that displays gametangios that is invisible or transparent.
• During development of cryptogams displays male gametes that hold flagellos which transport through fluid. By that means, briófitas and pteridófitas are connected fluid replication

Angiosperms and Gimnosperms

• Species of phanerogamous are displays the structures reproductive traits which is evident. During the groupings the male traits possesses no flagellos since its not transportive. This fluid travels via tube polinico in the grain. Gimnospermas dont have fluid replication is referred to be siphonagmas.

Animal Tissues

• Epithelial Tissue
  • Characteristics: Origins
    • Is from endoderm, mesoderm and ectoderm
  • Characteristics : Functions
    • Performs functions like covering, lining, and protecting
    • Are filtration, diffusion, secretion, absorption