Beyond The Microscope - The hidden diversity of prokaryotes - Bacteria & Archea (Lecture 2)

Biology 112 Lecture 02

What are prokaryotes?

• Bacteria + Archaea

why do prokaryotes outnumber eukaryotes in species diversity?

their ability to thrive in extreme and diverse environments.

What are key features of Prokaryotes?

What lacks a nucleus and & membrane bound organelles?

Is bacteria or archaea more similar to eukaryotes?

Archaea.

What do prokaryotic cell walls do?

provide structure support and shape.

what do archea cell walls contain?

PSEUDOPEPTIDOGLYCAN

What is a horizontal gene transfer?

movement of genes across organisms

what is the goal of horizontal gene transfer?

uptake of DNA from the environment

what is transduction?

DNA transfer via viruses

what is conjugation? What does it have a role in?

direct transfer between cells via pilli

• Antibiotic resistance.

What does gene transfer fuel?

GENETIC DIVERSITY & ADAPTABILITY

What are plasmids?

small, circular DNA molecules

What is the function of plasmids?

carry genes for antibiotic resistance

Where do extremophiles thrive in?

extreme conditions

What roles do extremophiles play?

• in Earth's ecosystems

• decomposition

What is monophyletic? Examples?

includes all descendants of a common ancestor

• Bacteria + Archaea

What is paraphyletic?

excludes some descendants

• Prokaryotes

What is the metabolism of firmicutes?

Chemoheterotrophs

What is the importance of firmicutes?

• gut microbiota regulate digestion & immunity

What is the metabolism of cyanobacteria?

Photoautotrophs

what is the importance of cyanobacteria?

• produced the oxygen that transformed Earth's atmosphere

• important in carbon and nitrogen cycling

what is the metabolism of actinobacteria?

chemoheterotrophs

What is the importance of actinobacteria?

• decompose organic matter

• produce antibiotics

What is the metabolism of a spirochaetes?

chemoautotrophs

What is the importance of spirochaetes?

• some play roles in breaking down organic matter

What are the features of chlamydiae?

aspherical & small

What is the biphasic life cycle of chlamydiae?

• Elementary bodies

• reticulate bodies

what is elementary bodies?

infectious, dormant form that invades host cells

What is reticulate bodies?

• non-infectious, form that replicates inside host cells

• lack peptidoglycan in cell walls, relying on host cells for nutrients

What is the metabolism of chlamydiae?

chemoheterotrophs

What is the importance of chlamydiae?

significant human pathogens causing diseases like chlamydia

what is the metabolism of proteobacteria?

heterotrophs or chemoautotrophs

what is the importance of proteobacteria?

• nitrogen fixation

• sulfur cycling

How do we adapt and survive in extreme enironments?

• Diverse shapes and sizes

What are the shapes of bacteria?

• Cocci (spheres)

• Bacili (rods)

• spirilla (spirals)

What is a flagella?

• Unique structure for movement

What is the final electron acceptor in aerobic respiration?

• Oxygen

What is th efinal electron acceptor is anaerobic respiration?

• Nitrate

• sulfate

what allowed aerobic respiration?

oxygenic photosynthesis

What do autotrophs use?

• Co2 or CH4 to build organic molecules

What do heterotrophs use?

organic molecules from other organisms

What do photoautotrophs use?

• Light

• CO2

What do photoheterotrophs use?

• light

What do chemoheterotrophs do?

— break down organic molecules for carbon & energy

what do chemoautotrophs do?

use inorganic molecules for energy,

what do enzymes secreted outside the cells digest?

complex molecules such as proteins and polysaccharides

What do nitorgen fixing bacteria convert

• Atmospheric nitrogen to ammonia

What are biofilms?

communities of prokaryotes in a slimy extracellular matrix

What do biofilms provide?

resistance to antibiotics & harsh environments

How are endospores formed?

• By bacteria like bacillus under harsh conditions

How do endospores look? What are they resistant to? wHEN DO THEY GERMINATE?

• THICK-WALLED STRUCTURES

• to heat, desiccation & chemicals

• germinate when conditions improve

What is symbosis?

close ecological relationships with other organisms

What is mutulism?

• a relationship that benefits the organisms involved.

What is parasitism? Example?

• relationship that benefits one organism but harms the other.

What is human microbiome?

bacteria & archaea that inhabit the body

what are the functions of human microbiome?

• digestion

• immune system support

What are probiotics?

live bacterial supplements that support gut health

What do pathogenic bacteria do?

cause diseases such as tb + Lyme disease

What is mechanisms of virculence?

toxins + antibiotic resistance

How is antibiotic resistance accelerated?

misuse in medicine.

What is bioremidation? What is an example?

using bacteria to degrade pollutants

e.g.— oil spill cleanup

What are enrichment cultures?

growing bacteria under specific conditions to study their behaviour

what does gram staining differentiate?

gram pos and gram neg

what is gram pos?

• thick peptidoglycan purple bacteria

what is gram neg

thin peptidoglycan pink bacteria

what is the importance of gram staining?

• identifies bacterial types and predicts antibiotic susceptibility

what does antibiotic sensitivity do?

measure zones of inhibition on agar plates

WHAT DO LARGER ZONES of inhibiton mean?

higher bacterial sensitivity

importance of zone inhibition?

helps combat antibiotic resistance by identifying effective treatments

what are the antibiotic resistance mechanisms?

• enzyme production,

• efflux pumps

How does antibiotic resistace spread?

HORIZONTAL GENE TRANSFER

Prokaryotes in food?

• lactic acid bacteria convert milk to yogurt & cheese

• fermentation