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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?
ā 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.ā 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
Note 
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