Lesson 3: Tree of life

What is the differences between Eukaryotic and bacteria cells

Eukaryotic cells tend to be bigger on general in average

Describe bacterial cell size

Can vary dramatically in size

most are close to 1 micrometer but 60me can even get to 1cm

What do all cells have? What cells have walls?

1) cytoplasmic membrane: define and contain cytoplasm

2) cytoplasm(has nutrients, very crowded) - has ribosomes and metabolic enzymes

3) DNA

Bacteria, Fungi, and platns have cell walls which helo tolerate and regulate osmotic pressure and shape

animal cells use cytosleketon for sae purposes

What are differences in subcellular organization in prokaryotic cells vs eukaryotic cells

Prokaryotic cells don’t have organeeles or a membrane bound nuclues. They have a nucleoid which is free flowing through the cell

Eukaryotic cells have internal membrane bound organelles. DNA is in the membrane bound nucleus

Descirb DNA in prokaryotic cells: What is it like, type of chromosome, haploid or diploid, sexual reproduction?

DNA is condensed in nucleoid region. THere are more prokaryotic complete genes than in eukaryotic

single circular chromosome

haploid

no sexual reproduction- there are other methods of exchanging material so they can still generate genetic diversity

Plasmids: small circular extra chromosomal DNA

Why are plasmids important

THey can self replicate, not all prokaryotic cells have it, but plasmids can contain antibiotic genes which gives antibioitc resistance

Plasmids can code for toxins, infections, so make you sick

Describe eukaryotic cells: where is DNA, chromosomes structure, haploid or diploid, how do they divide, how are gametes produced,

DNA is in nucleus

multiple linear chromosomes, genomes tent to be segmented

Diploid (animal centric but wtv)

Divide by mitosis: chromosomes condense, nuclear envelope breaks, spindle forms. chromosomes alighn, sister chromatids seprate and move to opposite poles. nuclear envelope reform, cytoplasm divides, 2 cells made

Produce haplid gametes by meiosis

sexual reproduction

What are three things viruses lack

no cytoplasm, no ribosomes, no metabolic activity (on their own)

What are three things viruses do have?

Nucleis acid henome structure, DNA/RNA single or double strand

protein capsid

sometimes a membrane, membrane can also be derived by a host cell

Whya ren’t virsues technically considered alive

They must infect a prokaryotic or eukaryotic cell in order to reproduce

Virsues don’t have metabolic activity but they have metabolic genes and create a relationship with some bacteria

What did Linnaeus do/ believe (how many kigndons, what was included)

He gave us scientific naming system

2 kingdoms (Animalia and plantae)

Animals: high animals and protozoa, if they moved it was animal

Plantae (higher plants, algae and fungi) - he thought fungi were plants w/o chrooplats

No prokaryotes for Linnaeus - microbes were jut being discovered, so we didn’t know about them

What did haeckel believe (How nany kingdoms, what is included in each kingdom, etc)

Animalia (higher animals)

Plantae (higher plants and multicellular algae)

Protista (All microorganisms including bacteria, protozoa, algae, molds, and yeast)

Haeckely believed darwins evolution theory and tried to roganize organisms in a tree

What did Whittaker believe in (ho wmany kingdoms and what)

5 kingdoms, plantae, fungi, animalia, protista, monera

What is the molecular based approach phylogeny?

Central dogma stuff essentially, DNA → RNA → protein

transcription through RNA polymerase and then transaltion through ribosome

Who discovered molecular based approach to phylogeny? what are the difference in prokaryotes and eukaryotes? How does it work?

Carl Woese (1970s)

So cells have rRNA and it is 16s in prokaryotes and 18s in eukaryotes. It is part of ribosome and essential for translation.

RNA changes verys lowly over time, so you can use the changes to map out a phylogeny as it is also sequenced easily and abundant in genes

What are the steps for molecular based approach to phylogeny

1) isolate genes from each organism

2) make copes of rRNa gens by PCR

3) sequence genes

4) analyse sequence by alining rRNA gene sequences

5) general phylogenetic trees

What prokaryote are we most closely related to?

Archaea. This is because archaea have similar mechanisms.

How many domains are threr? What are each domain

THere is Bacteria, Archaea, and eukaryea

What is the LUCA, what did it diverge into

Last universal common ancestor

diverged into two lines: bacteria in one line and archaea and eukarya in the other

What is endosymbiosis in three domains

Bacteria were engulfed by ancient eukaryotes and then evolved into eukaryotic cells and organelles

mitochondria and chroloplasts are an example

What are the three classifications absed on use of energy

Chemoorganotrophs, chemolithotrophs, phototrophs

What are heterotrophs

Require organic compounds as their carbon source: ex. proteins, lipids, sugars, amino acids

What are autotrophs

Utilize CO2 as their carbon source: photosynthesis and chemosynthesis

What are chemoheterotrophs

energy and carbon from organic molucues (humans, many bacteria, fungi, other eukaryotes)

what are Chemolithoautotrophs

Energy from inorganic molecules; carbon come from co2

WHat are photoautotrophs

Energy comes from light, carbon from co2 (plants, cyanobacteria)

What are photoheterotrophs

Energy from light carbon from organic molecules

Describe bacterial diversity? What are the biggest groups

Highly diverse, most diverse out of the three domains

Proteobacteria (gamma, beta, alpha, zeta, epsilon, delta)

are the biggest gorup with actinobacteria and planctomycetes next, follwed by firmicutes

Dexcibr archaeal diversity? What are three types

Also diverse. Mostly extremeohiles.

Halophies, methanogens, hyperthermophiles

What are halophiles

require high salt

What are methanogens

anaerobes, produce methane

What are hyperthermophiles

require high temp, circled

Describe eukarya diveristy

Less diverse than archaea and bacteria

What are three closely related groupings in eukarya

fungi, plant, animals

Are fungi multicellular

Yes but still considered microbes

When did bacteria and archaea appear

About 4bya

When did eukaryotes emerge

about 2 billion years ago

What is the timeline for mitchondiran endosymyosis and chlororplast development

Mitochondrial endosymbyosis happened first and very early in eukaryote evolution

choroplasts arose from a second independent endosymbyosis event