whole final Knowt deck.

Eukarya — main features

Endosymbiosis, multicellularity, and diversity of Protista.

Eukaryotic cell

Much larger in size and more complex internally.

Eukaryotic cell — what makes it more complex?

It contains internal membrane-bound structures and DNA protected within a nucleus.

Eukaryotic cell — cytoskeleton

Allows shape-shifting.

Eukaryotic flagella

Move with side-to-side action.

Eukaryotic metabolism

Focused on photosynthesis and cellular respiration.

Photosynthesis

An anabolic pathway.

Cellular respiration

A catabolic pathway.

Mitochondria

Organelle associated with cellular respiration.

Chloroplasts

Organelle associated with photosynthesis.

Mitochondria and chloroplasts — unusual features

Internal membranes, own circular DNA, and small internal ribosomes.

Mitochondria and chloroplasts — why do those features matter?

Their unusual features support the idea of endosymbiosis.

Mitochondrial DNA

mtDNA; its own circular DNA.

Chloroplast DNA

cpDNA; its own circular DNA.

Internal membranes — function

Increase surface area.

Endosymbiosis

The best explanation for the origin of mitochondria and chloroplasts.

Primary endosymbiosis

A eukaryote engulfs a prokaryote.

Primary endosymbiosis — what does it mean?

The engulfed prokaryote becomes part of the larger eukaryotic cell.

Secondary endosymbiosis

A eukaryote engulfs a eukaryote.

Secondary endosymbiosis — what does it mean?

The engulfed eukaryotic cell already contains a chloroplast from an earlier endosymbiotic event.

Primary vs. secondary endosymbiosis

Primary = eukaryote + prokaryote; secondary = eukaryote + eukaryote.

Secondary endosymbiosis — membrane evidence

Additional chloroplast membranes.

Why can secondary endosymbiosis produce more membranes?

Membranes can come from the chloroplast, algal host cell, and engulfer's vesicle.

Evidence for multiple secondary endosymbioses

Pigments, phylogeny, and ultra-structure.

Multiple secondary endosymbioses

Secondary endosymbiosis occurred more than once.

Serial endosymbiosis

Additional endosymbiotic events followed by possible loss or modification.

Mitosis

Maintains ploidy state.

Mitosis — professor connection

Should create similarity.

Meiosis

Reduces ploidy state.

Meiosis — professor connection

Creates novelty.

Fertilization

Fusion of gametes that produces a zygote.

Fertilization — effect on ploidy

Returns the ploidy state to diploid.

What follows fertilization?

Mitosis.

Chlamydomonas

Unicellular green alga used as an example of sexual reproduction.

Chlamydomonas mating types

mt(+) and mt(-).

Chlamydomonas — isogamy

The two mating types are identical in appearance.

Chlamydomonas fertilization

mt(+) and mt(-) fuse to form a diploid zygote.

Chlamydomonas zygote

Not flagellated and can serve as a dormant form.

Chlamydomonas zygote — what happens in light?

It undergoes meiosis and releases four flagellated haploid cells.

Protists

Mostly microbial eukaryotes.

Protists — monophyletic?

No.

Protist diversity

Morphology, niche, shape, and interactions.

How should you study the protist examples?

Know their general role, shape, and niche.

Animal-like protists

Protozoa; most are heterotrophs.

Plant-like protists

Protophyta; most contain chloroplasts.

Fungus-like protists

Saprophytic forms including slime molds and water molds.

Euglena

Unicellular protist.

Euglena — energy acquisition

Photosynthetic and heterotrophic.

Euglena — movement

Flagella.

Euglena — eyespot

Photoreceptor that influences movement.

Euglena — how do its traits connect?

Its flagella and eyespot help movement while it can obtain energy in more than one way.

Volvox

Photosynthetic colonial organism.

Volvox — flagella

Face outward.

Volvox — division of labor

Different cells have different roles.

Volvox — reproduction

Complex reproduction involving the gonidium.

Volvox — why is it important?

It connects colonial organization with increasing division of labor.

Vorticella

Filter-feeding protist.

Vorticella — cilia

Create a whirlpool to engulf food.

Vorticella — pedicel/myoneme

Anchors it to a substrate and is flexible.

Vorticella — life stages

Free-swimming and anchored.

Vorticella — reproduction

Sexual reproduction with micro and macro gametes.

Paramecium

Aquatic, fast-moving predator.

Paramecium — movement

Cilia and contractile vacuoles.

Paramecium — nuclei

Macro- and micronucleus.

Paramecium — feeding

Oral groove.

Paramecium — symbionts

Some provide photosynthesis and sugars.

Amoeba

Aquatic heterotrophic predator.

Amoeba — movement

Pseudopods and contractile vacuoles.

Amoeba — feeding

Pseudopods aid in phagocytosis.

Amoeba — pathogenic role

Some can be pathogenic in humans.

Amoeba vs. Paramecium movement

Amoeba uses pseudopods; Paramecium uses cilia.

Plasmodium

Single-celled obligate parasite.

Plasmodium — life cycle

Complex life cycle with multiple hosts.

Plasmodium — hosts

Mammals and insects.

Plasmodium — reproduction

Asexual reproduction occurs within RBC of the host.

Slime molds

Paraphyletic group.

Slime molds — individual stage

Free-living as single cells.

Slime molds — reproduction

Reproduce as aggregations.

Slime molds — ecological role

Decomposers.

Slime molds — are they fungi?

No.

Slime mold fruiting bodies

Release spores.

Development of multicellularity

Unicellular → colonial → multicellular.

Division of labor

Different cells perform different roles.

Multicellularity — what increases?

Division of labor and cell-cell communication.

Benefits of multicellularity

Safety in numbers, larger size potential, longer lifespan, and division of labor.

Why does division of labor matter?

Cells can specialize for different roles instead of every cell doing the same thing.