lesson 11 - the first eukaryotes Flashcards
what are the functions of the cytoskeleton?
maintains cells shape, positions organelles, transports materials within the cell, and facilitates internal and external movements
what are the three types of movement enables by the cytoskeleton?
internal movement, external movement, phagotrophy
how do eukaryotic cells move internally?
cytoplasmic streaming, mitosis, and meiosis
how do eukaryotic cells move externally?
flagella, pseudopods, phagotrophy
what structures are included in the endomembrane system?
nuclear envelope, endoplasmic reticulum, and Golgi apparatus
how did the end-membrane system evolve?
through invagination of the plasma membrane
what is the primary endosymbiont hypothesis for mitochondria?
an early eukaryote engulfed an aerobic prokaryote, which became mitochondrion instead of being digested
what did the mitochondria evolve from?
an aerobic porkaryote
what evidence supports the endosymbiotic origin of mitochondira and chloroplasts
two membranes - one from the original host cells and one from the engulfed bacteria
circular dna - just like bacteria, they have their own circular dna
is the mitochondria in prokaryote cells?
no
what is the primary endosymbiont hypothesis for chloroplasts?
early eukaryote engulfed a photsynthetic prokaryote (cyanobacterium) and retained it for photosynthesis
what is secondary endosymbiosis?
a eukaryote engulfed another eukaryotic cell that already had a primary endosymbiont, leading to more than two membranes around plastids
what evidence supports secondary endosymbiosis?
- plastids with 3-4 membranes
- nucleomorph with three linear chromosomes
- chloroplast matches dna related to green algae
true or false - chloroplasts came from engulfing an algae, not from bacteria in secondary endosymbiosis
true
is the mitochondria part of secondary endosymbiosis
no
analogy for nucleomorph
imagine eating a burger and finding a tiny bit of the wrapper still stuck to the bun
true or false - in secondary endosymbiosis; the engulfed eukaryotic cell already has a chloroplast
true
what is the hypothesis for the evolution of the nucleus?
it may have evolved to protect dna from harmful byproducts of mitochondria
