CMB1004/L01 Eukaryotic Cells Flashcards
Name the 3 domains of life.
Bacteria
Archaea
Eukaryota
What can all life forms on Earth be traced back to?
LUCA (Last Universal Common Ancestor)
What theory encompasses the fundamental characteristic of cells being derived from other cells?
Darwin’s theory of descent with modification
Describe how modern eukaryotes evolved from ancient eukaryotic cells.
Bacterial endosymbiont evolved into modern mitochondria
What is the most widely used phylogenic marker?
Small subunit ribosomal RNA (SSU rRNA)
How can a phylogenic tree be inferred?
Nucleotide or amino acid sequence data
What does branch length relate to in the SSU rRNA tree of life?
Genetic differences between species
What governs protein transport and localisation in cells?
Intrinsic protein signals
What is the Archibald theory of nucleus origin?
An endosymbiont or host-derived membrane could surround mitochondria within eukaryotic cells
What is the Blobel theory of nucleus origin?
The membrane is host-derived so no new membrane material entered the cell
Describe the Archezoa Hypothesis (phase 1).
Invagination of membrane of an ancient procaryotic cell formed the nucleus and ER
What does the Archezoa Hypothesis suggest about ancient procaryotic cells?
There was a prokaryotic cell without mitochondria
Describe the Archezoa Hypothesis (phase 2).
Bacterium was engulfed by an ancestral eucaryotic cell and became a mitochondrion
What does the Archezoa Hypothesis suggest about ancestral eucaryotic cells?
They were anaerobes
What is the name given to double-membrane bounded organelles in Archezoa?
Hydrogengenosomes and mitosomes
What evidence supports the Archezoa Hypothesis?
Mitochondria and chloroplasts have their own DNA & ribosomes
How do Paramecium bursaria and Chorella algae achieve symbiosis?
Paramecium contains heat for algal survival
Algae receives protection and gives the ciliate nutrition
Which two organelles have endogenous origins?
Nucleus and RER
Which two organelles have exogenous origins?
Mitochondria and plastids
What organism was engulfed to become mitochondria?
Alpha-cyanobacteria
What organism was engulfed to become chloroplasts?
Cyanobacteria
Give 2 functions of the plasma membrane.
Receiving information
Import/export of molecules
Movement and expansion
Which type of organism has no plasma membrane?
Xenobacteria
Give the function of the cytosol.
Metabolic pathways
Protein synthesis
Give the function of the nucleus.
Contains main genome
DNA and RNA synthesis
Give the function of the endoplasmic reticulum.
Synthesis of most lipids
Synthesis of proteins for distribution
Give the function of the Golgi apparatus.
Modification, sorting and packaging of proteins and lipids
Give the function of lysosomes.
Intracellular degradation
Give the function of endosomes.
Sorting of endocytosed (internalised) material
Give the function of peroxisomes.
Oxidation of toxic molecules
Give the function of mitochondria.
Oxidative phosphorylation
FeS cluster biosynthesis
Give the function of chloroplasts.
Photosynthesis
