Lecture 4 - The Diversity of Life Flashcards
What are the 3 domains of life?
bacteria, archaea, and eukarya
What does eukarya include?
fungi, protista, plants, animals
What were the first organisms to live on earth?
prokaryotes in 3.5 bya. They live in crazy places due to their ability to adapt
Are prokaryotes unicellular or multicellular?
they are unicellular
What is the common shape of a prokaryotic cell?
cocci aka round, bacilli aka rod , or spiral
Whats the capsule?
it surrounds the cell wall; it is a sticky dense layer of polysaccharide or protein
What is the cell wall of bacteria made of?
peptidoglycan: polymer of sugars and amino acids
What is the cell wall of archaea made of?
mostly glycoproteins
What are the different types of appendages for prokaryotic cells?
flagella, pili, and fimbriae
DNA in prokaryotic cells?
dna: single circular chromosome located in the nucleoid, there are also small plasmids of dna in the cell.
How do prokaryotic cells reproduce?
they divide via binary fission
What are the energy sources for living things?
sunlight and chemical: by breaking down chemical bonds for energy when we eat food
Living things need nutrients from a?
carbon source. carbon creates macromolecules. theres 2 types of carbon source. 1) organic compounds: when carbon is taken from sources such as protein lipid or carbs 2) inorganic compounds: carbon taken from co2
What is a phototroph?
energy source is sunlight
What is a chemotroph?
energy source is chemical energy
What is an autotroph?
carbon source is co2
What is a heterotroph?
carbon source is from organic compound
what are the 4 nutritional modes?
1) photoautotroph: protists, prokaryotes, plants
2) chemoautotroph: prokaryotes
3) photoheterotrophs: prokaryotes
4) chemoheterotrophs: prokaryotes, protists, fungi, animals, some plants
Obligate aerobes vs obligate anaerobes vs facultative anaerobes
aerobes: must use o2
anaerobes: poisoned by 02
facultative: use o2 if there but can survive without it
what is decomposition?
breaking down of dead organisms or waste ad recycle nutrients back into soil for uptake by plants. prokaryotes are ESSENTIAL for nutrient cycling
How do organisms oxygenate the atmosphere
photosynthesis: cyanobacteria were the first photosynthetic organisms on earth
What is nitrogen important for?
required to make dna/rna/proteins. prokaryotes can conduct nitrogen fixation = convert the nitrogen from the atmosphere into ammonia
symbiosis?
a relationship in which 2 species live in close contact. The larger organism is called the host and the smaller organism is called the symbiont.
What are the 3 types of symbiotic relationships?
mutualism, commensalism, and parasitism
What is mutualism?
an interaction that benefits both the host and the symbiont. Example: bacteria gives usable nitrogen to plant and plant gives sugar to bacteria
What is commensalism?
an interaction that benefits one species but not the other. eg: e coli in the gut; nutrients are given to the bacteria and safe place to live but they dont harm or help you
What is parasitism?
an interaction that benefits one species while causing harm to the other. Eg: food borne illnesses
What is bioremediation?
some types of bacteria eat pollutants and metabolize them into harmless products
What are the similarities between bacteria and archaea?
cell wall, ribosomes, single circular chromosome, lack nucleus and organelles
What are the differences between bacteria and archaea?
- composition of the cell wall
- dna structure
- different proteins used to copy dna
- different start codon for building proteins
What does extremophiles mean?
some archaea are extreme loving
extreme thermophiles vs extreme halophiles?
thermophiles: dna stable at temp up to 120 degrees celcius
halophiles: tolerate or need extreme salinity: majority of extremophiles are archaea
What are methanogens?
archaea that live in anoxic environments. 0% oxygen. eg: gut of cow. when cows fart they release methane
Thaumarchaeota?
live in soil and in skin, protect against skin infections, aid in nitrogen cycling, lower skin pH
How did we go from organelle-less prokaryotic cells to eukaryotic cells with membrane bound organelles?
too long to type but explain it
What is endosymbiont?
symbiotic relationship where the symbiont lives within the host cell
Protists?
eukaryotes that are not fungi, plants, or animals.
- majority are unicellular
Animal like protists?
chemoheterotrophs: feed by consuming other organisms, can move, lack cell wall. EX: amoeba and plasmodium(causes malaria)
Plant like protists?
photoautotrophs: have chloroplasts and a cell wall, make sugar using photosynthesis, volvox, seaweed
fungi like protists?
chemoheterotrophs: feed by absorption, decompose dead material and recylce nutrients, have a cell wall, they are molds
Fungi?
chemoheterotrophs, release enzymes and digest food outside the body and absorb nutrients, multicellular except for yeast, cell walls are composed of chitin, they have hyphae which absorb water and nutrients
Whats the largest organism on earth?
fungi: armillaria ostoyae
whats the first antibiotic made by fungi?
penicillin
