midterm Prep Flashcards
Characteristics of living organisms (3)
- Grow/survive
- Reproduce
- Heredity
How do organisms achieve processes (4)
- Organization of cells
- ATP
- Synthesis/degredation of molecules
- Common nucleic code
Protocells
Lipids/amino acids
Could form membrane-bound vesicles
What did Millar’s experiment show
Amino acids, sugar, and nucleic acids generated spontaneously from earth’s early atmosphere- disfavoured
Most favoured current theory of beginning of life
Alkaline deep sea vents
Order of evolution from early earth rough
- prokaryotes
- photosynthetic
- oxygen
- eukaryotes
- multicellular cells
- colonization of land by plants
- flowers
How do you define a species
Biologicallu
Morphological
Ecologically
Phylogenetically
Prokaryotes
Biological species
Members can interbreed and produce viable fertile offspring
Morphological species
Members have common structures
Ecological species
Same niche similarities
Phylogenetic species
Nucleic acid similarities
Prokaryotic species
Strains with common biochemical properties
Why are viruses not organisms (4)
- Lack cellular structures
- Do not grow
- Do not respond to external stimuli
- No independent metabolism
Viral replication cycle
- Release capsid into host cell
- Host enzymes replicate viral proteins and mRNA
- Host makes more capsids
- Self assemble into new viral particles
Biological characteristics of prokaryotes
- 1 DNA circular chromosome
- no nucleus
- no membrane bound organelles (except photosynthesizers)
- no cytoskeleton
- small ribosomes
- asexual reproduction
Traits of being microscopically small
- fast reproduction
- easy dispersal
- high sensitivity to environment (low SA to V ratio)
- high rate of living
- affects water
- water is viscous
- restricted mobility
High rate of living
- SA determines absorbtion and excretion ability
- Low ratio = more nutrients per cell
- High ratio = less nutrients per cell
More nutrients=faster metabolism = shorter life span
Why is water viscous for microorganisms
Energy expenditure per unit of mass moved
Low ratio of SA to V = more friction per unit mass
High ratio = less friction per unit mass
Implications of restricted mobility in microorganisms
“Spacial and temporal heterogeneity in nutrients and environment is critical to prokaryotic activity”
- limited movement = dependent on changing environments to deliver nutrients
Uptake of nutrients for prokaryotes
Via Cell wall: small molecules only = extracellular hydrolysis to break down larger
Diffusion through extracellular matrix
Photoautotrophs
Light
Inorganic Carbon
Photoheterotroph
Light
Organic C source
Chemoautotroph
Chemical
Inorganic C
Chemoheterotroph
Chemical
Organic C
Prokaryotic Reproduction (fission)
- Duplication of chromosome
- Cell elongation
- Septum forms
- Cell divides
Phases of prokaryotic growth
- Lag
- Log
- Stationary
- Death
Genetic variation prokaryotes causes
- Mutation
- Rapid generation time
- Gene flow
ARCHEA vs bacteria
- rRNA different
- Cell wall composition different
Bacteria…
- endospores
- disease
- diverse in energy acquisition
- Phospholipid bilayer
- peptidoglycan
Archea…
- branched lipid tails
- some tails link = monolayer, not bilayer
- pseudomurein not peptidoglycan
Chemoheterotrophs - saprobes
“Recyclers/decomposers’
- waste is used by another organism
- food production
- lead to antibiotics
Chemoheterotrophs - symbionts
Rumen - 4 chambered stomach of cows
- break down cellulose
- cow regurgitates and enters new chamber
- regular digestion
Soil - Fabaceae and achtinorhizal
- nodes on plant roots
- assists in nitrogen fixing
Chemoheterotrophs - parasitic / pathogenic
Cause illness
Cyanobacteria
Chlorophyll A
- can fix nitrogen
- symbiotes (many)
- store C,P,N
Chemoautotrophs types
- Nitrifiers
- Iron oxidizers
- Sulfur oxidizers
- Methanotrophs
- Methanogens
Nitrifiers
NH4 —> NO3
Iron Oxidizers
Fe2+ —> Fe3+
Sulfur oxidizers
S —> SO2-
Methanotrophs
CH4 —> CO2
Methanogens
H2 + CO2 —> CH4 + H2O (chemoautotrophs)
H2 + acetate (C2H3O2-) —> CH4 + H2O (Chemoheterotrophs)
ONLY anaerobic respiration
Natural gas (CH4) methane
Greenhouse gas
What kingdoms make up Eukarya
- Plants
- Animals
- Fungi
- Protists
Structure differences - Prokaryotes vs eukaryotes
Prokaryotes
- smaller
- no nucleus
- no membrane bound organelles
Eukaryotes
- larger
- nucleus
- Membrane bound organelles = compartimentalized functions
Similarities
- plasma membrane
- Cytoplasm
- Ribosomes
- cytoskeleton
What part do all prokaryotic and eukaryotic cells have?
Plasma membrane
How does a typical prokaryotic cell compare in size to a eukaryotic cell?
Smaller by 100x
Prokaryotic cells are surrounded by a ________ membrane and have _______, ________, and ________, like eukaryotic cells. They also have ________ walls and may have a cell __________ . Prokaryotes have a _________ large chromosome that is not surrounded by a _________ membrane. Prokaryotes may have _________ for motility, __________ for conjugation, and __________ for adhesion to surfaces.
- plasma
- DNA
- cytoplasm
- Ribosomes
- cell
- capsule
- single
- nuclear
- flagella
- pilli
- fimbriae
What are fimbriae
Finger like projections
Allow for adhesion
“Short pilli”
Function of internal membranes in eukaryotes
- organization
- discrete processes
- increased SA for respiration
- nuclear membrane = transcription separate from translation
Benefit of having a nucleus
Transcription and translations peerage = post transcriptional modification of mRNA
Function of having paired chromosomes
Mitosis and meiosis = sexual reproduction
Why have no rigid cell wall
Phagocytosis
Benefit for of cytoskeleton
Organization and transport
Function of larger ribosomes eukaryotes
Eukaryotes = larger = more complex requirements
Function of complex flagella
Better cell motility