Lecture 5 - The Nature Of Earth Flashcards
What are the 6 attributes of life?
Order
- Structure to divide and coherent activity
Reproduction
- Guards against death of individuals and allows heredity mechanisms to operate
Growth
- Increase in size, complexity, ability
Energy utilization
- Consumes food
Response to enviro
- Avoids being killed, goes where life’s best
Evolutionary adaptation
- Species adapt to current enviro and changing enviros
What does evolutionary adaptation explain?
Diversity of life on earth
Relations between different organisms
Explain the theories of evolution by: Anaximander Aristotle Jean Baptiste Lamarck Gregor Mendel Charles Darwin
Anaximander: Simple life arose in water and evolved to become complex
Aristotle: Species are fixed and don’t change
Lamarck: Suggested link through similarities of fossils and heredity
Mendel: Studied heredity
Darwin: Natural selection
What 2 facts result in unequal reproductive success?
1) Over-reproduction: More offspring than the enviro can support leads to competition
2) Individual variation: Individuals vary in inheritable traits passed from parents to offspring
What are the 2 kingdoms based on appearance? And the 3 additional ones?
Appearance: Animals, Plants
Additional: Fungi, 2 for microorganisms
What are the 3 Domains of the Tree of Life?
Bacteria
Archaea
Eukarya
Prokaryotes vs Eukaryotes
Prokaryotes: No cell nucleus, single-celled, small, DNA distributed in central parts
Eukaryotes: Has nucleus w/ DNA, multi-celled, complex
What is the most common element in living organisms?
What is the most important element for life?
1) Oxygen
2) Carbon
Ionic bond
Covalent bond
Hydrogen bond
Ionic: Atom bound by opposite/transferred charges
Covalent: Atoms share electrons
Hydrogen bond: Molecules electrically asymmetric (polarity)
What are the ways to represent molecules?
Molecular formulas
Structural formulas
Ball-and-stick models
Space-filling models
What can carbon molecules form?
Allotropes
Graphite (soft)
Diamond (unusually hard)
Graphene (strong)
Fullerens
NanotubesWhy is silicon based life unlikely?
1) Si chem bonds weaker than C bonds and can’t exist long in water
2) Does not normally form double bonds
3) SiO2 is solid unlike CO2 so it’s not easily mobile in enviro
4) 1000x more abundant than C in Earth’s crust but life is still C-based
Why does ice float on water?
Ice is lower density because the molecules are spaced further apart.
What happens at the water surface?
The hydrogen bonds are unbalanced.
What are the molecular components of a cell?
Carbohydrates: Provide energy and cell structure.
Lipids: Store energy and can form membranes.
Proteins: Many functions, including enzymes as catalysts. Made of amino acids through polymerization. 20 amino acids.
Nucleic acids: Transferring genetic info.
List which organic molecule each of these groups belong in: Hydroxyl Carbonyl Carboxyl Amino Phosphate
Carbohydrates: Hydroxyl
Lipids: Carbonyl
Proteins: Carboxyl and Amino
DNA and ATP: Phosphates
How do amino acids polymerize into polypeptides and break into single components?
Polymerize - Loss of water (Condensation)
Break - Hydrolysis
What are the primary and secondary structures of proteins?
Primary structure: Order of amino acids into polypeptides
Secondary structure: 3D links between polypeptides
What are the 4 categories of metabolism?
Source of raw material (carbon compounds):
- Heterotrophs: By consuming
- Autotrophs: From atmosphere or dissolved in water
Source of energy:
- Photo: Using light
- Chemo: Using organic or non-organic compounds
What are the energy sources of a: Photoautotroph Chemoautotroph Photoheterotroph Chemoheterotroph
Photoautotroph: Sunlight
Chemoautotroph: Inorganic chemicals (iron, sulfur, ammonia, etc)
Photoheterotroph: Sunlight
Chemoheterotroph: Organic compounds
What are nucleotides made of?
Phosphate group
Sugar
Nitrogenous base (A, C, T/U, G)
Define:
Gene
Chromosome
Genome
Gene: Sequence of bases coding one protein
Chromosome: Many genes combines (46 in humans)
Genome: Entire set of genes of an organism
What are 2 types of mutations?
Replacement: of base, changing one amino acid
Insertion/Deletion: of base, changing entire rest of gene
What are the 3 types of gene transfer?
Vertical (normal): Parent to offspring
Lateral (horizontal): Copying of genes to other organisms (mainly in prokaryotes)
Artificial: Genetic engineering
What are extremophiles?
- Live in volcanic vents in mid-oceanic ridges
- Chemoautotrophs: Consume dissolved CO2 and energy from inorganic rxns in water
- Mostly archaea
- Anaerobic
What are endospores?
- Dormant bacteria cells
- Can survive meteorite journeys
- Can survive without water, extreme heat/cold and the space vacuum
What are stromatolites?
- Colonies or single-cell microbes
- Sediment layers intermixed with microbes
- 3.5 Gyr old
How old are microfossils?
3.5 Gyr but most other microfossils with evidence are found 2.7-3 Gyr ago
Which Carbon isotope do living organisms prefer?
12 C
What is the earliest record of life?
3.85 to 3.5 Gyr ago
