Lecture 5 - The Nature Of Earth

Question 1

What are the 6 attributes of life?

Answer 1

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

Question 2

What does evolutionary adaptation explain?

Answer 2

Diversity of life on earth

Relations between different organisms

Question 3

Explain the theories of evolution by:
Anaximander
Aristotle
Jean Baptiste Lamarck
Gregor Mendel
Charles Darwin

Answer 3

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

Question 4

What 2 facts result in unequal reproductive success?

Answer 4

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

Question 5

What are the 2 kingdoms based on appearance? And the 3 additional ones?

Answer 5

Appearance: Animals, Plants
Additional: Fungi, 2 for microorganisms

Question 6

What are the 3 Domains of the Tree of Life?

Answer 6

Bacteria
Archaea
Eukarya

Question 7

Prokaryotes vs Eukaryotes

Answer 7

Prokaryotes: No cell nucleus, single-celled, small, DNA distributed in central parts

Eukaryotes: Has nucleus w/ DNA, multi-celled, complex

Question 8

What is the most common element in living organisms?

What is the most important element for life?

Answer 8

1) Oxygen

2) Carbon

Question 9

Ionic bond
Covalent bond
Hydrogen bond

Answer 9

Ionic: Atom bound by opposite/transferred charges

Covalent: Atoms share electrons

Hydrogen bond: Molecules electrically asymmetric (polarity)

Question 10

What are the ways to represent molecules?

Answer 10

Molecular formulas
Structural formulas
Ball-and-stick models
Space-filling models

Question 11

What can carbon molecules form?

Answer 11

Allotropes
     Graphite (soft)
     Diamond (unusually hard)
     Graphene (strong)
Fullerens
Nanotubes

Question 12

Why is silicon based life unlikely?

Answer 12

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

Question 13

Why does ice float on water?

Answer 13

Ice is lower density because the molecules are spaced further apart.

Question 14

What happens at the water surface?

Answer 14

The hydrogen bonds are unbalanced.

Question 15

What are the molecular components of a cell?

Answer 15

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.

Question 16

List which organic molecule each of these groups belong in:
Hydroxyl
Carbonyl
Carboxyl
Amino
Phosphate

Answer 16

Carbohydrates: Hydroxyl
Lipids: Carbonyl
Proteins: Carboxyl and Amino
DNA and ATP: Phosphates

Question 17

How do amino acids polymerize into polypeptides and break into single components?

Answer 17

Polymerize - Loss of water (Condensation)

Break - Hydrolysis

Question 18

What are the primary and secondary structures of proteins?

Answer 18

Primary structure: Order of amino acids into polypeptides

Secondary structure: 3D links between polypeptides

Question 19

What are the 4 categories of metabolism?

Answer 19

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

Question 20

What are the energy sources of a:
Photoautotroph
Chemoautotroph
Photoheterotroph
Chemoheterotroph

Answer 20

Photoautotroph: Sunlight
Chemoautotroph: Inorganic chemicals (iron, sulfur, ammonia, etc)
Photoheterotroph: Sunlight
Chemoheterotroph: Organic compounds

Question 21

What are nucleotides made of?

Answer 21

Phosphate group
Sugar
Nitrogenous base (A, C, T/U, G)

Question 22

Define:
Gene
Chromosome
Genome

Answer 22

Gene: Sequence of bases coding one protein
Chromosome: Many genes combines (46 in humans)
Genome: Entire set of genes of an organism

Question 23

What are 2 types of mutations?

Answer 23

Replacement: of base, changing one amino acid

Insertion/Deletion: of base, changing entire rest of gene

Question 24

What are the 3 types of gene transfer?

Answer 24

Vertical (normal): Parent to offspring

Lateral (horizontal): Copying of genes to other organisms (mainly in prokaryotes)

Artificial: Genetic engineering

Question 25

What are extremophiles?

Answer 25

• Live in volcanic vents in mid-oceanic ridges
• Chemoautotrophs: Consume dissolved CO2 and energy from inorganic rxns in water
• Mostly archaea
• Anaerobic

Question 26

What are endospores?

Answer 26

• Dormant bacteria cells
• Can survive meteorite journeys
• Can survive without water, extreme heat/cold and the space vacuum

Question 27

What are stromatolites?

Answer 27

• Colonies or single-cell microbes
• Sediment layers intermixed with microbes
• 3.5 Gyr old

Question 28

How old are microfossils?

Answer 28

3.5 Gyr but most other microfossils with evidence are found 2.7-3 Gyr ago

Question 29

Which Carbon isotope do living organisms prefer?

Answer 29

12 C

Question 30

What is the earliest record of life?

Answer 30

3.85 to 3.5 Gyr ago