Unit 5 Diversity of life

Question 1

7 characteristics of life?

Answer 1

1. Display order, but does not maintain
2. Harness and utilize energy
3. Reproduce
4. Respond to stimuli (react to changes in environment etc.)
5. Exhibit homeostasis (homeo-life, stasis-stand still, regulation ex: running but body temp stays the same)
6. Grow and develop
7. Evolve (better adapt to the environment)

Question 2

Basis of life?

Answer 2

The cell

Question 3

Life is e—–

Answer 3

emergent

Question 4

What do we mean when we say life is emergent?

Answer 4

Life is not planned, things emerge rather than being planned

Question 5

Meaning of Archaeon

Answer 5

Archaeon = beginning, origin

Question 6

How was the earth suitable for the development of life?

Answer 6

• Size and gravitational pull facilitated an atmosphere, was sufficient to hold said atmosphere
• Lies within the habitable zone around the sun (region around sun where water would exist in a liquid state)
• Red: no oxygen (mars for example), high CO2, Nitrogen, Hydrogen, etc.
• No ozone= no protection from UV light

Question 7

What are macromolecules? Examples?

Answer 7

• Macromolecules (carbohydrates, proteins, lipids, nucleic acids) = necessary components of life derived from simpler organic molecules (saccharides, amino acids) their assembly requires input of energy

Question 8

-What was Stanley Miller’s experiment?

Answer 8

Stimulated earth’s early atmosphere (assortment of organic molecules like urea, amino acids, lactic, formic, and acetic acids)

First experiment to demonstrate abiotic formation of molecules critical to life

Question 9

what does abiotic mean?

Answer 9

abiotic (physical rather than biological; not derived from living organisms)

Question 10

what was the deep-sea vent hypothesis?

Answer 10

Origin Hypothesis: deep sea vent hypothesis
o Nutrient rich waters
o Methane, ammonia, hydrogen sulfide
o Deep ocean cold, vents are hot (300 degrees Celsius combination of hot and cold creates = ambient temperature for life)

Question 11

What was the extraterrestrial origin hypothesis?

Answer 11

3. Origin hypotheses: extraterrestrial origins hypothesis (some data supporting mostly theoretical)
   a. Meteorites rich in organic, key molecules

Question 12

What were two major early hypotheses about early life?

Answer 12

Deep sea vent and extraterrestrial

Question 13

How do we go from simple sugars to complex proteins?

Answer 13

Polymerization.
o Today cells use enzymes to lower the amount of activation energy
 Unlikely to have occurred in ocean
 Monomers to polymers via dehydration synthesis

Question 14

Why is clay efficient in dehydration synthesis?

Answer 14

• Clay as catalyst for polymerization, provides reaction sites, undergoes dehydration, and continues to bond
layers of minerals separated via levels of H2O
allowed molecular adhesion forces to bring monomers together
clay stores potential energy used for energy requiring polymerization formation

Question 15

What does modern life need? (hint 3 key conditions)

Answer 15

o Macromolecules of life: evolution of three things

1. A membrane – defined compartment
2. A system to store information and use this to guide protein synthesis
3. Mechanisms to harness energy from the surroundings to sustain life (energy-harvesting pathways)

Question 16

Condition 1:

Answer 16

• allowed primitive metabolic reactions to occur in environment diff. to external surroundings
• higher concentration of ley molecules
• greater complexity maintained in close space

Early protobiont:

• similar to liposome
• self assemble of phospholipids into membrane similar to bilayer (vesicle) isolating organic molecules

DNA and RNA

• All organisms contain deoxyribonucleic
  acid (DNA) – Large, double-stranded, helical molecule – Information in DNA copied onto
  molecules of ribonucleic acid (RNA) • Directs production of protein molecules
• living cells require development of system based on nucleic acid that could store and pass on info to make proteins
  process:

DNA: provide cell with genetic info
to
RNA : DNA copied into RNA which directs protein synthesis on ribosomes (translated into proteins)
to
Protein

Question 17

what is a protobiont?

Answer 17

Protobiont – abiotically produced organic molecule

Question 18

Is a virus alive?

Answer 18

No, viruses’ straddle line between abiotic and biotic since they display many properties of life i.e reproduce

Most consider them dead due to their dependency on other cells to reproduce

Viruses contain RNA and DNA but cannot make their own proteins

Question 19

The foundation of earth was … years ago

Answer 19

4.6 billion

Question 20

What was the approximate time line of evolution?

Answer 20

3.5 - prokaryotic cells
2 billion - eukaryote cell
525 million -animals, land plants
65 million years - extinction of dinos
150 thousand years - homo sapiens

Question 21

True or false, biologically important molecules can be synthesized outside living cells?

Answer 21

True

Question 22

What are the four classes of essential Macromolecules?

True or false, these are all derivative of simpler molecules like amino acid?

Answer 22

1. nucleic acid
2. proteins
3. lipids
4. polysaccharides

Question 23

What are nucleic acids?

Answer 23

DNA and RNA made up of nucelotides which are made up of nitrogenous base, 5 carbon sugar and phosphorus atoms bonded to 4 O atoms

Question 24

Difference between DNA and RNA

Answer 24

RNA= carries instructions for assembling proteins from DNA to the ribosome

DNA = stores hereditary info

Question 25

What are proteins?

Answer 25

Polymers of amino acids role: support, increase rate of bio reactors, produce cellular movements, defense against invading molecules, hold amino acids in stored form

Question 26

What are lipids?

Answer 26

Non polar molecules organic compound containing H,C, O atoms forms framework for structure of function of living cells contains polar head and non polar tails

Question 27

What are polysaccharides?

Answer 27

long chains formed end-to-end linking of monosaccharides through dehydration synthesis reactions Provide structural support, string energy, sending cellular communication signals Ex: glycogen, cellulose, plant starches

Question 28

Simple forms of macromolecules produced in early life via abiotic synthesis: what are the three major hypotheses to explain?

Answer 28

1. Reducing atmosphere | - primordial atmosphere contained water vapour, high quantities of H2, CO2, NH3, CH4, complete lack of O2

Question 29

What was the Oparin, Haldane hypothesis?

Answer 29

early atmosphere: reducing atmosphere b/c of presence of large concentrations therefor these elements reacted w. each other to form complex organic molecules earth had no ozone, energetic ultra-violet light provided activation energy

Question 30

4 examples of monomers and their corresponding polymers?

Answer 30

1. simple sugars = starch, cellulose 2. amino acid= proteins 3. nucleotides = nucleic acid 4. fatty acids = lipids

Question 31

What is polymerization? What is the difference between today's polymerization and early life?

Answer 31

formation of polymers via dehydration synthesis Today: requires enzymes to lower activation energy early: (think early bacteria) lack of polymerization in ocean more likely to have occurred on solid surfaces

Question 32

Condition 2: Central Dogma

Answer 32

- flow of info from DNA to RNA to proteins Ribozymes: - RNA molecule that act as catalyst = where solely the RNA provides catalytic activity (leads to own RNA synthesis) - fold into specific conformations due to specific H bonding (similar to functioning conformations of proteins) - system no longer requires DNA - RNA -Protiens, just RNA

Question 33

Cond. 2 | Why don't we solely use RNA?

Answer 33

- efficiency: proteins better catalyzed than ribozymes giving organisms with DNA-RNA-protein combos an evolutionary advantage - Versatility: proteins are more versatile than RNA due to: 1. increased catalytic powers 2. typical cell contains a huge amount of proteins vs. RNA which is limited 3. 20 amino acids to 4 nucleotides, amino acids interact with each other in formations not possible between nucleotides

Question 34

in early life, why was RNA favoured over DNA?

Answer 34

RNA: - ribose sugar easier to synthesize than deoxyribose - DNA too structurally complex

Question 35

As time progressed, which was favoured and why DNA or RNA?

Answer 35

DNA - more chemically stable and less likely to degrade - uracil (base in RNA) not found in DNA (replaced with base thymine) cytosine to uracil in DNA common mutation that gets repaired - DNA double stranded: info is duplicated and in case of mutation complementary strand to the rescue with proper info

Question 36

Condition 3: Energy Harvesting

Answer 36

earliest life forms = energy from life geo-chemical activity ``` Hydrothermal vents are sources of free energy • Rich in H2 , CH4 , low concentration of H+ compared with the ocean. • Concentration gradient of H+ can synthesize ATP (Adenosine triphosphate) • Energy coupling reactions – Oxidation/Reduction (Explored later) • These reactions occur without oxygen = Anaerobic • Still used by many microorganisms today ```

Question 37

Why is life dependant on energy?

Answer 37

to work biosynthetic reactions

Question 38

where does most energy come from today?

Answer 38

from sun via photosynthesis to fuel photosynthesis