BIOSCI101: Lecture 1 + 2

What are some hypotheses for how life begun?

Through chemical evolution, with simple molecules forming increasingly complex ones under energy sources (lightning, hydrothermal vents)

What are the main chemical components of life?

Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur

Why is water essential in life

It’s a solvent, it regulates temperatures, allows chemical reactions, provides structure and helps transport molecules

Why is energy required for life

To drive chemical reactions, maintain order and enable growth and reproduction

Why do scientists think central components of metabolism existed prebiotically

Because many core metabolic reactions (like ATP use, redox reactions) are universal and likely arose early

How are polymers formed

By linking repeated units of the same or similar monomers

How do polymer bonds form and break

They form through dehydration and they break through hydrolysis

What are lipids made from

Acetate units that form acyl chains, which can be saturated (no double bonds) or unsaturated (double bonds)

Why are phospholipids amphipathic

Because the phosphate group is hydrophilic, while fatty acid tails are hydrophobic

Why are phospholipid membranes important for cells

They form barriers that separate internal and external environments, a requirement for the first cells

What are two major roles of sugars in life

Storing energy (e.g. glycogen, starch) and building structures (e.g. cellulose, chitin)

How do different monomer bonds affect polymer properties

They change structure and function, e.g., starch is digestible, cellulose is not (different glycosidic bonds)

What are two major biological polymers, and how do they vary

Nucleic acids (vary by bases) and proteins (vary by amino acid sequence)