Biochem lec 1

What was the first application of biochemistry?

Fermentation.

What is vitalism?

The now-discredited belief that living (organic) matter contains a "vital force" absent from nonliving (inorganic) matter.

How did Wöhler's synthesis of urea challenge vitalism?

It showed that an organic compound could be produced without a living organism.

What did Eduard Buchner's fermentation experiments demonstrate?

Cell-free yeast extract could convert sugar into ethanol and CO₂, showing that fermentation does not require living cells.

What are enzymes?

Chemical substances from cells that can carry out biochemical reactions.

What major conclusion came from early studies of enzymes and fermentation?

Chemical processes associated with living things follow the same chemical and physical rules as nonliving matter.

What are the major characteristics of living things?

They extract/store/use matter and energy, generate chemical complexity, replicate information and structure, respond to environmental changes, and evolve over time.

How do living systems create order and complexity?

They use energy from thermodynamically favorable processes to drive thermodynamically unfavorable processes.

What does "biochemical similarity underlies biological diversity" mean?

Despite their diversity, living things share common molecular constituents, information-transfer mechanisms, biochemical pathways, and cells.

What does the biochemical similarity among organisms suggest?

All living cells descended from a common ancestor.

What are the four major classes of small biological molecules?

Amino acids, monosaccharides, nucleotides, and fatty acids.

What are the major biological macromolecules?

Proteins, nucleic acids, and polysaccharides.

Why is the sequence of monomers in a macromolecule important?

The sequence is nonrandom and contains information.

What is the relationship between DNA sequence and protein function?

DNA sequence → amino acid sequence → protein structure/conformation → protein function.

What carries out most biochemical functions?

Proteins.

What is the Central Dogma?

DNA → RNA → Protein.

What is DNA replication?

DNA serves as a template to produce complementary DNA.

What is transcription?

DNA serves as a template to produce complementary RNA.

What is translation?

mRNA serves as a template for protein synthesis.

What allows complementary DNA strands to form a double helix?

Specific hydrogen bonding between nucleotides (base pairing).

What is metabolism?

The process through which organisms acquire and use free energy and matter; it is the sum of the chemical transformations occurring in a life form.

What are examples of core metabolic pathways?

Glycolysis, the citric acid/Krebs/TCA cycle, and the urea cycle.

What is the fundamental structural unit of life?

The cell.

What features are shared by all cells?

A plasma membrane, cytoplasm/cytosol, ribosomes, and chromosome(s).

What are the three minimal molecular requirements for life?

Compartmentalization, self-replicating molecules, and catalysis.

What are the roles of DNA, RNA, and proteins in modern organisms?

DNA = information storage/template; RNA = information transmission; proteins = catalysts (enzymes).

What is the RNA world hypothesis?

Early life may have been based on self-replicating catalytic RNA.

Why could RNA theoretically have supported early life?

RNA can store information, act as a template, and some RNAs can catalyze chemical reactions.

What did the Miller-Urey experiment demonstrate?

Building blocks of biological macromolecules can form spontaneously under conditions simulating prebiotic Earth.

How do evolution and natural selection produce biological change?

Random changes such as mutations and gene duplications create variation; advantageous changes can increase survival and reproduction through natural selection.

What are ribozymes?

RNA molecules that can catalyze chemical reactions.

How are cells in multicellular organisms organized functionally?

Cells have specialized biochemical functions and use chemistry to communicate and coordinate with one another.