Biochemistry Test 1 Flashcards
Why are cells considered the fundamental unit of life?
They make up every aspect of life.
What are the three domains of living organisms?
Archaea, Bacteria, Eukarya
Plasma Membrane
thin, flexible, hydrophobic barrier around the cell; composed of lipids and proteins; contains transport proteins, receptor proteins, and membrane enzymes
Cytoplasm
internal volume enclosed by the plasma membrane; composed of cytosol
Cytosol
highly concentrated solution; contains enzymes, RNA, amino acids, nucleotides, metabolites, and inorganic ions
What are the four major classes of biomolecules and what are they used to build?
- Proteins: enzymes, structural elements, signal receptors, transporters
- Nucleic Acids: DNA and RNA; store and transmit genetic information, some RNA molecules have structural and catalytic roles in supramolecular complexes
- Polysaccharides: polymers of simple sugars; energy rich fuel stores; structural components of cell walls; extracellular recognition elements that bind to proteins on other cells
- Lipids: water insoluble hydrocarbons; structural components of membranes, energy rich fuel stores, pigments, intracellular signals
What does it mean that living organisms exist in a dynamic steady state (avoiding equilibrium) with their surroundings?
Living organisms stay in a dynamic steady state, never reaching equilibrium. The laws of Thermodynamics state that living organisms extract energy from their surroundings and use it to maintain homeostasis.
Where do cells store information needed to build proteins and carry out self-replication and self-assembly? What biomolecule is used to store the information?
DNA; Nucleic Acids
Mutation
change in nucleotide sequence
Wild Type
normal; unmutated
The textbook claims life arose by chance over long periods of time from pools of chemicals. What are some objections to this model for the origin of life?
The laboratory that the experiments were ran in are unable to replicate the real world. There are not perfectly pure chemicals in the real world and the climate is not controlled like it is in the lab.
The textbook assumes that genetic similarity is only (or best) explained by common descent. What is another possible explanation for genetic similarity?
Genetic similarity could exist due to common design instead of common descent. Common design shows that the reasoning for the similarity could be because it was the best way, not just the only one.
Why is the origin of life a “chicken or egg question”?
It is a chicken or an egg question because no one is sure what organism came first. “No chicken without the egg. No egg without the chicken”
What is meant by saying the biological molecules are interdependent?
The biological molecules are interdependent due to Causal Circularity: product of one part of the process is used in the next part of the process.
What is a hydrogen bond?
The electrostatic interaction between the oxygen on 1 H2O molecule with the hydrogen on a second H2O molecule
How many hydrogen bonds are formed in ice vs. liquid H2O?
Ice: 4 H bonds
Liquid: 3.4 H bonds
Polar
Hydrophilic, or water loving, soluble in water
Nonpolar
Hydrophobic, poorly soluble in water
Amphipathic
containing both polar and nonpolar domains