Lecture 2 – Molecular Building Blocks

These flashcards cover key concepts from Lecture 2 of BICD 110 Cell Biology, focusing on molecular building blocks and their significance in cellular structure and function.

What was the last eukaryote common ancestor (LECA) estimated to have existed?

1.5 to 2 billion years ago.

Who are key scientists that contributed to the founding of cell biology?

Hooke, Leeuwenhoek, Schleiden, Schwann, Virchow, Palade.

What are the three tenets of cell theory?

1) All living organisms are made of cells. 2) The cell is the basic unit of life. 3) All cells arise from pre-existing cells.

What is the relationship between wavelength and energy in the visible spectrum of light?

Lower wavelength corresponds to higher energy.

What technology is used for live-cell microscopy?

Recombinant proteins, GFP (Green Fluorescent Protein).

What is the difference between SEM and TEM in electron microscopy?

SEM (Scanning Electron Microscopy) provides 3D images, while TEM (Transmission Electron Microscopy) provides detailed internal structure.

What are the two types of noncovalent interactions?

Ionic and hydrogen bonds.

What unit of measurement is the binding dissociation constant (Kd)?

A measure of affinity between two molecules, with lower values indicating stronger associations.

What drives the hydrophobic effect?

Entropy: it maximizes disorder by aggregating nonpolar substances together.

What is the significance of a phospholipid bilayer?

It forms a semi-permeable membrane, critical for cellular structure.

What are the four key concepts of chemistry of life related to molecules?

1) Molecular complementarity, 2) Polymerization, 3) Chemical equilibrium, 4) Energy.

What are the four macromolecules mentioned in the notes?

1) Proteins, 2) Nucleic acids, 3) Carbohydrates, 4) Lipids.

What are disulfide bonds and where do they play a role?

They stabilize protein structure by forming covalent links between cysteine side chains.

What is the primary structure of proteins?

The linear sequence of amino acids linked by peptide bonds.

How do amino acid side chains affect proteins?

They determine the properties and function of individual proteins.

What is a peptide bond?

A bond formed by a dehydration reaction linking one amino acid's C-terminus to another's N-terminus.

Describe the role of cholesterol in cellular membranes.

Cholesterol regulates membrane fluidity and decreases permeability.