biol 1306 unit 1

What are the four most abundant biological elements in living organisms?

Carbon (C), Hydrogen (H), Nitrogen (N), and Oxygen (O).

What is the atomic number?

The number of protons in an atom.

Define mass number.

The total number of protons and neutrons in an atom.

What is the mass unit for subatomic particles?

Dalton (Da), where 1 Da = 1x10⁻²⁴ g.

What are valence electrons?

The unpaired electrons in the outermost electron shell of an atom.

How does electronegativity change on the periodic table?

Electronegativity increases moving up and to the right.

What type of bond involves equal sharing of valence electrons?

Nonpolar covalent bond.

What creates partial charges in a polar covalent bond?

Differing electronegativities between atoms.

What results from the complete transfer of electrons between atoms?

Ionic bond.

What is a hydrogen bond?

A weak electrical attraction between a partially positive H atom and a partially negative electronegative atom.

What makes water an effective universal solvent?

Its polar nature and ability to form hydrogen bonds.

What is cohesion in terms of water properties?

The tendency of water molecules to stick to each other via hydrogen bonds.

What is the significance of the density anomaly of water?

Liquid water is denser than solid ice due to its open crystal lattice structure.

What is evaporative cooling?

The process by which water absorbs thermal energy, utilizing the high heat of vaporization.

How is pH measured?

On a logarithmic scale, where pH = -log[H⁺].

What is the neutral pH of pure water?

7.

Explain the theory of chemical evolution.

Complex carbon-containing molecules developed from simple environmental inputs, leading to biological evolution.

What does the First Law of Thermodynamics state?

Energy cannot be created or destroyed, only transferred or transformed.

What is potential energy in a chemical context?

Stored energy in chemical bonds.

Define spontaneous reactions.

Reactions that proceed if products have lower potential energy than reactants or if entropy increases.

What is the Prebiotic Soup Model?

Atmospheric gases formed an organic soup of complex compounds exposed to sunlight or lightning.

What did the Stanley Miller Experiment demonstrate?

It simulated early Earth conditions and synthesized precursors to life, such as amino acids.

What is a functional group in organic chemistry?

Specific groups of atoms within molecules that have characteristic properties.

How many covalent bonds can carbon form?

Four covalent bonds due to its four valence electrons.

What does the carboxyl group do in biological molecules?

Acts as an acid by donating protons (H⁺).

What stabilizes the secondary structure of proteins?

Hydrogen bonds between backbone carbonyl and amino groups.

What is a peptide bond?

Covalent bond formed between the carboxyl group of one amino acid and the amino group of another.

What is meant by protein tertiary structure?

The overall 3D spatial conformation of a single polypeptide chain.

What does the term 'oligopeptide' refer to?

A polypeptide with fewer than 50 amino acids.

Define quaternary protein structure.

Assembly of two or more distinct polypeptide subunits into a functional complex.

What are chaperones in protein biology?

Molecular chaperones that assist in proper protein folding.

What is the main role of enzymes?

To catalyze biochemical reactions by lowering activation energy.

What constitutes a nucleotide?

A phosphate group, a 5-carbon sugar, and a nitrogenous base.

Differentiate between ribose and deoxyribose.

Ribose has a hydroxyl group on the 2' carbon, while deoxyribose has a hydrogen atom instead.

What are purines?

Nitrogenous bases with a two-ring structure, specifically adenine (A) and guanine (G).

What type of bond forms the sugar-phosphate backbone of nucleic acids?

Phosphodiester bond.

Describe the base pairing in DNA.

Purines pair with pyrimidines: adenine pairs with thymine and guanine pairs with cytosine.

What role do hydrophobic interactions play in DNA?

They help stabilize the double helix structure.

What is the primary structure of RNA?

Contains ribose sugar, a sugar-phosphate backbone, and bases A, U, G, C.

How do ribozymes function?

They have active sites that catalyze chemical reactions, demonstrating RNA's catalytic capabilities.

What is the general formula for monosaccharides?

(CH₂O)n, where n is the number of carbon-hydrate units.

Define glycosidic linkage.

A covalent bond formed between monosaccharides during condensation reactions.

What are the two types of energy storage polysaccharides?

Starch in plants and glycogen in animals.

What distinguishes cellulose from starch?

Cellulose consists of beta-glucose monomers, while starch is made of alpha-glucose monomers.

Define lipid structure in terms of solubility.

Lipids are insoluble in water due to high proportions of nonpolar hydrocarbon chains.

What defines saturated fatty acids?

Fatty acids that contain only single bonds between carbon atoms.

What are phospholipids?

Molecules made of a glycerol, two fatty acids, and a phosphate group.

How do bilayers form in aqueous environments?

Phospholipids arrange with hydrophobic tails inward and hydrophilic heads outward.

What is selective permeability in membranes?

The condition where some substances cross the membrane more easily than others.

Define passive transport.

Movement of substances across a membrane without energy input.

What is the function of the sodium-potassium pump?

To transport sodium out of the cell and potassium into the cell against their concentration gradients.

What is a nuclear localization signal (NLS)?

A sequence that tags proteins for entry through the nuclear pore complex.

What is the primary function of ribosomes?

To synthesize proteins.

What is the role of the Golgi apparatus?

Processing, sorting, and shipping proteins, lipids, and carbohydrates.

Define phagocytosis.

The process where the plasma membrane engulfs large particles to form a phagosome.

What role do motor proteins play in the cytoskeleton?

They facilitate movement along microtubule tracks.

What is the structure of eukaryotic flagella?

Membrane-bound structures that move in a whiping motion.

What is the structural arrangement of cilia?

Cilia have a "9 + 2" arrangement of microtubules.