Biomolecules - Lesson 2 Notes

Vocabulary flashcards covering atoms, biomolecules, carbohydrates, proteins, lipids, nucleic acids, amino acids, and related concepts from the Lesson 2 notes.

Atom

Fundamental unit of an element; consists of protons and neutrons in the nucleus and electrons orbiting the nucleus.

Molecule

Two or more atoms bonded chemically.

Subatomic particles

Protons (positive), neutrons (neutral), and electrons (negative) that compose atoms.

Nucleus

Center of an atom containing protons and neutrons.

Proton

Positively charged subatomic particle within the nucleus.

Neutron

Electrically neutral subatomic particle within the nucleus.

Electron

Negatively charged subatomic particle orbiting the nucleus.

Biomolecule

Organic molecules produced by living organisms; include carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrate

Biomolecule class; main energy source; composed of carbon, hydrogen, and oxygen in a ~1:2:1 ratio; many are hydrophilic.

Glucose

Monosaccharide and primary energy source for the body; chemical formula C6H12O6.

Monosaccharide

Simple sugar; the monomer of carbohydrates (e.g., glucose, fructose, galactose).

Fructose

Fruit sugar; found in fruits and honey.

Galactose

Milk sugar; found in dairy products.

Disaccharide

Two monosaccharides joined by a glycosidic bond (e.g., sucrose, lactose, maltose).

Glycosidic bond

Bond that links monosaccharides in disaccharides.

Sucrose

Disaccharide formed from glucose and fructose; common table sugar.

Lactose

Disaccharide formed from glucose and galactose; main sugar in milk.

Maltose

Disaccharide formed from two glucose molecules.

Polysaccharide

Long chains of monosaccharides; complex carbohydrates that provide energy over time.

Starch

Plant energy storage polysaccharide.

Glycogen

Animal energy storage polysaccharide; stored in liver and muscles.

Cellulose

Plant cell wall polysaccharide; provides structural support; indigestible by humans (dietary fiber).

Chitin

Polysaccharide found in insect exoskeletons and fungal cell walls.

Lipids

Organic compounds primarily composed of carbon and hydrogen; hydrophobic or amphipathic; energy-dense and versatile components of cells.

Triglycerides

Glycerol backbone with three fatty acid chains; main form of fat; energy storage; can be saturated or unsaturated.

Saturated fat

Fat with no double bonds between carbon atoms; tends to raise LDL cholesterol.

Unsaturated fat

Fat with one or more double bonds; tends to lower LDL and raise HDL.

Phospholipids

Glycerol with two fatty acid tails and a phosphate-containing head; amphipathic and main component of cell membranes forming bilayers.

Steroids

Lipids with four fused carbon rings; include cholesterol and steroid hormones (testosterone, estrogen, cortisol).

Cholesterol

Steroid lipid; component of membranes and precursor for steroid hormones.

Waxes

Long-chain fatty acid plus long-chain alcohol; hydrophobic; provide waterproofing.

Glycolipids

Lipids with carbohydrate groups; involved in membrane structure, recognition, signaling, especially in nerve cells.

Nucleic Acids

Biomolecules that store and transmit genetic information; includes DNA and RNA.

DNA

Deoxyribonucleic acid; genetic material that stores hereditary information.

RNA

Ribonucleic acid; mediates gene expression and protein synthesis.

Protein

Large, complex molecules built from amino acids; perform structural, enzymatic, transport, hormonal, and immune functions.

Amino acids

Building blocks of proteins; linked by peptide bonds.

Essential amino acids

Nine amino acids that the body cannot synthesize and must be obtained from diet.

Histidine (His, H)

Essential amino acid; important for growth, tissue repair, and nerve protection.

Isoleucine (Ile, I)

Essential amino acid; involved in energy regulation and muscle metabolism.

Leucine (Leu, L)

Essential amino acid; stimulates muscle protein synthesis.

Lysine (Lys, K)

Essential amino acid; important for calcium absorption and hormone production.

Methionine (Met, M)

Essential amino acid; starts protein synthesis; involved in metabolism.

Phenylalanine (Phe, F)

Essential amino acid; precursor of neurotransmitters (dopamine).

Threonine (Thr, T)

Essential amino acid; maintains healthy skin and teeth; supports metabolism.

Tryptophan (Trp, W)

Essential amino acid; precursor of serotonin and melatonin.

Valine (Val, V)

Essential amino acid; supports muscle growth and energy production.

Non-essential amino acids

Amino acids that can be synthesized by the body; some are conditionally essential in certain states.

Alanine (Ala, A)

Non-essential amino acid.

Arginine (Arg, R)

Non-essential amino acid; conditionally essential in some states.

Asparagine (Asn, N)

Non-essential amino acid.

Aspartic acid (Asp, D)

Non-essential amino acid.

Cysteine (Cys, C)

Non-essential amino acid containing sulfur.

Glutamic acid (Glu, E)

Non-essential amino acid; neurotransmitter precursor (glutamate).

Glutamine (Gln, Q)

Non-essential amino acid; important for nitrogen transport and metabolism.

Glycine (Gly, G)

Non-essential amino acid.

Proline (Pro, P)

Non-essential amino acid; contributes to collagen structure.

Serine (Ser, S)

Non-essential amino acid; involved in metabolism.

Tyrosine (Tyr, Y)

Non-essential amino acid; conditionally essential; precursor to dopamine and thyroid hormones.

Hydrophobic

Water-repelling property; lipids are largely hydrophobic.

Hydrophilic

Water-attracting property; many carbohydrates are hydrophilic.

Omega-3 fatty acids

Type of polyunsaturated fats important for brain development, mood, and cognitive function.