KAP biology unit 1.2 Vocabulary

Macromolecules

are large, complex molecules essential to life, built by linking smaller chemical units together.

main classes of biological macromolecules

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic Acids

Carbohydates

Energy-rich molecules made of carbon, hydrogen, and oxygen

Primary Functions: provide fast energy

Lipids

A diverse group of hydrophobic (water - fearing) molecules,commonly known as fats and oils

Protein

an essential macronutrient made of amino acid chains that builds and repairs tissues,powers chemical reactions, and supports immune health in the body.

What Protein Does

1. Building blocks: forms muscles, bones, skin, hair and organs.

2. Enzymes and hormones: Powers chemical reactions and coordinates biologic processes.

3. Defense: Creates antibodies to fight infections and protect the body.

Nucleic acids

large biological molecules essential for all known forms of life, serving as the primary information-carrying molecules of the cell. They store, transmit, and express genetic instructions needed to build and operate organisms.

Main Types of Nucleic Acids

DNA and RNA

RNA

Typically single-stranded. It acts as a template and messenger, translating the genetic information stored in DNA into functional proteins.

DNA

Usually double-stranded in a twisted double helix shape. It holds the master genetic blueprint for an organism's traits and functions.

Biomolecule

are chemical substances produced by living organisms that drive essential cellular processes, ranging from structure and growth to energy storage and genetic reproduction.

Monomer

a small, basic molecule that can bind chemically with other identical or similar molecules to form a larger, complex structure called a polymer.

Polymer

a large macromolecule made up of many repeating smaller units (monomers) chemically bonded together in a long chain.

Fatty acids

are organic molecules that serve as key building blocks for lipids (fats and oils). They consist of a long hydrocarbon chain attached to an acidic carboxyl group (-COOH) at one end.

Unsaturated Fat

Contain one or more double bonds between carbon atoms, creating bends or "kinks" in the chain. They are usually liquid at room temperature (e.g., olive oil, vegetable oil).

Saturated Fat

Have only single carbon-carbon bonds, packing tightly together. They are typically solid at room temperature (e.g., butter, lard).

Amino acid

small organic molecules that serve as the building blocks (monomers) of proteins. When linked together by peptide bonds in long chains, they fold into functional 3D proteins.

Enzyme

a specialized protein that acts as a biological catalyst, speeding up chemical reactions in living organisms without being permanently changed or consumed in the process.

Inorganic

matter or chemical compounds that are not derived from living organisms and generally do not contain carbon-hydrogen ($\text{C-H}$) bonds.

DNA

Deoxyribonucleic Acid

RNA

Ribonucleic Acid

Nucleotide

the basic chemical unit (monomer) that links together to form long chains of nucleic acids, such as DNA and RNA.

Dehydration Synthesis

a chemical reaction in which two smaller molecules (monomers) combine to form a larger molecule (polymer), releasing a molecule of water as a byproduct.

Hydrolysis

a chemical reaction in which a molecule of water is used to break down a larger chemical compound (polymer) into smaller units (monomers).

Hydrolysis

direct reverse of dehydration synthesis.

organic

chemical compounds centered around carbon atoms, typically bound to hydrogen ($\text{C-H}$ bonds), as well as oxygen, nitrogen, and other life-essential elements.

monosaccharide

the simplest form of carbohydrate, consisting of a single sugar molecule. Because they cannot be broken down into simpler sugars

monosaccharide

serve as the basic monomer building blocks for complex carbohydrates like disaccharides and polysaccharides.

polysaccharide

a complex carbohydrate polymer composed of long chains of simple sugar monomers (monosaccharides) linked together by glycosidic bonds.

phospholipid

a class of lipid molecule that forms the primary structural component of all cell membranes.

Bilayer

a thin, two-layered membrane composed of lipid molecules that forms the fundamental continuous barrier around all living cells and intracellular organelles.

hydrophilic

describes molecules or chemical substances that interact favorably with water and dissolve easily in it

hydrophobic

describes nonpolar molecules or chemical substances that repel water and do not dissolve in it.

Common Biological Examples of hydrophobic

oils and fats

Common Biological Examples of hydrophobic

Waxes: Found on plant leaves and bird feathers to create water-repelling protective barriers.

Common Biological Examples of hydrophilic

Salts and sugars

solution

a uniform mixture made when one substance dissolves completely into another

semipermeable

describes a barrier or membrane that allows certain molecules or ions to pass through while blocking others.

passive transport

the movement of substances across a cell membrane without requiring cellular energy (ATP). Molecules naturally move down their concentration gradient, shifting from an area of higher concentration to an area of lower concentration until equilibrium is reached.

diffusion

the natural movement of particles from an area of higher concentration to an area of lower concentration until they are evenly spread out.

osmosis

the movement of water molecules across a semipermeable membrane from a region of lower solute concentration (higher water concentration) to a region of higher solute concentration (lower water concentration).

concentration gradient

the difference in the concentration of a solute between two adjacent areas or across a cell membrane.

solute

a substance that is dissolved in a fluid (the solvent) to create a uniform mixture called a solution.

isotonic

the same concentration of dissolved solutes as the fluid inside a cell

Hypertonic

has a higher concentration of dissolved solutes (like salt or sugar) compared to the inside of a cell.

Hypotonic

has a lower concentration of dissolved solutes (like salt or sugar) compared to the inside of a cell.

plasmolysis

the process where a plant cell loses water when placed in a hypertonic solution, causing its cell membrane and cytoplasm to shrink and pull away from the rigid cell wall.

lysis

the breaking down or rupture of a cell's outer membrane, leading to the release of its internal contents and the death of the cell.

lysis

from the Greek word for "unbinding" or "loosening"

turgor pressure

the force exerted outward by water inside a plant cell pressing its cell membrane against the rigid outer cell wall.

facilitated diffusion

a type of passive transport that moves molecules across a cell membrane with the help of specialized membrane proteins.

active transport

the movement of molecules or ions across a cell membrane against their concentration gradient (from an area of lower concentration to an area of higher concentration), requiring cellular energy in the form of ATP.

homeostasis

the self-regulating process by which a biological system maintains a stable internal environment despite continuous changes in external conditions.

endocytosis

a cellular process in which a cell engulfs extracellular material by folding its plasma membrane inward to form a membrane-bound vesicle.

exocytosis

a cellular process where a cell expels materials by fusing internal vesicles with the plasma membrane. It is the functional opposite of endocytosis.

polymerization

a chemical process in which small, individual molecules called monomers bond together to form long, repeating chains or three-dimensional networks called polymers.