Biology Chapter 2: Chemical Basis of Life

Anything that occupies space and has mass.

A pure substance that cannot be broken down into simpler substances by ordinary chemical means.

Substances formed when two or more different elements combine in a fixed ratio.

Characteristics of a compound that are different from the characteristics of its individual elements.

Elements that are essential for life and are present in the body in small amounts.

Elements required by all life forms.

Elements that make up about 99% of the human body.

Elements necessary for specific organisms, like iodine for vertebrates.

The smallest unit of matter that retains the properties of an element.

A positively charged particle found in the nucleus of an atom.

A negatively charged particle that orbits the nucleus of an atom.

A neutral particle found in the nucleus of an atom.

The number of protons in an atom's nucleus, which determines the identity of an element.

Atoms of the same element that have different numbers of neutrons.

The outermost shell of an atom, containing electrons that participate in chemical bonding.

The number of electrons an atom needs to gain or lose to achieve a full outer shell.

Atoms with incomplete valence shells tend to interact with other atoms to fill their outer shells.

A chemical bond formed by the sharing of electrons between two atoms.

The attraction between shared electrons and the nucleus of an atom is measured by its electronegativity.

A covalent bond where electrons are shared equally between two atoms with similar electronegativity.

A covalent bond where electrons are shared unequally between two atoms with different electronegativity.

A chemical bond formed by the transfer of electrons between two atoms, creating an attraction between oppositely charged ions.

A weak bond that occurs when a hydrogen atom, covalently bonded to a more electronegative atom like oxygen or nitrogen, is attracted to another electronegative atom in a different molecule or a different part of the same molecule.

A molecule with an uneven distribution of charges, resulting in regions with partial positive and partial negative charges.

Hydrogen bonds are critical for holding the two strands of a DNA molecule together, enabling the transfer of genetic information.

Hydrogen bonds contribute significantly to the three-dimensional shape of proteins, influencing their function.

Most drugs are manufactured as salts because they are stable when dry and dissolve easily in water.

Water molecules have a partial positive charge on their hydrogen atoms and a partial negative charge on their oxygen atom due to the polar covalent bonds between them.

The ability of water molecules to form hydrogen bonds with up to four other water molecules.

Hydrogen bonds are a type of weak bond that is crucial for many biological processes, including the properties of water and the structure of DNA and proteins.

The tendency of molecules of the same kind to stick together. This is especially strong for water.

The clinging of one substance to another. This is important for water transport in plants.

A substance that is dissolved. It's the smaller component in a solution.

The dissolving agent. It's the larger component in a solution.

A liquid consisting of a uniform mixture of two or more substances.

The energy associated with the random movement of atoms and molecules. It's related to temperature.

The transfer of thermal energy from a warmer to a cooler body.

The average kinetic energy of molecules within a substance. Higher temperature means faster molecular motion.

A solution where water is the solvent.

A measure of a solution's acidity or basicity, ranging from 0 (most acidic) to 14 (most basic).

A substance that increases the hydrogen ion (H+) concentration in a solution.

A substance that decreases the hydrogen ion (H+) concentration in a solution.

The process where a tiny fraction of water molecules break apart into hydrogen ions (H+) and hydroxide ions (OH-).

Carbon's ability to form four covalent bonds with other atoms, enabling the creation of a wide variety of complex organic molecules.

The basic framework of most organic molecules, formed by chains of carbon atoms.

Molecules with the same molecular formula but different structural arrangements.

The three-dimensional shape of a molecule, which often determines its function.

Compounds that contain carbon bonded to other elements, particularly hydrogen.

Molecules composed solely of carbon and hydrogen atoms.

Isomers that differ in their arrangement of atoms around a double bond.

Isomers with the same molecular formula but different arrangements of atoms.

Mirror images of each other. They have the same connections but differ in their 3D arrangement.

A chemical group containing a carbon atom linked to an oxygen atom with a double bond.

A chemical group consisting of a hydrogen atom bonded to an oxygen atom.

A nonpolar and non-reactive chemical group that influences molecular shape and function.

A type of lipid that serves as the primary energy storage molecule in living organisms.

A three-carbon molecule with three hydroxyl groups (-OH) attached to each carbon.

A long hydrocarbon chain attached to a carboxyl group (-COOH).

A fat molecule composed of three fatty acids linked to a glycerol molecule.

A fatty acid with one or more double bonds in its hydrocarbon chain, causing kinks or bends.

A fatty acid with no double bonds in its hydrocarbon chain, making it straight.

The process by which water is removed to link two molecules together.

The opposite of dehydration, where water is added to break a bond between two molecules.

A protein's overall shape, described as either globular or fibrous.

A macromolecule, usually a protein, that acts as a biological catalyst, speeding up chemical reactions without being consumed.

The process where a protein loses its specific shape and function due to factors like heat or changes in pH.

The unique three-dimensional structure of a protein, determined by its amino acid sequence and interactions.

The building blocks of proteins, each composed of an amino group, a carboxyl group, a hydrogen atom, and a variable R group.

A covalent bond that links amino acids together to form a polypeptide chain.

A chemical group that determines the properties of an amino acid, influencing its interactions and protein structure.

The characteristic of an amino acid's R group, either nonpolar (hydrophobic) or polar (hydrophilic).

The main component of cell membranes, made up of a glycerol molecule linked to two fatty acids and a phosphate group. They have a hydrophilic head and hydrophobic tails.

The process of adding hydrogen to unsaturated fats, converting them into saturated fats. It can also produce unhealthy trans fats.

A type of lipid that is a four-ring structure. Examples include cholesterol and hormones.

The function of fats in the body. They store energy more efficiently than carbohydrates. They also cushion organs and insulate the body.

Cells rely on phospholipids for their membranes, as they create a barrier between the cell and its environment due to their unique structure.

The primary structure of a polypeptide determines the shape of a protein. This structure is determined by the sequence of amino acids, which is programmed by genes.Genes are made of DNA, a nucleic acid found in cell nuclei.

RNA is another type of nucleic acid. RNA helps assemble polypeptides based on DNA's instructions.

Nucleic acids are polymers made of monomers called nucleotides. Each nucleotide has three parts: a 5-carbon sugar, a phosphate group, and a nitrogenous base.

DNA's sugar is deoxyribose, while RNA has ribose. Ribose has an extra oxygen atom compared to deoxyribose.

The phosphate group in nucleotides is negatively charged. It's linked to the sugar on one side.

Nitrogenous bases: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G) are found IN DNA. RNA has Uracil (U) instead of Thymine.

A polynucleotide is a chain of nucleotides linked by dehydration reactions. This forms the sugar-phosphate backbone, with bases sticking out.

DNA forms a double helix with two polynucleotide strands. The bases pair up in the center: A with T, and C with G. These bonds hold the strands together.