AnatomyandPhysiology ch 2

double helix

Structure of human DNA resembling a molecular spiral staircase.

chromosomes

Humans have 46 of these structures that organize DNA.

atom

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

subatomic particles

The three primary components of an atom: protons, neutrons, and electrons.

ionic bonds

Chemical bonds formed through the transfer of electrons between atoms.

covalent bonds

Chemical bonds formed by the sharing of electron pairs between atoms.

hydrogen bonds

Weak attractions between oxygen and hydrogen atoms in different molecules.

chemical reactions

Processes that involve the breaking and forming of chemical bonds.

inorganic compounds

Compounds that do not contain both carbon and hydrogen.

organic compounds

Compounds that contain carbon and hydrogen, typically large and complex.

proteins

Organic molecules that serve as the building blocks of tissues.

carbohydrates

Organic molecules made of carbon, hydrogen, and oxygen, used for energy.

lipids

Hydrophobic organic compounds involved in long-term energy storage.

nucleic acids

Molecules made up of nucleotides, essential for genetic information storage.

mass number

The sum of protons and neutrons in an atom's nucleus.

atomic number

The number of protons in an atom's nucleus that defines the element.

isotopes

Variants of an element with the same number of protons but different numbers of neutrons.

valence shell

The outermost electron shell of an atom involved in chemical reactions.

electrons

Negatively charged subatomic particles that orbit the nucleus of an atom.

protons

Positively charged particles found in the nucleus of an atom.

neutrons

Neutral particles found in the nucleus of an atom.

molecule

Two or more atoms chemically bonded together.

compound

A substance made up of two or more different elements joined by chemical bonds.

reactants

The starting substances in a chemical reaction.

products

The substances produced as a result of a chemical reaction.

enzymes

Proteins that act as catalysts in chemical reactions.

cations

Positively charged ions formed by the loss of one or more electrons.

anions

Negatively charged ions formed by the gain of one or more electrons.

synthesis reaction

A chemical reaction that combines simpler substances to form a more complex compound.

decomposition reaction

A chemical reaction that breaks down a compound into simpler products.

exchange reaction

A reaction where elements from two different compounds exchange places.

hydrolysis

A chemical reaction that breaks down a compound by adding water.

dehydration synthesis

A chemical reaction that forms a new compound while releasing water.

pH

A measure of the acidity or alkalinity of a solution.

buffer solution

A solution that resists changes in pH when small amounts of acid or base are added.

carboxyl group

A functional group characterized by -COOH, found in fatty acids and amino acids.

hydroxyl group

A functional group characterized by -OH, found in alcohols and carbohydrates.

amino group

A functional group characterized by -NH2, found in amino acids.

phosphate group

A functional group characterized by -PO4, found in nucleotides and phospholipids.

glycogen

A polysaccharide that serves as a form of energy storage in animals.

starches

Polysaccharides that are the main form of stored energy in plants.

cellulose

A polysaccharide that forms the primary structure of plant cell walls.

amino acids

The building blocks of proteins; contain an amino group, carboxyl group, and a side chain.

peptide bond

A covalent bond formed between two amino acids via dehydration synthesis.

ATP

A nucleotide that serves as the primary energy carrier in cells.

nucleotides

Building blocks of nucleic acids composed of a sugar, a phosphate group, and a nitrogenous base.

DNA

A nucleic acid that stores genetic information and is composed of deoxyribose and four nitrogenous bases.

RNA

A nucleic acid that helps convert the genetic code into proteins, containing ribose and uracil.

catabolic reaction

A type of reaction that breaks down larger molecules into smaller ones, releasing energy.

anabolic reaction

A type of reaction that builds larger molecules from smaller ones, requiring energy.

chemical energy

Energy stored in the bonds of chemical compounds that is released in chemical reactions.

mechanical energy

Energy associated with the motion of an object, including muscles and movements.

radiant energy

Energy transmitted in waves, such as light energy or electromagnetic radiation.

electrical energy

Energy resulting from the movement of charged particles, essential for nerve impulses.

hydrophilic

Substances that are water-loving and dissolve well in water.

hydrophobic

Substances that are water-fearing and do not dissolve well in water.

saturated fatty acids

Fatty acids that have no double bonds and are solid at room temperature.

unsaturated fatty acids

Fatty acids that contain one or more double bonds and are liquid at room temperature.

lipoproteins

Complexes of lipids and proteins that transport lipids in the blood.

cholesterol

A type of sterol that is important for cell membrane structure and function.

prostaglandins

Signaling molecules derived from unsaturated fatty acids that play roles in inflammation and pain.

glycoproteins

Proteins that are covalently bonded to carbohydrates, involved in cellular recognition.

glycolipids

Lipids with carbohydrate attachments, playing a role in membrane structure.

metabolism

The sum total of all chemical reactions that occur within a living organism.

homeostasis

The maintenance of stable internal conditions in the body despite external changes.

valence electrons

Electrons located in the outermost shell of an atom involved in chemical bonding.

octet rule

The principle that atoms tend to bond in such a way that they have eight electrons in their valence shell.

mass number

The sum of protons and neutrons in the nucleus of an atom.

atomic structure

The arrangement of protons, neutrons, and electrons in an atom.

periodic table

A tabular arrangement of the elements based on their atomic number and chemical properties.

solvent

A substance in which solutes are dissolved, forming a solution.

solute

A substance that is dissolved in a solvent to form a solution.

solution

A homogeneous mixture of two or more substances.

colloid

A mixture where small particles are dispersed throughout but not dissolved.

suspension

A mixture in which particles are temporarily suspended in a liquid but settle out over time.

molarity

A measure of concentration expressing the moles of solute per liter of solution.

millimoles

One-thousandth of a mole, often used in biochemical contexts.