Chapter 2: The Chemical Level of Organization

Vocabulary flashcards covering key terms and concepts from Chapter 2: The Chemical Level of Organization.

Calcium

Essential mineral required for bone formation; obtained from dietary sources such as dairy products.

Oxygen

Essential element for cellular respiration; obtained from the air.

Hydrogen

Lightest element; major component of water and organic molecules.

Carbon

Element fundamental to all organic molecules; backbone of life.

Nitrogen

Essential element in amino acids and nucleic acids.

Compound

Substance composed of two or more elements joined by chemical bonds.

Glucose

Monosaccharide; primary energy source in the body; composed of carbon, hydrogen, and oxygen.

Atom

Smallest unit of an element that retains its properties; made of protons, neutrons, and electrons.

Proton

Positively charged subatomic particle in the nucleus.

Neutron

Electrically neutral subatomic particle in the nucleus.

Electron

Negatively charged subatomic particle orbiting the nucleus.

Planetary model

Atom model with electrons in fixed orbits around the nucleus.

Electron cloud model

Atom model where electrons occupy regions of space around the nucleus rather than fixed orbits.

Isotope

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

Radioactive isotope

Isotope whose nucleus decays, emitting particles and energy.

Radioactive Tracer

Used to show how an organ is functioning in real time. Used in PET scan

Carbon-12

Stable carbon isotope with 6 protons and 6 neutrons.

Carbon-13

Isotope of carbon with 6 protons and 7 neutrons.

Carbon-14

Radioactive carbon isotope with 6 protons and 8 neutrons.

Radioembolization

Interventional radiology procedure that introduces radioactive seeds into blood vessels feeding liver tumors to destroy them.

PET scan

Positron Emission Tomography

Monosaccharide

Simple sugar; basic unit of carbohydrates (e.g., glucose, fructose, galactose, deoxyribose, ribose).

Glucose

Monosaccharide. (Hexoses)

Fructose

Monosaccharide found in fruits (Hexoses)

Galactose

Monosaccharide component of lactose. (Hexoses)

Deoxyribose

Pentose sugar in DNA.

Ribose

Pentose sugar in RNA.

Disaccharide

Two monosaccharides linked together (e.g., sucrose, lactose, maltose).

Sucrose

Disaccharide; Table sugar; glucose linked to fructose.

Lactose

Disaccharide; Milk sugar; glucose linked to galactose.

Maltose

Disaccharide; found in multigrain or germinating seeds.

Polysaccharide

Large carbohydrate composed of many monosaccharide units (e.g., starch, glycogen, cellulose).

Starch

Plant storage polysaccharide; consists of amylose and amylopectin.

Amylose

Linear component of starch (unbranched glucose polymer).

Amylopectin

Branched component of starch (branched glucose polymer).

Glycogen

Animal storage polysaccharide; highly branched; stored in liver and muscle.

Cellulose

Structural polysaccharide in plant cell walls; dietary fiber; not digestible by humans.

Phospholipid

Lipid with two fatty acids, glycerol, and a phosphate group; forms cell membranes and regulates permeability.

Sterol

Ring-shaped lipid; cholesterol is a key example; component of membranes and hormone precursors.

Prostaglandin

Lipid derived from unsaturated fatty acids; involved in inflammation and clotting; example: PGE2.

Prostaglandin Function

Helps with blood clotting at site of tissue injury or infection

Amino acid

Building block of proteins; some are essential, others nonessential.

Amino acid structure

Amino group in the front, side chain, carboxyl group in the back

Essential amino acid

Amino acids not synthesized by the body and must be obtained from the diet; nine total.

Nonessential amino acid

Amino acids that the body can synthesize; not required in the diet.

Tryptophan

Essential amino acid; precursor to serotonin and melatonin (sleep regulation).

Glutamine

Nonessential amino acid; important for tissue repair and DNA biosynthesis.

Peptide bond

Bond formed between amino acids during dehydration synthesis to build peptides, polypeptides, or proteins.

Dehydration synthesis

How amino acids join to form peptides, polypeptides, or proteins. Water loss

Primary structure

Linear sequence of amino acids in a polypeptide.

Secondary structure of proteins

Local folding patterns like alpha-helix or beta-pleated sheet held by hydrogen bonds.

Tertiary structure of proteins

folding and bonding of the secondary structure.

Quaternary structure of proteins

interactions between two or more tertiary subunits (e.g., hemoglobin).

Enzyme

Biological catalyst that speeds up chemical reactions by lowering activation energy.

Active site

Region of an enzyme where the substrate binds.

Enzyme–substrate complex

Temporary complex formed when a substrate binds to an enzyme.

Nucleotides

Building blocks of DNA and RNA; consist of a nitrogenous base, a pentose sugar, and a phosphate.

Purine

Double-ring nitrogenous bases (adenine, guanine).

Pyrimidine

cytosine, thymine, uracil in RNA

Adenine

Purine base that pairs with thymine in DNA and with uracil in RNA.

Thymine

Pyrimidine base that pairs with adenine in DNA.

Guanine

Purine base that pairs with cytosine.

Cytosine

Pyrimidine base that pairs with guanine.

Base pair

Two nucleobases on opposite DNA strands that pair together (A–T and G–C in DNA; A–U and G–C in RNA).

Double helix

Structure of DNA; two polynucleotide strands winding around each other.

DNA

Deoxyribonucleic acid; stores genetic information; typically organized into 46 chromosomes in humans.

RNA

Ribonucleic acid; single-stranded; mediates genetic decoding and protein synthesis.

Genome

Complete set of genetic material in an organism.

Human Genome Project

International effort (1990–2003) to sequence the human genome and other organisms, improving disease diagnosis and transplantation matching.

Chromosome

Single strand of DNA wrapped around histone proteins; carriers of genetic information; humans have 46 in each cell.

Histone

Protein around which DNA winds to form chromosomes; essential for packing DNA into the nucleus.

Nucleus

Cellular organelle that houses the DNA; highly organized with minimal empty space.

Sanger sequencing

A DNA sequencing method to determine the exact order of the bases in DNA (A, C, G, T).

What percentage of the body’s glucose does the brain use?

25%

Phospholipid function

Regulation of cell permeability

Phospholipid structure

1 polar head, 2 non-polar tails

Examples of essential amino acids (9 total)

Tryptophan & Lysine

Structure of amino acid

Amino group in front, side chain, carboxyl group in the back

Sickle-call anemia

genetic material is damaged, changes in hemoglobin molecule

3 uses for the genome project

Improved diagnosis of diseases, Earlier detection of genetic predisposition, organ transplantation matching

What binds the phosphorous-containing group (head) to the nonpolar fatty acid chains in a phospholipid?

Glycerol backbone

What binds the Amino group to the carboxyl group in an amino acid?

R chain. (May differ)