Final exam/ cumulative

Atom

Smallest unit of matter; composed of protons, neutrons, and electrons.

Element

Substance made of one kind of atom.

Compound

A substance formed from two or more elements chemically bonded together.

Covalent bonds

Chemical bonds formed when atoms share electrons.

Hydrogen bonds

Weak attractions between a hydrogen atom and an electronegative atom.

Ions

Atoms that have a net positive or negative charge due to the loss or gain of electrons.

Cohesion

The attraction between molecules of the same substance, such as water.

Adhesion

The attraction between different substances, such as water and plant cell walls.

pH

A measure of the acidity or basicity of a solution; acidic if less than 7, basic if greater than 7.

Buffers

Substances that help maintain a stable pH in biological systems.

Carbohydrates

Macromolecules made of monosaccharides; serve as quick energy and structural components.

Lipids

Hydrophobic macromolecules made from fatty acids and glycerol, used for energy storage and membrane structure.

Proteins

Macromolecules made of amino acids; play crucial roles in structure, enzymes, and signaling.

Nucleic acids

Macromolecules made of nucleotides; include DNA and RNA, which store genetic information.

Prokaryotes

Cells without a nucleus or membrane-bound organelles.

Eukaryotes

Cells that contain a nucleus and membrane-bound organelles.

Organelles

Specialized structures within a cell that perform distinct functions.

Cell membrane

A phospholipid bilayer that surrounds and protects the cell, maintaining selective permeability.

Double helix

The shape of DNA consisting of two antiparallel strands twisted around each other.

Sugar-phosphate backbone

The structural framework of DNA, consisting of alternating sugar and phosphate groups.

Base pairing

The specific hydrogen bonding between nitrogenous bases in DNA; A-T and G-C.

Euchromatin

Loosely packed form of chromatin that is active in gene expression.

Heterochromatin

Tightly packed form of chromatin that is generally inactive in gene expression.

Kinetic energy

Energy of motion, such as that found in moving muscles.

Thermal energy

A form of kinetic energy arising from the movement of atoms and molecules.

Potential energy

Stored energy, such as that found in chemical bonds.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed.

Second Law of Thermodynamics

The total entropy of an isolated system can never decrease over time.

Free energy (G)

The energy in a physical system that can be converted into work.

Exergonic reaction

A reaction that releases energy, characterized by a negative ΔG.

Endergonic reaction

A reaction that requires an input of energy, characterized by a positive ΔG.

Catabolism

The metabolic pathway that breaks down molecules to release energy.

Anabolism

The metabolic pathway that builds molecules and requires energy.

Energy coupling

The use of energy released from catabolism to drive anabolism.

ATP

Adenosine triphosphate; the primary energy currency of the cell.

Hydrolysis of ATP

The reaction in which ATP is broken down into ADP and inorganic phosphate, releasing energy.

Enzymes

Biological catalysts that speed up chemical reactions by lowering activation energy.

Active site

The specific region of an enzyme where substrate molecules bind.

Competitive inhibition

A form of enzyme inhibition where a substance competes with the substrate for the active site.

Noncompetitive inhibition

A form of enzyme inhibition where an inhibitor binds to an enzyme away from the active site, altering its shape.

Glycolysis

The first stage of cellular respiration where glucose is broken down into pyruvate, producing ATP and NADH.

Pyruvate oxidation

The process by which pyruvate is converted into Acetyl-CoA, releasing CO2 and producing NADH.

Citric Acid Cycle

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of Acetyl-CoA.

Oxidative phosphorylation

The final stage of cellular respiration where ATP is produced using energy from the electron transport chain and chemiosmosis.

Substrate-level phosphorylation

A type of ATP production that occurs when a phosphate group is directly transferred to ADP from another molecule.

Chemiosmosis

The movement of ions across a selectively permeable membrane, down their electrochemical gradient, which drives ATP synthesis.

Fermentation

An anaerobic process that regenerates NAD+ from NADH to allow glycolysis to continue.

Photosynthesis

The process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose.

Light reactions

The first stage of photosynthesis, where light energy is converted into chemical energy (ATP and NADPH) and oxygen is produced.

Calvin Cycle

The second stage of photosynthesis, where carbon dioxide is converted into glucose using ATP and NADPH.

Mitosis

Cell division process that results in two identical daughter cells from a single parent cell.

Meiosis

A type of cell division that produces four non-identical haploid gametes from a single diploid cell.

Crossing over

The exchange of genetic material between homologous chromosomes during Prophase I of meiosis.

Independent assortment

The random distribution of homologous chromosomes during meiosis.

Random fertilization

The chance combination of different gametes to form a zygote.

Semi-conservative replication

The method of DNA replication where each new DNA molecule contains one original strand and one newly synthesized strand.

Point mutation

A mutation affecting only one or a few nucleotides in a gene sequence.

Inheritance

The transmission of genetic information from one generation to the next.

Gene

A segment of DNA that contains the instructions for making a specific protein.

Allele

A variant form of a gene.

Homozygous

Having two identical alleles for a given gene.

Heterozygous

Having two different alleles for a given gene.

Dominant allele

An allele that is expressed in the phenotype if present.

Recessive allele

An allele that is masked in the phenotype unless two copies are present.

Segregation

The principle that alleles separate during the formation of gametes.

Non-Mendelian inheritance

Inheritance patterns that do not follow Mendel's laws of segregation and independent assortment.

Incomplete dominance

A form of inheritance in which one allele is not completely dominant over another, resulting in a blended phenotype.

Codominance

A form of inheritance where both alleles are fully expressed in the phenotype.

Polygenic inheritance

A type of inheritance that involves multiple genes contributing to a single trait.

Sex-linked traits

Traits that are associated with genes located on sex chromosomes.

Pedigree

A diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism from one generation to the next.

Chromosome mutations

Changes to the structure or number of chromosomes, including deletions and duplications.

Genetic variation

Diversity in gene frequencies, usually due to mutations, recombination, and sexual reproduction.