Science Final Exam Study Guide

Comprehensive vocabulary flashcards covering biology (genetics, evolution, selection), chemistry (compounds, nomenclature, reactions, acids/bases), and physics (energy forms, nuclear physics, radioisotopes).

Biodiversity

A species with varied traits present in several individuals.

Deoxyribonucleic acid (DNA)

The molecule responsible for genetic material that allows for differences between organisms; it consists of a phosphate, deoxyribose, and nitrogenous bases forming a double helix.

Chromatin

The form of DNA found in the nucleus that is accessible to enzymes for replication and transcription.

Chromosomes

Condensed chromatin that forms specifically before mitosis or meiosis.

Semi-conservative Replication

The process where a single parental double helix separates and duplicates into two copies, each containing one original strand and one new complementary strand.

Genes

Small segments located at specific spots on chromosomes that contain the information necessary for genetic expression.

Transcription

The process in the nucleus where enzymes prepare a complementary mRNA strand from a gene in the DNA.

Translation

The process where mRNA leaves the nucleus and attaches to a ribosome, which reads the message to code for amino acids and form a polypeptide chain (protein).

Codon

A combination of three nucleotides that represent genetic codes.

Phenotype

The physical traits or characteristics of an organism.

Genotype

The genetic makeup of an organism, represented by its DNA and genes.

Dominant Allele

An allele that expresses its trait independently of whether there are one or two copies present ($R$).

Recessive Allele

An allele that only expresses its trait if two copies are present ($r$).

Mutation

A modification in the sequence of nitrogenous bases in the DNA.

Natural Selection

The evolutionary mechanism where individuals with advantageous genetic characteristics survive better and reproduce more, gradually modifying the species over generations.

Artificial Selection

A process where humans intentionally choose and breed individuals of a species with the most advantageous characteristics.

Ionic Compound

A compound formed by the transfer of electrons between a metal and a non-metal, resulting in an electrically neutral substance.

Covalent Compound

A compound formed by the sharing of electrons between two non-metals.

Synthesis Reaction

A chemical reaction where two reactants combine to form a single compound ($A + B \rightarrow AB$).

Decomposition Reaction

A chemical reaction where a single compound breaks down into two or more products ($AB \rightarrow A + B$).

Single Displacement Reaction

A reaction where a more reactive element replaces a less reactive element within a compound ($A + BC \rightarrow AC + B$).

Double Displacement Reaction

A reaction where two compounds exchange ions to form two new compounds ($AB + CD \rightarrow AD + CB$).

Acids

Substances with a sour taste and a $pH < 7$ that produce hydrogen ions ($H^+$).

Bases

Substances with a bitter taste and slippery texture with a $pH > 7$ that contain hydroxide ($OH^-$).

pH Scale

A scale where each unit change represents a $10\times$ difference in acidity (e.g., pH 3 is $10 \times$ more acidic than pH 4).

Law of Conservation of Energy

Energy is neither created nor destroyed; it only transforms from one form to another or transfers from one object to another.

Kinetic Energy

The form of energy linked to the movement of an object or particles.

Potential Energy

Energy stored by an object due to its state or position.

Thermal Energy

The random movement of particles that compose a substance.

Isotopes

Versions of an element that have the same number of protons and electrons but a different number of neutrons.

Alpha Decay

Radioactive decay involving a particle with a mass of $4$ and an atomic number of $2$ ($\alpha$).

Beta Decay

Radioactive decay involving the emission of a beta particle ($\beta$) which changes the atomic number.

Gamma Decay

The emission of high-energy rays ($\gamma$) that do not change the mass or atomic number of the nucleus.

Nuclear Fission

The process where a large, heavy, and unstable nucleus splits into two smaller, lighter nuclei.

Nuclear Fusion

The process where two small, light nuclei unite to form a larger, heavier nucleus, typically occurring in stars like the sun.