Comprehensive Science Review: Data Science, Genetics and Evolution, and Chemical Reactions

Vocabulary flashcards covering core scientific concepts across Data Science, Genetics & Evolutionary Change, and Chemical Reactions.

Investigable Question

A specific and focused question that includes measurable variables and can be tested through an experiment using available time, tools, and materials.

Hypothesis

A testable prediction evaluated through a fair experiment, structured in the format: "If _____ changes, then _____ will happen because _____."

Reliability

The consistency of results obtained when an experiment or investigation is repeated.

Validity

The extent to which an experiment tests the intended hypothesis by isolating the effect of the independent variable on the dependent variable, controlling other variables, and including an experimental control.

Accuracy

The degree to which experimental measurements are correct.

Scatter Plot

A graph used to compare two variables in order to identify trends and correlations.

PEEL Paragraph

A framework for writing a scientific argument consisting of Point (state claim), Evidence (use data), Explanation (explain the science), and Link (connect back to the question).

Interquartile Range (IQR)

A measure of spread representing the middle $50\%$ of a dataset, calculated as $\text{IQR} = Q_3 - Q_1$, which is less affected by extreme values.

Correlation Coefficient ($r$)

A statistical value measuring the strength of a correlation, ranging from $r = -1$ (perfect negative correlation) to $r = 0$ (no correlation) to $r = +1$ (perfect positive correlation).

Causal Relationship

A relationship where one event or variable directly causes another (cause $\rightarrow$ effect), which cannot be proven by correlation alone and requires controlled experiments.

Univariate Data

Data involving only one variable (such as student heights), typically analysed using mean, median, mode, range, and IQR.

Bivariate Data

Data involving two variables (such as hours studied and test scores), analysed using scatter plots, correlation, and trend identification.

DNA (Deoxyribonucleic Acid)

The molecule that stores genetic instructions controlling how an organism looks, grows, and functions, typically found in the nucleus of most cells or floating in the cytoplasm of simple organisms.

Chromosome

A structure found in the nucleus consisting of tightly wound coils of DNA packaged and held together with proteins.

Gene

A section of DNA located along a chromosome that carries the genetic code and instructions for making specific proteins, which determine traits.

Genome

The complete set of genetic material present in an organism, encompassing both protein-coding genes and non-coding DNA.

Nucleotide

The basic building block or subunit of DNA, composed of a nitrogenous base, a deoxyribose sugar molecule, and a phosphate molecule.

Complementary Base Pairing

The specific pairing rule in DNA where adenine (A) always pairs with thymine (T), and cytosine (C) always pairs with guanine (G).

DNA Replication

The process occurring before cell division where DNA strands unwind, separate, and serve as templates for complementary bases to attach, producing two identical DNA molecules.

Photo 51

The historic X-ray diffraction image produced by Rosalind Franklin that provided crucial evidence allowing James Watson and Francis Crick to determine DNA's double helix structure in 1953.

Asexual Reproduction

Reproduction involving a single parent organism that produces genetically identical offspring through mitosis without the fusion of gametes.

Mitosis

A type of cell division where chromosomes replicate and divide to produce two daughter cells that are genetically identical to each other and to the parent cell.

Meiosis

A process of cell division in reproductive organs where chromosomes replicate and the cell divides twice, producing four genetically unique gametes with half the original chromosome number.

Gamete

A reproductive sex cell, such as a sperm cell or egg cell, that contains a single haploid set of chromosomes ($23$ single chromosomes in humans).

Fertilisation

The union of two haploid gametes (sperm and egg) to form a diploid zygote containing a full set of chromosomes ($23\text{ pairs}$ or $46\text{ chromosomes}$ in humans).

Spontaneous Mutation

A mutation that occurs randomly due to copying mistakes made while DNA is copied during mitosis, meiosis, or protein synthesis.

Induced Mutation

A genetic mutation caused by exposure to environmental agents or mutagens, such as radiation, X-rays, UV light, or chemicals in cigarette smoke.

Genotype

The genetic makeup or combination of alleles an organism carries for a specific trait, represented by letter symbols such as $GG$, $Gg$, or $gg$.

Phenotype

The observable physical appearance or expressed characteristic of an organism resulting from its genotype.

Allele

An alternative version or form of the same gene.

Heterozygous

A genotype possessing two different alleles for a specific trait (e.g., $Bb$, $Tt$), also referred to as a hybrid.

Homozygous

A genotype possessing two identical alleles for a specific trait, either homozygous dominant (e.g., $BB$) or homozygous recessive (e.g., $bb$), also referred to as pure-breeding.

Polygenic Trait

A characteristic controlled by the additive contribution of multiple genes, often located on different chromosomes (such as height, skin colour, and eye colour).

Punnett Square

A diagrammatic grid used to model genetic crosses and predict the probability of offspring inheriting specific genotypes and phenotypes.

Pedigree Chart

A family tree diagram using standardized symbols (squares for males, circles for females, shading for affected individuals) to track inheritance patterns of traits across generations.

Polymerase Chain Reaction (PCR)

A genetic technology used to amplify and generate millions of copies of a specific DNA fragment from a small original sample.

Gel Electrophoresis

A laboratory method used to separate and sort DNA fragments based on molecular size and charge, often used in DNA fingerprinting and sequencing.

CRISPR

A gene-editing tool that uses the Cas9 protein as molecular scissors, guided by RNA to cut DNA at a precise location so genes can be added, removed, or changed.

Recombinant DNA

A genetic technology that combines DNA fragments taken from different species or organisms to produce new genetic combinations.

Natural Selection

The process whereby organisms with traits better adapted to their environment are more likely to survive, compete, and reproduce, passing these advantageous genes to their offspring.

Speciation

The formation of new and distinct species occurring when populations are isolated by geographical or physical barriers, stopping gene flow and accumulating genetic differences independently.

Divergent Evolution

The evolutionary pattern in which an ancestral species splits into distinct species with homologous structures that share an internal blueprint but adapt to different functions (e.g., Darwin's finches).

Convergent Evolution

The evolutionary process where unrelated species independently evolve analogous structures that look and function similarly due to facing similar environmental challenges (e.g., shark and dolphin body shapes).

Relative Dating

A method of establishing the comparative chronological sequence of rock layers and fossils using the Law of Superposition, without providing absolute calendar ages.

Absolute Dating

A dating technique that calculates the exact numerical age of a rock or fossil by measuring the decay of radioactive isotopes (e.g., Carbon-14 for items up to $60\,000\text{ years}$ and Potassium-Argon for rocks up to several billion years).

Law of Conservation of Mass

The scientific principle stating that matter can neither be created nor destroyed during a chemical reaction, meaning the total mass of reactants equals the total mass of products in a closed system.

IUPAC

The International Union of Pure and Applied Chemistry, an organization establishing standardized chemical nomenclature conventions globally.

Synthesis Reaction

A chemical reaction in which two or more simpler reactants combine to form a single, more complex product, following the pattern $A + B \rightarrow AB$.

Corrosion

A synthesis oxidation reaction in which a metal reacts with oxygen to form a metal oxide, such as iron reacting with oxygen and water to produce rust ($\text{Fe}_2\text{O}_3$).

Decomposition Reaction

A reaction where a single compound breaks down into two or more simpler substances ($AB \rightarrow A + B$), often requiring an energy input such as heat or electricity.

Single Displacement Reaction

A chemical reaction in which a more reactive element displaces a less reactive element from its compound, following the general pattern $A + BC \rightarrow AC + B$.

Double Displacement Reaction

A reaction in which the cations and anions of two reacting compounds exchange partners to form two new compounds ($AB + CD \rightarrow AD + CB$).

Precipitation Reaction

A specific type of double displacement reaction occurring when two soluble ionic solutions react to yield an insoluble solid product known as a precipitate.

Neutralisation Reaction

A chemical reaction between an acid and a base that produces a salt and water ($\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water}$).

Catalyst

A substance (or biological enzyme such as catalase) that accelerates the rate of a chemical reaction without being consumed or chemically altered in the process.

Big Bang Theory

The scientific cosmological theory stating that the universe originated approximately $13.8\text{ billion}$ years ago from an extremely hot, dense singularity and has expanded and cooled since.

Cosmic Microwave Background Radiation

A faint, uniform leftover glow of electromagnetic radiation filling all of space, serving as key evidence supporting the Big Bang Theory.

Isotopes

Atoms belonging to the same element that contain the same number of protons and electrons but differing numbers of neutrons, resulting in different mass numbers.

Half-Life

The duration of time required for half of the radioactive nuclei in a parent isotope sample to decay into daughter isotopes.

Nuclear Fission

A nuclear reaction where a heavy, unstable atomic nucleus splits into two smaller nuclei, releasing free neutrons, radiation, and substantial energy.

Nuclear Fusion

A nuclear process in which two light atomic nuclei combine to form a heavier nucleus, releasing massive amounts of energy (such as hydrogen fusing into helium in stars).

Alpha Radiation ($\alpha$)

A particulate radiation consisting of $2\text{ protons}$ and $2\text{ neutrons}$ (a helium nucleus), characterised by high ionising ability and low penetrating power, easily stopped by paper or air.

Beta Radiation ($\beta$)

Nuclear radiation consisting of high-speed electrons emitted from a decaying nucleus, exhibiting medium ionising ability and penetrating power that can be stopped by thin aluminium, plastic, or wood.

Gamma Radiation ($\gamma$)

High-frequency electromagnetic wave radiation travelling at the speed of light with no mass, possessing low ionising ability and very high penetrating power requiring thick lead or concrete shielding.