ESSLCE flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Cell theory

All living organisms are composed of one or more cells, the cell is the basic unit of life, and new cells arise from pre-existing cells. Prokaryotes lack a nucleus; eukaryotes have membrane-bound organelles.

Photosynthesis equation

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂. Light reactions occur in thylakoid membranes producing ATP and NADPH; the Calvin cycle in the stroma fixes carbon into glucose.

Mendelian monohybrid ratio

Crossing two heterozygotes (Aa × Aa) gives a 3:1 phenotype ratio (dominant:recessive) and a 1:2:1 genotype ratio (AA:Aa:aa) when alleles show complete dominance.

Newton's second law

The net external force on an object equals its mass times acceleration: F_net = ma. Weight is the gravitational force W = mg, where g ≈ 9.8 m/s² near Earth's surface.

Ohm's law

Current through a conductor is directly proportional to voltage and inversely proportional to resistance: V = IR. Electric power is P = VI = I²R = V²/R.

Mole concept

One mole contains 6.022 × 10²³ particles and has a mass in grams equal to the substance's molar mass. Molarity equals moles of solute divided by liters of solution.

pH scale

pH = −log[H⁺]. Values below 7 are acidic, 7 is neutral, and above 7 are basic. Strong acids fully dissociate; weak acids partially dissociate in water.

Quadratic formula

For ax² + bx + c = 0, x = [−b ± √(b² − 4ac)]/(2a). The discriminant b² − 4ac determines whether roots are two real, one repeated, or non-real.

Logarithm rules

log(ab) = log a + log b; log(a/b) = log a − log b; log(aⁿ) = n log a; log_b x = ln x / ln b. Also log_b b = 1 and log_b 1 = 0.

Law of cosines

In any triangle, c² = a² + b² − 2ab cos C, where C is the angle opposite side c. It generalizes the Pythagorean theorem to non-right triangles.

Geometric series sum

For a geometric sequence with first term a₁ and ratio r ≠ 1, the sum of the first n terms is Sₙ = a₁(1 − rⁿ)/(1 − r). The nth term is a₁rⁿ⁻¹.

Chain rule

The derivative of a composite function f(g(x)) is f'(g(x))·g'(x). For example, d/dx (3x + 1)⁵ = 5(3x + 1)⁴ · 3.

Combinations formula

The number of ways to choose r items from n without regard to order is nCr = n!/(r!(n−r)!). Permutations nPr = n!/(n−r)! count ordered arrangements.

Battle of Adwa

Fought on 1 March 1896, Ethiopian forces led by Emperor Menelik II and Empress Taytu defeated an Italian army, preserving Ethiopia's independence and inspiring anti-colonial movements.

Berlin Conference

Held in 1884–1885, European powers set rules for partitioning Africa. Ethiopia and Liberia remained independent; the conference accelerated the Scramble for Africa.

Ethiopian dynasty sequence

Aksumite Empire (c. 1st–7th century CE), Zagwe dynasty (c. 1137–1270), Solomonic dynasty (1270–1974), Derg military regime (1974–1991), Federal Democratic Republic from 1991.

Earth's layers

The Earth consists of a crust (continental ~30–70 km, oceanic ~5–10 km), mantle, liquid outer core, and solid inner core. Plate tectonics explains earthquakes and volcanoes.

Map scale

Scale equals map distance divided by ground distance. A large-scale map shows a small area in detail; a small-scale map shows a large area with less detail.

Separation of powers

Government power is divided among legislature (makes laws), executive (implements laws), and judiciary (interprets laws) to prevent abuse and protect liberty.

Rule of law

The principle that government and citizens are bound by law, laws are applied equally and fairly, and no one is above the law. It underpins democratic accountability.

Present perfect tense

Formed with have/has + past participle, e.g., 'She has finished.' It describes past actions with present relevance or experiences without specifying when they occurred.

Third conditional

If + past perfect, would have + past participle, e.g., 'If I had studied, I would have passed.' It describes unreal past situations and their imagined results.

Passive voice

Formed with be + past participle, e.g., 'The letter was written.' Used when the doer is unknown, unimportant, or when the focus is on the action or receiver.

Ge'ez script

An abugida script written left to right, used for Amharic and Tigrigna. Each consonant has vowel-modified forms, and the script is also called Fidel.

Qubee alphabet

The Latin-based alphabet used to write Affan Oromoo. It includes digraphs such as ch, dh, ny, ph, and sh, and represents long vowels by doubling letters.

Subject-verb agreement

A singular subject takes a singular verb (he goes) and a plural subject takes a plural verb (they go). Indefinite pronouns like everyone and each are singular.

Percentage change

Percent change = (new value − old value)/old value × 100%. Successive percentage changes multiply; a 10% rise followed by a 10% fall gives a net 1% decrease.

Combined work rate

If A completes a job in a days and B in b days, working together they finish in ab/(a+b) days. Rate equals work divided by time.

Average speed equal distances

For two equal distances traveled at speeds v₁ and v₂, average speed = 2v₁v₂/(v₁ + v₂), not the arithmetic mean of the speeds.

Syllogism validity

An argument is valid if the conclusion follows necessarily from the premises. A valid argument with true premises is sound. Watch for undistributed middle terms and illicit conversion.

Ratio division

To divide quantity Q in ratio a:b:c, the shares are Q·a/(a+b+c), Q·b/(a+b+c), and Q·c/(a+b+c). Ratios express proportional parts of a whole.

Number series rule

Check differences (constant, increasing, alternating), ratios, squares, cubes, primes, and Fibonacci-type patterns. Test a rule against at least three terms before committing.