Meiosis
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40 free Meiosis trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Every animal, plant and fungus that reproduces with two parents depends on one unusual kind of cell division. Meiosis takes a cell with a double set of chromosomes and deals out single sets, reshuffling the genetic deck along the way, which is why no two siblings, identical twins aside, are exactly alike. This quiz covers the ground a biology class does: the stages of meiosis I and meiosis II in order, how chromosomes pair, swap and separate, how sperm and egg formation differ, and what happens when the sorting goes wrong. It also wanders past the textbook into seedless fruit, sterile hybrids and the scientists who first worked out what they were seeing under the microscope. The questions run from easy basics to a handful of hard ones for AP and college biology. Every answer comes with a short explanation, so the quiz works as a review before a test as well as a round for a trivia night.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Which fruit, sold mostly as the Cavendish variety, is seedless because its three chromosome sets jam meiosis?
Banana
Banana plants sold in shops carry every chromosome in triplicate, so some are left without a partner and seeds almost never form. Growers have to clone every plant instead.
Q 02Which hybrid animal is usually sterile because its 63 chromosomes cannot form matching pairs in meiosis?
Mule
Mule cells hold 32 chromosomes from a horse mother and 31 from a donkey father, so one is always left over. A few female mules have still managed to produce offspring.
Q 03Human egg cells begin meiosis at which point in a woman's life, then pause partway for years or decades?
Before birth
Before birth is the surprising answer: every egg a woman will ever release started dividing while she was still a fetus. Each one resumes only around the time it is ovulated, which may be decades later.
Q 04Which condition, the commonest human chromosome disorder, arises when meiosis fails to split a chromosome 21 pair?
Down syndrome
Down syndrome affects about 1 in 1,000 babies worldwide. In nearly nine cases in ten, the extra chromosome arrives in the egg rather than the sperm.
Q 05Which fact about a mother most sharply raises the odds that meiosis mis-sorts the chromosomes in her eggs?
Her age
Her age matters because eggs sit paused in mid-division for decades, and the ties holding their chromosomes together slowly weaken. Sperm, by contrast, are made continuously from puberty onward.
Q 06Which monk's pea-plant laws of heredity were later explained by how chromosomes separate in meiosis?
Gregor Mendel
Gregor Mendel never saw a chromosome, and his results were ignored for more than three decades. Meiosis later supplied the mechanism: his paired 'factors' travel on chromosome pairs.
Q 07Which insect's males grow from eggs that never met a sperm, so every sperm they make is genetically identical?
Honeybee
Honeybee drones carry only one set of chromosomes, so their sperm form without the halving and shuffling of ordinary meiosis. A single drone makes some 10 million sperm this way.
Q 08One cell that completes both divisions of meiosis in a man's body gives rise to how many sperm?
Four
Four sperm come from each starting cell, but in women the same two divisions yield a single egg. The other three products are tiny cells that are simply discarded.
Q 09A human sperm or egg leaves meiosis carrying how many chromosomes, half the count of a body cell?
23
23 is one complete set, so when sperm meets egg the embryo is back to 46. Without the halving, the chromosome count would double with every generation.
Q 10Which process in meiosis swaps matching segments between partner chromosomes, so no two eggs are alike?
Crossing over
Crossing over leaves each chromosome a patchwork of DNA from both of a person's parents. At least one swap happens on every chromosome pair.
Q 11Which collective name, from a Greek word for 'wife', covers the sperm and egg cells that meiosis produces?
Gametes
Gametes carry half the chromosomes of a body cell, so they must fuse in pairs to start a new individual. The name shares its root with the Greek word for marriage.
Q 12Where in a man's body, held slightly cooler than his core temperature, does meiosis turn out sperm?
Testes
Testes sit outside the abdomen because sperm production runs best a few degrees below core body temperature. The work happens inside tiny tubules packed within them.
Q 13Which event restores the full chromosome number that meiosis halved, producing a single cell called a zygote?
Fertilization
Q 21Which stage of meiosis, by far the longest, is when paired chromosomes trade segments of DNA?
Prophase I
Prophase I takes up 13 of the 14 days that meiosis lasts in a mouse. In a human egg it can stretch across decades.
Q 22Which name is given to the two matching chromosomes, one from each parent, that pair up during meiosis?
Homologs
Homologs, short for homologous chromosomes, carry the same genes at the same positions, though often in different versions. That match is what lets them find and line up with each other.
Q 23In which stage of meiosis do chromosome pairs line up across the middle of a cell, each facing a random way?
Metaphase I
Fertilization in humans usually happens in a fallopian tube, where the chromosomes of one sperm join those of the egg. The cell that results is genetically unlike any before it.
Q 14Which sex chromosome does meiosis place in about half of a man's sperm, where it makes a baby male?
Y
Y sperm and X sperm are made in equal numbers, because the two chromosomes pair up and then part company in the first division. Every egg carries an X.
Q 15Compared with cloning, reproducing by meiosis gives a species which advantage for natural selection to work on?
Genetic variation
Genetic variation is the payoff: the new DNA combinations made in meiosis are, alongside mutation, a major cause of the differences between individuals. Cloning is quicker but copies the parent.
Q 16Which other type of cell division, the kind that yields two identical cells, does meiosis II closely resemble?
Mitosis
Mitosis and meiosis II use the same machinery, but meiosis II starts with half the chromosomes. Its products are therefore sex cells rather than new body cells.
Q 17Which term, written as n rather than 2n, describes a sperm or egg carrying a single set of chromosomes?
Haploid
Haploid cells are the everyday state for mosses and most fungi, which spend the main stage of their lives with one set. Most animals reserve it for sperm and eggs.
Q 18Which microbes, lacking a nucleus, never undergo meiosis and instead multiply by simple binary fission?
Bacteria
Bacteria still manage a kind of sex without it, passing stretches of DNA directly from one cell to another. Their distant cousins the archaea do the same.
Q 19The word meiosis, coined in 1905 by Farmer and Moore, comes from a Greek word meaning what?
Lessening
Lessening refers to the cut in chromosome count. The two coiners actually spelled their new word 'maiosis', and other biologists corrected it within a year.
Q 20Which structure, built from protein fibers called microtubules, drags chromosomes apart in both divisions of meiosis?
Spindle
Spindle fibers in human eggs assemble without centrosomes, the organizing centers that most animal cells rely on. The same is true of the eggs of most other animals.
Metaphase I is where chance steps in: each pair can face either pole, so chromosomes from a person's mother and father are dealt out at random.
Q 24In which stage of meiosis are partner chromosomes pulled to opposite poles while each one's two chromatids stay joined?
Anaphase I
Anaphase I is when the chromosome count is halved, as whole chromosomes head for each pole. A protein named from the Japanese for 'guardian spirit' keeps each one's two chromatids together.
Q 25Which law of heredity, found by tracking two traits at once, reflects chromosome pairs lining up at random in meiosis?
Independent assortment
Independent assortment has many exceptions: genes that sit close together on one chromosome are linked and tend to be inherited as a block.
Q 26Which tiny cells, cast off as a human egg forms, let the egg keep nearly all of the cytoplasm?
Polar bodies
Polar bodies receive a full share of chromosomes but only a scrap of the cell's contents, and most soon die. The lopsided split leaves one egg stocked with enough supplies to feed an embryo.
Q 27Which term names the alternative versions of a single gene that meiosis deals out one per sperm or egg?
Alleles
Alleles is short for 'allelomorphs', a word coined in the early 1900s to mean 'other forms'. The gene behind the ABO blood groups alone has six common ones.
Q 28Which lineage, set aside early in an embryo, is the only one in the body able to enter meiosis?
Germ cells
Germ cells travel through the gut of the early embryo to reach the organs where eggs or sperm will one day form. Every other cell in the body divides only by copying itself.
Q 29In ferns and mosses, meiosis produces which single cells that can grow into a new plant entirely on their own?
Spores
Spores from a fern grow into a tiny separate plant, and only that plant goes on to make the sperm and eggs. Fungi use meiosis to make theirs too.
Q 30Which condition, the only survivable loss of a whole human chromosome, can arise when faulty meiosis leaves a single X?
Turner syndrome
Turner syndrome affects roughly one girl in every 2,000 to 5,000, and short stature is a common sign. It is named after the American endocrinologist who described it in 1938.