DNA Crossword

Print a criss-cross vocabulary crossword on DNA, from the double helix and its four bases to how it is copied.

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DNA Crossword

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Answer key: DNA Crossword

1A2CID3TOHDY4A5LA6DDERMDOIE7MUTATION8RUNGBEIL9NUCLEOTIDEEH10BASEPAIR11GLE12REPLICATIONXE

Across 1 ACID · 5 LADDER · 7 MUTATION · 8 RUNG · 9 NUCLEOTIDE · 10 BASEPAIR · 12 REPLICATION

Down 2 CODE · 3 THYMINE · 4 ADENINE · 6 DOUBLEHELIX · 11 GENE

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The Double Helix 24

  • Acid What the A in DNA stands for
  • Adenine The DNA letter A, in full
  • Antiparallel Like DNA's two chains, which lie side by side but point contrary ways
  • Backbone Spine-like name for the outer rail that holds a strand's units in line
  • Base pair Two partner letters joined across the middle, such as A with T
  • Complement What one strand is to the other: every A faces a T, every G a C
  • Covalent Strong kind of bond that links one sugar to the next phosphate
  • Cytosine The DNA letter C, in full; it always faces a G
  • Deoxyribose Sugar that puts the D in DNA
  • Double helix What DNA's two wound-up chains form, first made public in 1953
  • Groove Major or minor: a gap that winds around the outside of the helix
  • Guanine The DNA letter G, in full; it always faces a C
  • Hydrogen Kind of bond, named for an element, that joins A to T and G to C
  • Ladder Untwist DNA and it would look like this tool for reaching a roof
  • Nitrogen N in a chemical formula; all four DNA letters contain it
  • Nucleotide The repeating unit of DNA; its four kinds differ only in their bases
  • Purine Double-ringed kind of base: A or G
  • Pyrimidine Single-ringed kind of base: C or T in DNA
  • Right-handed Way that DNA's usual form twists, like an ordinary screw
  • Rung One step of the DNA staircase, made of two letters
  • Sequence ATTGCA, for example: the letters of a stretch of DNA in order
  • Spiral Everyday word for the shape of a helix, as in a staircase
  • Thymine The DNA letter T, in full; RNA does not use it
  • Turn One full twist of the helix, about ten pairs of bases long

How DNA Is Copied 23

  • Bubble Opened-up stretch of DNA that widens as copying spreads both ways
  • Clamp Protein that DNA threads through; it holds the copying enzyme in place
  • Continuous In one unbroken run: how one of the two new strands is made
  • Daughter ___ cell: either of the two that get a full set of the copied DNA
  • Division Cell ___: it cannot happen until the DNA has been copied
  • Error A wrong base in a new strand, which the cell usually catches
  • Fork Two-pronged spot where the old strands are being separated
  • Fragment Short piece of new DNA, later joined to its neighbors
  • Helicase Motor protein that splits the weak bonds between partner letters
  • Lagging ___ strand: the new one made backward, a piece at a time
  • Leading ___ strand: the new one made in a single run
  • Ligase Enzyme that seals the gaps between pieces of new DNA
  • Okazaki Japanese couple whose name is on the short pieces of one new strand
  • Origin Particular spot on a DNA molecule where copying begins
  • Phase S ___: the part of a cell's life when its DNA is copied
  • Polymerase It adds units to a growing chain of DNA, pairing each with the old chain
  • Primase Enzyme that builds the short RNA piece a new strand grows from
  • Primer Short starter piece of RNA or DNA; a new chain can only grow from one
  • Proofread To check each new base and take out a wrong one
  • Repair What special enzymes do to damaged or mismatched DNA
  • Replication Process by which one DNA molecule becomes two alike
  • Template Pattern to copy from; in DNA copying, each old strand is one
  • Unwind What the two coiled strands must do before they can be copied

DNA in the Cell and the Code 29

  • Alphabet DNA's has only four letters: A, T, G and C
  • Bacteria Microbes such as E. coli, which keep their DNA loose in the cell
  • Billion Three ___: roughly the count of letters in one set of human DNA
  • Chloroplast Sunlight-catching part of a leaf cell, with DNA of its own
  • Chromatin DNA together with the proteins that package it
  • Chromosome X or Y, for example: one of 46 DNA packages in a human cell
  • Code DNA carries one, written in A, T, G and C
  • Codon Three bases in a row: one word of the genetic message
  • Forty-six DNA threads in a typical human body cell: 23 pairs
  • Gene What a parent hands on: a single piece of DNA with a single job
  • Genome All the DNA of a living thing, counted as one; the human one was read by 2003
  • Histone Packing protein of a cell's DNA; eight of them form one bead
  • Identical Kind of twins who start life with the same DNA
  • Inherit To receive DNA from your mother and your father
  • Junk ___ DNA: nickname for stretches with no job at all
  • Loop Most DNA in microbes forms one: it has no ends
  • Messenger ___ RNA: the go-between that takes DNA's message to the protein builders
  • Mitochondria They hand down their own small DNA through the mother's line
  • Mutation A change in the order of DNA's letters
  • Nucleus Cell's DNA vault: a compartment with a membrane and pores of its own
  • Plasmid Little DNA circle, separate from a microbe's main DNA, that microbes can swap
  • Sixty-four How many different three-base words can be spelled
  • Spool DNA winds around proteins as thread winds around one
  • Telomere Cap of repeated DNA that keeps the tip of a DNA thread from fraying
  • Transcribe To copy a stretch of DNA into RNA
  • Triplet A set of three; DNA's message is read in these
  • Twenty Number of different building blocks that proteins are made from
  • Uracil The RNA letter U, in full; it stands where DNA has a T
  • Virus Not a cell, yet it carries DNA or RNA inside a protein coat

DNA in the Lab 31

  • Agarose Jelly-forming substance from seaweed, used for sorting DNA pieces
  • Amplify To make a great many copies of one piece of DNA
  • Ancient ___ DNA: genetic material recovered from very old remains
  • Centrifuge It whirls tubes so that the heavy parts sink to the bottom
  • CRISPR Tool for changing DNA at a chosen spot, adapted from a defense system of microbes
  • Cycle One round of warming and cooling in a DNA copying machine
  • Detergent Soapy chemical that breaks open cell membranes to free the DNA
  • Edit To change the letters of DNA on purpose
  • Extract To take DNA out of cells so that it can be studied
  • Fingerprint Genetic ___: a DNA test result that can single out one individual
  • Forensic ___ science uses DNA to help work out who was at a scene
  • Gel Slab of jelly through which DNA pieces are pulled by electric current
  • Heat It separates the two strands at the start of each round of lab copying
  • Lane Column of a sorting slab: each loaded mixture travels down its own
  • Mammoth Animal of the Siberian permafrost; teeth more than a million years old still held its DNA
  • Match What investigators look for between two DNA patterns
  • Mullis American chemist who in 1983 invented the chain-reaction way to copy DNA
  • Neanderthal Archaic kind of human; DNA from its bones has been studied
  • Negative Electric charge of DNA, which pulls it toward the positive end
  • PCR Three letters for the lab reaction that multiplies a stretch of DNA
  • Profile A person's DNA pattern at chosen spots, used to tell people apart
  • Recombinant ___ DNA: pieces from different sources joined in the lab
  • Restriction ___ enzyme: a protein that cuts DNA at particular spots
  • Sample What a DNA lab needs to start with: a little blood, for example
  • Sanger British chemist, twice a winner of science's top prize, whose method reads DNA
  • Scissors Molecular ___: nickname for enzymes that cut DNA
  • Size DNA pieces are sorted by this: short ones travel farther
  • Stain Dye that makes DNA visible after it has been sorted
  • Swab Soft-tipped tool wiped over an item to pick up traces of DNA
  • Taq Copying enzyme that survives near-boiling water, named for a hot-spring microbe
  • Yellowstone National park where the hot-spring microbe used in DNA copying was found

The Discovery of DNA 23

  • Avery In 1944 he and two colleagues reported that the transforming substance was DNA
  • Bandages Used ones from a hospital supplied the white blood cells in which DNA was first found
  • Blender Appliance that gave the famous 1952 DNA experiment its nickname
  • Cambridge English university city where the 1953 model of DNA was built
  • Chargaff His rules: the amount of A equals T, and G equals C
  • Crick Francis ___, the English member of the pair who solved DNA's structure in 1953
  • Franklin Rosalind ___, whose diffraction pictures at King's College revealed DNA's helical shape
  • Griffith His experiment reported in 1928 pointed to a "transforming principle"
  • Hershey Alfred ___, who with Martha Chase ran the 1952 experiments confirming DNA as genetic material
  • Levene Chemist who gave the name to the DNA unit of phosphate, sugar and base
  • London City of King's College, where DNA's diffraction pictures were taken
  • Miescher Swiss doctor who first isolated DNA, in 1869
  • Nature Journal that printed the structure of DNA on 25 April 1953
  • Nobel Honor that three men received in 1962 for DNA's structure
  • Nuclein The first name given to DNA, after the cell part it came from
  • Pauling American chemist whose early 1953 model of DNA wrongly had three strands
  • Phage Short name for a particle that infects microbes; its DNA was tracked in 1952
  • Phosphorus Element found in DNA but not in protein building blocks, used as a radioactive tag
  • Photo ___ 51: the sharp 1952 picture that gave away DNA's shape
  • Thirteen Years it took to read all of human DNA in a project begun in 1990
  • Watson American who, with an English partner, worked out DNA's structure in 1953
  • Wilkins King's College biophysicist who shared the 1962 prize for DNA's structure
  • X-ray Kind of beam aimed at DNA fibers to make diffraction pictures

How this list was compiled: Clues written for this site for middle and high school life science, in five sets: the double helix, how DNA is copied, DNA in the cell and the code, DNA in the lab, and the discovery of DNA. Definitions were checked against the Talking Glossary of the National Human Genome Research Institute (genome.gov), and the history, people and dates against English Wikipedia (CC BY-SA 4.0), in October 2026. No disease is an answer. Licence: own work

How it works

This printable DNA crossword fits Letter or A4, answer key included. The first puzzle has 12 basic words, among them Double helix, Nucleotide, Base pair, Adenine, Thymine, Replication and Gene. Clues write the four bases as letters: A, T, G and C.

Read the full guide

Five sets after the basics

The Double Helix has Backbone, Purine, Pyrimidine and Antiparallel. How DNA Is Copied has Helicase, Primase, Ligase and Okazaki. DNA in the Cell and the Code has Chromatin, Histone, Codon and Telomere. DNA in the Lab has PCR, Gel, CRISPR and Fingerprint.

A set for the story of the discovery

The Discovery of DNA runs from 1869 to the Nobel Prize of 1962: Miescher and Nuclein, Griffith, Avery, Hershey and the Blender experiment, Chargaff, Franklin and Photo 51, then Watson and Crick.

  • Print The Double Helix after a model-building lesson, and How DNA Is Copied the day after replication is taught.

Questions and answers

What grade is the DNA crossword puzzle for?

DNA Basics suits grades 7 to 9, with answers such as Gene, Nucleus, Ladder and Mutation. The five themed sets use high school biology vocabulary, such as Antiparallel and Okazaki. These bands are our judgment, not a published standard.

Does the DNA crossword come with an answer key?

Yes. The answer key prints last, on its own sheet: the filled-in grid and every answer by clue number. Printing is free and needs no sign-up.

What are the four bases of DNA?

Adenine, thymine, guanine and cytosine, written A, T, G and C. A always pairs with T, and G with C.

What does DNA stand for?

Deoxyribonucleic acid. The name comes from deoxyribose, the sugar in the backbone of each strand. Deoxyribose and Acid are both answers.

Who discovered DNA?

Friedrich Miescher first isolated it in 1869 and called it nuclein. In 1953 James Watson and Francis Crick published its double helix structure, drawing on the X-ray work of Rosalind Franklin and others.

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