History of DNA
These two scientists are credited with building the first accurate 3D model of DNA in 1953.
Who are Watson and Crick?
This is the basic building block, or monomer, of DNA, consisting of a sugar, a phosphate, and a nitrogenous base.
What is a nucleotide?
During cell division, DNA tightly coils into these visible, X-shaped or rod-like structures so it can be evenly divided.
What are chromosomes?
DNA replication occurs during this phase of the cell cycle.
What is the S phase?
This small insect, known scientifically as Drosophila melanogaster, is one of the most famous model organisms used to study DNA and genetics.
What is the fruit fly?
Her famous "Photo 51" used X-ray crystallography to reveal the helical shape of the DNA molecule.
Who is Rosalind Franklin?
This specific 5-carbon sugar alternates with phosphate groups to make up the "backbone" of the DNA molecule.
What is deoxyribose?
To pack neatly into the nucleus, DNA tightly winds around these specific spool-like proteins.
What are histones?
This enzyme acts like a zipper, unwinding the DNA double helix by breaking the hydrogen bonds between base pairs.
What is helicase?
Scientists are currently using CRISPR to genetically modify the DNA of Anopheles mosquitoes so they can no longer transmit this deadly disease.
What is malaria?
In 1928, this scientist discovered "transformation" by observing that a harmless strain of bacteria could become deadly when mixed with a heat-killed deadly strain.
Who is Frederick Griffith?
According to Chargaff's rules, this pyrimidine always pairs with the purine Guanine.
What is Cytosine?
When a cell is not dividing, its DNA is in this loose, stringy, "spaghetti-like" form inside the nucleus.
What is chromatin?
This key enzyme adds complementary nucleotides to the growing DNA strand and "proofreads" for errors.
What is DNA polymerase?
In this highly social insect species, male drones develop from unfertilized eggs, meaning they only have half the DNA of their female worker counterparts.
What are honey bees?
Using radioactive sulfur and phosphorus, these scientists conclusively proved that DNA, not protein, is the genetic material in bacteriophages.
Who are Hershey and Chase?
These specific, relatively weak bonds hold the two complementary nitrogenous base pairs together in the center of the helix.
What are hydrogen bonds?
This term describes the basic unit of DNA packaging, consisting of a segment of DNA wrapped around a core of eight histone proteins, looking like a "bead on a string."
What is a nucleosome?
This term describes the model of replication where each new DNA molecule contains one original parent strand and one newly synthesized strand.
What is semi-conservative replication?
These master control genes dictate the basic body plan of an insect embryo, ensuring the antennae and legs grow on the correct segments.
What are Hox genes?
This scientist and his team used enzymes to destroy proteins, RNA, and DNA, proving DNA was the "transforming principle."
Who is Oswald Avery?
This term describes the orientation of the two DNA strands, where one runs 5' to 3' and the opposite runs 3' to 5'.
What is antiparallel?
These are the protective caps at the ends of eukaryotic chromosomes that get slightly shorter every time a cell divides, playing a role in cellular aging.
What are telomeres?
DNA polymerase only works in the 5' to 3' direction, so the lagging strand is built in these short pieces, which are later joined by ligase.
What are Okazaki fragments?
To create incredibly strong fibers for clothing, the DNA of these insects contains highly repetitive sequences of the amino acids Glycine and Alanine, allowing the proteins to stack into "beta-sheets."
What are silkworms?