DNA Structure and Replication: Crash Course Biology #10
Available at https://youtu.be/8kK2zwjRV0M or just youtube/google “Crash Course Biology 10”
1. DNA is what stores our _____________ instructions—the
information that programs all of our ________’s activities.
a. ____________________________ are the fourth major group
of biological molecules. Structurally, they’re
__________________, which means that each one is made up
of many small, repeating molecular units.
b. What three parts make up a nucleotide?
c. In DNA, the sugars and phosphates bond together to form twin _______________.
These sugar-phosphate bonds run down each side of the ____________ but,
chemically, in ________________ directions.
d. If one nucleotide has an ______________ base, only _______________ can be its
counterpart. Likewise, _______________ can only bond with ________________.
These bonded nitrogenous bases are called __________________________.
e. What would be the other strand base sequence for 5’ – AGGTCCG – 3’?
f. What is RNA? Describe its composition and differences from DNA.
g. DNA itself was discovered in 1869 by Swiss biologist ______________________.
i. Using a technique called ____________________________, Rosalind
Franklin may have been the first to confirm the helical structure of DNA.
h. The point where the splitting starts is known as the
_________________________, has a top strand called the
_____________________________, and another bottom
strand called the _______________________________.
i. What are Okazaki fragments?
ii. DNA gets _________________ wrong about one
in every ______________________ nucleotides.
Biology Crash Course Answer Keys
Crash Course 10 – DNA Structure and Replication
1. genetic; cell
a. nucleic acids; polymers
b. 5-carbon sugar molecule, a phosphate group, 1 of 4 nitrogen bases
c. backbones; helix; opposite
d. adenine; thymine; guanine; cytosine; base pairs
e. 3’ – TCCAGGC – 5’
f. has a sugar-phosphate backbone with nucleotide bases attached to it; it’s a single-strand
molecule; the sugar in RNA is ribose; RNA does not contain thymine
g. Friedrich Miescher
i. x-ray diffraction
h. replication fork; leading strand; lagging strand
i. an RNA primer that gives DNA Polymerase a starting point to work backwards along the
strand
ii. replication; 10 billion