DNA STRUCTURE QUIZ Flashcards
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What is the full name of DNA?
Deoxyribonucleic acid
Nucleotide components
- Deoxyribose sugar
- Phosphate
- Nitrogenous base
What are the 4 nitrogenous bases
adenine (A),
thymine (T)
cytosine (C)
guanine (G)
Purines
Adenine & Guanine
Pyrimidines
Cytosine & Thymine
Complementary Base Pairing
A - T
C - G
Helps to hold the two antiparallel strands of the DNA molecule together to form the helix.
Hydrogen bonding
A - T = 2 hydrogen bonds
G - C = 3 hydrogen bonds
5’ to 3’ and 3’ to 5’
Leading 5’ to 3’
Lagging 3’ to 5’
What is meant by the term antiparallel?
the strands run in OPPOSITE directions, parallel to one another.
What makes DNA twist?
Sugar phosphate backbone is hydrophilic
Nitrogenous bases are hydrophobic
The backbone protects the inside portion of the molecule from the aqueous environment of the cell.
DNA & RNA
Single strand vs. double strand?
DNA is a double-stranded molecule that has a long chain of nucleotides. RNA is a single-stranded molecule which has a shorter chain of nucleotides. DNA replicates on its own, it is self-replicating. RNA does not replicate on its own.
What sugar is in RNA? How is this sugar different from DNA?
RNA contains the sugar ribose, while DNA contains the slightly different sugar deoxyribose (a type of ribose that lacks one oxygen atom)
What nitrogenous base does RNA have instead of thymine?
Uracil
Which stays in the nucleus vs. leaves the nucleus? DNA or RNA
DNA never leaves the nucleus
RNA may leave the nucleus
Replication bubble
Two replication forks are formed at the replication bubble
DNA replication occurs in both directions.
Replication Fork
FORKS LOOK LIKE Y
A Y-shaped region where the parent DNA splits into two strands
Lagging Strand
THINK ABOUT WHEN LAGGING IN A GAME YOUR FRAMS ARE ___
The strand that opens in the 3’ to 5’ direction towards the replication fork
Replication is fragmented
Leading Strand
The strand that runs in the 5’ to 3’ direction in the replication fork
Can be replicated continuously
Topoisomerase
TOP - SPINNING TOP - TWIST
Untwists the DNA and holds it steady so that helicase can move down the replication bubble