Chapter 10 Flashcards
What did microbiologists first think of DNA?
It was discovered and characterized long before its role in heredity was understood.
What was the first experiment done in the 1850s/1860s by Gregor Mendel?
he experimented with true-breeding garden peas to demonstrate the heritability of specific observable traits.
What are nucleic acids composed of?
Nucleotides
What does each nucleotide contain?
A pentose sugar, a phosphate group, and a nitrogenous base.
What do deoxyribonucleotides contain?
Deoxyribose as the pentose sugar.
Which side of the molecule is the phosphate group at (5’ or 3’)?
5’ phosphate group
Which side of the molecule is the hydroxyl group at (5’ or 3’)?
3’ hydroxyl group
What is the difference between nucleotides and a nucleic acid strand?
Nucleotides are linked together by phosphodiester bonds between the 5ʹ phosphate group of one nucleotide and the 3ʹ hydroxyl group of another. A nucleic acid strand has a free phosphate group at the 5ʹ end and a free hydroxyl group at the 3ʹ end.
What are the pyrimidines?
- Cytosine and thymine
- One ring
What are the purines?
- Adenine and guanine
- Two rings
Which purines pair with which pyrimidines?
Guanine and cytosine
Adenine and thymine
What type of bonds hold together A & T?
Two hydrogen bonds
What type of bonds hold together G & C?
Three hydrogen bonds
What is antiparallel?
Parallel but oppositely directed or oriented.
What does it mean that DNA is composed of two complementary strands oriented antiparallel?
The strands are parallel to each other, but the 5’ directionality is opposite on each.