DNA Flashcards
What role does DNA play in inheritance?
DNA is important in terms of heredity. It packs in all the genetic information and passes it on to the next generation. The basis for this lies in the fact that DNA makes genes and genes make chromosomes.
What is the structure of DNA?
Each molecule of DNA is a double helix formed from two complementary strands of nucleotides held together by hydrogen bonds between G-C and A-T base pairs.
What is Chargaff’s rule?
The rule that in DNA there is always equality in quantity between the bases A and T and between the bases G and C.
Nucleotide
A nucleotide is the basic building block of nucleic acids, such as DNA and RNA. It consists of three components:
A nitrogenous base (which can be adenine, thymine, guanine, cytosine, or uracil in RNA).
A five-carbon sugar (deoxyribose in DNA and ribose in RNA).
One or more phosphate groups.
Deoxyribose
Deoxyribose is a five-carbon sugar molecule that is a component of DNA nucleotides. It differs from ribose (found in RNA) by lacking one oxygen atom on the second carbon in the ring, hence the name “deoxy.”
Adenine
Adenine is one of the four nitrogenous bases found in DNA and RNA. It is a purine base and pairs with thymine in DNA and uracil in RNA through hydrogen bonds.
Thymine
Thymine is one of the four nitrogenous bases found in DNA. It is a pyrimidine base and pairs with adenine through two hydrogen bonds. In RNA, thymine is replaced by uracil.
Guanine
Guanine is one of the four nitrogenous bases found in DNA and RNA. It is a purine base and pairs with cytosine through three hydrogen bonds.
Cytosine
Cytosine is one of the four nitrogenous bases found in DNA and RNA. It is a pyrimidine base and pairs with guanine through three hydrogen bonds.
Phosphate
A phosphate group consists of a phosphorus atom bonded to four oxygen atoms. It is a crucial component of nucleotides, linking the sugar molecules of adjacent nucleotides to form the backbone of a nucleic acid strand.
Pentose Sugar
A pentose sugar is a five-carbon sugar molecule. In nucleic acids, the pentose sugar is either ribose (in RNA) or deoxyribose (in DNA).
Base-pair
A base-pair refers to a pair of complementary nitrogenous bases in a DNA molecule. The pairs are adenine-thymine (A-T) and guanine-cytosine (G-C). These pairs are held together by hydrogen bonds and form the rungs of the DNA double helix ladder.
