DNA Flashcards
What are the monomers that make up DNA called?
- Nucleotides.
What are the 3 components of a DNA nucleotide?
1.) Deoxyribose (pentose sugar.)
2.) Nitrogen- containing base.
3.) One phosphate group
What is the name of the pentose sugar that makes up DNA?
- Deoxyribose sugar.
What are the 4 different nitrogen- containing/ organic bases in DNA?
1.) Guanine.
2.) Cytosine.
3.) Adenine.
4.) Thymine.
What is the function of DNA?
- DNA holds genetic information/ codes for sequence of amino acids in primary structure of protein.
What is the general structure of DNA molecule like?
- The DNA **(polymer of nucleotides) **is a double- helix with two polynucleotide chains held together by hydrogen bonds between specific complementary base pairs.
How are polynucleotides formed?
- Formed by condensation reactions between deoxyribose sugar (on one nucleotide) and phosphate group (on another nucleotide) , forming phosphodiester bond.
True or False
Phosphodiester bonds, in DNA, between deoxyribose sugar and phosphate group are weak.
- False.
- Phosphodiester bonds are strong covalent bonds. This helps to ensure the genetic code isn’t broken down.
How many bases code for 1 amino acid?
3 bases code for 1 amino acid.
What is the “back- bone” of a polynucleotide?
- Sugar- phosphate backbone.
- Descirbing strong covalent bonds between sugar and phophate groups (ie. phosphodiester bonds.)
Finish the sentence
A ……. reaction between two ……… forms a ………… bond.
- Condensation.
- Nucleotides
- Phosphodiester bond.
How is the double- helix structure of DNA formed?
- DNA polymer occurs in pairs, these pairs are joined by hydrogen bonds (between the complementary bases.)
What are the complementary base pairs in DNA?
- Guanine and cytosine (ie. guanine can only form hydrogen bonds with adenine.)
- Adenine and thymine (ie. adenine can only form hydrogen bonds with thymine.)
How many hydrogen bonds form between adenine and thymine (complementary base pairs?)
- 2 hydrogen bonds form between these complementary base pairs.
How many hydrogen bonds form between cytosine and guanine (complementary base pairs?)
- 3 hydrogen bonds form between these complementary base pairs.
Why is complementary base pairing important?
- Important to help maintain order of genetic code when DNA replicates.
Finish the sentence
DNA and RNA are important ………. …….. molecules.
- information
- carrying
How is DNA’s structure suited to its function of being genetic information- carrier molecule/ very stable molecule?
6 main ways.
1.) Stable due to sugar- phosphate back- bone (strong covalent bonds) in double helix.
2.) Double stranded (replication can occur by using one strand as template.)
3.) Weak hydrogen bonds for easy unzipping of 2 strands during replication.
4.) Large molecule: carries/ stores a lot of information.
5.) Complementary base pairing allows identical copies to be made in DNA replication.
6.) Helical so can compact, large amount of genetic material in small space.
Although DNA is large, why is it said to be “compact?”
- DNA coiled around proteins (called histones) - so, a lot of information can be stored in a small space in the molecule.
Why did scientists doubt that DNA carried a genetic code?
- Due to the relative simplicity of the DNA molecule, many scientists doubted that it carried a genetic code.
What is the full name of DNA?
- Deoxyribonucleic acid.