Chapter 3.8 - Nucleic acids Flashcards
What are nucleotides?
The monomers used to form the polymer nucleic acids
Give two examples of polymers of nucleotides
- Dimers - dinucleotides
- Polynucleotides (nucleic acids)
What are the three components of nucleotides?
- Pentose sugar (contains 5 carbon atoms)
- Nitrogenous base (contains carbon and nitrogen)
- Phosphate group (contains phosphate)
How are polynucleotides formed?
They are formed by the joining of nucleotides via condensation reactions, the phosphate group of one nucleotide forms a covalent bond with a sugar of another, the bond is called a phosphodiester bond
How can phosphodiester bonds be broken?
They can be broken by hydrolysis reactions which release the nucleotide monomers
What are the two types of nucleic acids?
DNA and RNA
What is DNA?
A type of nucleic acid that contains the instructions needed to make proteins
What is each DNA nucleotide made up of?
- Deoxyribose - pentose sugar
- A,T,G, or C base - nitrogenous base
- Phosphate group
What are the six features of the structure of DNA?
- Sugar-phosphate backbone
- Double stranded
- Large molecule
- Double helix
- Complimentary base pairing
- Weak hydrogen bonds
How does the sugar-pentose backbone allow DNA to pass genetic information from one generation to another?
It protects the coding bases on the inside of the helix
How do the double strands allow DNA to pass genetic information from one generation to another?
Both strands can act as templates in DNA replication
How does DNA being a large molecule allow DNA to pass genetic information from one generation to another?
It can store lots of information
How does DNA having a double helix allow DNA to pass genetic information from one generation to another?
It makes the molecule compact
How does complimentary base pairing allow DNA to pass genetic information from one generation to another?
It makes sure the replication of DNA is accurate
How do the weak hydrogen bonds allow DNA to pass genetic information from one generation to another?
The strands can separate in DNA replication as the hydrogen bonds hold the strands together and do not require much energy to overcome
What does it mean when DNA is anti-parallel?
The two strands of DNA are antiparallel which means one strand runs in a 5’ to 3’ direction while the other runs in a 3’ to 5’ direction
What are the two types of nitrogenous bases?
Purines and pyrimidines
What are purines?
Larger nitrogenous bases that contain two carbon ring structures (A and G)
What are pyrimidines?
Smaller nitrogenous bases that contain one carbon ring structure (T and C)
How are DNA strands held together?
The nitrogenous bases are bonded via hydrogen bonds, holding the two DNA strands together
How is the arrangement of purine and pyrimidine bases always binding together effective?
The arrangement maintains a constant distance between the two sugar-phosphate backbones
What are the base pairs and how many hydrogen bonds are required to hold them together?
- Adenine pairs with Thymine and has 2 hydrogen bonds
- Cytosine pairs with Guanine and has 3 hydrogen bonds
What is RNA
A type of nucleic acid that uses information from DNA to synthesise proteins
What are the three components of RNA?
- Ribose - pentose sugar
- A,U,G or C base - nitrogenous base
- Phosphate group
Describe the structure of RNA in three points
- Contains the pentose sugar ribose
- Contains the base uracil
- Single stranded molecule made up from one polynucleotide
Compare DNA and RNA (4 points)
- Pentose sugar : DNA = deoxyribose , RNA = ribose
- Bases : DNA = A,T,C,G , RNA = A,U,C,G
- Size : DNA = long , RNA = short
- Number of strands : DNA = 2 , RNA = 1
What is the difference between the pentose sugars in DNA and RNA?
The pentose sugar in DNA, deoxyribose, has one fewer oxygen atoms than the pentose sugar in RNA, ribose
What bond joins the nitrogenous base and the pentose sugar in nucleic acids?
Glycosidic
What bond joins the phosphate and the pentose sugar in nucleic acids?
Phosphodiester
What bond joins the nitrogenous bases together in nucleic acids?
Hydrogen bonds
