Unit Eight - Molecular DNA Flashcards
Definition of DNA (2)
Classification & Function
- Type of Nucleic Acid
- Carries Genetic Material
Classification & Function
Definition of RNA (2)
- Type of Nucleic Acid
- Messenger in process of converting DNA to Protein
What is a nucleotide made up of? (3)
- Phosphate Group
- Pentose Sugar
- Nitrogen Base
What are the 3 main types of RNA? (3)
- mRNA (messenger RNA)
- rRNA (ribosomal RNA)
- tRNA (transfer RNA)
Definition of Deoxyribose (3)
Classification, Structure & Function
- Pentose Monosaccharide
- Forms the backbone of DNA
- Links w/ phosphate & nitrogenous bases in nucleotides
What is a saying that can help you memorize base pairings?
Apples in the Tree (Adenine & Thymine)
Cars in the Garage (Cytosine & Guanine)
What are the 4 nitrogenous bases of DNA?
Adenine, Thymine, Guanine and Cytosine
Definition of Purines (3)
Classification, Structure & Example
- Nitrogenous Base
- Two-ring structure
- Adenine & Guanine
Definition of Pyrimidines (3)
Classification, Structure & Example
- Nitrogenous Base
- Single ring structure
- Cytosine, Thymine & Uracil
What is the structure of DNA? (2)
- Backbone
- Rungs/Bases
Definition of the Backbone (2)
- Alternating Phosphates & Sugars
- Held together by strong covalent bonds
How are Nitrogenous Bases of DNA held together?
Hydrogen Bonds
What is Chargaff’s Base Pairing Rule?
Percent of Purines = Percent of Pyrimidines
(In each base pairing)
The amount of adenine (A) roughly equals the amount of thymine (T).
The amount of guanine (G) roughly equals the amount of cytosine (C).
What does it mean when DNA is antiparallel? (2)
- DNA has two strands that run in opposite directions
- One strand runs from 5’ to 3’, and the other runs from 3’ to 5’
What is 5’ and 3’ in context of DNA? (3)
- The ends of each strand is 5’ & 3’
- 5’ end has a phosphate group attached to 5th carbon atom of deoxyribose
- 3’ end has a hydroxyl group attached to 3rd carbon atom of deoxyribose
WHY is DNA antiparallel? (3) (READ THROUGH)
- H - bonds are formed between bases in a way that requires the strands to run in opposite directions
- Alignment maximizes H - Bonds & consistent distance between both strands, stabilizing the double helix structure
- Allows DNA polymerase to add new nucleotides bc it can only add nucleotides in one direction (5’ to 3’), so having the strands run in opp. directions ensures that both new strands can be synthesized simultaneously
What is the process of DNA Replication? (7)
- Helicase Unzips DNA
- Primase forms RNA primers to bind to template strand
- DNA Polymerase III adds nucleotides continuously (leading) & separately (lagging)
- RNA primers are replaced w/ DNA nucleotides by DNA Polymerase I
- Ligase seals Okazaki fragments
- DNA Polymerase I checks/corrects errors
- Semiconservative Replication is Complete
Definition of Replication Fork (3)
Structure, How, Function
- Y-shaped structure
- Formed during DNA replication (Helicase Unzips DNA)
- Forms two template strands for synthesis of new complementary strands
Definition of Okazaki Fragment (2)
- Short segment of DNA synthesized on the Lagging strand
- Fragments join together by Ligase to form a continuous strand
Definition of Lagging Strand (5)
Classification, Definition, & Importmant Characteristics
- Newly synthesized DNA strand in the process of DNA replication
- DNA Strand in the 3’ to 5’ Direction
- DNA Polymerase can only add nucleotides in the 5’ to 3’ direction
- Lagging Strand is synthesized in short fragments called Okazaki Fragments
- Ligase joins these fragments together to form a continuous strand
Definition of Leading Strand (3)
- Newly synthesized DNA strand in DNA replication
- DNA Strand in 5’ to 3’ Direction
- DNA Polymerase III adds nucleotides to the 3’ end, causing it to grow from in the direction of 5’ to 3’
Definition of DNA Polymerase III (2)
- Enzyme adds nucleotides to template strand
- Can only add nucleotides to the 3’ end
What do they mean by “Original DNA is a Template”?
Each strand of DNA guides the formation of a new complementary strand