Key Area 1 Flashcards
What is the basic unit of DNA?
The basic unit of DNA is a nucleotide, which consists of a deoxyribose sugar, a phosphate group, and a nitrogenous base.
What are the four nitrogenous bases in DNA?
Adenine (A), Thymine (T), Cytosine (C), and Guanine (G)
What type of bond holds the two DNA strands together?
Hydrogen bonds between the nitrogenous bases hold the two strands of DNA together.
What does antiparallel mean in the context of DNA structure?
Antiparallel means that the two strands of DNA run in opposite directions, with one strand running 5’ to 3’ and the other running 3’ to 5’.
Describe the structure of the DNA double helix.
DNA has a double helix structure, with two antiparallel strands wound around each other, forming a twisted ladder. The sugar phosphate backbone forms the sides of the ladder and the paired bass from the rings.
What is the complementary base pairing rule?
Adenine (A) with Thymine (T), and Cytosine (C) with Guanine (G)
What is the significance of the 5’ and 3’ ends of DNA?
The 5’ end has a phosphate group attached to the 5th carbon of the sugar, and the 3’ end has a hydroxyl group attached to the 3rd carbon of the sugar. DNA replication and synthesis occur in the 5’ to 3’ direction.
What is a gene?
A gene is a specific sequence of nucleotides in the DNA that codes for a protein or a RNA molecule.
What is the role of DNA in cells?
DNA stores genetic information that directs the synthesis of proteins and regulates cell activities.
How is DNA organised in eukaryotic cells?
In eukaryotic cells, DNA has wrapped around histone proteins, forming nucleosomes, which further coil and fold to form chromatin. During cell division chromatin condenses to form chromosomes.
What is a chromosome?
A chromosome is a long, linear DNA molecule that is tightly coiled and is associated with proteins. Each chromosome contains many genes.
How does DNA replication ensure accurate copying of genetic information?
DNA replications is a semi-conservative, meaning each new DNA molecule consists of one original strand and one newly synthesised strand, ensuring the genetic information is accurately copied.
What are telomeres and what is their function?
Telomeres are repetitive nucleotide sequence at the ends of chromosomes that protect the chromosome from degradation and prevent the loss of important genetic information during DNA replication.
What is a mutation?
A mutation is a change in the nucleotide sequence of DNA, which can lead to changes in protein structure and function.
What is the central dogma of molecular biology?
The central dogma of molecular biology states that genetic information flows from DNA to RNA to protein.
