1.1 DNA structure Flashcards
(16 cards)
What are the steps of DNA replication
- The helices breaks the hydrogen bonds and the helix opens
- Then each strand of the DNA acts as a template for synthesis of a new complementary strand.
- Replication produces two identical DNA double helices, each with one new and one old strand.
What is the function of DNA in living organisms?
DNA stores and transmits genetic information and functions in the same way in all living organisms.
How is DNA organized in eukaryotes?
In eukaryotes, DNA is bound to proteins (histones) and is organized into linear chromosomes found in the nucleus.
What is the structure of DNA?
DNA is a helical double-stranded molecule made up of nucleotides, with two strands running in opposite directions.
How is DNA organized in prokaryotes?
In prokaryotes, DNA is unbound and exists as a circular chromosome in the cytosol.
How is DNA in mitochondria and chloroplasts different from nuclear DNA in eukaryotes?
In mitochondria and chloroplasts, DNA is unbound and circular, similar to prokaryotes, unlike the linear chromosomes found in the nucleus.
How do chromosomes in prokaryotes and eukaryotes differ?
Prokaryotes have a single, circular DNA molecule in the cytosol, while eukaryotes have multiple linear chromosomes in the nucleus.
Why is DNA replication important?
DNA replication is essential for passing genetic information from one generation to the next, ensuring inheritance of traits.
What are the base-pairing rules of DNA?
In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).
What is the importance of complementary base pairing (A–T and C–G)?
Complementary base pairing ensures the accuracy of DNA replication and the stability of the double-stranded molecule.
What is the nucleotide composition of DNA?
DNA is made of nucleotides, each containing a phosphate group, a sugar (deoxyribose), and a nitrogenous base (A, T, C, or G).
What are the weak bonds between DNA strands that allow for replication?
The weak hydrogen bonds between complementary base pairs (A–T, C–G) allow the strands to separate during replication.
How are DNA strands directional?
DNA strands are directional and are read in the 5’ to 3’ direction.
What is semi-conservative replication of DNA?
Semi-conservative replication means that each new DNA molecule consists of one original strand and one newly synthesized strand.
How is semi-conservative replication represented?
Semi-conservative replication is represented by two DNA molecules, each containing one old (parent) strand and one new (daughter) strand.
