DNA - The blueprint Flashcards
What does DNA stand for?
Deoxyribonucleic acid
What is a DNA nucleotide made of?
Deoxyribose sugar (5 carbon sugar molecule), a phosphate group (-ve charge), and a nitrogenous base.
What are the 2 classes of nitrogen bases?
Purines (Made of 2 rings), and Pyrimidnines (Made of 1 ring)
What are the 4 nitrogen bases and their respective classification?
Adenine (Purine), Guanine (Purine), Thymine (Pyrimidine), Cytosine (Pyrimidine).
How are the monomers of DNA joined together?
Condensation polymerisation.
What are the bonds that hold the monomers of DNA to other monomers?
Phosphodiester bonds.
What is the structure of DNA?
Double-Helix made up of a sugar-phosphate backbone and with complementary nitrogen bases in between.
What is Chargaff’s rule?
Adenine always pairs with Thymine, and Cytosine always pairs with Guanine.
What is a histone?
It is a protein that DNA molecules carefully twist around. It looks like beads on a string.
What is chromatin?
The DNA-histone complex.
What are single chromosomes and replicated chromosomes made of?
Chromatids. Replicated chromosomes are joined by a centromere.
What are the components of the cell theory?
- All living organisms are made up of one or more cells
- The cell is the smallest unit of life
- All cells arise from existing cells
What is step 1 of DNA replication?
DNA helicase unwinds the double helix and breaks the H bonds between the nitrogen bases.
What is DNA helicase?
It is an enzyme that unwinds the double helix of DNA
What is step 2 of DNA replication?
Single-strand binding proteins attach to each strand of DNA to prevent them from rejoining/reannealing together.
What is step 3 of DNA replication?
A short sequence of RNA nucleotides is added to the DNA by an enzyme called RNA primase.
What is step 4 of DNA replication?
DNA polymerase adds complementary nucleotides to the template strand one at a time, starting at the 3’ end of the RNA primer. A protein called the sliding clamp helps the polymerase fill in the gaps with the complementary DNA nucleotides..
What is step 5 of DNA replication?
Another enzyme called nuclease removes the primer from the template strands and DNA polymerase fills in the gaps with complementary DNA nucleotides.
What is step 6 of DNA replication?
The enzyme DNA ligase joins the sections of replicated DNA into a single long strand.
