DNA. Flashcards
What are genes?
Short section of DNA which codes for a characteristic.
What are Chromosomes?
Long molecule of tightly packed DNA.
What is the DNA helix?
Biological polymer made from nucleotide monomers, in a helix formation.
What is the backbone?
Support made of phosphate sugar.
How do the bases pair up?
Adenine to Thymine (straight letters) + Cytosine to Guanine (curly letters).
What are bases?
Nitrogenous base found in DNA that undergo complimentary base pairing- adenine, thymine, cytosine or guanine.
How many hydrogen bonds hold together A and T?
Two.
How many hydrogen bonds hold together C and G?
Three.
Why do the bases pair up?
They are different sizes-that is partly the reason why they pair. Because A + T pair and C+G pair, they make the chain stay the same size throughout.
How was DNA discovered?
James Watson and Francis Crick determined the structure of the double helix of the DNA, in 1953, in Cambridge University, to further the understanding of cell biology and genetics.
Rosalind Franklin, in Cambridge, had her photo stolen. Crick and Watson used her photo and Franklin received little commendation for her work. she died before receiving her Nobel prize. Her X-Ray diffraction studies assisted greatly in the research into DNA.
What are bases held together by?
The bases are held together by WEAK HYDROGEN BONDS.
In which two circumstances can you have identical DNA?
If you are a clone or an identical twin.
What does the code that a gene contains do?
The code that a gene contains causes specific proteins to be made. The particular proteins determine the cell’s function.
What does the combination of genes in an organism do?
The combination of genes in an organism controls how the organism functions, and what it looks like.
What is the structure of DNA?
DNA is made up of two strands.
These strands are joined together by bases.
The strands are then twisted together.
This forms a shape known as a double helix- this is the phosphate-sugar backbone.
DNA is made of lots of small units called nucleotides, which are joined together.
This means that DNA is a polymer.
Each nucleotide is made is made of a sugar (called deoxyribose), a phosphate group and a base. The two strands of DNA are held together by weak hydrogen bonds between the bases.
