Nucleic acids 1-2 Flashcards
What is a nucleotide?
A sugar, phosphate and base bonded together.
What kind of bond holds the nucleotides together?
Phosphodiester
What kind of bond is between the base and the sugar?
Covalent
What kind of bond is between the two DNA strands?
Hydrogen
How many hydrogen bonds between cytosine and guanine?
3
How many hydrogen bonds between adenine and thymine?
2
Why do the sugar and phosphate head point outwards?
Because they are negatively charged.
How large is the human genome?
6x10^9 base pairs
What is a karyotype?
Organised profile of an individual’s chromosomes, including 22 pairs of autosomes and 1 pair of sex chromosomes.
What is chromatin?
A tightly packed complex of DNA, RNA and protein found in eukaryotes.
What are nucleosomes?
Protein complexes (histone) that are used to condense DNA into chromosomes so that it is able to fit into the nucleus. Provides a 7-fold condensation of DNA.
How many histone proteins is a nucleosome made up of?
8 ( 2 each of the following: 2A, 2B, 3 and 4)
How do histone proteins interact with DNA?
Histone proteins are positively charged so interact with the negatively charged sugar-phosphate backbone.
What connects each nucleosome to one another?
Histone 1
How is DNA replication semi-conservative?
The daughter cell inherits half of one DNA strand from the parent (template) and a newly synthesised one that is complementary to the template strand.