Unit 1 Key area 1 Flashcards
What is the name given to the basic units that make up a DNA molecule?
Nucleotides
Explain how a DNA nucleotide is structured?
A nucleotide consists of a phosphate group attached to a deoxyribose sugar molecule which make up the sugar phosphate backbone of the nucleotide. Which is attached to one of four bases.
Explain the different types of base pairs and the process of complementary base pairing in a DNA molecule?
Each nucleotide contains either Adenine, Guanine, Cytosine, or Thymine. The process of complementary base pairing means that nucleotides with adenine bases will only be attached to nucleotides with thymine bases. Similarly nucleotides with guanine bases can only be attached to nucleotides with cytosine bases
How are bases held together in a DNA molecule?
Bases are held together by hydrogen bonding
State the shape of a molecule of DNA?
Double stranded helix (with an antiparallel structure)
What is meant by an antiparallel structure of DNA?
Each strand of DNA runs in the opposite directions of each other. One stand from 5’ to 3’ end and the other from 3’ to 5’.
What is meant by the genetic code of an organism?
The sequence of bases formed by the DNA
Explain the organisation of DNA in a prokaryotic cell?
In prokaryotes DNA is organised in circular chromosomes and also in smaller circular rings called plasmids. (Prokaryotes do not have a nuclear membrane genetic information is stored in the cytoplasm)
Explain the organisation of DNA in Eukaryotic cells?
In eukaryotes DNA is arranged in linear chromosomes In the nucleus of the cell. These linear chromosomes are tightly coiled and packaged around associated histone proteins. Eukaryotes also contain circular chromosomes.
Where can circular chromosomes be found in eukaryotic cells?
Circular chromosomes can be found in the mitochondria, and the chloroplast of the cells.
State what makes yeast a “special Eukaryote”
Yeast contains plasmids.
