Introduction to Molecular Biology Flashcards
Describe the Phosphodiester Linkage
A hydroxide group from carbon 3 of a sugar and another hydroxide form carbon 5 of another both binds to phosphorous group to make the linkage
Distinguish between purines and pyrimidines
Purines have double ring structure (thymine and cytosine), pyrimidines have a single ring structure (adenine and guanine)
What is difference between thymine and uracil?
Thymine is a part of DNA and uracil is a part of rna. Also uracil is missing a methyl group whereas thymine is the exact same as uracil but with an extra methyl group
Describe the difference in base pairing in A and T and G and C
A and T form 2 hydrogen bonds and G and C form 3 hydrogen bonds
What is DNA made up of?
DNA is made up of a phosphate backbone with a 5 carbon sugar called deoxyribose and one of four nitrogenous bases
Describe the structure of DNA
DNA is a right handed double helix with the phosphate and sugar as the outside of the helix and the groove are the bases. There are major and minor grooves within DNA as well.
What is the charge of DNA?
DNA is negatively charge from the phosphate groups on the outside
Why is polarity of DNA important?
The members of each base pair can fit together within the double helix only if the two strands of the helix are antiparallel—that is, only if the polarity of one strand is oriented opposite to that of the other strand. Important for structure
What is DNA packaged into
DNA is packaged into chromosomes
What is function of a histone protein?
Their function is to package DNA into nucleosomes. DNA which is negatively charged wraps around the histone proteins to form chromatin
Describe the creation of a chromosome
DNA is wrapped around histones to create nucleosomes which are then made into a beads on a string like structure. The nucleosomes are then packaged tightly into chromatin. This is the section of a chromosome. When the whole chromosome is made is then tightly packed into shape of the chromosome we see under microscopes.
Why is repetitive DNA important?
It is important to protect DNA from erosion
What are the types of repetitive DNA?
Interspersed repeat: Same genetic information on different chromosomes SINE 100s or LINE 1000s of chromosomes long
Tandem repeats adjacent chromosome repeats. For example telomeres always have TTAGGG.
Explain how repetitive DNA can be used in diagnostics
We can compare the number of tandem repeats in the maternal and paternal chromosome and make a fingerprint of people
