Flashcards in Molecular Basis of Inheritance Deck (29):
Name the 3 components of a nucleotide.
What distinguishes deoxyribose sugar from ribose?
It contains a hydrogen only at position C2 as opposed to an OH group.
What 2 groups are the nitrogenous bases categorised into?
What are the X2 purines?
What are the X2 pyramidines?
Which base is replaced in RNA and which base does it replace?
Thymine is replaced by Uracil.
Are the purines single or double ring structures?
Are the pyramidines single or double ring structures?
A sugar + base makes a...
DNA nucleotides have how many phosphate groups?
X3, they are nucleotide TRIphosphates.
What type of bonds do nucleotides form?
Which part of the nucleotide is the 5-prime end?
The phosphate group.
Which part of the nucleotide is the 3-prime end?
The hydroxyl (OH) group.
What is the name given to the inorganic molecule consisting of X2 phosphates (PPi) released when nucleotides bond.
An inorganic pyrophosphate.
What is the name of the enzyme which catalyses the formation of DNA molecules from deoxyribonucleotides?
Describe the complementary base pairings.
A - T (X2 hydrogen bonds)
C - G (X3 hydrogen bonds)
What is the orientation of the X2 DNA strands and their base pairings?
The X2 strands run ANTIPARALLEL with the bases PERPENDICULAR to the helical axis.
What is semi-conservative DNA replication?
The process whereby X2 new daughter DNA strands are produced from a single DNA helix, each retaining X1 strand of the original DNA helix due to complementary base pairing.
What are INTRONS and EXONS?
INTRONS = non-coding regions of DNA which are lost during transcription.
EXONS = coding regions of DNA.
45% of the human genome consists of transposing based repeats such as retrotransposable elements, what are these and how do they work?
Sequences of DNA are transcripted into RNA before being reversely transcribed back to a DNA sequence and inserted back into the genome at a different site.
LINES (Long interspersed elements)
SINES (Shirt interspersed elements)
6.6% of the human genome is heterochromatin. What is this?
Chromatin that is so tightly compact it is transcriptionally inactive.
What is the name of the gene which is responsible for x-chromosome inactivation in females?
What is it called when one X chromosome in females is transcriptively inactive in order to prevent over transcription?
What is the name of the X inactivation centre on the X chromosome which causes mass compression of the X chromosome into heterochromtin?
What has its own circular genome?
Is mitochondrial DNA (mtDNA) inherited from the mother only, father only, or both parents?
How many polypeptides does mtDNA encode for?
Does mtDNA contain introns only, exons only or both?