Macromolecules of the Cell - Nucleic Acids, Structure & Function Flashcards
What does DNA stand for?
DeoxyriboNucleic Acid.
The main role of DNA in the cell is the long-term storage of …………….. .
Information.
All known cellular life and all known viruses contain DNA - true or false?
False. All known cellular life does contain DNA, but only some viruses contain DNA.
In vertebrates, which cells do not contain DNA, because their nuclei are lost when the cells are made?
Erythrocytes (red blood cells).
What are the five nitrogenous bases found in DNA?
Cytosine, thymine, uracil (in RNA), adenine and guanine.
What are the two categories of nitrogenous bases? What are the differences between the two?
Pyramidines - one ring in the atom.
Purines - two rings in the atom.
Name the three pyramidine nitrogenous bases.
Hint: CUt The PYe!
Cytosine, uracil and thymine.
Name the two purine nitrogenous bases.
Hint: PURe As Gold!
Adenine and guanine.
Besides the nitrogenous base, what are the two other components of DNA?
Phosphate and deoxyribose.
Deoxyribose is a …………. sugar with … -group on the second carbon atom.
Pentose, hydrogen.
A nitrogenous base linked to a sugar is known as a ……………. ?
Nucleoside.
What sort of linkages join nitrogenous bases to deoxyribose in a nucleoside?
N-glycosidic linkages.
Which carbon of deoxyribose is a nitrogenous base bonded to with an n-glycosidic linkage in a nucleoside?
C 1’.
Where are phosphates added to nucleosides to form nucleotides?
At C 5’ of the sugar (top of the pentagon).
Name some biochemical uses of nucleotides.
- Chemical energy - ATP is a nucleotide.
- It is a product of phosphorylation and cellular respiration.
- Used in motility and cell division.
- Signal transduction pathways and secondary messenger systems.
In the DNA structure, the two strands run antiparallel - what does this mean?
They run in opposite directions - one from the 5’ to the 3’ end and one from the 3’ to the 5’ end.
True or false? One strand of DNA has purines (adenine and guanine), the other side has pyramidines (thymine and cytosine).
True.
Which DNA bases always pair together?
Adenine / thymine.
Cytosine / guanine.
How many hydrogen bonds are there between adenine and thymine?
Two.
How many hydrogen bonds are there between cytosine and guanine?
Three.
What implications does the difference in the number of hydrogen bonds between adenine and thymine (two) and cytosine and guanine (three) have?
Although the H-bonds are relatively easy to break, it is slightly easier to break the two bonds between adenine and thymine than it is to break the three bonds between cytosine and guanine.
By convention, DNA base pairs are always written from which end?
From the 5’ end to the 3’ end.
True or false? Watson and Crick’s 1953 paper was the first time genes and DNA were known about?
False. They discovered DNA’s double helix structure, but genes and DNA were alreaday known about prior to 1953.
What is the minor groove and the major groove?
The minor groove is where the turns of the DNA doube helix are closer together; the major groove is where they are further apart.