Carson Ticer Flashcards
Genetics 210- Riddle (39 cards)
In humans, 20 percent of the bases in DNA are cytosine, what percentage of the bases are Thymine?
Cytosine and Guanine are in equilibrium. That being said, Cytosine and Guanine each have values of 20 percent, adding up to 40 percent. As Thymine and Adenine are in equilibrium, they will amount to the remaining 60 percent of the total 100 percent, which makes both Thymine and Adenine 30 percent.
Relations to DNA
DNA strands are antiparallel, contain Thymine (as opposed to RNA which contains Uracil), consists of a 5 carbon sugar, a deoxyribose sugar ( RNA consists of a ribose sugar), and the synthesis occurs from 5’ to 3’)
Euchromatic characteristics
Gene rich, Early Replicating, Recombines during meiosis, transcribed, and contains chromosome arms.
How is DNA packaged?
DNA is tightly wound around a histone complex (and octamer) as well as an H1 histone. (H1 histones are composed of chromatin in eukaryotic cells)
What will happen to a linear chromosome that lacks a telomere at one end?
The end of the chromosome will degrade very quickly and become unstable. This occurs because telomeres are used as protectants.
What are hairpin structures, where are they usually found, and what is their purpose?
It is a structure where a loop is formed usually with complementing base pairs lining up with a loop at the end. They are usually found in RNA. They usually serve as recognition sites for proteins.
Endosymbiotic theory and its significance to life today
This theory states that once the mitochondria and the chloroplasts were free-living organisms that got engulfed by eukaryotic cells. This theory is backed by the fact that both mitochondria and chloroplasts have their own DNA.
Why does replication within the cells have to be extremely accurate?
Since cells replicate so much, even a small percent of errors are fatal to the cells.
What does semiconservative mean? DNA replication is semi-conservative. Explain-
Semiconsevative means half preserved. A DNA strand is held apart and new strands are built onto the old strands. In the end you will have 2 new strands, one old and one new.
What are the products of theta replication
2 circular DNA molecules
What are the products of eukaryotic DNA replication
2 linear DNA molecules
What is the difference between a leading and lagging strand?
The leading strand is synthesized all in one piece and the lagging strand is synthesized in small fragments since DNA can only be synthesized in the 5’ to 3’ direction.
Okazaki fragments
They are small fragments that are built onto the lagging strand. They are later pieced together with DNA ligase.
Enzyme functions- DNA helicase
unwinds DNA at the replication fork
Enzyme functions- DNA gyrase
Moves ahead of the replication fork and works to break some bands and reduce torque
Enzyme functions- DNA primase
Synthesizes a short RNA primer to provide a point of attachment for the DNA nucleotides
Enzyme functions-DNA poly 1
Removes RNA primer and replaces with DNA
Enzyme functions-DNA poly 2
Elongates the nucleotide sequence
Enzyme functions-DNA poly 3
Elongates the nucleotide sequence
Enzyme functions-DNA ligase
glues together the Okazaki fragments from the lagging strand.
If there is a malfunction in the way DNA ligase works, what would be the outcome?
The lagging strand would exist in a bunch of small pieces and would not be able to function properly and would not be able to code for any important genes or proteins which would be fatal.
Is DNA or RNA more stable? Why?
DNA is more stable as it is double stranded which is more stable. Also the ribosome sugar in RNA molecules is more unstable than the deoxyribose sugar in DNA molecules.
Is the promoter region downstream or upstream of the coding region?
Upstream
Which strands are genes transcribed from?
Genes can be transcribed from either leading or lagging strands.
