DNA and RNA Flashcards
What does tRNA do?
Binds with amino acids to allow for protein synthesis
What are the main differences between DNA and RNA?
Uracil instead of Thymine
RNA is single stranded
Ribose instead of deoxyribose
RNA can’t self replicate
RNA can leave the nucleus
What are the key features of mRNA?
Single stranded polynucleotide Made by the transcription of the DNA (can form hydrogen bonds with DNA) Much shorter than DNA (length of gene) Leaves the nucleus Unstable so easily broken down
What are the complementary base pairs?
Adenine - Thymine
Cytosine - Guanine
What is DNA replication?
When a cell divides a perfect copy of the information in the DNA needs to be reproduced
What did Hammerling use to do his experiment on the part of the cell controlling characteristics? Why?
Acetabularia
It is a single cell organism
Has distinguishable parts (cap, stalk, foot)
Quick regenerative properties
Nucleus in the foot
What was the first Hershey-Chase experiment involving?
A bacteriophage with a sulfur (S35) labeled protein capsule i.e radioactively labelled
When the cell became infected the labelled capsule remained on the outside
What happens in DNA replication?
DNA helicase separates the two strands breaking the hydrogen bonds between nitrogenous bases
Free nucleotides are attracted to their complementary base pairs on the template strands
Then DNA polymerase joins the nucleotides together when they have lined up
Two identical strands are formed each one contains half the original DNA material
Why does semi-conservative describe DNA replication?
One original parental strand remains in the new DNA molecule whilst one new strand coils around the original
What is significant about DNA polymerase?
It can only replicate a bit at a time in short sections
It can only travel in one direction
3’ - 5’
3 to 5 refers to the carbons on the deoxyribose
What did Griffiths conclude about DNA in 1928?
That if a virile strain was heated and put with a non-virile then the DNA in the virile strain can survive the heating and be taken in by the non-virile strain making it now virile
Therefore DNA was important
What does mRNA do?
Transfers genetic information from DNA in the nucleus to the ribosomes in the cytoplasm
What is the structure of rRNA?
60S and 40S subunits
S = svedbergs
Measures how fast molecules move in a centrifuge
What are the key features of mRNA?
Single stranded polynucleotide Made by the transcription of the DNA (can form hydrogen bonds with DNA) Much shorter than DNA (length of gene) Leaves the nucleus Unstable so easily broken down
How does DNA having the property of bases in sequence help?
It allows a lot of variation
They form triplet codes to relate to one amino acid
Therefore 64 variations of the triplet
What are some features of DNA?
Long coiling molecule Sugar phosphate backbone Bases in sequence Complementary pairs Hydrogen bonds Helical structure
What are the bases in RNA?
Adenine
Cytosine
Guanine
Uracil