Nucleic Acids Flashcards
Describe the structure of DNA.
It has a double helix that are two separate stands wound together to form a spiral and strands are polynucleotides joined in a long chain. The chains are antiparallel and the base pairs are joined together by hydrogen bonds.
What is the function of DNA?
Contains all of the genetic information
Describe the structure of a nucleotide
It is made up a phosphate group, a pentose sugar called deoxyribose and a varying nitrogenous base.
Name the purines
Adenine and guanine
Name the pyrimidines
Thymine and cytosine
How do polynucleotide strands join?
Between the phosphate group and the pentode sugar created a sugar phosphate backbone.
Which bases pair up and describe the hydrogen bonding between them.
A and T join up and they have two hydrogen bonds between the base pairs and C and G pair up and they have three hydrogen bonds between them.
What is the main type of RNA and what is its function?
The main type of mRNA and it is used to make proteins from the instructions contained within DNA.
Describe the structure of RNA.
It is made up of nucleotides joined together by the phosphate and the sugar. It is single stranded. It has uracil instead of thymine. The sugar is ribose that is also a pentode sugar.
Compare the structure of DNA and mRNA
Double stranded joined by H bonds compared to a single stranded mRNA. DNA has a deoxyribose sugar compared to mRNA ribose sugar. mRNA has uracil instead of thymine.
Why does DNA replicate?
It copies it self before cell replication so a new cell has the full amount of DNA. Important for making new cells and passing on genetic information.
How does DNA replicate?
H bonds between the strands break down between the two polynucleotide strands break. The helix unzips to form single strands due to DNA helixase. Then the original strand will act a template stand by complementary base pairing. The new strands are joined together by the enzyme DNA polymerase. H bonds form between bases between new and old strands. Each DNA molecule has an old and new strand.
Where are DNA molecules found?
In the nucleus of the cell
What is the organelle called that assembles proteins?
It’s called a ribosome
Why does mRNA help in protein synthesis?
DNA is too large to move out the nucleus. Therefore mRNA copies a section if the DNA strand and moves out of nucleus and joins the free ribosome in the cytoplasm where synthesis will occur. Codons are read and the amino acids form into a long chain creating a protein.
