Genetics And Inheritance Flashcards
What does DNA do
Stores genetic information and controls cell activity- has instructions for building all proteins
How is DNA found in eukaryotes
Within the nucleus as straight chromosomes
How is DNA found in Prokaryotes
in the cytoplasm in the form of a circular chromosomes and many small plasmids
DNA is composed of Nucleotides
What do Necleotides consist of
a sugar (deoxyribose), a phosphate and a nitrogenous base
4 types of nitrogenous base
Adenine, Cytosine, Guanine, Thymine
How are nucleotides joined together
covalent bonds between the sugar of one nucleotide and the phosphate group of the next nucleotide - this forms the sugar phosphate backbone.
Adenine pairs with
Thymine
Thymine pairs with
Adenime
Cytosine pairs with
Guanine
Guanine pairs with
Cytosine
RNA is a type of nucleic acid called
Ribonucleic acid
3 differences between RNA and DNA
RNA- single stranded DNA- double stranded
RNA- sugar called ribose DNA- sugar called deoxyribose
RNA- base uracil DNA- base thymine
Transcription
1) DNA helix is untwisted and unzipped
2) mRNA nucleotides (messenger RNA: a different type of nucleotide) match to their
complementary base on the strand.
3) The mRNA nucleotides themselves are then joined together, creating a new strand
called a template strand of the original DNA. This process is called transcription.
4) The template strand of mRNA then moves out of the nucleus to the cytoplasm and
onto structures called ribosomes.
Translation
5) At the ribosomes, the bases on the mRNA are read in threes to code for an amino
acid the first three bases code for one amino acid, the second three bases code
for another etc). This is called translation.
6) The corresponding amino acids are brought to the ribosomes by carrier
molecules.
7) These amino acids connect together to form a protein. It is therefore the triplet
code of bases that determines which protein is produced and therefore expressed.
8) When the chain is complete the protein folds to form a unique 3D structure.
