Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
10 Cards in this Set
- Front
- Back
|
Describe the structure of DNA |
Supercoiled - large amounts of genetic info can fit into small nucleus. Double-stranded - allows semi-cons. DNA replication to occur. H-bonds - strong enough to hold strands together but break easily to allow replication to occur. Sugar-phosphate backbone - supports & strengthens strand |
|
|
What is 'The Genetic Code'? |
DNA is degenerate - more than 1 triplet of bases can code for same amino acid. DNA is universal - the same 3 bases code for the same amino acid in every organism. DNA is non-overlapping - 1 base can only belong to 1 triplet |
|
|
Name the 2 purine bases and the 2 pyrimadine bases |
Purine - adenine and guanine Pyrimadine - cytosine and thymine |
|
|
What are the differences between DNA and RNA? |
DNA is double-stranded, contains thymine, is only available in 1 version, contains no codons/anticodons, is helical & contains deoxyribose sugar. RNA is single-stranded, has uracil, comes in 2 versions (mRNA & tRNA), has codons/anticodons, can be clover shaped & has ribose sugar |
|
|
Define 'nucleosome', 'gene' & 'allele' |
Nucleosome - DNA + histone Gene - sequence of bases that codes for a sequence of amino acids which codes for a polypeptide Allele - one version of a gene |
|
|
Name the 3 types of chromosome |
Heterochromatin, euchromatin & chromatin |
|
|
Describe the features of heterochromatin, euchromatin & chromatin |
Heterochromatin - tightly coiled, genetically inactive, stains darkly in karyotyping Euchromatin - partially coiled, genetically active, stains lightly in karyotyping Chromatin - DNA wrapped around histone proteins, found in nuclei of most eukaryotic cells |
|
|
5 types of DNA Mutation? |
Silent, missense, nonsense, addition & deletion |
|
|
Describe silent, missense, nonsense, addition and deletion mutations |
Silent - change in base sequence of DNA, doesn't affect amino acid expressed as DNA is degenerate Missense - change in base sequence of DNA, affects amino acid sequence, changes protein structure Nonsense - change in base sequence of DNA causes 'stop-codon' to be expressed, protein synthesis stops here Addition - base added to sequence, causes frameshift to right Deletion - base removed from sequence, causes frameshift to left |
|
|
Who discovered DNA & in what year was it discovered? |
Watson & Crick in 1953 |
