What is a phenotype?
Physical manifestation of genotype
What is a genotype?
All of the genes in our DNA, even the ones that are not expressed
Why are proteins functionally different?
Due to their different structures
What does the structure of a protein depend on?
The primary structure (sequence of amino acids)
What is DNA?
A chain of nucleotide monomers that contains all of our genetic information
What does each nucleotide contain?
What structure does DNA form?
How many bases is there per turn of the helix?
How do polypeptide chains of DNA run to each other?
Antiparralel to one another
How are the groves in DNA described?
Major and minor groves which is important for the interaction of proteins
What is the pairing of bases called?
Compliment base pairing
What bases pair with what in DNA?
Thymine paires with adenine
Guanine pairs with cytosine
What does compliment base pairing happen?
Due to the structures of the bases:
Thymine pairs with ademine due to both forming 2 hydrogen bonds
Guanine pairs with cytosine due to both forming 3 hydrogen bonds
What bases form 3 hydrogen bonds with each other?
Cytosine and guanine
What bases form 2 hydrogen bonds with each other?
Thymine and adenine
What is the site of a cells genetic information (DNA)?
Where does the first step of protein production take place and what is this?
DNA replicaiton which takes place in the nucleus
What does each nucleus contain?
A nucleolus which can take up to 25% of its volume and is where transciption and assemble of rRNA takes place
Where does transcription and assemble of rRNA take place?
What is DNA packaged into?
Thread like structures called chromosomes
When are chromosomes visible?
During cell division
What is a chromosome?
Single piece of DNA containing many genes, regulatory elements and other nucleotide sequences
How many chromosomes does a human have?
What can the structure of chromosomes be described as?
Highly ordered to contain vast amounts of DNA
What is the process of packaging chromosomes?
1) Chromatin is the double stranded helical structure of DNA
2) DNA is packed with histones to form nucleosomes, with each consiting of 8 histones
3) Binded with H1 histone to form chromatosome
4) Folded up and tightly coiled to produce fibre called chromatid of the chromosome
What is chromatin?
Mixture of DNA, proteins and RNA thay packages DNA within the nucleus
What are the 2 forms of chromatin?
What must the chromatin do for transcription and replication to occur?
Open up to allow enzymes to access the DNA template
What are the 2 mechanisms for opening up chromatin to allow replication or transcription to occur?
Histones can be enzymatically modified
Histones can be displaced by chromatin remodelling complexes
What should be noted about both processes of opening up chromatin?
They are reversible