Biology- chapter 6

First half of C6

Genome

The entire set of genetic material in an organism

DNA

A polymer made up of nucleotide monomers. Two strands forming a double helix shape.

Gene

A section of DNA which codes for sequence of amino acids to make a specific protein.

Why is it important to understand the human genome?

-Allows scientists to identify genes that are linked to diseases
-Help to develop treatments for inherited conditions
-Can be used to trace the past migration of humans

Parts of a nucleotide

Each nucleotide is made up of a sugar, a phosphate group, and a ‘base’ (A, T, C or G)

Complementary base pairing

A with T, C with G

Purpose of non-coding DNA

To switch genes on and off and control whether or not a gene is expressed

Proteinsynthesis

-A messenger molecule called mRNA makes a copy of a section of the DNA code and carries it to the ribosomes
-The correct amino acids in the correct order are brought to the ribosomes by carrier molecules
-When a chain of amino acids has been assembled, it folds into a unique shape to form a protein

How can mutations affect a protein

If the shape of the active site is changed, the substrate may no longer bind to it.

Types of mutation

Insertions- when a new base is inserted into the DNA base sequence, changing the way the groups of three bases are ‘read’
Deletions- when a base is deleted from the sequence, changing the way the groups are read
Substitutions- when a base is changed for another in the sequence