Gene expression at
molecular level
Gene expression means the production of mRNA and proteins to convert
the genetic code into something useful
Genes just store information
DNA Size
Humans have 23,300 genes
In chromosome 1
Largest biomolecule in Human cells
There are 249 million base pairs of DNA
We have 46 chromosomes which means theres 2-3 meters of DNA per
cell
There the total length of your DNA is
(Length of one base pair)(# base pairs per cell)(# cells per body) =
(0.34x10-9 metres)(6x109)(1013) = 2x1013 metres
That’s 70 round trips between the Earth and the Sun!
,Genes
A gene is a specific sequence of DNA within the much longer chromosome
which contains coding information for (usually) a protein and some code
for RNA
Genes contain the information necessary to make the organism and allow
it to favorably interact with its environment
Genes that code for polypeptides (proteins) are known as structural
genes.
Traits or characteristics of organisms are based on cellular activities
I.e we look the way we do because of the chemical reactions in our
bodies
A polypeptide becomes a unit of function or protein
Activities of proteins determine the structure and function of cells
So if all cells have the same DNA so why are they radically different in
form and function?
Its because different subsets of genes are ‘expressed’ in different
cell typesf proteins determine the structure and function of cells
For example, kidney cells and stomach cells have the same genes BUT
some are switched on/ off to give its differences
,Gene expression
Gene expression is the process of reading the DNA code to produce
proteins
Genes function to produce visible traits by coding for the proteins that
do the work in cells
Each gene has different variants within a population (alleles)
Each allele codes for a slightly different version of the protein
These protein versions that are produced by different allelles, alter
phenotypes in subtle ways
, Genes and proteins
In 1908, Archibald Garrod proposed a relationship between genes and the
production of enzymes
Much of his early work centered on the inherited diesase alkaptonuria
Alkaptonuria - a disease in which a patient’s body accumulates abnormal
levels of homogentisic acid
Results in the discolouration of the skin and cartilage and causes
the urine to appear black
Garrod hypothesised that this disease was due to a ‘missing’ enzyme
He proposed a relationship between the inheritance of a mutant gene and
a defect in metabolism
Metabolic pathways
This condition is an example of a condition caused by a mutation in an
enzyme cascade event
molecular level
Gene expression means the production of mRNA and proteins to convert
the genetic code into something useful
Genes just store information
DNA Size
Humans have 23,300 genes
In chromosome 1
Largest biomolecule in Human cells
There are 249 million base pairs of DNA
We have 46 chromosomes which means theres 2-3 meters of DNA per
cell
There the total length of your DNA is
(Length of one base pair)(# base pairs per cell)(# cells per body) =
(0.34x10-9 metres)(6x109)(1013) = 2x1013 metres
That’s 70 round trips between the Earth and the Sun!
,Genes
A gene is a specific sequence of DNA within the much longer chromosome
which contains coding information for (usually) a protein and some code
for RNA
Genes contain the information necessary to make the organism and allow
it to favorably interact with its environment
Genes that code for polypeptides (proteins) are known as structural
genes.
Traits or characteristics of organisms are based on cellular activities
I.e we look the way we do because of the chemical reactions in our
bodies
A polypeptide becomes a unit of function or protein
Activities of proteins determine the structure and function of cells
So if all cells have the same DNA so why are they radically different in
form and function?
Its because different subsets of genes are ‘expressed’ in different
cell typesf proteins determine the structure and function of cells
For example, kidney cells and stomach cells have the same genes BUT
some are switched on/ off to give its differences
,Gene expression
Gene expression is the process of reading the DNA code to produce
proteins
Genes function to produce visible traits by coding for the proteins that
do the work in cells
Each gene has different variants within a population (alleles)
Each allele codes for a slightly different version of the protein
These protein versions that are produced by different allelles, alter
phenotypes in subtle ways
, Genes and proteins
In 1908, Archibald Garrod proposed a relationship between genes and the
production of enzymes
Much of his early work centered on the inherited diesase alkaptonuria
Alkaptonuria - a disease in which a patient’s body accumulates abnormal
levels of homogentisic acid
Results in the discolouration of the skin and cartilage and causes
the urine to appear black
Garrod hypothesised that this disease was due to a ‘missing’ enzyme
He proposed a relationship between the inheritance of a mutant gene and
a defect in metabolism
Metabolic pathways
This condition is an example of a condition caused by a mutation in an
enzyme cascade event
