Transcript Vitamin D and Chemical Pathways

“Genome”
The story of Archibald Garrod
Genes Make Proteins (Enzymes),
Enzymes Catalyze the Reactions of
One Substrate to Another
Substrate 1
Enzyme 1
Enzyme 2
Enzyme 3
Substrate 2
Substrate 3
Substrate 4
Melanocytes Animation
Where do proteins come from?

Like all proteins, enzymes follow this central dogma:
 DNA

RNA
Transcription
Proteins
Translation
Genes Make Proteins (Enzymes), Enzymes Catalyze the
Reactions of One Substrate to Another
Substrate 1
Gene 1
Enz 1
Gene 2
Enz 2
Substrate 2
Substrate 3
Gene 3
Enz 3
Substrate 4
Genes Make Proteins (Enzymes),
Enzymes Catalyze the Reactions of
One Substrate to Another
Substrate 1
Gene 1
Enz 1
Gene 2
Enz 2
Substrate 2
Substrate 3
Gene 3
Enz 3
Substrate 4
Gene 4
Substrate 5
Alleles are alternate forms of a gene
A
Allele
a
Allele
A allele
ability to
make an
enzyme
a allele
inability to make
an enzyme
Typical Gene
Structure
Regulatory
sites
Promoter
(RNA polymerase
binding site)
Start transcription
DNA strand
Stop transcription
Human biochemical pathways can be very complicated. Although the Human
genome project has mapped out the locations of gene on chromosomes, the
next frontier is to map out human biochemical pathways.
(An amino acid)
(An amino acid)
The enzyme
What is Phenylketonuria (PKU)?
1. is a rare condition in which a baby is born without the
ability to properly break down an amino acid called
phenylalanine.
2. Phenylketonuria (PKU) is inherited (autosomal rescessive
trait), which means it is passed down through families.
What does this mean? Both parents must pass on the
defective gene in order for a baby to have the
condition.
3. Babies with PKU are missing an enzyme called
phenylalanine hydroxylASE, which is needed to break down
an essential amino acid called phenylalanine. The substance is
found in foods that contain protein.
4. Without the enzyme, levels of phenylalanine and two
closely-related substances build up in the body. These
substances are harmful to the central nervous system and
cause brain damage.
5. Phenylalanine plays a role in the body's production of melanin, the
pigment responsible for skin and hair color. Therefore, infants with the
condition often have lighter skin, hair, and eyes than brothers or sisters
without the disease.
Other symptoms may include:
-Delayed mental and social skills
-Head size significantly below normal
-Hyperactivity
-Jerking movements of the arms or legs
-Mental retardation
-Seizures
-Skin rashes
-Tremors
-Unusual positioning of hands
If the condition is untreated or foods containing phenylalanine are not
avoided, a "mousy" or "musty" odor may be detected on the breath and
skin and in urine. The unusual odor is due to a build up of phenylalanine
substances in the body.