Read Chapter 3 from the book “Genome” The story of Archibald Garrod

Biochemical pathways Name 10 different types of diseases found in humans.

What is the leading cause of these diseases?

Genes Make Proteins (Enzymes), Enzymes Catalyze the Reactions of One Substrate to Another Substrate 1 Substrate 2 Substrate 4 Substrate 3 Enzyme 1 Enzyme 2 Enzyme 3

Where do proteins come from? Like all proteins, enzymes follow this central dogma: DNA RNA Proteins Transcription Translation

Genes Make Proteins ( Enzymes), Enzymes Catalyze the Reactions of One Substrate to Another Substrate 1 Substrate 2 Substrate 4 Substrate 3 Gene 1 Enz 1 Gene 2 Enz 2 Gene 3 Enz 3

Genes Make Proteins (Enzymes), Enzymes Catalyze the Reactions of One Substrate to Another Substrate 1 Substrate 2 Substrate 4 Substrate 3 Gene 1 Enz 1 Gene 2 Enz 2 Gene 3 Enz 3 Substrate 5 Gene 4

Alleles are alternate forms of a gene A allele ability to make an enzyme a allele inability to make an enzyme A Allele a Allele

Regulatory sites Promoter (RNA polymerase binding site) Start transcription DNA strand Stop transcription Typical Gene Structure

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)

PKU is an autosomal recessive genetic disease. Individuals who have PKU have inherited a p allele from their mother and a p allele from their father. The P allele controls the transcription of the P allelle DNA into and RNA that is used in translation to make a protein. What protein enzyme is being made?

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.

How do you treat this condition????? PKU is a treatable disease. Treatment involves a diet that is extremely low in phenylalanine, particularly when the child is growing. The diet must be strictly followed. “Diet for life” Phenylalanine occurs in significant amounts in milk, eggs, and other common foods.

Also, why should aspartamine, an artificial sweetener found in many diet soft drinks, be avoided by individuals who have PKU?

Phenylketonuria-PKU-.html DNA Interactive PKU

GBBE 2012 Yeast lab “The Perfect Organism”

Yeast –Saccharomyces cerevisiae Unicellular fungus Eukaryote Complex life cycle Exists in the diploid and haploid stages Has mating types in the haploid state Mates to form a diploid organism 32 chromosomes Many biochemical variants Genome completed Economically important organism

Yeast Chromosomes Entire genome sequenced (12 Mb; 6,200 genes) Centromeres small (~120 bp), unique; three regions bind proteins, allowing interaction with a single microtubule for segregation; no transcriptional silencing at centromeres Telomeres (TG1-3)n [Note that human telomere sequence is (TTAGGG)n] Replication origins (ARS elements) bp

Yeast Genes Yeast genes are given three letter abbreviations Genes are named after the protein that they encode Wild type genes (dominant) begin in upper case letters Mutants or recessive begin in lower case

Yeast Cells – Phase Contrast

Yeast Cell Types Mating types(a and alpha) Attraction via pheromones Mating Shmoo formation Budding Asexual cell formation Sporulation Short life cycle Easily manipulated in laboratory Easily cultured Non-pathogenic

Yeast Cell Types

Mating

Yeast Gene Example My favorite Yeast Gene

Culture of Yeast Complex media YED- Yeast extract dextrose – Yeast extract and glucose YEAD – Yeast extract dextrose with an excess of adenine MV- Minimal media ( no adenine ) – This medium should support wild type

Aseptic Technique Use disinfectant on work area Use fresh sterile media. Yeast media is placed in Petri Dishes. Remove from refrigerator. Warm to room temperature Use sterile toothpicks for transfer of yeast Work with care to limit exposure of plate to the air Dispose of all toothpicks in cup on desk. Empty cup into hazardous waste bag. Label all plates with date, your initials, experiment, and other pertinent facts. Incubate cultures agar side up at room temperature. Secure with tape on edges to insure Petri Dish does not open. When plates have grown out. Place in refrigerator.

Supplies Get all supplies from lab table Return all supplies to lab table Clean up lab bench