Protein SynthesisTranscription and Translation

Translation• Each amino acid is added to the protein chain

• Peptides are the chain that will eventually form into a protein.

The 20 Amino Acids of Life• All of our millions of possible proteins are made of just

20 amino acids.

• Those amino acids then wrap around each other using hydrogen bonding to form the protein structure.

Basic Structure of an Amino Acid

Humans can only make 10 of the 20!

• We can only make 10 of the 20 necessary amino acids in our cells.

• Thus, we need to consume the other 10 from the food we eat – in the form of protein.

• Unlike fat/carbohydrates, humans can not store excess protein. Any extra protein consumed must be eliminated in our urine.

• It also means you need to eat enough every day to maintain protein synthesis.

Healthiest and Best Sources of Protein

• Eggs

• Nuts/Seeds

• Beans

• Soy

• Oats

• Broccoli

• Chicken

• Fish

• Milk

Worst Sources of Protein

• 1. Processed meats

• Hot dogs, bacon, sausage and other processed meats price tag for your health is high.

• “Hot dogs have very little nutrition for the amount of calories you’re consuming, and contain only a small amount of poor-quality protein,”

• 2. Grain-fed red meats

• Eating lots of red meat — meaning beef, pork and lamb — can be hazardous for your health.

• “Grain-fed red meat is my least favorite source of protein, due to its high saturated fat content and impact on the environment,”

• 3. Low-quality protein powder

• Add protein powder to your smoothie every morning? Be sure to read the ingredients. “All protein powders are not created equal,”

• 4. Dairy products

• Are you a cheese lover? Relying chiefly on dairy for your protein has pitfalls. It may be wise to cut back if you want to avoid weight gain.

Effects of Too Much Protein

• Kidney Damage – because the kidneys have to work harder to excrete the excess amino acids. Risks of kidney stones are higher.

• Cancer – a strong correlation between high protein diets and increased risks of colon, breast, and prostate cancer.

• Heart Disease – high protein diets also contain cholesterol and other compounds that can contribute to high blood pressure and heart failure.

But, how does tRNA know which amino acids to add to the protein chain?

• Codons- 3 letter combinations that spell out which amino acid to attach.

How to Read a Codon Chart

Start and Stop Codons

• RNA polymerase searches the mRNA strands for a “start codon” to begin translation to make proteins.

• When it discovers a AUG (methionine), it begins translation and starts adding amino acids.

• It will continue adding amino acids until it reaches a “stop codon” that indicates to stop.

• UAA, UAG, and UGA are all stop codons.

Translation with Start and Stop Codons

Let’s Try One

1) Find the start codon2) Determine the amino acids that will be added3) Find the stop codon

DNA and RNA Overview

DNA to RNA to Protein

Gene- Segment of DNA that codes for a specific protein

Introns and Exons• Exons are the segments that code for proteins

• Introns are the segments that do not code for proteins

• Spliceosomes are able to cut out the the non-coding introns and remove them from the final mRNA

• Spliceosomes recognize certain RNA sequences to know when to and when not to remove segments

Intron Splicing

Splicing Exons – non-coding strands of DNA