1. Protein synthesis begins when a section of DNA unwinds, exposing a single portion (a gene). The gene contains coded info about the order of amino acids that comprise a specific protein
2. The gene undergoes **transcription**, that is, the sequence of amino acids copied is copied in a special manner, forming **messenger RNA** (mRNA) in the process.
3. mRNA transforms the information concerning the amino acid sequence form the nucleus to **ribosomes**, protein manufacturing sites in cytoplasm.
4. During the **translation** process, ribosomes "read" mRNA. The coded instructions indicate which amino acid to add to the polypeptide chain and its sequence.
5. Each specific **transfer RNA** (tRNA) molecule conveys a particular amino acid to the ribosome.
6. At the ribosome, the amino acid that has been delivered by the tRNA attaches to the peptide chain, lengthening it.
7. When the translation process is complete, the ribosome release the polypeptide, and the new protein generally undergoes further processing at other sites within the cytoplasm.
Summary:
- Transcription: DNA unwinds, gene gets copied forming mRNA, happens in the nucleus
- Translation: mRNA give info to ribosomes and they "read" mRNA. trNA gets each amino acid and brings it to the ribosome to be attached to the peptide chain. Happens in **cytoplasm**.
- **Denaturation** alters a protein's natural shape and function by exposing it to conditions such as heat, acids, and physical agitation. This change is permanent.
# In Foods
- Animal foods generally provide higher amounts of protein than similar quantities of plant foods.
- Certain parts of plants provide more protein than other parts
- Seeds, tree nuts, legumes supply more
- Fruits or edible leaves, roots, flowers, and stems of vegetables provide less
- Legumes are parts of plants that produce pods with a single row of seeds.
- Peas
- Peanuts
- Lentils
- Soybeans
- High quality (complete) protein is a protein that contains all essential amino acids in amounts that support the deposition of protein in tissues and the growth of a young person.
- Meat, fish, poultry, eggs, **milk**
- Low quality (incomplete) protein is a protein that lacks or has inadequate amounts of one or more of the essential amino acids
- A carbon skeleton is the remains of an animo acid following deanimation and removal of the nitrogen containing component of the amino acid. Can be used to create glucose, energy, or fatty acids.
- **Protein-eneregy malnutrition (PEM)** occurs where the diet lacks sufficient protein and energy
- Edema is a sign of PEM
- **Kwashiorkor** is a form of undernutrition that results from consuming adequate energy and insufficient high quality protein
- Symptoms in children include:
- Stunted growth
- Blond, sparse, brittle, hair
- Patches of skin that have lost normal coloration
- Swollen cheeks, arms, legs, and belly
- **Marasmic kwashiorkor** is a form of undernutrition that results in a child with kwashiorkor who then starts to not consume enough energy; characterized by edema and wasting
- Marasmus is a form of undernutrition that results from starvation; diet lacks energy and nutrients
- Phenylketonuria is a genetic metabolic disorder characterized by the inability to convert the amino acid phenylalanine to tyrosine, resulting in an accumulation of phenylalanine.
- Celiac disease and gluten sensitivity
- Celiac disease is an inherited condition in which the protein gluten cannot be absorbed, resulting in damage to the small intestine and poor absorption of nutrients.
- Gluten is a type of protein found in many grains, provides texture and shape to baked products
