proteins (exam 2)

Name 3 conditions where certain proteins or amino acids may be detrimental to health.

PKU- inherited condition attributed to a defective gene. requires low phenylalanine diet with tyrosine. celiac disease- gluten intolerance- protein found in wheat, rye, barley. causes an autoimmune reaction in certain people- body attacks lining of small intestine. GI distress, malabsorption, weight loss.

What are amino acids?

The building blocks of proteins. 20 different kinds. it is a central carbon atom bound to hydrogen, an amino group, an acid group and a side chain. EAA, don't make enough on own and must get from diet. 9 essential amino acids. 11 non essential amino acids.

What is a limiting amino acid and how does it affect protein synthesis?

a limiting amino acid limits protein synthesis. a limiting amino acid is the EAA that is available in the shortest supply. if we are missing EAA, we will break down body protein, obtaining limiting AA from less important protein. limiting AA are problems in plant foods- must eat a combination of foods to provide adequate EAA.

How does protein quality compare between animal and plant sources?

animal proteins are complete, plant proteins are not. animal sources contain all of the essential amino acids that your body needs to function effectively, but plant proteins lack some of these EAA.

What foods are the richest sources of protein?

animal sources such as chicken breast, beef, salmon, eggs, kidney beans, milk

Why is protein deficiency most common in infants and children?

because children require more protein per kilogram of body weight than adults to support the rapid growth and development that occurs during childhood

List three structural and/or regulatory functions of proteins in the body.

enzymes and protein hormones. ex is insulin. transport proteins- move lipids from cell to cell, ex is proteins of lipoproteins. contractile proteins: ex is actin and myosin

list some plant sources of protein

grains and vegetables. edamame, lentils, chickpeas, peanuts, almonds, quinoa.

What are conditionally essential amino acids? What are some examples that we talked about?

if someone has a certain condition/illness, they might need more a certain protein if they're lacking it now so it makes a certain protein become an essential amino acid if it wasn't before. it could be essential under physical stress (trauma victims- glutamine and arginine), certain stages of life (premature infancy- glycine), metabolic effects (phenylketonuria- tyrosine)

Explain how proteins are synthesized.

in the nucleus, the code for a protein is copied from the DNA into molecule of mRNA. (transcription) the mRNA takes the genetic information from the nucleus to ribosomes in the cytosol, where proteins are made. (translation) at the ribosomes, tRNA reads the genetic code and delivers the needed amino acids to the ribosome to form a polypeptide chain.

"Compare and contrast the causes and symptoms of kwashiorkor and marasmus.

kwashiorkor and marasmus are protein-energy malnutrition (PEM)- protein deficiency conditions. kwashiorkor- pure protein deficiency. common in children that have stopped breastfeeding. diet is adequate in energy but low in protein. characterized by a swollen belly- edema or fluid buildup and fat accumulation in liver. marasmus- energy and protein deficiency. "to waste away." occurs in all age groups, anorexia nervosa. depletion of fat stores and wasting of muscles. effects of both are growth impairment, infection, death.

What is the "amino acid pool" and where do these amino acids come from?

most AA from breakdown of body proteins (200g/day) and the rest from diet digestion (100g/day). amino acid pool is a group of free amino acids used for energy (not really), synthesis of glucose or fatty acids (when overeating), used for synthesis of nonprotein molecules that contain nitrogen (DNA, RNA, ATP), but MAINLY used for protein synthesis of body proteins.

"What is protein complementation and when is it important?

most plant foods contain incomplete proteins-lacing an EAA in sufficient quantity-limiting AA. it combines foods with different limiting AA. should be consumed over span of day

What is an essential amino acid?

must get from diet, we do not make enough of these on our own

What is protein turnover?

process by which proteins are continuously broken down and resynthesized. highly regulated proteins have a high turnover rate- ex is hormones- they get used for their purpose and then get broken down immediately. structural proteins have a low turnover rate- ex is collagen- has a life span of a few months.

Describe the general structure of a protein. How do they differ from other macronutrients?

protein has nitrogen which differs from other macronutrients. constructed of one or more folded, chain-like strands. amino acids are building blocks of proteins. peptide bonds are chemical bonds that link amino acids together. a protein is one or more polypeptide chains folded into a 3D shape.

Explain how the shape of a protein is important for its function. What is protein denaturation and how do temperature and pH affect it?

structure=function. if shape is altered, the protein is denatured and does not perform function expected. the polypeptide chain uncoils in denaturation, which can be caused by heating up a protein. a ph change to more acidic or basic solutions can induce unfolding of protein. temperature can also induce denaturation.