Protein Structure and Function Quiz

Amino acids

The function of that amino acid

Peptide bonds

<p>Polypeptide</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>Valine</p> Signup and view all the answers

<p>Limiting amino acids are the essential amino acids found in the smallest quantity in foods. They are often found in cereals (lysine and threonine) and legumes (methionine and cysteine).</p> Signup and view all the answers

<p>Conditionally essential amino acids are usually synthesized by the body, but they can become essential under certain conditions, such as illness or stress. They are therefore important for maintaining adequate protein synthesis during these times.</p> Signup and view all the answers

<p>Tissue growth and maintenance</p> Signup and view all the answers

<p>The primary function of protein is to supply material for the growth and maintenance of body tissues.</p> Signup and view all the answers

<p>Anabolism is the process of building up new cellular material from smaller components, whereas catabolism is the breakdown or destruction of body tissues.</p> Signup and view all the answers

<p>1 gram of nitrogen</p> Signup and view all the answers

<p>Nitrogen balance is the difference between nitrogen intake and nitrogen excretion. It has three different types: nitrogen equilibrium, where intake and loss are equal, negative nitrogen balance, where more nitrogen is excreted than consumed, and positive nitrogen balance, where intake exceeds excretion.</p> Signup and view all the answers

<p>Proteins are essential for manufacturing enzymes, which are proteins that exist in all cells of living things. They accelerate biochemical reactions necessary for digestion and metabolism.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Proteins are necessary for manufacturing hormones, which are chemicals synthesized in the body that act as messengers or signals to control various physiological processes.</p> Signup and view all the answers

<p>Proteins are components of thyroid hormones, which regulate metabolic rate and cellular development, and insulin and glucagon, which maintain stability of blood glucose concentrations.</p> Signup and view all the answers

<p>A buffer is a compound that helps stabilize fluids and tissues by maintaining a constant pH level. Proteins act as buffers by releasing or accepting hydrogen ions to counteract any pH changes, helping to maintain a stable internal environment.</p> Signup and view all the answers

<p>Oncotic pressure is the effect of proteins on fluid balance. Proteins in blood vessels attract water, creating a pressure that pulls fluid from surrounding tissues back into the capillaries, maintaining proper blood volume and preventing edema, or swelling.</p> Signup and view all the answers

<p>Edema is swelling that occurs due to an accumulation of fluid in tissues. It can result from inadequate protein intake, which reduces oncotic pressure and allows fluid to leak into tissues.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Proteins provide a source of energy during times of inadequate energy supply from fats and carbohydrates.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Adequate intake of all macronutrients, including proteins, fats, and carbohydrates, is essential for optimal health and to prevent the depletion of lean body tissue that can occur from relying solely on protein for energy.</p> Signup and view all the answers

<p>In the stomach, hydrochloric acid (HCL) denatures proteins by breaking some of the bonds that hold them together. This process prepares the proteins for further breakdown.</p> Signup and view all the answers

<p>HCL activates the enzyme pepsin, which further breaks down remaining bonds in the proteins, reducing them to smaller polypeptides and some free amino acids.</p> Signup and view all the answers

<p>After partial digestion in the stomach, polypeptides and some free amino acids are emptied into the small intestine for further digestion.</p> Signup and view all the answers

<p>Partially digested proteins in the small intestine trigger the release of regulatory peptides.</p> Signup and view all the answers

<p>Proenzymes are inactive forms of enzymes that are activated in the small intestine. They further degrade polypeptides and amino acids, completing the process of protein digestion.</p> Signup and view all the answers

<p>After intestinal degradation, some small peptides and free amino acids are used by intestinal cells for energy and synthesis of other compounds, while the remaining amino acids are transported into the liver.</p> Signup and view all the answers

<p>The liver monitors the amount of amino acids absorbed and adjusts the rate of their metabolism, ensuring that the body has the right balance of amino acids for various needs.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>The remaining carbon skeleton after deamination can be used for energy or to make other substances.</p> Signup and view all the answers

<p>Transamination transfers nitrogen from one chemical group to another without forming ammonia.</p> Signup and view all the answers

<p>Protein turnover is a continuous process where proteins are constantly synthesized and degraded.</p> Signup and view all the answers

<p>During protein turnover, new amino acids mix with existing amino acids in the body, forming an amino acid pool.</p> Signup and view all the answers

<p>A stable amino acid pool allows for the efficient use of these amino acids to make other compounds, ensuring that the body has a sustainable source of amino acids for various functions.</p> Signup and view all the answers

<p>Protein quality is assessed based on its composition and digestibility, which determine how well the protein provides the necessary building blocks for the body.</p> Signup and view all the answers

<p>PDCAA, also known as biological value, measures protein quality based on its composition and digestibility.</p> Signup and view all the answers

<p>Complete proteins contain all essential amino acids in adequate amounts, while incomplete proteins lack one or more essential amino acids.</p> Signup and view all the answers

<p>Complete proteins are found in animal sources like meat, poultry, fish, eggs, and dairy products, and plant sources like soy. Incomplete proteins are typically found in plant sources like beans, lentils, grains, and nuts.</p> Signup and view all the answers

<p>Complementary proteins are proteins from different sources that combine to form a complete protein, providing all essential amino acids when consumed together.</p> Signup and view all the answers

<p>The RDA for protein in adults aged 19-70 is approximately 0.8 grams per kilogram of body weight per day.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>An inborn error of metabolism is an inherited defect in the way a certain substance is metabolized. Phenylketonuria (PKU) is an example, caused by a deficiency in the phenylalanine hydroxylase enzyme.</p> Signup and view all the answers

<p>Individuals with PKU must follow a strict diet that is low in phenylalanine, limiting high-protein foods and relying on special phenylalanine-free supplements for additional protein, micronutrients, and energy.</p> Signup and view all the answers

<p>Stress induced by critical injury can lead to accelerated tissue breakdown, resulting in negative nitrogen balance and loss of body mass.</p> Signup and view all the answers

<p>Brain injury</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Certain types of kidney or liver failure make the body unable to effectively metabolize proteins, reducing the intake can help alleviate the burden on these organs.</p> Signup and view all the answers

<p>Protein malnutrition occurs when there is insufficient intake of nitrogen-containing foods, leading to a deficiency in protein, affecting various bodily functions.</p> Signup and view all the answers

<p>Kwashiorkor is a form of protein malnutrition characterized by adequate energy intake but insufficient protein intake, often seen in children from underdeveloped countries after weaning from breast milk. Symptoms include edema, hair discoloration, and altered skin pigmentation.</p> Signup and view all the answers

<p>Marasmus is a form of malnutrition characterized by inadequate consumption of energy combined with compromised protein status, often observed in underdeveloped countries where food sources are scarce, individuals with wasting diseases causing significant weight and muscle loss, and the elderly population. Symptoms include dry or loose skin, hair discoloration, severe tissue loss, and delayed development.</p> Signup and view all the answers

<p>Treatment for malnutrition typically involves identifying the underlying cause and formulating interventions to address it. It also focuses on ensuring adequate intake of protein and energy to correct nutritional deficiencies and support recovery.</p> Signup and view all the answers