Unit-4 Nutrition Bsc nursing 1st year

 UNIT  IV 

                   AK Media

PROTIENS

II.SHORT ESSAY

1)How are proteins classified? What are the sources of proteins? What is the calorific value of protein?

Proteins can be classified into groups according to sequence or structural similarity. These groups often contain well characterised proteins whose function is known. Thus, when a novel protein is identified, its functional properties can be proposed based on the group to which it is predicted to belong. 

Sources of proteins

Some food sources of dietary protein include:

lean meats  beef, lamb, veal, pork, kangaroo

poultry  chicken, turkey, duck, emu, goose, bush birds

fish and seafood  fish, prawns, crab, lobster, mussels, oysters, scallops, clams

eggs

dairy products  milk, yoghurt (especially Greek yoghurt), cheese (especially cottage cheese)

nuts (including nut pastes) and seeds  almonds, pine nuts, walnuts, macadamias, hazelnuts, cashews, pumpkin seeds, sesame seeds, sunflower seeds

legumes and beans  all beans, lentils, chickpeas, split peas, tofu.

calorific value of protein

Carbohydrates provide 4 calories per gram, protein provides 4 calories per gram, and fat provides 9 calories per gram.

2)What is PEM? Write note on excessive intake and deficiency symptoms of protein. 

According to World Health Organization, protein energy malnutrition (PEM) refers to an imbalance between the supply of protein and energy and the body's demand for them to ensure optimal growth and function.

Risks of eating too much protein

Weight gain. High-protein diets may tout weight loss, but this type of weight loss may only be short-term. ...

Bad breath. ...

Constipation. ...

Diarrhea. ...

Dehydration. ...

Kidney damage. ...

Increased cancer risk. ...

Heart disease.

This article lists 8 symptoms of low protein intake or deficiency.

What Is Protein Deficiency? Share on Pinterest. ...

Edema. ...

Fatty Liver. ...

Skin, Hair and Nail Problems. ...

Loss of Muscle Mass. ...

Greater Risk of Bone Fractures. ...

Stunted Growth in Children. ...

Increased Severity of Infections.

3)Explain in detail digestion, absorption, and metabolism of proteins. 

Digestion

Protein digestion begins when you first start chewing. There are two enzymes in your saliva called amylase and lipase. They mostly break down carbohydrates and fats. Once a protein source reaches your stomach, hydrochloric acid and enzymes called proteases break it down into smaller chains of amino acids 

Protein digestion in the mouth

Unless you are eating it raw, the first step in digesting an egg (or any other solid food) is chewing. The teeth begin the mechanical breakdown of large egg pieces into smaller pieces that can be swallowed. The salivary glands secrete saliva to aid swallowing and the passage of the partially mashed egg through the esophagus.

Protein digestion in stomach

The mashed egg pieces enter the stomach from the esophagus. As illustrated in the image below, both mechanical and chemical digestion take place in the stomach. The stomach releases gastric juices containing hydrochloric acid and the enzyme, pepsin, which initiate the chemical digestion of protein. Muscular contractions, called peristalsis, also aid in digestion. The powerful stomach contractions churn the partially digested protein into a more uniform mixture, which is called chyme.

Protein digestion and absorption in the small intestine

The two major pancreatic enzymes that digest proteins in the small intestine are chymotrypsin and trypsin. Trypsin activates other protein-digesting enzymes called proteases, and together, these enzymes break proteins down to tripeptides, dipeptides, and individual amino acids. The cells that line the small intestine release additional enzymes that also contribute to the enzymatic digestion of polypeptides.

Tripeptides, dipeptides, and single amino acids enter the enterocytes of the small intestine using active transport systems, which require ATP. Once inside, the tripeptides and dipeptides are all broken down to single amino acids, which are absorbed into the bloodstream. 

4)List the functions of proteins. What is the daily requirement of protein for an adult?

1. Protein is required for the growth and maintenance of tissues. Your bodys protein needs are dependent upon your health and activity level.

Causes Biochemical Reactions

Enzymes are proteins that aid the thousands of biochemical reactions that take place within and outside of your cells 

Acts as a Messenger

Some proteins are hormones, which are chemical messengers that aid communication between your cells, tissues and organs

Provides Structure

Some proteins are fibrous and provide cells and tissues with stiffness and rigidity.

These proteins include keratin, collagen and elastin, which help form the connective framework of certain structures in your body Keratin is a structural protein that is found in your skin, hair and nails.

Maintains Proper pH

Protein plays a vital role in regulating the concentrations of acids and bases in your blood and other bodily fluids The balance between acids and bases is measured using the pH scale. It ranges from 0 to 14, with 0 being the most acidic, 7 neutral and 14 the most alkaline.

Balances Fluids

Proteins regulate body processes to maintain fluid balance. Albumin and globulin are proteins in your blood that help maintain your bodys fluid balance by attracting and retaining water 

Transports and Stores Nutrients

proteins carry substances throughout your bloodstream  into cells, out of cells or within cells. The substances transported by these proteins include nutrients like vitamins or minerals, blood sugar, cholesterol and oxygen 

Provides Energy

Proteins can supply your body with energy. Protein contains four calories per gram, the same amount of energy that carbs provide. Fats supply the most energy, at nine calories per gram.

Requirement of protein  for adult

The current recommended dietary allowance (RDA) for protein is 0.8 grams per kilogram (g/kg) of body weight a day for adults over 18, or about 2.3 ounces for a 180-pound adult.

5)Explain PEM.

Proteinenergy malnutrition (PEM), sometimes called protein-energy undernutrition (PEU), is a form of malnutrition that is defined as a range of conditions arising from coincident lack of dietary protein and/or energy (calories) in varying proportions. The condition has mild, moderate, and severe degrees. 

           Types include:

Kwashiorkor (protein malnutrition predominant)

Marasmus (deficiency in calorie intake)

Marasmic kwashiorkor (marked protein deficiency and marked calorie insufficiency signs present, sometimes referred to as the most severe form of malnutrition)

Clinical signs and symptoms of protein-energy malnutrition (PEM) include the following:

Poor weight gain

Slowing of linear growth

Behavioral changes - Irritability, apathy, decreased social responsiveness, anxiety, and attention deficits

        Management

Mild or moderate PEM are best judged by anthropometry; regular weighing, for monitoring growth, may be a useful control strategy. Because infections play such an important role in PEM, three practical approaches-immunization, deworming of children, and oral rehydration therapy for diarrhea

III.SHORT ANWERS

1)What are amino acids?

Amino acids are organic compounds that contain amino and carboxyl functional groups, along with a side chain specific to each amino acid. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, although other elements are found in the side chains of certain amino acids.

2)What are essential amino acids?

An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life forms, the nine amino acidshumanscannotsynthesizeare phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.

3)What are non-essential amino acids?

NONESSENTIAL AMINO ACIDS. Nonessential means that our bodies produce an amino acid, even if we do not get it from the food we eat. Nonessential amino acids include: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine

4)Mention the biological value of proteins?

Biological value (BV) is a measure of the proportion of absorbed protein from a food which becomes incorporated into the proteins of the organism's body. It captures how readily the digested protein can be used in protein synthesis in the cells of the organism. Proteins are the major source of nitrogen in food

5)What are complete proteins/first class proteins?

A food is considered a complete protein when it contains the nine essential amino acids    that our body cannot produce on its own.

6)What are incomplete proteins/class II proteins?

Plant foods are considered incomplete proteins because they are low or lacking in one or more of the amino acids we need to build cells. Incomplete proteins found in plant foods can be mixed together to make a complete protein.

7)Give examples of complete proteins.

Here are some complete protein examples:

Fish.

Poultry.

Eggs.

Beef.

Pork.

Dairy.

Whole sources of soy 

8)Give examples of incomplete proteins 

Legumes (beans, peas, lentils).

Nuts.

Seeds.

Whole grains.

Vegetables.

9)What is Kwashiorkor?

Kwashiorkor is a condition resulting from inadequate protein intake. Early symptoms include fatigue, irritability, and lethargy. As protein deprivation continues, one sees growth failure, loss of muscle mass, generalized swelling (edema), and decreased immunity. A large, protuberant belly is common.

10)Define Marasmas.

Marasmus is a form of severe malnutrition. It can occur in anyone who has severe                     malnutrition, but it usually occurs in children. It typically occurs in developing countries. Marasmus can be life-threatening, but you can get treatment for it.