BSc Nursing 1 St Year Nutrition And Biochemistry Nursing Chapter 4 Proteins Question And Answers

Proteins

Question 1. Classification of proteins.
Answer.

Definition Of Proteins

Proteins are polymers of amino acids.

They are the fundamental structural components of the body

Classification Of Proteins

Proteins can be classified in four ways

• Classification based on shape and size
• Functional classification
• Classification based on chemical nature and solubility
• Nutritional classification

Classification On The Basis Of Shape And Size

On the basis of shape and size proteins are classified into 2 types – fibrous and globular

Fibrous Proteins

When the axial ratio of length to width of a protein molecule is more than 10, it is called a fibrous protein eg – keratin and collagen

Globular Proteins

When the axial ratio of length to width of a protein molecule is less than 10, it is called globular protein eg – haemoglobin and ribonuclease

Functional Classification Of Proteins

Based on the functions they perform, proteins are classified as

• Structural proteins – they are involved in formation of structures of the body e.g. – keratin of hair and nail and collagen of bone
• Enzyme proteins – all enzymes are protein in nature e.g. – hexokinase, pepsin
• Transport proteins – proteins involved in transport of substances e.g. –
  • Haemoglobin transports oxygen
  • Albumin transports bilirubin
• Hormonal proteins- some of the hormones are protein in nature e.g. Insulin and growth hormone
• Contractile proteins – proteins which take part in muscle contraction. e.g. – Actin and myosin
• Storage proteins – proteins involved in storage of substances e.g. – Ferritin stores iron
• Genetic proteins – proteins involved in genetic function e.g. – Nucleoprotein
• Defence proteins – proteins involved in defence function e.g. – Immunoglobulins
• Receptor proteins – protein which act as receptors e.g. – Cytokine receptor, integrin
• Respiratory proteins – proteins involved in the function of respiration e.g. – Haemoglobin and cytochrome

Classification Based On Chemical Nature And Solubility

According to this proteins are classified into 3 groups – simple, conjugated and derived

Simple Proteins

These are proteins which on complete hydrolysis yield only amino acids.

Example:

• Protamine – they are small molecules rich in arginine
• Histones – they are found in association with DNA
• Albumin – normal serum level is 3.5 to 5 gm %
• Globulin – normal serum level is 1.8 to 3.6 gm %
• Gliadin – it is rich in proline
• Glutelin – it is rich in glutamic acid
• Scleroproteins – these proteins have great stability and very low solubility and form supporting structures in the body e.g. –
  • Keratin of hair
  • Collagen of bone
  • Elastin of connective tissue

Conjugated Proteins

• Conjugated proteins are simple proteins combined with a non protein group called prosthetic group
• Protein part is called apoprotein and the entire molecule is called holoprotein
• E.g. nucleoprotein, mucoprotein, glycoprotein, chromoprotein, phosphoprotein, lipoprotein and metalloprotein

Nutritional Classification Of Proteins

From the nutritional point of view proteins are classified as

• Complete proteins
• Partially incomplete proteins
• Incomplete proteins

Complete Proteins

These proteins have all the essential amino acids in the required proportions by the human body to promote good growth e.g. egg albumin and milk casein

Partially Incomplete Protein

These proteins are partially lacking one or more essential amino acids and hence can promote moderate growth e.g. – wheat and rice proteins (lack lysine and threonine)

Incomplete Proteins

These proteins completely lack one or more essential amino acids, hence do not promote growth at all e.g. – gelatin (lacks tryptophan), maize/corn (lacks tryptophan and lysine)

Question 2. Functions of proteins.
Answer.

Functions Of Proteins

• Primary Tissue Building
  • Protein is the fundamental structural material of every cell in the body. The primary functions are to repair the worn out, wasted or damaged tissue and build up new tissue. Thus, protein meets the growth needs and maintains tissue health during adult years. In addition to body building functions, protein has other body functions related to energy, water balance, metabolism and body’s defence mechanism.

Energy System

• • Carbohydrates are the primary fuel source for the body assisted by fat as stored fuel. In times of need (e.g., Starvation) protein may also furnish additional fuel to sustain heat and energy. Fuel supplied by protein is 4 k cal/gm (like carbohydrates).
• Water Balance
  • Plasma proteins, especially albrumin helps to control water balance throughout the body by exerting osmotic pressure to maintain internal circulation of body fluids and capillary blood flow.
• Metabolism
  • Protein aids metabolic functions through enzymes, hormones and transport agents. Digestive and cell hormones are hormones that control metabolic functions. Enzymes are necessary for the digestion of Carbohydrates (amylase) fats (lipase) and proteins (proteases) are all proteins. Proteins also act as vehicles in which nutrients are carried throughout the body. Lipoproteins are necessary to transport fats in the water soluble blood supply. Other examples are haemoglobin and transferrin, the iron transport proteins in blood. Hormones such as insulin and glucagen are also proteins that have a major role in the metabolism of glucose.
• The Body Defence System
  • Protein is used to build special white blood cells (lymphocytes) and antibodies as part of body’s immune system to help defend against infection and diseases.
• Energy Supply
  • A small part of body’s need for energy (about 6 to 12%) is supplied by products of protein metabolism.

Question 3. Kwashiorkor.
Answer.

Kwashiorkor is due to inadequate protein in the diet despite an adequate calories intake

Children are more affected by kwashiorkor than adult . it typically than adults. It typically starts after the child has breast milk has been replaced by diet with low in protein, although it can occur in infants if the mother is protein deprive .

Kwashiorkor is a form of severe protein malnutrition characterized by edema and an enlarged liver with fatty infiltrates.

It cause by sufficient calories intake but with insufficient protein consumption, which distinguishes it from marasmus.

Kwashiorkor is occurred in area of famine or poor food supply.

Read And Learn More: BSc Nursing 1st Year Nutrition And Biochemistry Previous year Question and Answers

Kwashiorkor is a severe form of malnutrition associated with a deficiency in dietary protein , the extreme lack of protein causes osmotic imbalance in gastro-intesteinal system causing swelling of the gut diagnosis as an edema or retention of water.

Sign and symptoms:

The defining sign of kwashiorkor in a malnourished child is pitting edema. (Swelling of ankles and feet) .

Other signs includes a distended abdomen, an enlarged liver wuth fatty infiltrate, thinning of liver, loss of teeth, skin depigmentation and dermatitis.

Generally the disease can be treated by adding protein to the diet, however, it can have a long term impact on a child physical and mental development, and in severe cases may leads death.

Question 4 .Importance of protein in children.
Answer.

Children need adequate amount of protein for good health.

Proteins are essential for the development of both the brain and the body, and maintenance of structure such as bone, muscle and skin.

As a child hood is a phase of growth and development. The protein requirement of children are significantly higher than that of adults. So it is ensure that their children grt enough protein every day .

Protei is an importent component of every cell in the body . Children body need more proteins because they are at growing stage, Proteins also make enzymes, hormones, and other body chemicals. Protein is an important building block of bones, muscles, cartilages, skin and blood.

Protein is quickly digested providing a rapid rise in amino acids that may helps increases muscle mass and strength. It may also reduce appetite and promote fat loss.

If protein deficiency occurs in children during growth period produces kwashiorkor and marasmus.

Protein calorie malnutrition is one of the largest nutritional problem of India.

Question 6. Malnutrition.
Answer.

Definition of malnutrition: faulty nutrition due to inadequate or unbalanced intake of nutrients or their impaired assimilation or utilization .

Malnutrition occurs when the body doesn’t get enough nutrients.

Causes include a poor diet , digestive conditions or another disease .

Malnutrition is a condition that occurs that result from eating a diet in which one more nutrients are not enough or are to much that the diet causes health problems.

It may involve calories , protein, carbohydrates, fat , vitamins, or minerals.

No enough nutrient is called under nutrition or undernourishment while too much is called overnutrition.

Malnutrition is often used to specifically refer to undernoutrishment where an individual is not getting enough calories, proteins, or micronutrients.

If undernutrition occurs during pregnancy,or beforetwo years of age it may results in a permant problems with a physical and mental development.

Extreme undernourishment knows as starvation may have symptoms that include a short height, thin body, very poor energy levels , and swollen legs and abdomen.

People also often get infectious and are frequently cold . The symptom of micronutrients deficiencies depend on the micronutrient deficiencies depend on the micronutrient that is lacking.

Undernourishment is most often due to not enough high quality food being available to eat . this is food being available to eat This is often related to high food price and poverty.

There Are Two Main Types Of Undernutition :

Protein energy malnutrition (PEM)

Dietary deficiencies .

• Protein energy malnutrition has two severe forms: (a) Marasmus ( A lack of protein and calories) (b) Kwashiorkor ( A lack of protein )
• Dietary deficiencies: A lack of iron , iodine , vitamins, and minerals.
  We can beat malnutrition by giving food security to people . Gov to be take a proper actions and efferts to bring modern agricultural techniques to increase food quality and quantity and increases nutrients contains.

Question 7. Clinical features of marasmus and kwashiorkor.
Answer.

Marasmus

Weight loss Dehydration , Dirrhea.

Stomach shrinkage

Severe wasting of muscles

• Loss of subcutaneous fat (Limbs appear as skin and bones)
• Skin is dry and atrophic
• Anaemia
• Eye lesions due to Vitamin A deficiency
• Irritability and fretfulness
• Diarrhoea
• Dehydration
• Body temperature is sub-normal
• Failure to thrive
• Wrinkled skin – Old man’s face
• Grossly underweight

Kwashiorkor

Inability to grow or gain weight , Edema ,or swelling of the hands and feet.

Stomach bulging

Growth failure

• Oedema of the face and lower limbs
• Muscle wasting
• Fatty liver
• Anorexia(loss of appetite)
• Diarrhoea
• Change in the colour, sparse, soft and thin hair.
• Change in the colour of the skin(hypo and hyperpigmentation)
• Anaemia
• Vitamin A deficiency
• Angular stomatitis(Cracks in the corners of mouth)
• Cheilosis (inflammation and cracks in lips)
• Moon face

Question 8. Difference between kwashiorkor and marasmus.
Answer.

Question 9. Protein-energy malnutrition.
Answer.

Protein Energy Malnutrition

Protein Energy Malnutrition (PEM) is defined as a range of pathological conditions arising from coincident lack of varying proportions of protein and calorie, occurring most frequently in infants and young children and often associated with infection (WHO,1973) PEM affects children under 5 years of age belonging to the poor underprivileged communities.

Under nutrition is a complex condition with multiple deficiencies such as proteins,energy and micro nutrient deficiencies often occurring together. According to WHO, malnutrition is an underlying factor in over 50 % of the 10 – 11 million yearly deaths of children under 5 years.

Classification of PEM

Protein energy malnutrition may be classified into three types as follows:

Kwashiorkor

Kwashiorkor is due to inadequate protein in the diet despite an adequate calories intake

Children are more affected by kwashiorkor than adult . it typically than adults. It typically starts after the child has breast milk has been replaced by diet with low in protein, although it can occur in infants if the mother is protein deprive .

Kwashiorkor is a form of severe protein malnutrition characterized by edema and an enlarged liver with fatty infiltrates.

It cause by sufficient calories intake but with insufficient protein consumpxion, which distinguishes it from marasmus.

Clinical Signs And Sympxoms

Growth failure

• Oedema of the face and lower limbs
• Muscle wasting
• Fatty liver
• Anorexia(loss of appetite)
• Diarrhoea
• Change in the colour, sparse, soft and thin hair.
• Change in the colour of the skin(hypo and hyperpigmentation)
• Anaemia
• Vitamin A deficiency
• Angular stomatitis(Cracks in the corners of mouth)
• Cheilosis (inflammation and cracks in lips)
• Moon face

Marasmus

This is caused by severe deficiency of proteins and calories in the diet. The important features are as follows:

Severe wasting of muscles

• Loss of subcutaneous fat (Limbs appear as skin and bones)
• Skin is dry and atrophic
• Anaemia
• Eye lesions due to Vitamin A deficiency
• Irritability and fretfulness
• Diarrhoea
• Dehydration
• Body temperature is sub-normal
• Failure to thrive
• Wrinkled skin – Old man’s face
• Grossly underweight

Marasmic Kwashiorkor

Children suffering from this disease show signs of both kwashiorkor and marasmus.