UNIT# 08
NUTRITION
Q. What is
nutrition? Describe types of nutrition.
NUTRITION
Process by which organisms obtain and use the nutrients
required for maintaining life is called nutrition.
Q. What is
autotrophic nutrition and heterotrophic nutrition?
Autotrophic nutrition - it is the mode of nutrition in which
an organism makes its own food from the simple inorganic materials like carbon
dioxide, water and minerals present in the surrounding (with the help of
energy). The processes are photosynthesis or either chemosynthesis.
PHOTOSYNTHESIS
Photosynthesis is a process by which green plants, algae and
some bacteria having chlorophyll, synthesize the simple sugar (glucose) from
the simple raw materials i.e. water and carbon dioxide by using the energy of
sunlight.
6CO2
+ 12H20 ⟶ C6H12O6
+ 6H2O + 6O2
CHEMOSYNTHESIS
The synthesis of
organic compounds by bacteria or other living organisms using energy derived
from reactions involving inorganic chemicals, typically in the absence of
sunlight.
Heterotrophic nutrition
It is the mode of nutrition in which an organism can't make
its own organic material but depends on other organisms for its food and use it
for growth and energy.
Depending upon the mode of living and the mode of intake of
food, heterotrophs may be parasitic, symbiotic, saprotrophic or holozoic.
PARASITIC NUTRITION
Those organisms which obtain the food from host body and
causes harm to them are called parasites while the mode of nutrition is called
Parasitic nutrition.
For instance: Mosquitoes, Cuscuta, leech, tapeworm etc.
SYMBIOTIC NUTRITION
The type of nutrition in which an organisms make colonies with
other organisms in a way that both partners gets benefits from each other. Such
type of nutrition is called Symbiotic Nutrition.
For instance: Lichens
LICHENS
It is a stable
symbiotic association between a fungus and algae and/or cyanobacteria. Like all
fungi, lichen fungi require carbon as a food source; this is
provided by their symbiotic algae and/or cyanobacteria that are photosynthetic.
SAPROPHYTIC NUTRITION
Such organisms derive their food from dead and decaying
organic material. This mode of nutrition is called saprotrophic nutrition.
For instance: Fungi (Molds, mushrooms, yeasts) and many
bacteria.
HOLOZOIC NUTRITION
In holozoic nutrition complex organic substances are ingested
(taken in) without their being degraded or decomposed. After intake, such food
is digested by enzymes produced within the organism. Digested food is absorbed
into the body and the undigested product is egested (expelled out) from the
body. This kind of nutrition is found mainly in non-parasitic animals-simple
ones like Amoeba and complex ones like human beings.
Q. Define
mineral nutrition in plants.
MINERAL NUTRITION IN PLANTS
The process involving the absorption, distribution and
utilization of mineral substances by the plants for their growth and
development is called mineral nutrition.
Q. Describe
the role of Nitrogen and Magnesium in plant body.
ROLE OF NITROGEN
Nitrogen is essential for plants to synthesize amino acids and
also required for the production of chlorophyll, nucleic acids, and enzymes.
SYMPTOMS OF NITROGEN DEFICIENCY
Nitrogen-deficient plants exhibit stunted growth, reduced
yields and their foliage pale green.
MAGNESIUM
Many enzymes in plant cells require magnesium in order to perform
properly and is a constituent of the chlorophyll molecule.
SYMPTOMS OF MAGNESIUM DEFICIENCY
Interveinal chlorosis (dark green veins with yellow areas
between the veins).
Q. What are
fertilizers? Describe the importance of fertilizers.
FERTILIZERS
Fertilizers are substances containing chemical elements such
as manure or mixture of nitrates that improves the growth of plants.
Importance of fertilizers
·
Fertilizers give nutrition
to the crops and produce more fruit, faster growth, more attractive flowers.
·
Plants can develop
tolerance against pests like weeds, insects and diseases.
·
They supplement required
elements found naturally in the soil.
Q. What is
environmental hazard? What are environmental hazards related to chemical
fertilizers?
An environmental hazard is a condition, which has the
potential to threat natural environment or adversely affect people's health,
including pollution and natural disasters.
1. Chemical fertilizers affect the soil nutrient holding
capacity.
2. The high solubility of fertilizers degrade ecosystem
through eutrophication (an increase in chemical nutrients typically compounds
containing nitrogen or phosphorus in an ecosystem).
3. Storage and application of some nitrogen fertilizers may
cause emission of greenhouse gas, e.g. nitrous oxide.
4. The extra ammonia can increase soil acidity.
5. Excessive nitrogen fertilizers can lead to pest problem by
increasing their reproduction rate.
Q. What are
the components of human food?
COMPONENTS OF HUMAN FOOD:
There are seven major classes of nutrients: carbohydrates, protein, fats, minerals,
fiber, vitamins, and water.
Heterotrophic
organisms have to acquire and take in all the organic substances they need to
survive.
Q. Write
note on Carbohydrates.
CARBOHYDRATES
A carbohydrate is
an organic compound such as sugars, starches, celluloses and gums that occurs
in living tissues and food. It is important for nutrition since it can be
broken down into energy by people or animals. Carbohydrates are the
first source of energy.
Carbohydrates are generally of two types:
·
Simple
carbohydrates such as sucrose, which digest quickly
Source of simple carbohydrates are fruits, sugars, processed
grains such as white rice or flour
·
Complex
carbohydrates such as starch etc which digest slowly
Sources of Complex carbohydrates are green or starchy
vegetables, potatoes, whole grains, beans and lentils
Q. Write
note on Proteins.
PROTEINS
Proteins are large
biomolecules, or macromolecules, consisting of one or more long chains of amino
acid residues. Proteins are required for the structure, function, and
regulation of the body's cells, tissues, and organs. They are
much slower and long lasting source of energy than carbohydrates.
There are 20 amino acids. The body synthesizes some of them
from components within the body, but it cannot synthesize 9 of the amino acids
called essential amino acids. They must be consumed in the diet.
Sources of Proteins are lean meat and poultry, fish, eggs,
tofu, nuts and seeds and legumes/beans' group.
Q. Describe
the disorders related to the Proteins.
Protein deficiency disorders
Protein energy malnutrition (PEM) refers to inadequate
availability or absorption of energy and proteins in the body. It is the
leading cause of death in children in developing countries.
PEM may lead to diseases such as;
(a)
Kwashiorkor:
It is caused by the deficiency in dietary protein.
It is characterized as the swelling of the gut diagnosed as an
edema or retention of water.
(b)
Marasmus:
It is characterized as energy deficiency. It can occur in
anyone with severe malnutrition but usually occurs in children. A child with
marasmus looks emaciated. Body weight is reduced to less than 62% of the normal
(expected) body weight for the age.
Q. Write
note on Fats.
FATS
Fats are complex molecules composed of fatty acids and
glycerol.
The body needs fats for growth and energy. It also uses them
to synthesize hormones and other substances needed for the body's activities.
Fats are the slowest source of energy but the most
energy-efficient form of food.
The body deposits excess fat in the abdomen (omental fat) and
under the skin (sub cutaneous fat) to use when it needs more energy. The body
may also deposit excess fat in blood vessels and within organs, where it can
block blood flow and damage organs, often causing serious disorders.
Some typical sources of saturated fats include:
·
Fatty cuts of beef and
lamb.
·
Poultry skin.
·
High fat dairy foods
(whole milk, butter, cheese, sour cream, ice cream)
·
Tropical oils (coconut oil,
palm oil, cocoa butter)
Q. Write
note on Vitamins.
VITAMINS
A vitamin is an organic molecule (or related set of molecules)
that an organism needs in small quantities for the proper functioning of its
metabolism. They are for maintaining normal health and development. Lack of
vitamins can cause several diseases.
They are divided into two types:
i.
Fat-soluble
Vitamins: Vitamin which can soluble in organic solvent are
called Fat-soluble vitamins (A, D, E and K) are less excreted from the body as
compared to water-soluble vitamins.
ii.
Water
soluble Vitamins: Vitamin which are soluble inH2O.
These are vitamins B and C. Cooking or heating destroys the water soluble
vitamins more readily than the fat-soluble vitamins.
|
Vitamins |
Deficiency
diseases |
|
Vitamin A |
Night
blindness, liver disorders |
|
Vitamin B |
Beri-Beri |
|
Vitamin C |
Scurvy |
|
Vitamin D |
Rickets
and osteomalacia |
|
Vitamin E |
Nerve and
muscle damage, muscle weakness, vision problems. |
|
Vitamin K |
Bleeding
disorder |
Q. Write
note on Minerals.
MINERALS
A class of naturally occurring solid inorganic substances.
Minerals are vital for proper human health.
Essential minerals include calcium, iron, zinc, iodine and
chromium.
DEFICIENCY
·
Brittle bones and poor
blood oxygenation.
SOURCES
·
Dairy and meat products.
Q. Describe
the metabolical function of Iron.
METABOLIC FUNCTION OF CALCIUM
Calcium metabolism refers to the movements and regulation of
calcium ions (Ca+2) in and out of various body compartments. Good
calcium nutrition, along with low salt and high potassium intake, prevents from
hypertension and kidney stones.
The food rich in Calcium includes:
·
Milk
·
Cheese and other dairy
foods
·
Green leafy vegetables
·
Soya beans
·
Nuts
·
Fish
·
Bread
DEFICIENCY SYMPTOMS OF CALCIUM
·
Fainting
·
Chest pains
·
Heart failure
·
Wheezing (whistling sound
when breath)
·
Numbness and tingling
sensations around the mouth or in the fingers and toes
·
Voice changes due to spasm
of the larynx
·
Difficulty swallowing
·
Muscle cramps
Q. Describe
the disorders caused by the deficiency of Minerals.
MINERAL DEFICIENCY DISEASE
Diseases resulting from deficiency of a mineral are given
below;
GOITER
This condition is characterized as enlargement of thyroid
gland which results in swelling of neck.
Goiter is caused by insufficient amount of “Iodine” in diet.
ANEMIA
This condition is characterized as the reduced number of red
blood cells.
As hemoglobin molecule contains four atom of iron. If body
fails to receive sufficient amount of iron, an adequate number of hemoglobin
will not be formed which results in non-functional red blood cells.
Q. Describe
the metabolical function of Iron.
METABOLIC FUNCTION OF IRON
Iron plays a major role in oxygen transport and storage. It is
a component of hemoglobin in red blood cells and myoglobin in muscle cells.
Some of the best plant and animal sources of iron:
·
Beans and lentils
·
Dark green leafy
vegetables such as spinach
DEFICIENCY SYMPTOMS OF IRON
·
Extreme fatigue
·
Pale skin
·
Chest pain
·
Fast heart beat or
shortness of breath
·
Brittle nails
·
Weakness
·
Headache, dizziness
·
Inflammation or soreness
of tongue
·
Poor appetite in infants
Q. Describe
the metabolic function of water.
METABOLIC FUNCTION OF WATER
Water is the medium for various enzymatic and chemical
reactions in the body. It moves nutrients, hormones, antibodies and oxygen
through the blood stream and lymphatic system. Water maintains the body
temperature through evaporation as in sweating. Severe dehydration causes
cardio-vascular problems.
Q. Describe
the metabolic function of dietary fibers.
METABOLIC FUNCTION OF DIETARY FIBERS
Dietary fiber is the edible part of plants, or similar
carbohydrates, that can't be digested and absorbed in the small intestine. Fiber
plays very important role to prevent from constipation. Soluble fiber helps in
lowering the blood cholesterol and blood sugar level.
Q. What is
malnutrition?
MALNUTRITION
The malnutrition is a condition that occurs when a body does
not get sufficient nutrients. Malnutrition results from a poor diet or a lack
of food.
There are two types of malnutrition.
·
Chronic malnutrition
·
Acute malnutrition
CHRONIC MALNUTRITION
It is characterized as the delayed growth in the children.
ACUTE MALNUTRITION
It is characterized by insufficient weight in the child's
height (emaciation).
Q. Describe
the nutrient deficiency disorders, worldwide.
Worldwide, three nutrient deficiencies are of particular
concern:
·
Vitamin A deficiency is
the common cause of preventable child blindness and vision impairment.
·
Iron deficiency is
associated with decreased cognitive abilities and resistance to disease.
·
Iodine deficiency is the
major preventable cause of mental retardation.
Q. What
results in the over intake of nutrients.
OVER INTAKE OF NUTRIENTS
·
High intake of
carbohydrates and fats leads to obesity, diabetes and cardiovascular problems.
·
High dose of vitamin A
causes loss of appetite and liver problems.
·
Excess dose of vitamin D
can lead to deposition of calcium in various tissues.
Q. Describe
the following conditions.
STARVATION
It is a severe deficiency in caloric energy intake.
In humans, prolonged starvation can cause permanent organ
damage and eventually, death.
HEART DISEASES
The term "heart disease" is often used
interchangeably with "cardiovascular disease." Cardiovascular disease
generally refers to conditions that involve narrowed or blocked blood vessels
that can lead to a heart attack, chest pain (angina) or stroke.
Fatty foods increase blood cholesterol level can result in cardiovascular
diseases.
CONSTIPATION
It can be well defined as a condition in which there is
difficulty in emptying the bowels, usually associated with hardened feces.
It is usually due to low water, fibers intake or irregularity
in meal schedule.
OBESITY
Obesity is most commonly caused by a combination of excessive
food intake, lack of physical activity, and genetic susceptibility. Obesity is
known as mother disease and may lead to heart problems, hypertension, diabetes
etc.
Q. Define
Digestion
DIGESTION
The breakdown of complex food substances into simplest form is
called digestion.
The set of organs which is responsible to carry out the
mechanism of Digestion is called Digestive system.
DIGESTIVE TRACT
The digestive tract also called alimentary canal includes:
·
Esophagus
·
Stomach
·
Small intestine
·
Large intestine
Accessory Organs of digestive are:
·
Liver
·
Pancreas
·
Gall bladder
Q. Describe
the stages of digestion.
STAGES OF DIGESTION
The digestion consists of following steps:
1.
Ingestion
Intake of food)
2.
Propulsion
Peristalsis-alternate waves of muscular contraction and
relaxation in the primary digestive organs.
3.
Mechanical
Digestion
Physical preparation of food for digestion.
4.
Segmentation
Mixing of food in the intestines with digestive juices.
5.
Chemical
Digestion
Carbohydrates, Fat, and Proteins are broken down by enzymes.
6.
Absorption
Transfer of the digested portion of food into the blood from
the digestive canal.
7.
Egestion
(Defecation)
Removal/elimination of the waste products from the body.
Q. Explain
Human digestive system.
HUMAN DIGESTIVE SYSTEM
Digestion begins in the oral cavity. Oral cavity grinds the
food by the help of four different types of teeth by means of chewing or
mastication. The saliva mixes with the
food to add water and mucus. Saliva also contain an enzyme called salivary
amylase which partially digest the starch. Than the pieces of food are rolled
up by the tongue into spherical mass called bolus. The food in the form of bolus is than enter
into pharynx.
The pharynx is a passageway for food and air. From the throat,
bolus travels down into esophagus. Peristalsis movement force down food through
the oesophagus to the stomach.
At the end of the oesophagus, sphincter allows food to enter
the stomach.
The stomach has three regions: cardiac end, fundus and pyloric.
When food is entered into the stomach, gastric glands releases gastric juice
which is composed of mucous, HCl and pepsinogen.
·
HCl converts the inactive
pepsinogen into pepsin (active form of enzyme). It also kills the
microorganisms by providing acidic environment.
·
Pepsin partially digests
the protein portion of the food
At this stage, food is processed into a thick paste like
liquid called chyme. The pylorus keeps chyme in the stomach until it reaches
the right consistency to pass into the small intestine.
The small intestine is made up of three parts:
·
The duodenum
·
The jejunum
·
The ileum
The duodenum receives chyme from the stomach. It receives bile
and pancreatic juice from liver and pancreas respectively.
·
Bile salts causes fat
globules to break down or be emulsified into minute, microscopic droplets.
·
Pancreatic juice contains
trypsinogen, pancreatic lipase and amylase, which digest protein, lipids and
carbohydrates respectively.
The inner wall of the small intestine is covered with villi.
Each villus is connected and richly supplied with blood capillaries and
lymphatic vessels, i.e. lacteal. Villi increase the surface area over which absorption
and digestion occur. These specialized cells help absorbed materials cross the
intestinal lining into the bloodstream. The bloodstream carries simple sugars,
amino acids and nucleosides to the liver via hepatic portal vein for storage or
further chemical changes.
Food that has not been digested (and some water) travels to
the large intestine. The large intestine's main function is to remove water
from the undigested matter and form solid waste that can be egested. The large
intestine is made up of three parts:
·
The caecum
·
The colon (The colon has
three parts: the ascending colon and transverse colon and the descending colon)
·
The rectum
Q. What is
the function of Liver in Digestive system?
LIVER AND ITS FUNCTIONS
The liver produces bile, which helps the body to digest and
absorb fat. Bile is stored in the gallbladder until it is needed. Bile travels
through special channel (bile duct) directly into the small intestine.
The liver also plays a major role in the handling and
processing of nutrients, which are carried to the liver in the blood from the
small intestine. The liver is a metabolically active organ responsible for many
vital life functions.
Q. What is
appendix?
APPENDIX
The appendix, a small, hollow, finger-like pouch, hangs at the
end of the cecum. It no longer appears to be useful to the digestive process.
Q. Discuss
the GUT disorders.
DISORDERS OF GUT
DIARRHEA
This condition is characterized as frequent watery, loose
bowel movements due to fast peristaltic movement. This condition may be
accompanied by painful abdominal cramps, nausea, and fever and generalized
weakness.
The main cause of diarrhea includes lack of adequate safe
water, virus and bacteria.
To control diarrhea consume adequate amounts of water,
preferably mixed with essential salts and some amount of nutrients (e.g. ORS)
CONSTIPATION
Constipation is a condition, where a person experiences hard
faeces that are difficult to eliminate. The main causes are excessive
absorption of water through colon, insufficient intake of dietary fibre,
dehydration, use of medicine.
To control constipation consume adequate amounts of water,
preferably mixed with essential salts and some amount of nutrients (e.g. ORS)
ULCER (PEPTIC ULCER)
It is a sore in gut lining and can be different organs such
as; ulcer of stomach is called “gastric ulcer”, Ulcer of duodenum is called
“duodenal ulcer”, ulcer of oesophagus is called “esophageal ulcer” and
breakdown of tissues by acidic gastric juice.
It can be due to the long term use of anti-inflammatory medicine
(e.g. aspirin), smoking, drinking coffee, colas and eating spicy food. Few of
the signs are as under; abdominal burning after meals, abdominal pain, rush of
saliva after an episode of regurgitation, nausea and loss of appetite and
weight.
Ulcer can be treated with medicine, containing and avoiding
spicy food.
