[Solved] KP PMS 2018 General Science Paper with Solution

Here, You will find KP PMS 2018 General Science Paper with Solution. KPPSC PMS 2018 paper has the following questions. Their answers are given below.

PMS KPK GSA 2018 PAPER

Q 1.

• a. The services of biology for mankind?
• b. Define Genetics, Ecology and biotechnology.

Q 2.

• a. The functions of arteries, veins and capillaries?
• b. Explain in detail the Cardiac cycle?

Q 3 Differentiate between the following?

4 What is food poisoning? Give its symptoms and causes?

5 MCQs

Q6. Short Note on the following

• Black Hole
• Dengue Virus
• Semi-conductors

Q7. Differentiate between Camera and Human eye? Describe working of a Camera?

Q8. What are lipids? Describe different types of their classification.

Solved PMS KPK GSA 2018 PAPER

Q 1.

• a. The services of biology for mankind?

The science of biology has been helping mankind in much way in increasing food production; in combating diseases and in protecting and conserving the environment. Biological advances in the field of food and health have resulted in high standard of living.

Plant production has been tremendously increased by improving existing varieties and developing new high-yield and disease — resistant varieties of plants and animals used as food. Plant and animal breeders have developed, through selective breeding, using the principles of genetics, new better varieties of wheat, rice, corn, chicken, cow and sheep. Poultry breeders have developed broilers for getting quick and cheap white meat. Genes for disease resistance and other desirable characters are introduced into plant, using the techniques of genetic engineering. Such transgenic plants (plants having foreign DNA incorporated into their cells) can be propagated by cloning (production of genetically identical copies of organisms/cells by asexual reproduction) using Special techniques such as tissue culture techniques etc. Plant pathogenic fungi and insect pests of crops which weaken he-plants and reduce the yield had traditionally been controlled by using chemical fungicides and insecticides (pesticides). Use of these chemicals poses toxicity problems for human beings as well as environmental pollution. Moreover, there are chances of insects becoming resistant to the effect of these chemicals. Biological control (control by some living organisms) eliminates all such hazards. In biological control, pests are destroyed by using some living organisms that compete with or even eat them up. An aphid that attacks walnut tree is being controlled biologically by a wasp that parasitizes this aphid.

Even some bacteria are being used as bio-pesticides. Effective control of a particular disastrous disease or all the common diseases of a plant can be achieved by using all relevant, appropriate methods of disease control. Such an approach of disease control is called “integrated disease management”.

Soil is a complex medium. It is almost impossible to conduct experiments on nutrient requirements of plants by growing them in soil. Hydroponic culture technique is used to test whether a certain nutrient is essential for plant or not. In this technique the plants are grown in aerated water to which nutrient mineral salts have been added. Hydroponic farming, however, is yet not feasible. Astronauts may use it for growing vegetables.

Different techniques of food preservation have been developed for protecting food from spoilage and for its use and transport over long distance without damaging its quality. One of these is pasteurization, developed by Louis Pasteur. It is being widely used for preservation of milk and milk products. Disease Control There has been fantastic progress in the area of health and disease control. Three pronged actions are usually taken against various diseases.

1. Preventive measures

2. Vaccination/Immunization

3. Drug treatment/Gene therapy

Preventive Measures:

The advances in biological sciences have provided us information about the causative agents of the diseases and their mode of transmission. For instance the AIDS (Acquired Immune Deficiency Syndrome) is caused by HIV (human immune deficiency virus) and it spreads through free sexual contact, through blood transfusion, by using contaminated syringes or surgical instruments etc. Therefore, doctors advise us to take precautions on these fronts so that we do not contract the disease, which is at present incurable. Similarly hepatitis is caused by H.virus which is spread through blood transfusion by using contaminated syringes and surgical instruments etc. In this case also doctors advise us to be careful and avoid the point of contact.

Vaccination/Immunization:

Many diseases such as polio, whooping cough, measles, mumps etc can easily be controlled by vaccination or “shots”.

Edward Jenner first developed the technique of vaccination in 1796, Cowpox pus is known as vacca (from Latin word vacca means cow). From this word evolved the present term vaccination and vaccine. Since then, inoculation or vaccination is carried out to make the people immune from viral or bacterial epidemics or, for some diseases the individuals are vaccinated in their early life to make them immune to those diseases. It is claimed that small pox has been totally eliminated from the world by using this method.

Scientists are making continuous efforts to develop vaccine against other diseases. Even vaccine against AIDS is being administered in humans on experimental basis.

Drug Treatment/Gene Therapy:

If a person becomes sick with disease, he is subjected to the action of antibiotics which can kill bacteria. The antibiotics are, however, useful in bacterial disease and that only when bacteria have not, developed resistance to antibiotics. In cancer, radiotherapy and chemotherapy is used.

In radiotherapy, the cancerous part is exposed to short wave radiations from the radioactive material repeatedly at regular intervals. Chemotherapy consists of administrating certain anticancer chemicals to the patients at regular intervals. These chemicals may kill both cancerous and normal cells.

Recently a new technique has been developed to repair defective genes. This consists of isolating the normal gene and inserting it into the host through bone marrow cells. This is called gene therapy. Combating disease utilizing all methods as and when required and ensuring a participation of community in this programme is known as integrated disease management. This requires awareness of the community about the severity of the problem, its causes and its remedies. This is a very effective programme for elimination and control of dangerous diseases from the human society.

Besides its contribution to food production and health of man, biology has discovered a number of means and developed technologies for the welfare of mankind as for example cloning; protection and conservation of environment etc.

• b. Define Genetics, Ecology and biotechnology?

Genetics: the study of heredity and the variation of inherited characteristics.

Ecology: the branch of biology that deals with the relations of organisms to one another and to their physical surroundings.

biotechnology: the branch of technology that dealt with the actions and requirements of human beings. Now, the industrial application of biological processes.

Q 2.

• a. The functions of arteries, veins and capillaries?

Blood vessels are channels that carry blood throughout your body. They form a closed loop, like a circuit, that begins and ends at your heart. Together, the heart vessels and blood vessels form your circulatory system. Your body contains about 60,000 miles of blood vessels.

There are three types of blood vessels their function are

• Arteries carry blood away from your heart.
• Veins carry blood back toward your heart.
• Capillaries, the smallest blood vessels, connect arteries and veins.

Here’s how blood flows through your body:

1. Veins bring blood to the right side of your heart.
2. Pulmonary arteries carry the blood to your lungs, where it receives oxygen.
3. Pulmonary veins move the blood oxygen-rich blood to the left side of your heart.
4. The aorta (the main artery in your body) carries the blood from the left side of your heart to the rest of your body through many branches of arteries.
5. Capillaries have thin walls that allow oxygen, nutrients, carbon dioxide and waste products to pass through, to and from the tissue cells.
6. Veins then carry the blood back to your heart, and the process begins again.
   

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• b. Explain in detail the Cardiac cycle.

The Cardiac Cycle

The cardiac cycle comprises all of the physiological events associated with a single heartbeat, including electrical events, mechanical events (pressures and volumes), and heart sounds.

The atria and ventricles alternately contract in each cardiac cycle.  The pressures in the chambers change greatly over the course of the cardiac cycle.

The cardiac cycle is essentially split into two phases, systole (the contraction phase) and diastole (the relaxation phase).  Each of these is then further divided into an atrial and ventricular component.

The cardiac cycle, therefore, proceeds in four stages:

1. Atrial systole: lasts about 0.1 seconds – both atria contract and force the blood from the atria into the ventricles.
2. Ventricular systole: lasts about 0.3 seconds – both ventricles contract, blood is forced to the lungs via the pulmonary trunk, and the rest of the body via the aorta.
3. Atrial diastole: lasting about 0.7 seconds – relaxation of the atria, during which the atria fill with blood from the large veins (the vena cavae).
4. Ventricular diastole: lasts about 0.5 seconds – begins before atrial systole, allowing the ventricles to fill passively with blood from the atria.
   

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Q 3 Differentiate between the following?

4 What is food poisoning? Give its symptoms and causes?

Food poisoning

Food poisoning, also called foodborne illness, is illness caused by eating contaminated food. Infectious organisms — including bacteria, viruses and parasites — or their toxins are the most common causes of food poisoning.

Infectious organisms or their toxins can contaminate food at any point of processing or production. Contamination can also occur at home if food is incorrectly handled or cooked.

Food poisoning symptoms, which can start within hours of eating contaminated food, often include nausea, vomiting or diarrhea. Most often, food poisoning is mild and resolves without treatment. But some people need to go to the hospital.

Symptoms of Food poisoning

Food poisoning symptoms vary with the source of contamination. Most types of food poisoning cause one or more of the following signs and symptoms:

Nausea
Vomiting
Watery or bloody diarrhea
Abdominal pain and cramps
Fever
Signs and symptoms may start within hours after eating the contaminated food, or they may begin days or even weeks later. Sickness caused by food poisoning generally lasts from a few hours to several days.

Frequent episodes of vomiting and inability to keep liquids down
Bloody vomit or stools
Diarrhea for more than three days
Extreme pain or severe abdominal cramping
An oral temperature higher than 100.4 F (38 C)
Signs or symptoms of dehydration — excessive thirst, dry mouth, little or no urination, severe weakness, dizziness, or lightheadedness

Causes of Food poisoning

Food can become contaminated at any stage during production, processing or cooking. For example, it can be contaminated by:

not cooking food thoroughly (particularly meat)
not correctly storing food that needs to be chilled at below 5C
leaving cooked food for too long at warm temperatures
not sufficiently reheating previously cooked food
someone who is ill or who has dirty hands touching the food
eating food that has passed its “use by” date
the spread of bacteria between contaminated foods (cross-contamination)
Foods particularly susceptible to contamination if not handled, stored or cooked properly include:

raw meat and poultry
raw eggs
raw shellfish
unpasteurised milk
“ready-to-eat” foods, such as cooked sliced meats, pâté, soft cheeses and pre-packed sandwiches

Contamination of food can happen at any point of production: growing, harvesting, processing, storing, shipping or preparing. Cross-contamination — the transfer of harmful organisms from one surface to another — is often the cause. This is especially troublesome for raw, ready-to-eat foods, such as salads or other produce. Because these foods aren’t cooked, harmful organisms aren’t destroyed before eating and can cause food poisoning.

Many bacterial, viral or parasitic agents cause food poisoning. The following table shows some of the possible contaminants, when you might start to feel symptoms and common ways the organism is spread.

Q5 MCQs can be found HERE

Q6. Short Note on the following

• Black Hole

A region of space having a gravitational field so intense that no matter or radiation can escape.• informal a place where money or lost items apparently disappear without trace.

Black holes are probably formed when a massive star exhausts its nuclear fuel and collapses under its own gravity. If the star is massive enough no known force can counteract the increasing gravity, and it will collapse to a point of infinite density. Before this stage is reached, within a certain radius (the event horizon) light itself becomes trapped and the object becomes invisible.

A black hole is a region of spacetime where gravity is so strong that nothing – no particles or even electromagnetic radiation such as light – can escape from it.[2] The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole.[3][4] The boundary of no escape is called the event horizon. Although it has a great effect on the fate and circumstances of an object crossing it, it has no locally detectable features according to general relativity.[5] In many ways, a black hole acts like an ideal black body, as it reflects no light.[6][7] Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly.

Objects whose gravitational fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace.[8] In 1916, Karl Schwarzschild found the first modern solution of general relativity that would characterize a black hole. David Finkelstein, in 1958, first published the interpretation of “black hole” as a region of space from which nothing can escape. Black holes were long considered a mathematical curiosity; it was not until the 1960s that theoretical work showed they were a generic prediction of general relativity. The discovery of neutron stars by Jocelyn Bell Burnell in 1967 sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality. The first black hole known was Cygnus X-1, identified by several researchers independently in 1971.[9][10]

Black holes of stellar mass form when massive stars collapse at the end of their life cycle. After a black hole has formed, it can grow by absorbing mass from its surroundings. Supermassive black holes of millions of solar masses (M☉) may form by absorbing other stars and merging with other black holes. There is consensus that supermassive black holes exist in the centres of most galaxies.

The presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. Any matter that falls onto a black hole can form an external accretion disk heated by friction, forming quasars, some of the brightest objects in the universe. Stars passing too close to a supermassive black hole can be shredded into streamers that shine very brightly before being “swallowed.”[11] If other stars are orbiting a black hole, their orbits can determine the black hole’s mass and location. Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identified numerous stellar black hole candidates in binary systems and established that the radio source known as Sagittarius A*, at the core of the Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses.

• b. Dengue Virus

Dengue Virus

Dengue (DENG-gey) fever is a mosquito-borne illness that occurs in tropical and subtropical areas of the world. Mild dengue fever causes a high fever and flu-like symptoms. The severe form of dengue fever, also called dengue hemorrhagic fever, can cause serious bleeding, a sudden drop in blood pressure (shock) and death.

Millions of cases of dengue infection occur worldwide each year. Dengue fever is most common in Southeast Asia, the western Pacific islands, Latin America and Africa. But the disease has been spreading to new areas, including local outbreaks in Europe and southern parts of the United States.

Researchers are working on dengue fever vaccines. For now, in areas where dengue fever is common, the best ways to prevent infection are to avoid being bitten by mosquitoes and to take steps to reduce the mosquito population.

Symptoms

Many people experience no signs or symptoms of a dengue infection.

When symptoms do occur, they may be mistaken for other illnesses — such as the flu — and usually begin four to 10 days after you are bitten by an infected mosquito.

Dengue fever causes a high fever — 104 F (40 C) — and any of the following signs and symptoms:

• Headache
• Muscle, bone or joint pain
• Nausea
• Vomiting
• Pain behind the eyes
• Swollen glands
• Rash

Most people recover within a week or so. In some cases, symptoms worsen and can become life-threatening. This is called severe dengue, dengue hemorrhagic fever or dengue shock syndrome.

Severe dengue happens when your blood vessels become damaged and leaky. And the number of clot-forming cells (platelets) in your bloodstream drops. This can lead to shock, internal bleeding, organ failure and even death.

Warning signs of severe dengue fever — which is a life-threatening emergency — can develop quickly. The warning signs usually begin the first day or two after your fever goes away, and may include:

• Severe stomach pain
• Persistent vomiting
• Bleeding from your gums or nose
• Blood in your urine, stools or vomit
• Bleeding under the skin, which might look like bruising
• Difficult or rapid breathing
• Fatigue
• Irritability or restlessness

Causes

Dengue fever is caused by any one of four types of dengue viruses. You can’t get dengue fever from being around an infected person. Instead, dengue fever is spread through mosquito bites.

The two types of mosquitoes that most often spread the dengue viruses are common both in and around human lodgings. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito. Then, when the infected mosquito bites another person, the virus enters that person’s bloodstream and causes an infection.

After you’ve recovered from dengue fever, you have long-term immunity to the type of virus that infected you — but not to the other three dengue fever virus types. This means you can be infected again in the future by one of the other three virus types. Your risk of developing severe dengue fever increases if you get dengue fever a second, third or fourth time.

Prevention

Vaccine

In areas of the world where dengue fever is common, one dengue fever vaccine (Dengvaxia) is approved for people ages 9 to 45 who have already had dengue fever at least once. The vaccine is given in three doses over the course of 12 months.

The vaccine is approved only for people who have a documented history of dengue fever or who have had a blood test that shows previous infection with one of the dengue viruses — called seropositivity. In people who have not had dengue fever in the past (seronegative), receiving the vaccine appears to increase the risk of severe dengue fever and hospitalization due to dengue fever in the future.

Dengvaxia is not available for travelers or for people who live in the continental United States. But in 2019, the U.S. Food and Drug Administration approved the vaccine for people ages 9 to 16 who have had dengue fever in the past and who live in the U.S. territories of American Samoa, Guam, Puerto Rico and the U.S. Virgin Islands — where dengue fever is common.

Prevent mosquito bites

The World Health Organization stresses that the vaccine is not an effective tool on its own to reduce dengue fever in areas where the illness is common. Preventing mosquito bites and controlling the mosquito population are still the main methods for preventing the spread of dengue fever.

If you live in or travel to an area where dengue fever is common, these tips may help reduce your risk of mosquito bites:

• Stay in air-conditioned or well-screened housing. The mosquitoes that carry the dengue viruses are most active from dawn to dusk, but they can also bite at night.
• Wear protective clothing. When you go into mosquito-infested areas, wear a long-sleeved shirt, long pants, socks and shoes.
• Use mosquito repellent. Permethrin can be applied to your clothing, shoes, camping gear and bed netting. You can also buy clothing made with permethrin already in it. For your skin, use a repellent containing at least a 10% concentration of DEET.
• Reduce mosquito habitat. The mosquitoes that carry the dengue virus typically live in and around houses, breeding in standing water that can collect in such things as used automobile tires. You can help lower mosquito populations by eliminating habitats where they lay their eggs. At least once a week, empty and clean containers that hold standing water, such as planting containers, animal dishes and flower vases. Keep standing water containers covered between cleanings.

• c. Semi-conductors

Semiconductor

A semiconductor material has an electrical conductivity value falling between that of a conductor, such as metallic copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way.

A semiconductor is a substance that has specific electrical properties that enable it to serve as a foundation for computers and other electronic devices. It is typically a solid chemical element or compound that conducts electricity under certain conditions but not others. This makes it an ideal medium to control electrical current and everyday electrical appliances.

A substance that can conduct electricity is called the conductor and a substance that cannot conduct electricity is known as the insulator. Semiconductors have properties that sit between the conductor and insulator. A diode, integrated circuit (IC) and transistor are all made from semiconductors.

The conductance can vary depending on the current or voltage applied to a control electrode or on the intensity of irradiation by infrared (IR), visible light, ultraviolet or X-rays. The specific properties of a semiconductor depend on the impurities — known as dopants — added to it.

What is the difference between N-type and P-type semiconductors?

An N-type semiconductor carries current mainly in the form of negatively charged electrons similar to the conduction of current in a wire. A P-type semiconductor carries current predominantly as electron deficiencies called holes. A hole has a positive electric charge, equal and opposite to the charge on an electron. In a semiconductor material, the flow of holes occurs in a direction opposite to the flow of electrons.

Elemental semiconductors include antimony, arsenic, boron, carbon, germanium, selenium, silicon, sulfur and tellurium. Silicon is the best known of these, forming the basis of most ICs.

Common semiconductor compounds include gallium arsenide, indium antimonide and the oxides of most metals. We also widely use gallium arsenide (GaAs) in low-noise, high-gain, weak-signal amplifying devices.

A semiconductor device can perform the function of the original vacuum tube, but with hundreds of times its volume. Like a microprocessor chip, a single IC can do the work of a set of vacuum tubes that would fill a large building and require its own electricity generating plant.

Q7. Differentiate between Camera and Human eye? Describe working of a Camera?

Differentiate between Camera and Human eye

Eye is an organ of sight while a camera is equipment that is used to record images.

The first and the foremost difference between an eye and a camera is that an eye cannot record an image. The eyes use living cells to detect and interpret the light and convert these into electrical signals that are relayed to the brain and processed into an image. The camera on the other hand uses a diaphragm from where the image is recorded on film or like in modern cameras on tape or digitally.

A camera sees in 2 dimensions while the eye sees in 3 dimensions. This means that when we see with our eyes we see height, width and depth. With a camera we only see height and width. There is no way to have the depth in the picture as a photograph is a flat medium. This is mainly achieved by the stereoscopic vision of the eye. A simple demonstration of this can be trying to bring the forefingers of both hands to meet from the sides. This is much simpler to do with both eyes open than with only one eye or almost impossible with a camera.

While changing the focus the retina and parts of the pupil adjust the size accordingly. However, in a camera the focus is changed by the movement of the lens. Eye has a blind spot which is also known as scotoma, whereas, the cameras do not have any such limitations. The eye can also adapt itself to the dark and within a few seconds one can get start seeing better in the dark. However, if a camera is not equipped to capture images in the dark it can never get accustomed.

The eye is highly sensitive to the dust and foreign particles settling on the outer film. In a camera there is no such problem as any dust can simply be wiped off the lens.

Summary
1. Eye is a live organ for sight whereas a camera is an equipment to capture images.
2. Eye uses live cells to detect light while the camera uses a diaphragm to detect light and capture images.
3. Stereoscopic vision of eyes allows 3 dimensional images while camera captures only 2 dimensional images.
4. The pupil adjusts the size while focusing while in a camera lens moves to change focus.
5. Eyes have blind spots while cameras do not.

Describe working of a Camera

Image Formation in Simple Camera and Human Eye
We know that if an object is lying at a distance more than the focal length of a convex lens, its
real and inverted image is formed on the other side of the lens. The image through the eye and
camera is formed in the same way. Let us compare the structure and function of both of them.

Camera

Camera is a kind of box to which a convex lens is mounted on the front side
(Figure 10.10). The lens forms a real and inverted image of an object on the sensitive film
placed behind it. A system is provided in the camera to move the lens back and forth so
that sharp image is obtained on the film. There is shutter behind the lens that remains
close normally. When the button is pressed, the shutter opens for a while. Light coming
from the object enters the camera during this interval and image is formed on the film.
The amount of light entering into the camera depends upon the size of aperture. Aperture
is an opening in the diaphragm behind the lens. This can be made smaller or larger as
required. The picture is obtained by developing the image on the film.

Human Eye

The human eye also works like a camera. Different parts of eye are shown in Figure10.11.

The eye is almost a sphere of diameter about 2.5 cm. Its outer boundary called the sclera is
thick and hard. At the front of the eye, there is a transparent hard skin known as cornea.
Behind the cornea there is iris and after that there is convex lens. The inner layer of the
back wall of eye is called retina. The retina of eye and the film of camera serve the same
purpose. Like camera, the eye lens forms a real and inverted image of the object on retina.
The optic nerve carries it in the form of signals to the brain. Although the image formed
on the retina is inverted, but our brain interprets this correctly i.e. the right way up.
The iris acts like the diaphragm of camera. The opening at the centre of iris is called pupil
which is just like aperture of a camera. When light outside is dim, the iris contracts to
make the pupil larger so that more light can enter the eye. In bright light, the iris makes
the pupil smaller.
In a camera, lens is moved back and forth to focus the image on the film, but the eye lens
does not move. Instead, the ciliary muscles make the lens thick or thin due to which its
focal length changes (Figure 10.12). When you are looking at distant object, the ciliary
muscles are in relaxed position and the image is formed on the retina. To look at
something closer to the eye, these muscles make the lens thicker. This makes its focal
length shorter and the image is again formed on the retina instead of forming at a point
beyond it.

Q8. What are lipids? Describe different types of their classification?

Lipids Definition

“Lipids are organic compounds that contain hydrogen, carbon, and oxygen atoms, which form the framework for the structure and function of living cells.”

What are Lipids?

These organic compounds are nonpolar molecules, which are soluble only in nonpolar solvents and insoluble in water because water is a polar molecule. In the human body, these molecules can be synthesized in the liver and are found in oil, butter, whole milk, cheese, fried foods and also in some red meats.

Let us have a detailed look at the lipid structure, properties, types and classification of lipids.

Lipids can be classified into two main classes:

• Nonsaponifiable lipids
• Saponifiable lipids

Nonsaponifiable Lipids

A nonsaponifiable lipid cannot be disintegrated into smaller molecules through hydrolysis. Nonsaponifiable lipids include cholesterol, prostaglandins, etc

Saponifiable Lipids

A saponifiable lipid comprises one or more ester groups, enabling it to undergo hydrolysis in the presence of a base, acid, or enzymes, including waxes, triglycerides, sphingolipids and phospholipids.

Further, these categories can be divided into non-polar and polar lipids.

Nonpolar lipids, namely triglycerides, are utilized as fuel and to store energy.

Polar lipids, that could form a barrier with an external water environment, are utilized in membranes. Polar lipids comprise sphingolipids and glycerophospholipids.

Fatty acids are pivotal components of all these lipids.

Within these two major classes of lipids, there are numerous specific types of lipids, which are important to life, including fatty acids, triglycerides, glycerophospholipids, sphingolipids and steroids. These are broadly classified as simple lipids and complex lipids.

Simple Lipids

Esters of fatty acids with various alcohols.

1. Fats: Esters of fatty acids with glycerol. Oils are fats in the liquid state

2. Waxes: Esters of fatty acids with higher molecular weight monohydric alcohols

Complex Lipids

Esters of fatty acids containing groups in addition to alcohol and fatty acid.

1. Phospholipids: These are lipids containing, in addition to fatty acids and alcohol, phosphate group. They frequently have nitrogen-containing bases and other substituents, eg, in glycerophospholipids the alcohol is glycerol and in sphingophospholipids the alcohol is sphingosine.

2. Glycolipids (glycosphingolipids): Lipids containing a fatty acid, sphingosine and carbohydrate.

3. Other complex lipids: Lipids such as sulfolipids and amino lipids. Lipoproteins may also be placed in this category.

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