Hydrophobic interactions

Some molecules just don’t play nicely with water. Because water is a polar molecule, it tends to stick to itself via hydrogen bonds. Other polar molecules also stick to water molecules and can mix right in, dissolv ing into the water. However, nonpolar molecules have evenly shared covalent bonds and lack the slight negative and positive charges of polar molecules. Because they’re uncharged, nonpolar molecules don’t mix well with water.

Nonpolar molecules are also called hydrophobic molecules because “hydro” means water and “phobic” means to fear.

When nonpolar molecules are placed in a watery environment, the polar mol ecules will all stick to each other and push the nonpolar molecules away. You can think of the scenario as if the polar molecules all belong to a clique that refuses to hang out with the nonpolar molecules. (The name of this clique, by the way, is the hydrophilic molecules.) Because the nonpolar molecules all get pushed together, they become associated with each other.

The interaction between nonpolar molecules is called a hydrophobic interaction.

You can easily demonstrate a hydrophobic interaction to yourself. Just go into your kitchen, put some water in a cup, and then add a little oil. Even if you stir the mixture vigorously to mix the oil into the water, as soon as you stop stirring, all the oil will gather together on top of the water.

The water molecules all stick to each other and push the oil molecules away. Hence the saying, “They get along like oil and water!”

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THOUGHT OF THE DAY-28

Life should be great rather than long.

-Dr. Bhimrao Ramji Ambedkar-

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Keep Your Mind Alive During Lecture

Some instructors are good lecturers, others not so much. But whatever your circumstance, you can do a lot on your end to get the maximum benefit out of attending lecture:

Write notes in your own words. Listen to what your instructor is saying and write your own notes. Writing your own notes is very different from just sitting there and writing down whatever the instructor says or writes on a board. If you’re listening and writing things in your own words, you’re processing the information as you go.

Take notes on interesting stories and anecdotes. Instructors often tell stories and give examples to show the relevance of the information they’re presenting. They don’t usually write down these stories, how ever, so many students don’t write them down either. If the instructor tells a good one that helps you grasp the concept they’re talking about, jot down a few notes about it in the margin of your notes. When you’re studying later, these side notes may help you recall the topic.

Sit in the best place for you in lecture. Usually, the front is best. It’s too easy to get distracted and tune out in the back. However, if you’re some one who gets sleepy and might need to move around a little to wake up, then try an aisle seat. If you get sleepy, you can get up and take a short walk to the rest room. It’s better to get up and move than to miss half of lecture because you took a nap.

Ask questions when you don’t understand. If you’re prepared for class and following the lecture but something doesn’t make sense to you, then ask about it. Chances are if you don’t get it, someone else doesn’t either.

Be in good physical shape for class. Get enough sleep, exercise, and healthy food so that you’re ready to participate.

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How viruses get into cells

Viruses attach to cells when viral proteins successfully bind to receptors on the host cell. If the viral protein has the right shape, it will tuck into the cor responding shape on the host cell receptor. You can think of viral attachment as a virus having the right key to fit into the lock on the host cell.

After the virus is attached, it may force itself into the cell by digging a hole through a cell wall slip in by fusing its envelope with the membrane of the host cell, or trick the cell into bringing it inside.

The ability of a virus to infect a host cell depends on a match between pro teins on the surface of the virus and receptors on the surface of the host cell.

The type of cells a particular virus can infect is called the host range of the virus. Because viruses can infect only cells that they can attach to with their proteins, each virus has a very specific range of hosts it can infect. In other words, each virus can infect only the host cells for which it has keys.

Some viruses have a key that works in the lock on many types of cells. These viruses have a broad host range. For example, the rabies virus can infect humans and many other mammals. On the other hand, some viruses have a key that fits into the lock on only a few cells. These viruses have a narrow host range. The HIV virus, which infects only certain cells of the human immune system, is a good example of a virus with a very narrow host range.

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The structure of viruses

The simplest viruses have just two components: a nucleic acid core and protein capsid. The nucleic acid core, which may be DNA or RNA, contains the instructions for taking over cells and making more virions, or viral par ticles. The nucleic acid is surrounded by the capsid, a protective protein coat. Each individual protein that makes up the capsid is called a capsomere.

All viruses have at least a capsid and a nucleic acid core. The core consists of one of four types of nucleic acid:

*Double-stranded DNA

*Single-stranded DNA

*Double-stranded RNA

*Single-stranded RNA

One difference between cells and viruses is that cells contain DNA and RNA. However, a single viral particle contains only DNA or RNA. Also, single stranded DNA and double-stranded RNA are commonly found in viruses, but not in cells.

In addition to the capsid and the core, some viruses have an outer membrane layer called an envelope. It’s no coincidence that the envelope of a virus is similar to the plasma membrane of a cell viruses that have envelopes steal them from their cellular victims as they leave the cell! Viral envelopes aren’t exactly the same as plasma membranes because they’ve been changed to suit the needs of the virus by the addition of viral proteins.

Once modified and adopted, the envelope helps the virus enter and exit from host cells. Viruses may also have proteins that stick out of the envelope or off the sur face of the capsid. These proteins, called spikes, help the virus attach to host cells.

Viruses come in three common shapes:

*Helical viruses have a capsid that forms a twisting helix around the nucleic acid core.

*Polyhedral viruses have a regular geometric shape. The most complex polyhedral viruses are icosahedrons with 20 faces.

*Complex viruses have separate patches of proteins, often forming unique structures or extensions on the virus.

Under the microscope, enveloped viruses appear irregular in shape. However, a helical or polyhedral capsid may be located underneath the envelope.

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THOUGHT OF THE DAY 28

 “The best thermometer to the progress of a nation is its treatment of its women”

Swami Vivekananda.

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SSC (STAFF SELECTION COMMISSION).

ARTICLE BY – penserstudypoint.com

SSC (STAFF SELECTION COMMISSION).

SSC, an organization that comes under indian government.
SSC recruit employees for different ministries and department on different posts.

SSC CGL POSTS:-

1-Inspector of Income Tax
2-Inspector (Examiner) [CBEC]
3-Inspector (Preventive Officer) [CBEC]
4-Inspector, (Central Excise) [CBEC]
5-Inspector of Posts [ Department of Post]
6-Assistant Enforcement Officer
7-Inspector [Central Bureau of Narcotics]
8-Divisional Accountant [Offices under CAG]
9-Statistical Investigator Gr.II
10-Assistant [Ministry of Railway]
11-Assistant [Central Vigilance Commission]
12-Assistant (Central Secretariat Service)
13-Assistant (Intelligence Bureau)
14-Assistant (Ministry of Affairs)
15-Assistant (Selection Officer)
16-Assistant (AHFQ)
17-Upper Divisional Clerk
18-Auditor (C& AG, CGDA, CGA)
19-Tax Assistant (CBEC & CBDT)
20-Junior Accountant

SSC CHSL POSTS:-

1-Lower Divisional Clerk (LDC)
2-Junior Secretariat Assistant (JSA)
3-Postal Assistant (PA)
4-Sorting Assistant (SA)
5-Data Entry Operator (DEO)

SSC JE POSTS:-

1-JE (Civil), Central Water Commission
2-JE (Mechanical), Central Water Commission
3-JE (Civil), CPWD
4-JE (Electrical), CPWD
5-JE (Civil), Department of Post
6-JE (Civil), Military Engineering Service
7-JE (Electrical and Mechanical), Military Engineering Service
8-JE (Quality Surveying and Contract), Military Engineering Service.
9-JE (Civil), Farrakka Barrage Project
10-JE (Mechanical), Farrakka Barrage Project
11-JE (Electrical), Farrakka Barrage Project
12-JE (Civil), Director General Border Roads
13-JE (Electrical), Director General Border Roads
14-JE (Mechanical), Director General Border Roads
15-Junior Engineer (Civil), Central Water Power Research Station
16-Junior Engineer (Electrical), Central Water Power Research Station
17-Junior Engineer (Mechanical) (Naval Quality Assurance), DGQA, Ministry of Defence
18-Junior Engineer (Electrical) (Naval Quality Assurance), DGQA, Ministry of Defence
19-Junior Engineer (Civil), National Technical Research Organisation
20-Junior Engineer (Electrical), National Technical Research Organisation.
21-Junior Engineer (Mechanical), National Technical Research Organisation.

SSC CGL AND SSC CHSL DIFFERENCE:-

The SSC CGL exam is the Combined Graduate Level exam. This exam is conducted to recruit candidates in different Group B and Group C posts in various Government Departments and Ministries. The SSC CHSL exam, however, is the Combined Higher Secondary Level Examination.

SYLLABUS FOR SSC

PART-1 :General intelligence and reasoning:

*Analogies
*Similarities and differences
*Space visualization
*Spatial orientation
*Problem solving
*Analysis
*Judgment
*Decision making
*Visual memory
*Discrimination
*Observation
*Relationship concepts
*Arithmetical reasoning and figural classification
*Arithmetic number series
*Non-verbal series
*Coding and decoding
*Statement conclusion
*Syllogistic reasoning etc
*Semantic analogy
*Symbolic/ Number Analogy
*Figural analogy
*Semantic classification
*Symbolic/ number classification
*Figural classification
*Semantic series
*Number series
*Figural series
*Word building
*Coding and de-coding
*Numerical operations
*Symbolic operations
*Trends
*Space orientation
*Venn diagrams
*Drawing inferences
*Punched hole/ pattern-folding and un-folding
*Figural pattern-folding and completion
*Indexing
*Address matching
*Date and city matching
*Classification of centre codes/ roll numbers
*Small and capital letters/ numbers coding
*Decoding and classification
*Embedded figures
*Critical thinking
*Emotional intelligence
*Social intelligence

Part-2 :General awareness:

*General Awareness of the Environment and its Application to Society
*Knowledge of current events and of such matters of every day observations, and experience in their scientific aspect
*India and its neighbouring countries especially pertaining history, culture, etc.

Part-3 :Quantitative aptitude:

*Computation of whole numbers
*Decimals
*Fractions and relationships between numbers
*Percentage
*Ratio and proportion
*Square roots
*Averages
*Interest
*Profit and loss
*Discount
*Partnership business
*Mixture and alligation
*Time and distance
*Time and work
*Basic algebraic identities of school algebra and elementary surds
*Graphs of linear equations
*Triangle and its various kinds of centres
*Congruence and similarity of triangles
*Circle and its chords
*Tangents
*Angles subtended by chords of a circle
*Common tangents to two or more circles
*Triangle
*Quadrilaterals
*Regular polygons
*Circle
*Right prism
*Right circular cone
*Right circular cylinder
*Sphere
*Hemispheres
*Rectangular parallelepiped
*Regular right pyramid with triangular or square base
*Trigonometric ratio
*Degree and radian measures
*Standard identities
*Complementary angles
*Heights and distances
*Histogram
*Frequency polygon
*Bar diagram and pie chart

Part-4 :English comprehension:
*Basic comprehension and writing ability

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THOUGHT OF THE DAY-27

“When you stand above the crowd, you must be ready to have stones thrown at you”

Vikram Sarabhai
Father of the Indian Space Program

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FOOD WEB

Food webs
Energy passes from one animate thing to a different within the sort of food. Food webs show however living things go after each other. At very cheap of a food cycle are plants, that build their own food, taking energy from the Sun. At the highest ar predators, that go after alternative animals.

Food chain
Food webs are created from totally different, many various, many alternative food chains that have different levels. In a very organic phenomenon, plants are referred to as producers as a result of they create their own food. Animals that eat plants are referred to as primary customers. Primary customers are ingested by alternative animals referred to as secondary customers, or predators. Once all living things die they become the food of organisms referred to as decomposers.


Food pyramid
As we have a tendency to go up a organic phenomenon, the number of food offered decreases. This is often as a result of living things use most of the energy within the food they eat respiration. A organic phenomenon shows however energy is lost at every level. close to the highest, there ar simply many predators, whereas at very cheap there are more producers.

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CLASSIFICATION OF BONES

BONES
The bones are the hard structure ,Which form the rigid framework the body.
Bone is a highly vascular mineralized connective tissue consisting of cell and dense intercellular organic matrix impregnated with organic salts. The organic material mainly consist of collagen fibers and form one third of the bone.
The inorganic material mainly consist of calcium phosphate and traces of other salts. It provides hardness and rigidity to the bone and makes it radiopaque in x-ray film.
FUNCTION

 Bone give shape and support to the body ,and resist any forms of stress.
 These provide surface for the attachment of muscle ,tendons,ligaments.
 These serve as levers for muscular actions.
 Bone marrow manufactures blood cells.
 Bone store 97%of the body calcium and phosphorus.
 Bone marrow contains reticuloendothelial cells which are phagocytic in nature and take part in immune responses of the body.
 The skull ,vertebral column and thoracic cage protect brain , spinal cord and thoracic and some abdominal viscera ,respectively.
 some bones around the nose contain large cavities filled with air (paranasal air sinuses which affect the timber of the voice).

CLASSIFICATION OF THE BONE

According to shape
According to the structure
According to the development

CLASSIFICATION ACCORDING TO THE SHAPE

Depending on the size and shape. the bone are classified into 7 type.
• Long Bones
• Short Bones
• Flat Bones
• Irregular Bones
• Pneumatic Bones
• Sesamoid Bones
• Accessory Bones

Long bones

Long bone are those in which length exceeds the breadth and thickness.
The long bone are two types.
 Typical long bones
 Miniature/short long bone

Short bones

Short bones are small in size and usually cuboidal in shape , presenting six surfaces. These bones are found in wrist (carpal bone ) and foot (tarsal bone).

Flat bones

Flat bone are flat and shallow plate-like bone.
They form boundaries of certain body cavities. the example of the flat bone frontal, parietal ,occipital ,scapula, ribs, sternum.

Irregular bones

Irregular bone are highly irregular shape ,hip bone vertebrae bone forming base of skull.

Pneumatic bones

Pneumatic bone are a variety of irregular bone which contain air filled cavity. These bones are mainly located around the nasal cavity.
Example maxilla ,frontal ,sphenoid and ethmoid bones.

Sesamoid bones

These are bony nodules found embedded in the tendons or joint capsules.they have no periosteum and ossify after birth. Ex. Patella.

Accessory bones

These bones are not always present. These may occur as ununited epiphysis developed from extra centres of ossification. Ex. Sutural or wormain bones.

CLASSIFICATION ACCORDING TO THE STRUCTURE

Microscopically the architecture of bone may be compact or cancellous.
Compact bone Compact bone is dense in texture like ivory ,but is extremely porous. It is best developed in the cortex of the long bone.
Cancellous bone The cancellous bone is a mesh work of bony spicules.it consist of interconnecting road and plates of bone called trabeculae.

CLASSIFICATION ACCORDING TO THE DEVELOPMENT

According to the process of the bone development. The bones are three type.
Membranous bones are developed by membranous ossification.
Cartilaginous bone are developed by endochondral ossification.
Membrano-cartilaginous bone developed by both membranous and endochondral ossification.

Parts of growing young long bone
 Epiphysis
 Diaphysis
 Metaphysis
 Epiphysis plate

Epiphysis these are ends of long bones which ossify from secondary centers.
Diaphysis It is the elongated part of bone between the metaphysis. It develops from primary ossification center.
Metaphysis the end of diaphysis toward the epiphyseal cartilage is called metaphysis.
Epiphysis plate Epiphysial plate separates epiphysis from metaphysis. Proliferation of the cells in this cartilaginous plate is responsible for lengthwise growth of a long bone.

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