DIFFERENCES FROM PAST PAPERS (2000 & 2001)

1. Cardiac & Skeletal Muscles:

Cardiac Muscles:
i) Cardiac muscles are present in the heart only.
ii) They have centrally placed nuclei.
iii) They never fatigue.
iv) They are composed of long fibres.
v) They are under involuntary control.

Skeletal Muscles:
i) Skeletal muscles are present in the skeleton of the body.
ii) Nuclei are not centrally placed in skeletal muscle.
iii) They can fatigue.
iv) They are not composed of long fibres.
v) They are under voluntary control.

2. Haze & Smog

Haze:
i) The dust particle smoke etc. that may be visible in atmosphere close to the earth’s surface is known as Haze.
ii) It does not affect natural visibility.
iii) It does not occur particularly near coastal areas.

Smog:
i) It is a mixture of solid and liquid fog as well as particles of smoke. It is formed when humidity is high.
ii) Smog reduces visibility.
iii) It occurs near coastal areas.

3. Enzyme & Hormone

Enzyme:
i) These are organic catalysts produced in the protoplasm of all living cells.
ii) These are mostly protein in nature.
iii) They control all biochemical reactions of the cell.
iv) These are present in all cells and show their activity there.

Hormone:
i) These are organic substances produced in places away from their functional sites.
ii) These are mostly acids.
iii) They promote and inhibit growth, flowering, sex expression, etc.
v) These are mobile. They are produced at one site and show their activities at other sites.

4. Igneous & Sedimentary Rocks

Igneous Rocks:
i) Igneous rocks are formed when magma (or molten rocks) has cooled down and solidified.
ii) Igneous rocks are commonly found inside the Earth’s crust or mantle,
iii) Igneous rocks can be an important source of minerals,
iv) Examples of Igneous rocks include granite and basalt.

Sedimentary Rocks:
i) Sedimentary rocks are formed by the accumulation of other eroded substances,
ii) Sedimentary rocks are usually found in water bodies (sea, oceans etc.).
iii) Sedimentary rocks, or their bedding structure, are mostly used in civil engineering; for the construction of housing, roads, tunnels, canals etc.
iv) Examples of Sedimentary rocks include shale, limestone and sandstone.

What is the difference between Igneous Rocks and Sedimentary Rocks?
- Igneous rocks are formed from molten liquid minerals called magma, while sedimentary rocks are formed from lithification (cementing, compacting and hardening) of existing rocks.

- Igneous rocks are non-porous for water, while sedimentary rocks are porous to the water. That is water cannot penetrate through igneous rocks but can through sedimentary rocks.

- Igneous rocks are having fossils very rarely, while sedimentary rocks are rich in fossils.

- Igneous rocks are harder than sedimentary rocks.

- Tendency to react with acids is higher to sedimentary rocks when compared to igneous rocks.

- Igneous rocks may be light or dark coloured, while sedimentary rocks have great colour variety.


5. Producers & Consumers

Producers:
Producers are organisms that make their own food through photosynthesis or other reactions and are a food source for other organisms (ex. plants, extremophile benthos communities).

Consumers:
Consumers are organisms that ingest other organisms, like plants, in order to gain energy (ex. herbivores, carnivores, omnivores, and detrivores).


6. Microcomputer & Minicomputer

Microcomputer:
i) A microcomputer is a standard desktop computer used at a home and in business.
ii) A microcomputer is a computer with a microprocessor as its CPU.
iii) They are cheap, compact and can be easily accommodated on a study table.
iv) Microcomputer is a single-user computer.
v) The two most common types of storage devices used with microcomputers are tapes and disks.
vi) Microcomputer is not powerful or as fast as minicomputer.
-vii) Examples are- Modern computers like desktop, laptop etc.

Minicomputer:
i) Minicomputers are mid-sized computer used in universities, research labs and small corporations.
ii) Minicomputers are faster than microcomputers.
iii) They are expensive and larger than microcomputer.
iv) Minicomputer is a multi-user computer.
v) For secondary storage, most minicomputers use magnetic disks or tapes.
vi) Minicomputer is powerful than microcomputer but not as super computer and mainframe computer.
vii) Examples are- IBM 9375, Motorola 68040 etc.

7. Mainframe & Super Computers

Mainframe Computers:
i) The largest computers called mainframe computers are the oldest category of computer system.
ii) They are capable of great processing speed and data storage.
iii) These are always kept in air-cooled rooms.
iv) They are mainly used in banks, airlines and industrial companies.

Super Computers:
i) The super computers are fastest of all computers.
ii) It was invented by two brothers Gregory and David in New York.
iii) These computers have high capacity to work.
iv) These also require air-conditioned rooms.
v) The super computers are mainly used in a) Automotive engineering b) Modelling nuclear explosion c) Aeroplane designing d) Oil exploration e) Weather forecasting etc.

8. RAM & Cache Memory

RAM
i) It stands for random access memory.
ii) It is an optical disc, where data and information is stored permanently.
iii) RAM is the primary storage media.
iv) RAM is the primary storage device from which the system boots.
v) RAM is stored on RAM chip.
vi) The data or information stored on it can be written on or it can be erased.

Cache Memory:
i) Cache memory is a special high speed memory that the CPU can access quickly.
ii) It is used in computers with very fast CPUs, so that these CPUs don’t have to wait for Data to be delivered from RAM.
iii) The most frequently used instructions are kept in the cache memory.
iv) This allows the CPU to run faster because it does not have to take time to swap instructions in and out of RAM.