Sunday, June 15, 2014

Useful Compare and Contrast in Biology

Comparison between mitosis in plant cell and animal cell

Mitosis in plant cell
Mitosis in animal cell
1.      Centrioles are absent.
Centrioles are present.
2.      No aster formation.
Aster formation occurs.
3.      Cell plate is formed.
No cell plate is formed.
4.      No furrowing of cytoplasm at cytokinesis.
Furrowing of cytoplasm occurs.
5.      Occurs mainly in meristems.
Occurs in tissues throughout the body.

Comparison between unicellular and multicellular organisms

Unicellular organism
Multicellular organism
1.        Body is made up of single cell
Body is made up of numerous cells
2.        Division of labour is at the organelle level. It gives a low level of operational efficiency
Division of labour may be at cellular, tissue, organ and organ system level. It gives high degree of operational efficiency
3.        A single cell carries out all the life processes
Different cells are specialized to perform different functions
4.        The cell body is exposed to the environment on all sides
Only outer cells are specialized to face the environment. Inner cells are devoted to other functions
5.        An injury of the cells can cause death of the organism.
Injury or death of some cells does not affect the organisms as the same can be replaced by new one.
6.        A cell body cannot attain a large size because of the limit imposed by surface area to volume ratio
A multicellular body can attain a large size increasing the number of small cells
7.        Lifespan is short due to heavy load of work
Lifespan is long due to limited load of work for each cell type
8.        Power of division is not lost
Certain specialized cells lose power of division
9.        A well-marked capacity of regeneration is present
The capacity of regeneration decreases with increasing specialization
10.      The cell has the same role for itself and the organism
Cells have a double role. One for themselves and other for the organism

Comparison between Hormones and vitamins


Hormone
Vitamin
1.      Synthesized in endocrine glands and some by neurosecretory cells.
Taken along with food from outside.
2.      These are steroids or proteinous or amino acid derivatives.
Simple organic compounds like amines, esters, organic acids etc.
3.      These are excitatory or inhibitory in action. They never act as coenzymes.
These are generally acts as coenzymes or constituents of coenzymes for enzyme action.
4.      Hormones directly influence gene expressions.
Vitamins have catalytic action.
5.      Their deficiency and overproduction cause metabolic disorders
Their deficiency (avitaminosis) causes specific deficiency diseases.


Comparison between continuous and discontinuous variations


Continuous variations
Discontinuous variations
1.      They refer to small, indistinct differences from the normal condition.
They refer to large, conspicuous differences from the parents.
2.      They are already present in population.
They are new variations through similar variations might have occurred previously.
3.      They are also known as fluctuations.
They are also known as mutations or spurts.
4.      They are usually unstable and non-inheritable.
They are usually stable and heritable.
5.      They are due to chance segregation of genes during gamete formation, crossing over or chance combination during fertilization.
They are produced by change in genes or genome.
6.      They can be represented by smooth curve.
A curve is not produced.
7.      They are very common in all organisms.
They appear suddenly and in few cases only.

Comparison between clone and offspring


Clone
Offspring
1.      It is the product of asexual reproduction
It is the product of sexual reproduction
2.      It is monoparental (derived from a single parent)
It is biparental (derived from two parents)
3.      It is formed by mitosis. Meiosis does not occur
Meiosis occurs prior to formation of gametes
4.      It exactly resembles the parent
It shows variations from parents
5.      There is no recombination of genes
Due to chance segregation and chance combination of genes, offspring exhibits genetic variations.

Comparison between cytokinesis in plant cell and animal cell


Cytokinesis in plant cell
Cytokinesis in animal cell
1.      Mechanism of cytokinesis is cell plate.
By cell furrow.
2.      Spindle usually persists.
Spindle begins to degenerate.
3.      Golgian and ER vesicles called phragmoplasts fuse to form cell plate.
A constriction is developed by the contraction of microtubules in the cell membrane.
4.      Cell plate grows centrifugally.
Cell furrow grows centripetally.

Comparison between neural control and hormonal control



Neural control
Hormonal control
1.      Its action is always quick
May be quick acting or slow acting
2.      Information are transmitted as electrochemical nerve impulses
Information are transmitted as chemical messengers (hormones)
3.      Impulse transmission occurs through nerve fibres
Hormonal transmission occurs through blood
4.      Information would be towards a specific direction (effector organ or CNS)
Hormones are released in general blood circulation from where taken by specific receptor.
5.      It is suitable for quick reactions like reflexes.
It is suitable for long-term changes such as maintenance of pregnancy.
6.      Short time effect
Long lasting effect

Comparison between quick acting hormones and lag period hormones


Quick acting hormones
Slow acting (Lag period) hormones
1.      They act immediately after secretion (within a few seconds)
They act after a lag period (may be hours or years)
2.      They are large sized molecules so are not diffusible through cell membrane of target cells.
They are small sized molecules so are diffusible through cell membrane
3.      The hormone receptors are present on the cell membrane of target cells
The hormone receptors are present in cytoplasm
4.      Their mode of action is through cascade effect
Mode of action is through mRNA synthesis.
5.      They will have second messengers such as cyclic AMP (cAMP), IP3 etc.
No second messengers
6.      E.g. Proteinous, peptide and amine hormones
E.g. Steroid hormones

Comparison between Enzymes and Hormones


Enzymes
Hormones
1.        All enzymes are proteins
They may be proteins, amines or steroids
2.        They are macromolecules with higher molecular weight
They have only low molecular weight
3.        They are non-diffusible through cell membrane
They are diffusible through cell membrane
4.        They either act intracellularly or carried by some ducts to another site
Generally carried by blood to a target organ
5.        Always act as biological catalysts and increases the rate of metabolic physiological processes.
They may be either excitatory or inhibitory in their action
6.        They catalyze reversible reactions
Hormone controlled reactions are not reversible
7.        Reaction rate increases with increase in their concentration up to a limit.
Deficiency or overproduction of hormone causes metabolic disorders or diseases.
8.        They act quickly
Some hormones are quick acting, while some are slow acting with a lag period.
9.        They are not used in metabolic functions
They are used up in metabolic functions.

Comparison between Cilia and Flagella

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Cilia
Flagella
1.      They are very small sized (5-10µ long).
They are very longer (about 150µ long).
2.      Their number per cell range from 300 to 14000, occurring all over the cell surface.
Number is very less, usually 1-4 per cell.
3.      They beat in a coordinated rhythm either simultaneously (synchronous) or one after the other (metachronic).
They beat independent of each other.
4.      They help in locomotion, feeding circulation, aeration, etc.
They help in locomotion only.

Comparison between plants and animals

Plants
Animals
1.      Plant cells contain chloroplasts bearing chlorophyll
Chloroplasts absent
2.      They show photosynthesis
They do not show photosynthesis
3.      Dependent upon inorganic substances like CO2 and H2O
They feed on complex organic compounds
4.      They are fixed organisms but exhibit bending, twisting etc
They are capable of moving the whole body
5.      They have branched body
They have compact body
6.      They are comparatively less sensitive and respond slowly
They are more sensitive and respond very quickly
7.      Cellulosic Cell wall present
No cell wall

Comparison between Asexual and sexual reproduction


Asexual reproduction
Sexual reproduction
1.      It involves no formation and fusion of gametes
It involves formation and fusion of gametes
2.      It is uniparental
It is generally biparental except Taenia, Fasciola etc
3.      Reproductive units are somatic cells of parent
Reproductive units are germ cells of parent
4.      It involves only mitotic division
It involves meiosis during gamete formation
5.      Offspring are genetically similar to parents
Offspring are genetically different from parents
6.      It occurs by binary fission or multiple fission or budding or fragmentation
It occurs by gametogenesis followed by fertilization.

Comparison between short range adaptation and long-range adaptation

Short-range adaptation
Long-range adaptation
1.      These are temporary changes
These are permanent changes
2.      These are developed in response to temporary changes in the environment
These are developed in response to permanent changes in the environment
3.      These are not inheritable
These are heritable
4.      No change in DNA
DNA is changed
5.      They have no role in evolution
They have important role in evolution

Comparison between homologous organs and analogous organs


Homologous  organs
Analogous organs
1.      Adapted for different functions
Adapted for similar functions
2.      Similar basic plan and origin
Different body plan and origin
3.      It is due to divergent evolution
It is due to convergent evolution
4.      It indicates evolutionary relationship
It does not indicate evolutionary relationship
5.      Example: Forelimbs of vertebrates
Example: Wings of insect and birds

Comparison between Spontaneous and Induced mutations

Spontaneous mutations
Induced mutations
1.      It is caused by natural agents, so it is also known as natural mutations or background mutations.
It is caused by man
2.      Frequency of mutation is very low (about one per million genes)
It is very faster
3.      It is due to  mutagens in many cellular products such as formaldehyde, nitrous acid, peroxides etc
It is due to physical mutagens (radiations, temperature etc) and chemical mutagens (mustard gas, vinyl chloride, acridine dyes, ammonia etc)

Comparison between Somatogenic variations and Blastogenic variations

Somatogenic variations
Blastogenic (Germinal) variations
1.      It involves somatic cells
It involves germ cells of gonads.
2.      It is also called acquired variation as it occurs during the lifespan of an individual.
It occurs in gametogenesis in parents
3.      It is developed in response to changes in environmental factors like temperature, food, humidity, light intensity etc
It is developed due to mutations or recombination of genes
4.      It is not heritable. It has no role in heredity and evolution and is lost with the death of organism.
It is heritable variation. It transmits from one generation to another. It has great role in evolution.
5.      Examples: Better developed muscles in an athlete, gymnastics etc. Development of median eye in the larva of Fundulus fish developing in magnesium chloride containing water.
Examples: Polydactyly in man
Sickle cell anaemia

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