Holozoic Nutrition: Steps

Holozoic Nutrition: Steps

1.      Ingestion

2.      Digestion

3.      Absorption

4.      Assimilation

5.      Egestion

Ingestion: it is the process of intake of food. Ingestion depends on the size of food and the structure of organ adapted of the ingestion of food. The different organisms have different features to ingest, like amoeba ingest through pseudopodia. Paramecium has cilia, hydra has tentacles, insect use their mouth parts and humans use their mouth.

Digestion: It is the process of breaking down of large sized, complex food that is insoluble and non-diffusible. digestion is a catabolic process. The ingested food is in form of protein, carbohydrates and fats, these are organic polymer compounds. When this food breaks in simpler form, which is soluble and diffusible. The protein converts in amino acids, carbohydrates in form of glucose and fats into fatty acids, these are organic monomer compounds. This breakdown takes place in presence of digestive enzymes that are in digestive juices which are secreted by the digestive glands. Digestion is basically of two types: intracellular digestion and intercellular digestion.  Intracellular digestion takes place inside the cell. This takes place generally in case of lower organisms. Eg; sponges, protozoa, amoeba. .  Intercellular digestion takes place inside the alimentary canal. This takes place generally in case of higher organisms. Eg; human beings

Absorption: it is the process of absorption of diffusible nutrient through the wall of alimentary canal of small intestine. This absorbed food goes in the blood and lymph. Generally the absorption is of two types: physical absorption and active absorption. Physical absorption involves diffusion or osmosis of nutrients whereas active transport involves movement of nutrient through the medium.

Assimilation: it is an anabolic process in which the food that is broken down as simple nutrient gets converted into complex bio molecule inside the cell these polysaccharides helps in the growth and repair of tissue.

Egestion: this is the process of expelling of undigested food in form of faeces. The excess of water, undigested enzymes comprises the faeces. The roughage adds bulk to faeces.

Latent heat of fusion (solid to liquid change)

Latent heat of fusion (solid to liquid change)

We can study the latent heat of fusion by a simple experiment.

We should first take a beaker and place it on a burner. A thermometer should be suspended in it. The temperature is 0^o C. When we supply heat to the beaker, ice start melting to form water. When temperature is again noted it is still 0. This temperature remains the same time even a little amount of ice is there in the beaker. Till this time all heat provided is used to convert ice in water. This heat is used up in breaking the attractive force between the ice molecules. When no ice is left and only water is there at 0^o C, any additional heat will increase the kinetic energy of molecule thus increasing the temperature, but before that all heat but only help in changing the state of matter.

The latent heat of fusion of a solid is the quantity of heat in joules required to covert 1 kg  solid (at its melting point) to liquid, without any change in temperature.

Latent heat of fusion of ice is 3.34 × 10⁵ J/kg. 1 kg of ice at   0^o C will need 3.34 × 10⁵ J to melt and become ice. When water at 0^o C converts in ice on freezing it gives out 3.34 × 10⁵ J of energy. 

Latent Heat

States of matter

Conversion of states

Latent heat

The heat energy that has to be supplied to a matter to change is state is called latent heat.

Latent does not change the temperature of substance instead this temperature is used up to change the state of matter. Normally, when we supply heat to a substance its temperature increases but when the substance undergoes a change in state this supplied heat is utilized in changing its state.  Literally the word “latent” means hidden or concealed. Latent heat means the hidden heat because it is not visible in form of temperature change by rising the temperature, but this heat is utilized to change the state.

As discussed earlier, every substance solid or liquid has some force of attraction between its particles which hold them together. When the substance changes its state ( from solid to liquid, from liquid to gas) it has to break these attractive forces and so that the particles can move.

Why latent heat only change the state but not the temperature?

Basically, when heat is provided some heat break the attractive force and some heat is utilized in increasing the kinetic energy of particles. Latent heat is used to break the attractive force between particles and not to increase the kinetic energy so the state change but not the temperature.

There are two types of latent heat:

1.      Latent heat of fusion

2.      Latent heat of vaporisation

Latent heat of fusion: It is the heat energy used in converting a substance from solid state to liquid state.

Latent heat of vaporisation: It is the heat energy used in converting a substance from liquid state to gaseous state.

Exchange of Gases in plants

Exchange of gases in plants, Diffusion, Opening and Closing of Stomata, structure of stomata, endosmois, exosmosis

Exchange of gases in plants

Exchange of gases is an important phenomenon that is essential for physiological processes like photosynthesis and respiration. Oxygen is released and carbon dioxide is absorbed in Photosynthesis and in respiration of plants carbon dioxide is released and oxygen and absorbed. Although, like animals plants do not posses any special respiratory organs but this exchange of gases take place by the process of diffusion.

Diffusion is the movement of molecules or ions of gas, liquid, or solute from an area of greater concentration to an area of lighter concentration.

All living cells of root, stem and leaves respire all through day and night. In higher plants, the respiration takes place through stomata present on leaves. The older stems exhibit the gaseous exchange through lenticels present on the bark. In lenticels the cells are loose and thin walled and have many air spaces in them. They are often projected above the outer covering of stem.

Opening and Closing of Stomata

Stomata are the minute pores found on the epidermis of leaves. These help in the exchange of gases during the time of photosynthesis and respiration. It also helps in transpiration; this kind of transpiration that takes place with the help of stomata is called stomatal transpiration.

Structure of stomata

In the stoma two guard cells bound a minute elliptical pore.

Guard cell : characters

1.      These guard cells are basically modified epidermal cells which are in shape of kidney beans.

2.       The wall of guard cells near the pore is thick but the outer wall is thin, elastic and semi-permeable.

3.      Guard cells are filled with chloroplast

4.      Sometimes the immediate cells surrounding the guard differ from epidermal cell and they are called subsidiary or accessory cells.

5.      In monocots the guard cells are dumb-bell in shape.

Mechanism of opening and closing of stomata

Opening and closing of stomata occur due to turgor change in guard cells.

Opening of guard cells

Due to endosmosis   -------------à increase in turgor of guard cells    -----------------à causes stretching and bulging of outer thin walls  --------------à results in pulling apart of inner thicker wall ---------à this creates an opening or pore in the guard cells of stomata

Due to endosmosis the turgor pressure of guard cells increases which leads to stretching and bulging of outer thin walls. When the outer thin wall swell, it stretches out and in turn pulls the inner thick wall. This pulling back of iner wall creates a pore between the guard cells.

Closing of guard cells

Turgor pressure of guard cells decreases due to exosmosis    ------------à inner wall of guard cell sags     -----------à the pore created closes.

When the turgor pressure of guard cells decreases due to exosmosis the inner wall of guard cells drop back in its position thus closing the pore.

What causes endosmosis and exosmosis?

During day the starch of guard cells is converted into sugar. This sugar increases the osmotic content of guard cells which lead to endosmosis and finally opens the stomata.

During night, the sugar is converted back to starch reversing the whole process and thus closing the stomata.

Change in states of matter

Change in states of matter

Matter exists in three different forms: solid, liquid and gaseous state. These forms are interchangeable, i.e. we can change a substance from solid state to liquid state or from liquid state to gaseous state and similarly the reverse from gaseous to liquid state and from liquid to solid state. For example, ice melts to from water and when water is heated it evaporates to form water vapour which is in gaseous state. Likewise when water vapour condenses it forms water and water freeze it converts to ice.

The physical state of matter can be change using two techniques:

1.      Changing the temperature

2.      Changing the pressure

Effect of change of temperature:

The state of matter can be changed by changing the temperature, either by heating or by cooling.

When temperature is increased the kinetic energy of particles increases causing more vibration in particles, this leads to decrease in inter particle attraction. Similarly when temperature is decreased the kinetic energy of particles decreases causing vibration of particles to reduce, this leads to increase in inter particle attraction.

1.      Solid to liquid (Melting):

The process in which a solid substance changes into liquid on heating is called melting. Ice melts to form water.

The temperature at which solid substance melts and changes into liquid form at atmospheric pressure is called the melting point of substance. . Ice melts to form water at 0^o C, so 0^o C is the melting point of ice

Melting point of substance is the measurement force of attraction between the particles of the substance. The greater the force of attraction greater will be the melting point. Melting point of ice is 0^o C and that of wax is 63^o C. this means the intermolecular force of attraction between wax particles is greater than that of ice.

Causes of conversion: when a solid substance is heated, the heat energy make the particles vibrate vigorously. At melting point the solid particles have sufficient kinetic energy to overcome the strong force of attraction which holds the particles of solid in fixed position. This kinetic energy break the particles in smaller units and thus the solid melts to form liquid.

2.       Liquid to gas (boiling or vaporisation):

The process in which a liquid substance changes into gas on heating is called boiling. Water boils to form water vapour.

The temperature at which liquid substance evaporates and changes into gaseous form at atmospheric pressure is called the boiling point of substance. Water evaporates to form water vapour at 100^o C, so 100^o C is the boiling point of water.

Melting point of substance is the measurement force of attraction between the particles of the substance. The greater the force of attraction greater will be the boiling point. Boiling point of water is 100^o C and that of alcohol is 78^o C. this means the intermolecular force of attraction between water particles is greater than that of alcohol.

Causes of conversion: when a liquid substance is heated, the heat energy make the particles vibrate vigorously. At boiling point the particles have sufficient kinetic energy to overcome the strong force of attraction which holds the particles of liquid together. This kinetic energy breaks the particles in individual units and thus the liquid evaporates to form gas.

3.      Liquid to solid (freezing):

The process in which a liquid substance changes into solid on decreasing the temperature is called freezing. Water freezes to form ice.

The temperature at which liquid substance freezes and changes into solid form at atmospheric pressure is called the freezing point of substance. Water freezes to form ice at 0^o C, so 0^o C is the freezing point of water.

Causes of conversion: when a liquid substance is cooled by lowering the temperature, the particles lose energy due to which they start moving slowly. When liquid is cooled enough till its freezing point, its each particle stop moving and vibrate about a fixed point. This is the point when liquid change and become solid.

Electron dot structure of alkane, alkene, alkyne

 Electron dot structure of alkane, alkene, alkyne

Let’s take the most simple alkane, alkene and alkyne to discuss their structure.

Structure of Ethane

Structure of Ethene

Structure of Ethyne 

Hydrocarbons, (alkane, alkenes, alkynes)

Hydrocarbons

Hydrocarbons are the organic compounds that are made up of carbon and hydrogen only.

Sources of hydrocarbons:

Hydrocarbons are obtained from petroleum or crude oil. Natural gas present above the oil deposits also contains hydrocarbons. All these are obtained from underground oil deposits by drilling oil wells.

Types of hydrocarbon

Basically there are three types of hydrocarbons: alkanes, alkenes, alkynes. These three hydrocarbons are grouped as saturated and unsaturated.

1.      Saturated hydrocarbons (alkanes)

2.      Unsaturated hydrocarbons (alkenes or alkynes)

Saturated hydrocarbons:

(Alkanes)

1.      Hydrocarbons in which carbon atoms are connected to each other by single covalent bonds are called saturated hydrocarbons.

2.      Name of these hydrocarbon end with “ane”.

3.      General formula of alkane is C_nH_2n+2.

4.      Single covalent bond is formed by sharing of one electron pair (two electrons) between two carbon atoms.

5.      The saturated hydrocarbons are very unreactive.

 Unsaturated hydrocarbon

(Alkenes and alkynes)

Hydrocarbons in which carbon atoms are connected to each other by double bond or triple bond are called unsaturated hydrocarbons.

Alkene

1.      Hydrocarbons in which carbon atoms are connected to each other by double bonds are called alkenes.

2.      Name of these hydrocarbon end with “ene”.

3.      General formula of alkane is C_nH_2n.

4.      Single covalent bond is formed by sharing of two electron pair (four electrons) between two carbon atoms.

5.      Simplest alkene is ethane. Its common name is ethylene.

Alkynes

1.      Hydrocarbons in which carbon atoms are connected to each other by triple bonds are called alkynes.

2.      Name of these hydrocarbon end with “yne”.

3.      General formula of alkyne is C_nH_2n-2.

4.      Single covalent bond is formed by sharing of three electron pair (six electrons) between two carbon atoms.

5.      Simplest alkyne is ethyne. Its common name is acetylene.

Alkyl Groups
The groups formed by the removal of one hydrogen atom from an alkane molecule is called an alkyl group. 

Types of organic compounds

 Types of organic compounds

1.      Hydrocarbons

2.      Haloalkanes (halogenated hydrocarbons)

3.      Alcohol

4.      Aldehyde

5.      Ketones

6.      Carboxylic acids

A brief discussion about the various organic compounds.

1.      Hydrocarbons: These are the compounds made up of hydrogen and carbon only. Example; methane, ethane

2.      Haloalkanes: The elements chorine, bromine, iodine are collectively known as halogens. When halogen group attaches to any hydrocarbon then these are called haloalkanes. These can be named as halogenated hydrocarbons. This group is denoted as –X, where X is Cl, Br, or I. Example; chloroethane, bromoethane.

3.      Alcohol: Alcohol atom is made when one oxygen atom and one hydrogen atom joins together. This is also known as alcoholic group or hydroxyl group. This group is denoted by –OH. Example; methanol, ethanol

4.      Aldehyde: Aldehyde group consist of one carbon atom, one hydrogen atom and one oxygen atom. This group is sometimes called aldehydic group. It is represented as      -CHO.  Example; methanol, ethanal

5.      Ketones: This group consist of one carbon and one oxygen atom. It is represented as –CO-. Example; propanone, butanone.

6.      Carboxylic acids: This group consist of one carbon, two oxygen and one hydrogen atom. Carboxylic acids are also called organic acids. This group is represented by       –COOH. Example; methanoic acid, butanoic acid.

Organic Compound

Organic Compound

All compounds of carbon are called organic compounds. Basically organic compounds consist of carbon and hydrogen, these are called hydrocarbons. Some organic compounds also contain oxygen.

1.      Organic compounds are covalent compounds, consist of covalent bonds.

2.      Organic compounds have low melting and boiling points.

3.      Generally they are non-conductors of electricity.

Why Organic compounds have low melting and boiling points?

These are covalent compounds having weak force of attraction between their molecules so they melt and boil at very low temperature.

Why are organic compounds generally non-conductors of electricity?

Since organic compounds are covalent in nature they do not contain ions, so they cannot conduct electricity.

Since Organic compound occur in all living things like plants and animals, earlier it was assumed that these carbon compounds are extracted from the living material be it plant or animal. Hence a “Vital Force Theory” was proposed. According to this theory all organic compounds can only be formed within a living body and hence a vital force that creates the living body was necessary for the formation of these compounds.

This vital force theory was disapproved by a scientist Friedrich Wohler in 1828. Wohler prepared Urea [CO(NH₂)₂], which is an organic compound in laboratory by an inorganic compound called ammonium cyanate (NH₄CNO). Thus it was proved that vital force theory was a misconception.

All carbon compounds are organic compound, but an exception to this is oxides, carbonates, hydrocarbonates and carbides. This is because their properties are very different from the basic organic compounds which are hydrocarbons and their derivatives.

Why a large number of organic compounds are available? 

There are a large number of organic compounds this is because

1.      Carbon atom can link to four other atoms a time, either carbon or other elements forming long chains or rings.

2.      Since the valency is four it can make covalent bond with many different elements like carbon(4), hydrogen(1), oxygen(2), nitrogen(3), sulphur, chlorine(1)

Buckminsterfullerene

Buckminsterfullerene

Buckminsterfullerene is an allotrope of carbon with 60 atoms of carbon joined together forming a hollow spherical structure.

Buckminsterfullerene: properties

1.      Dark, solid

2.      Neither hard nor soft

3.      Weight of buckminsterfullerene is 720.64 g mol

4.      It is a semiconductor

5.      When burned only carbon dioxide is released and no residue is left.

6.      Symbol is C₆₀

Buckminsterfullerene: structure

1.      Cluster of 60 carbon joined together to form small spherical molecule.

2.      Football shaped spherical structure arranged in hexagonal and pentagonal rings of carbon atoms.

3.      Hexagonal and pentagonal rings of carbon atom are interlocked with each other.

4.      One molecule of buckminsterfullerene consists of 20 hexagons and 12 pentagons.

GRAPHITE 

graphite is an allotrope of carbon used as electrode in cells, pencil lead and as lubricant.

Graphite: properties

1.      Greyish black opaque

2.      Soft and slippery to touch

3.      Lighter than diamond

4.      Good conductor of electricity

5.      When burned only carbon dioxide is released and no residue is left.

6.      Symbol is C

Graphite: structure

1.      Graphite crystals consist of layer or sheets of carbon sheet.

2.      Each carbon atom of graphite crystal is joined to three other carbon atoms by strong covalent bonds to form flat hexagonal rings.

3.      The various layer of graphite are quite far from each other so no covalent bonds exist between the layers. So the various layers are held together by Van Der Waals forces.

Why is graphite soft substance?

Since the various layers of carbon atoms in graphite are joined by weak Van Der Waals forces, so the layers can slide over each other. Due to this sheet like arrangement graphite is a soft substance

Why is graphite a good conductor of electricity?

In a graphite crystal each carbon atom is joined to three carbon atoms by covalent bonds. Thus only three electrons are used in bond formation and one electron is left free. This free electron helps in conduction of electricity. Due to presence of electrons graphite crystal conducts electricity.

Uses of graphite

1.      Since graphite is soft, powdered graphite is used as lubricant for fast machinery.

2.      Since graphite is non explosive or non volatile it can be used for lubricating machines that operate at high temperature.

3.      Graphite powder can be used as dry lubricant and when mixed with petro it can be used as graphite grease.

4.      It can be used for making carbon or graphite electrodes in dry cell and electric arcs.

5.      Carbon brushes of electric motor are made of graphite, because it is a good conductor of electricity.

6.      Graphite is used for making the cores of our pencils because of its soft nature.

Diamond

DIAMOND                                                                           

Diamond is an allotrope of carbon generally known for its use in jewellery.

Diamond: properties

1.      Transparent, colourless, Shiny, gleaming and has extreme brilliance

2.      Hard (hardest natural substance)

3.      Very heavy

4.      Does not conduct electricity

5.      When burned only carbon dioxide is released and no residue is left.

6.      Symbol is C

Diamond : structure

1.      Diamond crystal is a big molecule of carbon atoms

2.      Each carbon atom of a diamond crystal is arranged in form of regular tetrahedron, this is a tetrahedral arrangement of atoms.

Why is diamond very hard in nature?

Diamond crystals are made of carbon atom bonded by one another by a network of covalent bond making it very rigid. The rigid structure of diamond makes it a hard substance.

Why is the melting point of diamond very high (3500^o C)?

Lot of heat energy is required to bread the strong network of covalent bondin the diamond crystal.

Why is diamond a non conductor of electricity?

Carbon has 4 valence electrons, in diamond all the 4 valence electrons are engaged in making covalent bond. So, there are no free electrons left. Since there are no free electrons so it does not conduct electricity.

Why diamond shows extreme shine?

Diamond has an ability to reflect and refract light due to this diamond shows brilliance.

Uses of diamond

1.      Since diamond is extremely hard, it is used for cutting and grinding other hard matter. It is used in cutting instrument like glass cutter and rock drilling equipment.

2.      Diamond dies are used for drawing thin wires like tungsten filament of electric bulb

3.      Due to its shine it is used in jewelleries

4.      Sharp edge diamond are used by eye surgeon as tool to remove cataract

Synthetic diamond

Synthetic diamonds are diamond formed artificially. When pure carbon is subjected to high pressure and temperature diamond can be formed artificially.

Carbon and its compounds

Class X

Carbon and its compounds

Carbon is an element. It is a non-metal. All living thing, plant and animal are made up of carbon. These compounds made up of carbon are called organic compound. From The food substance we eat to the fibre we use all are carbon compounds. The fuels like LPG, kerosene, CNG, coal, petrol all are carbon compound. The various substances surrounding us are made up of carbon like wood, paper, rubber, plastic. So, it is a fact that we are surrounded by carbon and its compound.

Atomic number of carbon is 6. The number of electrons in carbon is 6. There are 2 electrons in the K shell of carbon atom. K shell is the innermost shell of an atom. The remaining 4 electrons are in the outer L shell.

Properties of carbon:

1.      Carbon is tetravalent

2.      Carbon form covalent bond

3.      Carbon posses the property of catenation

4.      Carbon burn in air to give carbon dioxide

Tetravalency: The outermost shell of a carbon atom contains 4 electrons. To gain inert gas configuration a carbon atom has to gain four electrons or it has to lose four electrons. Therefore the valency of carbon is 4 and it is called tetravalent.

Covalent bond: due to the tetravalent nature of carbon it is difficult to either remove 4 electrons or to add 4 electrons. Therefore it is obvious that to gain inert gain configuration carbon atom has to share 4 electrons. Since carbon always gain 8-electron configuration by sharing it forms covalent bond.

Catenation: property of carbon to form strong bonds by carbon atoms among themselves and with other elements is called catenation.

Carbon give carbon dioxide on burning: when carbon combines with oxygen it makes carbon dioxide.

Question: why carbon atoms form strong covalent bond?

The reason for formation of strong covalent bonds is the small size of carbon atoms. Due to small size, the nuclei hold the shared electrons for bond strongly, leading to formation of strong covalent bonds. Due to strong bonds these carbon compound they are very stable compounds.

Occurrence of carbon

Carbon occurs in nature in basically two forms:

Elemental form and combined form

Elemental form: the form in which carbon occur in free state that means elemental state. Diamond, graphite and buckminsterfullerene are the three forms that are available in nature

Combined form: carbon occurs in nature in form of compound. When carbon combine with oxygen, hydrogen and other elements present in nature then these are called carbon compound and this is the combined form of carbon. Example are CNG, petrol, coal, wood, carbonates, marble, cotton, grains etc.

Allotropy

The phenomenon in which an element exists in more than one physical form in nature is called allotropy. The various physical forms in which the element is available are called allotropes.

Allotropes of carbon are diamond, graphite, buckminsterfullerene, charcoal(amorphous).

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