Lab#1

Microscope

• Eyepiece: where you look through to see the image.

• Body tube: long tube that holds the eyepiece and connects it to the objectives

• Nosepiece: the rotating part of the microscope at the bottom of the body tube; it holds the objectives

Microscope

• Objective lenses: (low, medium, high, oil immersion) – 2, 3 or more objectives – they vary in length (the shortest is the lowest

power or magnification; the longest is the highest power or magnification).

Microscope

• Arm-part: – That carry the microscope with.

• Coarse adjustment knob– large, round knob on the side of the microscope– used for focusing the slide

• Fine adjustment knob– small, round knob on the side of the microscope – used to fine-tune the focus after using the coarse

adjustment knob

Microscope

• Stage:– large, flat area under the objectives – it has a hole in it (that allows light through) – the slide is placed on the stage for viewing

• Condenser:– Consists of the condenser lens, iris diaphragm and filter

holder – Diaphragm controls the amount of light

• light source: – usually found near the base of the microscope light

source

Starch

• Polysacchride

• Occurs in granules(diff. sizes,shapes)

• Almost in all organs (roots, rhizomes, fruits& seeds)

Physical properties

• Solubility:-Cold water suspension-Hot water gelatinization-Organic solvents( CHCl3, pet ether,

benzene) insoluble-Chloral hydrate soluble• Reaction with iodine:-I2+ starch solution blue color

white starch ( blue color disappears )-Not a chemical reaction

cold Evap.

Chemical properties

-Doesn’t reduce fehling solution) Being a polysaccharide)

- Fehling solution+ monosaccharide +ve test

- Starch +v test with fehlinghydrolysis

Chemical properties

Reduction of fehling reagent by monosaccharide:

• Hydrolysis of starch by dil. Acid (fehling solution work in alkaline medium)

• Neutralization by dil NaOH then alkalinization by excess of NaOH

• Equal volume of fehling A&B +starch sol any change in color +ve test

30 min

15 min W.B

Chemical properties

Molishes test:

• +ve result with any compound containing sugar part

• Starch solution + alcoholic naphthol drops on wall by conc H2SO4 violet ring

Microscopical examination

• Potato, wheat, maize, rice

• All have same physical & chemical properties but under microscope the granules have different sizes and shapes

Microscopical examination

Potato :• Shape: oval

• Hilum: droplet seen as a point (accentric)

• Striation: present

• Aggregation: simple

Microscopical examination

Wheat:• Shape: lenticular

• Hilum: as a point faint centric

• Striation: present

• Aggregation: simple

Microscopical examination

Maize:• Shape: polyhydral

• Hilum: present radial

• Striation: not present

• Aggregation: semicompound

Microscopical examination

Rice:• Shape: polyheadral

• Hilum: not present

• Striation: not present

• Aggregation: compound