Study Guides (380,000)
CA (150,000)
UW (6,000)
BIOL (1,000)
Final

BIOL130L Study Guide - Final Guide: Chon, Amylopectin, Amylose


Department
Biology
Course Code
BIOL130L
Professor
Dragana Miskovic
Study Guide
Final

This preview shows pages 1-3. to view the full 26 pages of the document.
Lab 1 7/13/2015 9:13:00 PM
Identification of Some Macromolecules
Tests based on structure and characteristics of molecules
Treatment controls: samples that are used to check if the experimental
conditions were set properly and/or if the experimental procedures were
followed
Positive Control: Sample that should give a positive result if everything
was set-up and done properly
Negative Control: Sample that should give a negative result if everything
was set-up and done properly
Time Points: If analyzing samples at different times need a control for
each time -> including time 0
Most abundant elements in living material are -> CHONPS
Biological macromolecules:
Carbohydrates
Lipids
Proteins
Nucleic Acids
Iodine Test:
Tests for presence of starch and glycogen
Negative control -> yellow colour
Positive control for starch -> blue-black colour (due to reaction
between amylose and iodine)
Positive control for glycogen -> reddish-brown colour (due to multi-
branched components reacting with iodine)

Only pages 1-3 are available for preview. Some parts have been intentionally blurred.

Starch -> found in plants -> polysaccharide of glucose molecules linked
together by glycosidic bonds
Glycogen -> found in animals -> polysaccharide of glucose molecules linked
together by glycosidic bonds
Differences between Starch and Glycogen:
Glycogen is larger in molecular weight than starch
Starch is mixture of amylose (unbranched, alpha 1->4 linkages)
and amylopectin (straight, alpha 1-4 linkages, and branched
sections, alphas 1->6 linkages)
Glycogen similar in structure to amylopectin but is more highly
branched
Starch has longer coiled areas -> more room for iodine to bind ->
darker colour
Observations:
Glucose -> negative
Glucose-1-phosphate -> negative
Maltose -> negative
Honey -> negative
Sucrose -> negative
Lactose -> negative
Glycogen -> positive
Starch -> positive
Protein -> negative
Beer -> negative
Distilled water -> negative
Benedict’s Test for Reducing sugars
Sample of solution is mixed with the Benedict’s solution and boiled
Negative control: Blue solution
Positive control: formation of precipitate with colour ranging from
yellow or green to red or brown

Only pages 1-3 are available for preview. Some parts have been intentionally blurred.

Benedict’s solution contains copper (II) ions -> reducing ends of
molecules reduce the copper (II) ions to copper (I) ions
The precipitate formed is the cuprous oxide formed when copper (I)
ions react with oxygen 4Cu+ + 2OH- + 2e- -> 2 Cu2O + 2H+ + 2e-
Sugars have two forms -> straight chain and ring form
In the straight chain form -> the presence of terminal aldehyde groups
(aldose) make a sugar a reducing one.
Ketoses are isomerized into aldoses due to the basic conditions of the
reaction
Observations:
Glucose -> positive
Glucose-1-phosphate -> negative
Maltose -> positive
Honey -> positive
Sucrose -> negative
Lactose -> positive
Glycogen -> negative
Starch -> negative
Protein -> negative
Beer -> positive
Distilled water -> negative
Biuret Test for Protein:
Alkaline conditions (10% NaOH)-> copper(II) ions react with
nitrogen atoms of peptide bonds of proteins forming a complex
Positive control: Violet colour
Negative control: Blue colour
Safety: NaOH can burn skin
Observations:
Glucose -> negative
Glucose-1-phosphate -> negative
Maltose -> negative
You're Reading a Preview

Unlock to view full version