Does this pH value indicate a strong acid or weak acid? Lemon Juice - pH2
Strong acid
Does this pH value indicate a weak or weaker acid - pH3
Weak acid
Does this color indicate that there are more Hydrogen Ions or equal amounts of Hydrogen & Hydroxide Ions? pH 7
Equal amounts of Hydrogen Hydroxide ions. Neutral solution.
Does this pH value indicate a strong or weak base? pH 10
Weak base
Does this color indicate a weak or strong base? pH 11
Weak base
Does this pH value indicate a strong base or strong acid?
Strong base
Does this color indicate more Hydroxide Ions or Hydrogen Ions?
Hydroxide ions b/c there is more H20 present.
Phenolphthalein
An indicator that turns pink in a base
What happens when you blow Carbon Dioxide (CO2) into Phenolphthalein?
The Carbon Dioxide exhaled forms Carbonic Acid in the water. Which, in turn, Carbonic Acid neutralizes (colorless) the basic solution.
Measuring pH
pH is a measure of how acidic/basic water is. The pH of water determines the solubility (amount that can be dissolved in the water).
The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.
Dehydration Synthesis
When 2 monosaccharides combine and removes OH- from one sugar and an H+ from another sugar.
Dehydration Synthesis creates ?
Disaccharide. The removal of H2O, causes the sugars to link and create Disaccharide.
When we add a small amount of Phenolphthalein (used for measuring pH) to the solution: H2O & NaHCO3 - baking soda, what color does the solution change to?
Bright pink
lab 2* Measuring pH - what indicator was used?
Phenolpthalein
Lab 2* The indicator (Phenolpthalein) tests whether the solution is Acidic or Basic.
Indicator turns bright pink in a Basic Solution.
Indicator remains colorless in a Acidic Solution.
Benedict's Reagent contains what?
Sodium Citrate, Sodium BiCarbonate, & Copper Sulfate.
Polysaccharides & some Disaccharies (Sucrose - table sugar) are?
NOT reducing sugars
Benedict's Reagent is blue b/c?
The Copper Ions (Cupric)
Testing for Carbohydrates (sugars), using Benedict's test *lab3 (sec. 5.1)
When the Reagent is mixed with a solution containing Reducing Sugars & heated, a colorful precipitate will form at the bottom of test tube.
(Benedict's test) If no Reducing Sugar is present, the solution will...
Remain blue and not form a precipitate.
(Benedict's test) If a very small amount of Reducing Sugar is present, the solution will...
Produce a green precipitate.
(Benedict's test) If a low amount of Reducing Sugar is present, the solution will...
Produce a yellow precipitate.
(Benedict's test) If a moderate amount of Reducing Sugar is present, the solution will...
Produce a yellowish-orange precipitate.
(Benedict's test) If a high amount of Reducing Sugar is present, the solution will...
Produce an orange precipitate.
(Benedict's test) If an extremely high amount of Reducing Sugar is present, the solution will...
Produce a brick-red precipitate.
Iodine test is used to distinguish...
Starch from other Carbohydrates.
Lab 3 (sec. 5, p2)* Iodine-Potassium Iodide (I2KI), interacts with Starch, producing what color?
A bluish-blackish color
Lab 3 (sec. 5, p2)* Iodine-Potassium Iodide (I2KI), does NOT react with noncoiled Carbohydrates and remains what color?
Yellowish-Brown
Lab 3 (sec. 5, p2)* Which substances contained Starch?
Potato juice
the most simplest carbohydrates contain only
carbon (C), oxygen (O), and hydrogen (H)
The simplest form of carbohydrate molecules are the
Monosaccharides (simple sugars)
The end product of Photosynthesis in plants is
Glucose
Other common Monosaccharides other than Glucose are?
Fructose, Galactose, Ribose
A Disaccharide a.k.a. Double Sugars, is simply what?
Two Monosaccharides linked together = Disaccharides
Before more sophisticated methods were developed, Benedicts Reagent was used to test urine samples for diagnosing Diabetes Mellitus. What is present in the urine of individuals with diabetes?
Glucose is present in the urine.
Describe the color of clear diet soda, potato juice, and distilled water after the Iodine test?
Clear diet soda: Starch not present; orange. Potato juice: Starch present; brown. Distilled water: Starch not present; orange.
How do milk, corn syrup, and pineapple juice react in the Benedict's Reagent?
Significant amount of reducing sugar; orange-red precipitate (off-white/beige colors in lab)
5 examples of Reducing Sugars...
Maltose, Lactose, Melibiose, Cellonbiose, Gentiobiose
2 examples of NON-Reducing Sugars...
Sucrose, & Trehalose
Maltose consists of?
Glucose and Glucose
Lactose consists of?
Glucose and Galactose
Sucrose (table sugar) consists of
Glucose and Fructose
Carbohydrates are also found in the form of "many sugars" aka
Polysaccharides
a Polysaccharide composed only of Glucose subunits, especially abundant in plants
Starch
How many Amino Acids serve as the building blocks of Protein?
20
What is the proper way to move the revolving nosepiece a.k.a. Turret, on a microscope?
This is the part that holds two or more objective lenses and can be rotated to easily change power by either moving the nosepiece toward the stage or moving the stage toward the nosepiece.
The Biuret test is commonly used to detect.....?
The presence of a Protein.
The Biuret reagent is a blue-green color containing what?
1% Copper Sulfate (CuSO4), and Sodium Hydroxide (NaOH), or Potassium Hydroxide (KOH)
The Biuret reagent changes from blue-green to ---> what color when proteins are present?
Violet
Biuret reagent solution change in color, results from the interaction between_______ & _______?
Copper Ions, & the Peptide Bonds of the Protein. *More Peptide Bonds = darker solution color.
What is a Peptide Bond?
A Covalent Bond that forms between the Amino group of 1 Amino Acid and the Carboxyl group of another Amino Acid.
The Grease-Spot test is used?
To identify the Lipid nature of substances.
Glucose subunits are bonded together a third way in the Polysaccharide
Cellulose
While Starch and Glycogen are metabolized for _______. Cellulose (the most abundant Carbohydrate in the world) is......?
Energy. A structural molecule that is designed not to be metabolized
Cellulose makes up the?
Cell walls of plants & its the primary component of dietary fiber.
For most animals_______is completely indigestible. Those that can digest it such as________do so only with the assistance of Organisms such as________.
Cellulose. Termites and cows. Bacteria, Fungi and Protistans
Most Disaccharides and Polysaccharides can be broken down into their component Monosaccharides by a process called?
Hydrolysis
Hydrolysis is accomplished in organisms by?
Digestive Enzymes
Hydrolysis of Starch begins when the
Seed takes up water and begins to Germinate
When Barley is germinated, what happens?
Starch to Sugar conversion begins
In the breakdown of Starch, Disaccharide_________are formed before the final product,__________is obtained.
Maltose Molecules. Glucose.
The process of Germinating the barley is called?
Malting // Brewing beer
A chemical Hydrolysis can be done in the lab by?
Heating the Molecules with Acid in the presence of water
Using Iodine reagent I2KI - (Iodine Potassium Iodide) a dark blue color indicates?
The presence of starch
in lab the positive test for the iodine reagent I2KI - (iodine potassium iodide) turned what color
dark blue (high concentration of starch)
why does hydrolysis of starch take longer than hydrolysis of sucrose?
starch is a polysaccharide consisting of longer chains of glucose. Sucrose is a disaccharide with only the 2 (glucose and fructose) monosaccharides linked together
Lipids are grouped together solely on the basis of their
insolubility of water
Proteins work by?
Selectively binding to other molecules
In lab we use_______to test for proteins?
Biuret reagent
what negative control should be used for Biuret test?
water
limitations in the Biuret test
-there is a general progression, not just black and white
-only test if proteins are present, not detailed results of which proteins
-qualitative not quantitative
why might a plant storage organ (such as a fruit or tuber) contain both starch and sugar?
-both need to be metabolized for energy
-starch is how a plant stores glucose during photosynthesis, during germination it starts to break down its starch into simpler sugars to begin making ATP and therefore containing BOTH starch and sugar.
what subunits make up carbohydrates?
monosaccharides, disaccharides and polysaccharides
what subunits make up proteins?
amino acids
why is each test done initially using water as well as a known sample?
the water is used as a negative control. something to compare the sample to.
you have tested an unknown sample with Biuret and Benedict's. the solution mixed with Biuret is blue. the solution boiled with Benedict's is also blue. what can this tell you about the sample?
the sample is negative for protein and negative for simple sugars. the sample could be a lipid.
Whole butter gives only a slightly positive test for protein. when the butter is clarified the liquid lower layer is definitely positive for protein. why?
-Protein is water soluble and water is denser than the solution on top, making the lower liquid layer have a higher concentration of protein.
since potatoes have starch in them, why dont they taste sweet after they are boiled?
the starch in the potatoes only boiled in water wouldn't be hydrolyzed. they would need to be heated with acid for this to occur. Also even when hydrolysis is done on starch glucose does not taste sweet compared to fructose or galactose.
what does not interact with Iodine reagent? glucose, starch, maltose?
glucose and maltose
adding HCL and boiling your starch samples facilitates this chemical reaction
hydrolysis
the process in which the water soluble parts are separated out of butter
clarification
Benedict's test results
starch
Iodine test (I2KI reagent):
HYDROLYSIS - a chemical reaction used to break down polymers; a molecule is cleaved into two parts by the addition of H2O
Chemical hydrolysis -
heating the molecule with acid in the presence of H2O.
Hydrolysis and Dehydration
lipids are
insoluble in H2O (hydrophobic)
proteins: blue reagent turns
pink in the presence of smaller peptides or amino acids
Does this pH value have a strong acid level or weak?
Strong acid level: 0-3
positive control
contains the variable for which you are testing; reacts positively and demonstrates the the test's ability to detect what you expect
negative control
does not contain the variable for which you are searching and does not react in the test
dehydration synthesis
an energy requiring process in which a molecule of water is removed and the two subunits are bonded covalently
hydrolysis
an energy releasing process in which a molecule of water is added to break a bond between two subunits
monosaccharides
a simple sugar: glucose, fructose
What does Benedict's test test for?
reducing sugars
What color represents a positive result for Benedict's test?
green to reddish orange
What color represents a negative result for Benedict's test?
blue
Which of the tested solutions was a positive control for Benedict's test?
glucose
Which of the tested solutions was a negative control for Benedict's test?
distilled water
Which of the solutions is a negative control for the Iodine test?
distilled water
Which of the solutions was a positive control for the Biuret test?
protein
Which of the solutions was a negative control for the Biuret test?
distilled water
Which contains more protein, egg albumen or honey? How can you tell?
egg albumen, it is violet
What does the Sudan IV test test for?
lipids
What color represents a positive result for the Sudan IV test?
red with absorbed solution
What color represents a negative result for the Sudan IV test?
orange
Is salad oil soluble in water?
no
What solutions do we use the Sudan IV test for?
salad oil+water
salad oil+sudan IV
honey+sudan IV
distilled water+sudanIV
Does honey contain much lipid?
No
Which of the food products that we tested contains large amounts of lipid?
oil
Dehydration Synthesis is?
When 2 Monosaccharides combine and removes OH- from one sugar and an H+ from another sugar.
When we add a small amount of Phenolphthalein (indicator used for measuring pH) to the solution: H2O & NaHCO3(baking soda), what color does the solution change to?
Bright pink
Lab 2* Measuring pH - what indicator was used?
Phenolpthalein
Lab 2* The indicator (Phenolpthalein) tests whether the solution is Acidic or Basic. Explain.
(+): Indicator turns bright pink in a Basic Solution.
(-): Indicator remains colorless in a Acidic Solution.
How to test for Carbohydrates (sugars), using Benedict's test? *lab3 (sec. 5.1)
When the Reagent is mixed with a solution containing Reducing Sugars & heated, a colorful precipitate will form at the bottom of test tube. Test (+).
If no Reducing Sugar is present, the solution will...
Remain blue and not form a precipitate. Test (-).
If a very small amount of Reducing Sugar is present, the solution will...
Produce a green precipitate.
If a low amount of Reducing Sugar is present, the solution will...
Produce a yellow precipitate.
If a moderate amount of Reducing Sugar is present, the solution will...
Produce a yellowish-orange precipitate.
If a high amount of Reducing Sugar is present, the solution will...
Produce an orange precipitate.
If an extremely high amount of Reducing Sugar is present, the solution will...
Produce a brick-red precipitate.
glucose subunits are bonded together a third way in the polysaccharide
cellulose
while starch and glycogen are metabolized for 1), cellulose (the most abundant carbohydrate in the world) is a 2)
1) energy
2) a structural molecule that is designed not to be metabolized
cellulose makes up the
1)cell walls of plants
2) and its the primary component of dietary fiber
for most animals 1) is completely indigestible, those that can digest it such as 2) do so only with the assistance of organisms such as 3)
1) cellulose
2) termites and cows
3) bacteria, fungi and protistans
most disaccharides and polysaccharides can be broken down into their component monosaccharides by a process called
hydrolysis
hydrolysis is accomplished in organisms by
digestive enzymes
hydrolysis is important in
seeds (if the seed's food resource is starch, it must be able to convert starch to glucose)
hydrolysis of starch begins when the
seed takes up water and begins to germinate
germination of barley seeds is part of the process of
brewing beer
when barley is germinated the
starch to sugar conversion begins
in the breakdown of starch, disaccharide 1) are formed before the final product, 2), is obtained
1) maltose molecules
2)glucose
the process of germinating the barley is called
malting
a chemical hydrolysis can be done in the lab by
heating the molecules with acid in the presence of water
general test for small sugars (monosaccharides and disaccharides)
benedict's reagent
when 1) is mixed with a solution containing single or double sugars and then 2), a 3) forms
1)Benedict's reagent
2)heated
3)a colored precipitate (solid material) forms
the precipitate formed using benedict's regent may be 1) if no monosaccharide or disaccharide is present, the reaction mixture remains 2).
1)yellow, green, orange, or red
2)blue and clear
Benedict's reagent does not react with all small sugars for example:
sucrose (table sugar) made up of glucose and fructose
1) will be used in the lab to demonstrate a positive Benedict's test.
1)glucose (positive control)
what should be used as a negative control for Benedict's test?
Sucrose
observations for Benedict's test using glucose
bright orange
observations for Benedict's test using negative control
(sucrose) - remained blue
describe a positive Benedict's test
the solution has yellow, green, orange or red precipitate
what are the limitations of Benedict's test?
1)it does not react with all small sugars
2)the test is qualitative not quantitative which allows us to only detect the presence of a certain molecule.
3)also the test does not allow for us to determine which sample sugar is present
1) is tested by using 2)
1)starch
2) iodine reagent I2KI - (iodine potassium iodide)
using iodine reagent I2KI - (iodine potassium iodide) a 1) color indicates 2)
1) a dark blue color
2) the presence of starch
in the lab we used a 1) to demonstrate a positive test for iodine reagent I2KI - (iodine potassium iodide)
1)solution of potato starch
the color the negative control for iodine reagent turned: I2KI - (iodine potassium iodide)
orangey/yellow
limitations of the iodine reagent I2KI - (iodine potassium iodide)
1) only test for starch, not cellulose or glycogen
2)qualitative- only allowing us to test the presence of starch not amt. of substance
polysaccharides are long chains of monosaccharides. the bonds joining these subunits can be broken in a process called
hydrolysis
in lab we hydrolyzed 1) and 2) by 3)
1)sucrose
2)starch
3)heating them with acid (HCL)
what monosaccharides will result from the hydrolysis of sucrose?
glucose and fructose
what monosaccharides will result from the hydrolysis of starch?
glucose
hydrolysis of carbohydrates: the results obtained using the Benedict's test on the sucrose
The HCL (heating w/acid) catalyzed a hydrolysis reaction which broke down the sucrose into fructose and glucose monosaccharides which would both be detected by the Benedict's reagent, unlike sucrose.
1) are compounds that contain mostly Carbon (C) and Hydrogen (H)
Lipids
the lipids considered in this lab are 1) and 2)
1)fats
2)oils
fats and oils are generally used as
storage molecules in both plants and animals
fat is stored in your 1) until your food intake is lower than your metabolic needs , at which time fat can be metabolized to generate 2), whose energy can be used for 3)
1)adipose tissue
2)ATP
3)cellular work
plants store fats in their
seeds
in lab we use a 1) to indicate the presence of lipids in various foods.
grease paper test
the negative control for paper test
water
describe positive test for the paper test
a positive test shows a translucent color on the area where lipids are rubbed.
what are the limitations for the paper test?
-qualitative
-does not inform us the type of lipid that is present
-can easily be contaminated
a 1) structure is determined by the amino acid subunits that make up a molecule
protein
there are only 1) naturally occuring amino acids, each protein molecule has a 2) sequence
1) 20
2) unique
proteins have a 1) diversity of roles than either carbohydrates or lipids.
1) greater
the 1) of a protein is key to its purpose
1) shape
proteins work by
selectively binding to other molecules
Glycogen is a polymer composed of 1) subunits
glucose
briefly describe the Benedict's test for starch before and after hydrolysis
before: aqua (neg.)
after: orange (pos.)
what are the 4 classes of the largest biological molecules?
macromolecules or (polymers): (monomers)
1) carbohydrates (monosaccharides)
2) proteins (amino acids)
3) lipids (fatty acids)
4) nucleic acids (nucleotides)
cellulose is an example of 1) and enzymes are an example of 2)
1)structural
2)functional