Download Ch. 3 Molecules of Life – Practice Questions – Answer on a separate

Ch. 3 Molecules of Life – Practice Questions – Answer on a separate sheet of paper
Carbohydrates, Fats, & Proteins: For all three groups create a chart and answer the
following
-Which molecules react well with water - hydrophilic? Which molecules do not mix well with
water- hydrophobic?
-Which molecules are polar? Which are nonpolar?
-What are the monomers of each? How does the molecule progress to become a polymer?
-How does dehydration synthesis work to the build a polymer of each group?
-What kind of bond / elements are involved with each type of bond to make a polymer?
-How does hydrolysis work to break down the polymer of each group?
-What are examples of chemical formulas for each of the groups?
-What are the common and scientific names for each group?
-What substances below to what groups – for example starch, hormones, glycerol?
-What are the different functions of each group (carbohydrates for energy and so on)
-Which and how are these groups listed on a food label?
Chemistry
-What is the pH range of an acid, alklaline, and neutral?
-What are the chemical structures and chemical reactivity (water interaction, polarity, acid/base)
for each of the following functional groups: hydroxyl, carboxyl, amino, ketone, aldehyde,
phosphate.
-Use a chart to determine what food types are present based on lab data.
-Draw the isomers of C2H4O. What are the similarities and differences between isomers.
Carbohydrates
-Name three monosaccharides and three disaccharides as well as describe important functions.
-What are the different forms and functions of a polysaccharide?
Fats
-How can you tell the difference between a phospholipid and triglyceride?
-How can you tell the difference between saturated, monounsaturated, and polyunsaturated fats.
-Explain the health factors related to cholesterol and fat saturation.
Proteins
-Predict the reactivity of an amino acid based on it R-groups, 4 sub-groups.
-Draw the basic structure of amino acid as neutral and as a zwitter ion.
-What are the 4 types of protein structures? What mechanisms are in place to cause the shape at
each level.
-How would a row of amino acids form a secondary protein structure based on its functional
groups?
Essays
1. Be able to draw the isomers and stereoisomers of a given formula.
2. Draw and explain the dehydration synthesis between two given amino acids.
3. Draw and explain the hydrolysis of maltose.
ANSWERS For Ch. 3 Study Guide
Category
React with water
Carbohydrates
Hydrophilic
Fats
Glycerol – polar
Fatty acids- nonpolar
Polarity
Polar – OH groups
Monomers
Polymers
Monosaccharide polysaccharide
Glycerol – polar
Fatty acids- nonpolar
Glycerol & fatty acids
 triglyceride.
Dehydration
synthesis & bonds
Remove 1 water to
make a disaccharide
from 2
monosaccharides
Polysaccarides 
Monosaccharides
Remove 3 water
molecules to bind
glycerol with 3 fatty
acids
Triglyceride 
Glycerol + 3 fatty
acids
Glucose- C6H12O6
Gycerol- C3H8O3
Linoleic acidC18H32O2
fats, oils
1.Stored energy
2.Cell membranes
Hydrolysis
Chemical formula
examples
Common names/ food Sugars, syrups
Functions
1.Energy for body
2.Stored energy
Food Label
Carbohydrates,
sugars
Fats, saturated,
cholesterol
Proteins
Amino acids – depends
on R group:
hydrophobic /
hydrophilic / acid /
base
Amino acids – polar
ion
Amino acids 
polypeptide chains 
primary, secondary,
tertiary, quarternary
Remove 1 water
molecule to make a
peptide bond
4th structure 3rd
structure  2nd
structure
polypeptide chain 
amino acids
Serine- C3H7NO3
meats, legumes
1.Structures- hair,
muscle, tissues
2.Hormones &
enzymes
Proteins
Chemistry
-What does it mean to be an organic molecule? Has carbon and hydrogens
-What is the pH range of an acid, alklaline, and neutral? Neutral – 7, Acid 0-7, Alkaline / base 714
-What are the chemical structures and chemical reactivity (water interaction, polarity, acid/base)
for each of the following functional groups: hydroxyl, carboxyl, amino, ketone, aldehyde,
phosphate, nitrogen with lone pair electron.
Hydroxyl- hydrophilic, polar
carboxyl-hydrophilic / acidic,
amino- alkaline /
hydrophilic,
ketone- hydrophilic/polar
aldehyde-hydrophilic/ polar phosphatepolar / hydrophilic,
nitrogen with lone pair electron- alkaline /polar
-Use a chart to determine what food types are present based on lab data.
-Draw the isomers and stereoisomers of C2H4O. What are the similarities and differences between
isomers and stereoisomers.
Carbohydrates
-Be able to identify alpha and beta glucose and fructose forms.
Glucose - has a six carbon ring structure; fructose has a 5 carbon ring structure. For
galactose the Hydroxyl group on the 4th carbon is up; at carbon 4 OH is down in glucose. –
Sucrose- table sugar (glucose +fructose), lactose milk sugar (galactose+glucose), Maltosemalt sugar )glucose+glucose) all have 2 rings.
What are the different forms and functions of a polysaccharide
Glycogen- branched chain stored energy for glucose
Cellulose- structural support in stems of plants
Starch- complex sugar food source found in potatoes, rice, and corn
Fats
-How can you tell the difference between a phospholipid and triglyceride?
Phospholipids have two fatty acid tails and a phosphate in the glycerol– triglycerides have
three fatty acid tails
-How can you tell the difference between saturated, monounsaturated, and polyunsaturated fats.
Saturated- have no C=C double bonds and all C are saturated with H atoms.
Monounsaturated- have one C=C double bond, and polyunsaturated has two or more C=C
bonds.
-Explain the health factors related to cholesterol and fat saturation.
Saturated fats and LDL cholesterol lead to clogged arteries. Unsaturated fats and HDL are
healthier choices of fats for a human diet.
Proteins
-Predict the reactivity of an amino acid based on it R-groups, 4 sub-groups.
1. Non-polar, hydrophobic – not interact due to carbons all full of hydrogens
2. Polar, hydrophilic- interacts in water due to the hydroxyl group
3. Acidic- the carboxyl group will release a H+ ion when in water – increasing the pH
4. Alkaline- the nitrogen with a lone pair of electrons will pull a hydrogen ion to it when in
water – increasing the pH of water (more OH- than H+)
-Draw the basic structure of amino acid as neutral and as a zwitter ion.
-What are the 4 types of protein structures? What mechanisms are in place to cause the shape at
each level. See notes: Primary- polypeptide; Secondary-alpha helix and beta-pleated sheets;
Tertiary- Ionic bonds, sulfur bridges, hydrophobic reactions, hydrogen bonds;
Quarternary- multiple amino acids form protein structure.
-How would a row of amino acids form a secondary protein structure based on its functional
groups? See above 4 types of amino acids. Hydrophobic on inside, hydrophilic on outside.