Chapter 3: The Chemical Basis of life II: Sections 3.4 Carbs & Lipids

in what organisms are starch and glycogen found?

Starch is found in plants and glycogen is found in animals.

What is the function of waxes?

They prevent water loss.

Which type of fatty acid contains one or more C=C double bonds?

Unsaturated fatty acid

A phospholipid molecule consists of

a head that is polar and hydrophilic, and two tails that are nonpolar and hydrophobic.

How are fats synthesized?

dehydration synthesis links three fatty acids to glycerol

The C=C double bonds in fatty acids introduce a(n) ____ into the linear shape of the fatty acid chain.

kink

Which of the following glycosidic linkages occur in cellulose?

β-1,4 glycosidic linkages

What type of monomers are combined to form carbohydrates?

Monosaccharides

How do cells obtain energy from glucose?

By breaking its bonds and using the energy they store to build ATP

What are the four categories of macromolecules?

Carbohydrates, lipids, proteins, and nucleic acids

Pentose sugars have_____ carbon atoms, and hexose sugars have _____carbon atoms.

5 6

What is a fatty acid?

A chain of carbon and hydrogen atoms with a carboxyl group at one end

Which of the following describes the chemical structure of steroids?

Four fused rings of carbon with one or more attached hydroxyl groups

How does the branching of chains of glucose influence the solubility of polysaccharides?

More extensive branching of glucose increases solubility in water.

Why do phospholipids arrange into bilayers? Select all that apply.

The bilayer is the most energetically favorable arrangement in aqueous solution. The hydrophilic ends attract water while the hydrophobic ends exclude water.

What are sources of variation in lipid molecules?

The length of the the fatty acids and presence of double bonds

What type of lipid consists of long structures resembling fatty acids attached to each other by their carboxyl groups?

Wax

Cells extract ______from glucose by breaking its bonds.

energy

chain of carbon and hydrogen atoms with a carboxyl group at one end is called a:

fatty acid

Starch, glycogen, and cellulose are all polymers of the monosaccharide

glucose

The most common hexose is

glucose

A phospholipid consists of a

glycerol attached to two fatty acids and a phosphate group.

Fats, or triglycerides, are composed of:

glycerol covalently bound to three fatty acids

Unsaturated fats have melting points than saturated fats.

lower

What type of organic molecule can assume both a linear or ring form?

monosaccharide

Carbohydrate monomers are known as

monosaccharides

Glucose and galactose are examples of:

monosaccharides

A monosaccharide with five carbon atoms is called a(n)______ sugar, and a monosaccharide with six carbon atoms is called a(n)_______sugar. Listen to the complete question

pentose;hexose

In living things, starch is found in cells and glycogen is found in certain types of cells.

plant; animal

What are the two major structural components of phospholipids that make them amphipathic?

polar phosphate group nonpolar fatty acids

Phospholipids are amphipathic because they contain both________ and ______groups.

polar; nonpolar

What are the two possible shapes formed by monosaccharides such as glucose?

ring linear

During the synthesis of a triglyceride, what is attached to glycerol in each dehydration reaction?

A fatty acid

What type of bond forms between two sugar molecules?

Glycosidic bond

Carbohydrate polymers are called:

polysaccharides

The chemical structure of all_________ consists of four fused rings of carbon atoms with one or more polar hydroxyl groups attached to the ring structure.

steroids

Match each polysaccharide with its function in living organisms.

Cellulose -- Cell wall of plants Starch -- Energy storage in plants Glycogen -- Energy storage in animals Chitin -- Exoskeleton of insects and crustaceans and the cell wall of fungi Exoskeleton of insects and crustaceans and the cell wall of fungi Glycosaminoglycan matches -- Extracellular matrix and cartilage of animals

Which of the following accurately describes the function of cellulose, starch, and glycogen in cells?

Cellulose is used for structural purposes while starch and glycogen are used for energy storage.

Which of the following is a precursor of all steroid hormones?

Cholesterol

Where are the complex lipids called waxes typically found?

Cuticles of insects and leaves of plants

What type of chemical reaction occurs when a glycosidic bond forms between two monosaccharides?

Dehydration

Which of the following sugars are pentoses?

Deoxyribose Ribose

How does the presence of a double bond influence the shape of a fatty acid?

Double bonds between carbon molecules introduce kinks in the otherwise linear structure of fatty acids.

Which of the following is the steroid hormone found primarily in females?

Estrogen

How can fats provide protection for mammals in cold weather?

Fats under the skin can provide insulation to protect against cold.

What feature of fats allows them to store high levels of energy?

Fatty acids contain long chains of C-H bonds.

How do fatty acids found in fats and other lipids differ from one another?

Fatty acids differ in the presence or amount of double bonds. Fatty acids differ in length of the hydrocarbon chain.

Which of the following are common monosaccharides found in nature?

Fructose Galactose Glucose

Which sugar monomer forms the polysaccharides starch, cellulose, and glycogen?

Glucose

Rank the following polysaccharides of glucose in order of most branched form (at the top of the list) to least branched form (at the bottom of the list).

Glycogen Starch Cellulose

What type of chemical reaction can break down a polysaccharide into monosaccharides?

Hydrolysis

What are the functions of fats in living organisms?

Insulation Energy storage Support cushion for organs

Glucose can exist as either _______-glucose or _______-glucose, which are enantiomers.

L D

What are the two enantiomers of glucose?

L-glucose and D-glucose

What are the four categories of macromolecules?

Lipids Carbohydrates Proteins Nucleic Acids

What feature of lipid molecules makes them insoluble or poorly soluble in water?

Lipids are nonpolar molecules.

Arrange these carbohydrates in order of increasing size, from smallest to largest, with the smallest at the top of the list.

Monosaccharide Disaccharide Polysaccharide

Match each type of carbohydrate with the number of sugar monomers it contains.

Monosaccharide-- One monomer Disaccharide-- Two monomers Polysaccharide--Many monomers

Polysaccharides can be hydrolyzed in the presence of water. What is the product of this reaction?

Monosaccharides

Fats consist of three fatty _______ covalently bonded to a three-carbon molecule called _____

acids;glycerol

Saturated fats are typically found in __________, and unsaturated fats are more commonly found in _____

animals; plants

In an aqueous environment, phospholipids form lipid ________with hydrophobic ends facing the interior because this is energetically most favorable for these molecules.

bilayers

Where is cholesterol commonly found in animals?

blood plasma membranes

Lipids are molecules that are composed of primarily what two elements?

carbon hydrogen

What are the three atoms found in all carbohydrates?

carbon oxygen hydrogen

The amount of energy a fat contains is determined by how many bonds it has between ____atoms and ____ atoms.

carbon ; hydrogen

Which elements are the primary components of lipids?

carbon and hydrogen

The three chemical elements that are found in all carbohydrates are ____, ____, and ______

carbon; hydrogen; oxygen

All steroid hormones are derived from ______

cholesterol

The steroid molecule called_______ is commonly found in the cellular membranes of animals.

cholesterol

Which of the following are common steroids?

cholesterol testosterone estrogen

Most unsaturated fatty acids found in nature are in______ the form while those that are manufactured are in the______ form.

cis ; trans

Most unsaturated fatty acids found in nature are in the _____while those that are manufactured are in the ____form.

cis; trans

What three polysaccharides play a structural role in organisms?

glycosaminoglycans cellulose chitin

The covalent bond formed between two monosaccharides by a dehydration reaction is called a(n) _______ linkage.

glycosidic

Compared to unsaturated fats, saturated fats:

have a higher melting point pack together more tightly

In a phospholipid bilayer, the _______regions of the phospholipids face water and the______ regions face the interior of the membrane away from water.

head; tail

More extensive branching of glucose chains exposes hydrophilic hydroxyl side groups that can form ______ bonds with water, which in turn ______ their solubility in water.

hydrogen; increase

Glucose exists in two forms, called alpha and beta, which differ in the position of the ______ group attached to carbon number 1.

hydroxyl

Lipids are nonpolar molecules that are

insoluble in water.

When many monosaccharides are linked together, they form long carbohydrate polymers called

polysaccharides

A fatty acid with two or more C=C bonds is a(n) ____fatty acid.

saturated

Typically, fats found in animals (usually solid) are _______fats while fats found in plants (usually liquid) are _________fats.

saturated ; unsaturated

Waxes are typically:

secreted onto the surface of an organism

Cholesterol, estrogen, and testosterone are examples of:

steroids

The chemical structure of all _________consists of four fused rings of carbon atoms with one or more polar hydroxyl groups attached to the ring structure.

steroids

Starch and glycogen are used for ______ in living cells.

storing energy

The hormone found primarily in males is

testosterone

The major classes of lipids are _______,________, steroids, and waxes.

triglycerides or fats; phospholipids

Oils are fats that are high in _____ fatty acids.

unsaturated

A(n)______ fatty acid contains one or more C=C double bonds. A(n) _____fatty acid contains no C=C double bonds.

unsaturated; saturated

A long hydrocarbon chain resembling a fatty acid attached by its carboxyl group to another long hydrocarbon chain is best described as a(n)_____

wax

Lipids called_______ help to prevent water loss from organisms.

waxes

Which of the following glycosidic linkages occur in starch and glycogen?

α-1,6 glycosidic linkages α-1,4 glycosidic linkages

What changes occur during the formation of a glycosidic bond?

A hydroxyl group is removed from one monomer, and a hydrogen atom is removed from the other monomer. Two monosaccharides are linked together by the removal of a hydroxyl group from one monosaccharide and a hydrogen atom from the other. When two monosaccharides form a glycosidic bond, there is a net yield of one molecule of water.

What are the two isomers of glucose that differ in the placement of the hydroxyl group attached the number 1 carbon atom?

Alpha-glucose and beta-glucose

What is the chemical formula of glucose?

C6H12O6

A fatty acid that is polyunsaturated contains two or more

C=C bonds.

Which of the following accurately describes oils, such as olive oil?

Oils have low melting points and are liquid at room temperature. Oils are fats high in unsaturated fatty acids.

What type of sugar are ribose and deoxyribose?

Pentose

Select all the parts that make up the polar hydrophilic region of a phospholipid molecule.

Phosphate group Charged nitrogen-containing region Glycerol backbone

What type of lipid consists of a molecule of glycerol attached to one phosphate group and two fatty acids?

Phospholipid

Which polysaccharides are used for energy storage in cells?

Starch Glycogen

Which regions of a phospholipid bilayer face water and which face the interior of the membrane away from water?

The polar regions face water, and the nonpolar regions face the interior.

What is the function of the polysaccharides cellulose, chitin, and glycosaminoglycan?

They provide structural support for cells and organisms.

Which form of unsaturated fatty acids are created during manufacturing processes and pose a risk to human health?

Trans unsaturated fatty acids