Biology 1, Chapter 5

The components of nucleic acids are __________.

a nitrogenous base, a pentose sugar, and a phosphate

Plant cell walls consist mainly of _____.

cellulose

The subunits (monomers) in cellulose are linked together by __________.

glycosidic linkages

Humans can digest starch but not cellulose because _____.

humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose

the secondary structure of a peptide backbone is stabilized by __________ forming either a(n) __________ or a(n) __________.

hydrogen bonds; α helix; β pleated sheet

One characteristic shared by sucrose, lactose, and maltose is that __________.

they are all disaccharides

Macromolecules, the molecules of life, include all of the following except __________.

trace elements

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?

5´-ATGC-3´ with 5´-GCAT-3´

Which of the following is a polymer?

Cellulose, a plant cell wall component

A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture __________.

DNA

Which of the following statements best summarizes the differences between DNA and RNA?

DNA nucleotides contain a different sugar than RNA nucleotides.

The flow of genetic information in a cell goes from _____.

DNA to RNA to protein

Which is the term for compounds that do not mix with water?

Hydrophobic

The sex hormones estrogen, progesterone, and testosterone belong to which class of molecules?

Lipids

Generally, animals cannot digest (hydrolyze) the glycosidic linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass?

Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units.

_________ is always involved in hydrolysis reactions.

Water

The peptide bond is __________.

a covalent bond joining amino acids together to form a polypeptide

Sickle-cell anemia is a disease that is caused by __________ in the __________ of the protein.

a single amino acid change; primary structure

Nitrogenous bases are classified as either purines or pyrimidines. Examples of purines are __________.

adenine and guanine

Protein molecules are polymers (chains) of __________.

amino acid molecules

Sugars have a(n) __________ group that interacts with a _________ group that forms ring structures when the dry molecule is placed in water.

carbonyl (-C=O); hydroxyl (-OH)

At a conference, the speaker's grand finale was sautéing mealworms (insect larvae) in butter and serving them to the audience. They were crunchy (like popcorn hulls) because their exoskeletons contain the polysaccharide __________.

chitin

The type of bond that forms to join monomers (such as sugars and amino acids) into polymers (such as starch and proteins) is a(n) __________ bond.

covalent

A polysaccharide that is used for storing energy in human muscle and liver cells is __________.

glycogen

The proper three-dimensional shape and folding of a protein is assisted by _________.

molecules called chaperonins

The building blocks or monomers of nucleic acid molecules are called _____.

nucleotides

The lipids that form the main structural component of cell membranes are __________.

phospholipids

The four main categories of large biological molecules present in living systems are _____.

proteins, nucleic acids, carbohydrates, and lipids

Which level of protein structure do the α-helix and the β-pleated sheet represent?

secondary

In a dehydration synthesis reaction, __________ is always formed as a by-product of the reaction.

water

When comparing saturated and naturally occurring unsaturated fats, the unsaturated fats have __________ and are __________ at room temperature.

cis double bonds; liquids

In living organisms, DNA exists as a __________ with the strand(s) __________.

double helix; running antiparallel

Carbohydrates are used in our bodies mainly for __________.

energy storage and release

The sequence of amino acids in a protein is called the __________ structure of the protein.

primary

The tertiary structure of a protein is the _____.

unique three-dimensional shape of the fully folded polypeptide

Which type of protein shields a newly forming protein from cytoplasmic influences while it is folding into its functional form?

Chaperonins

Sugars are molecules that have __________ C:H:O and are called __________.

a 1:2:1 ratio of; carbohydrates

The molecule with four fused rings that is found in animal membranes and is the precursor of vertebrate sex hormones is __________.

cholesterol

The tertiary structure of a protein includes all of the following interactions except _________ bonds.

peptide