Biology Chapter 3

Which of these functional groups is found in all amino acids? --PO42- --OH -=O --NH2

-NH2

All proteins can be made from varying combinations of ___________amino acids. -4 -20 -26 -100

20

What is another function of nucleic acids?

ATP (energy transfer)

Which of the following molecules is a carbohydrate? -C50H100O50 -C51H98O6 -C45H84O8P4 -C22H49O10N5

C50H100O50 (Carbohydrates have molecular formulas that are (or are very nearly) multiples of CH2O.)

Which of the following statements about carbon skeletons is true? -The length of carbon skeletons is always the same; it is the attachment of other chemical groups to the carbon skeletons that differentiates these molecules -Carbon skeletons are always linear and never branched. -Carbon skeletons may be arranged in rings. -Carbon skeletons only contain double bonds.

Carbon skeletons may be arranged in rings.

Which of the following is an example of a dehydration reaction? -Amylose, a polysaccharide, is broken down by amylase, an enzyme found in your saliva. -Casein, a type of protein found in milk, is broken down into amino acids by enzymes in the digestive tract. -A group of enzymes "cut" a mutated protein into smaller molecules, preventing it from harming the cell. -DNA molecules are replicated in a cell by building new DNA molecules from nucleotides.

DNA molecules are replicated in a cell by building new DNA molecules from nucleotides.

What is formed when two amino acids form a covalent bond? -H2O -O2 -two H+ -a triglyceride

H2O

Once you eat a cookie, enzymes in your digestive tract begin to break down the cookie into smaller molecules. Which two statements are true regarding this process? -Hydrolysis reactions are breaking the macromolecules in the cookie down into smaller molecules. -Dehydration reactions are breaking the macromolecules in the cookie down into smaller molecules. -Water is released during the reactions that break the macromolecules in the cookie down into smaller molecules. -Water is required for the reactions that break the macromolecules in the cookie down into smaller molecules.

Hydrolysis reactions are breaking the macromolecules in the cookie down into smaller molecules; Water is required for the reactions that break the macromolecules in the cookie down into smaller molecules.

What does the term amino acid signify about the structure of the molecule? -It consists of a carboxyl group only. -It consists of an amino group and a carboxyl group. -It will have an amino group as its only functional group. -It consists of an amino group and a carbonyl group.

It consists of an amino group and a carboxyl group.

Generally, animals cannot digest the linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass? -Cows make an enzyme in their saliva that hydrolyzes cellulose. -Cows and other herbivores are exceptions and make some cellulose-digesting enzymes in their digestive tracts. -Microorganisms in their digestive tracts hydrolyze the cellulose to glucose. -They have to eat a lot of grass.

Microorganisms in their digestive tracts hydrolyze the cellulose to glucose.

Which of these is NOT a lipid? -wax -cholesterol -RNA -phospholipid -steroids

RNA

How does DNA differ from RNA? -DNA has a sugar-phosphate backbone, RNA does not. -DNA contains adenine, RNA does not. -DNA is smaller, RNA is larger. -RNA contains ribose, DNA does not.

RNA contains ribose, DNA does not.

Two proteins have the same number and type of amino acids. How is it that they can have different shapes and therefore different functions? -The proteins were made in different locations in the cell. -The proteins have been chemically modified. -The sequence in which the amino acids are arranged differs between the two proteins. -The proteins were made at different times within the cell.

The sequence in which the amino acids are arranged differs between the two proteins.

In a hydrolysis reaction, __________. In this process, water is __________. -monomers are assembled to produce a polymer ... produced -a polymer breaks up to form monomers ... inserted -a polymer breaks up to form monomers ... produced -monomers are assembled to produce a polymer ... inserted

a polymer breaks up to form monomers ... inserted

Proteins are an important class of molecules because of the functions they perform. For example, proteins can _____. -form dietary fiber -act as signal receptors to receive signals in cell communication -store genetic information -form membrane bilayers

act as signal receptors to receive signals in cell communication

Manufacturers make vegetable oils solid or semisolid by _____. -adding hydrogens -adding chemicals to retard spoilage -chilling and refrigeration -adding animal fats to them

adding hydrogens

A(n) ______ is a building block of polypeptides, such as the protein hemoglobin.

amino acid

Lipids differ from other large biological molecules in that they _____. -are not truly polymers -do not have specific shapes -do not contain carbon -are much larger

are not truly polymers

A function of cholesterol that does not harm health is its role _____. -as a component of animal cell membranes -in calcium and phosphate metabolism -All of cholesterol's effects cause the body harm. -as the primary female sex hormone -the most abundant male sex hormone

as a component of animal cell membranes

Carbohydrates are mainly used in our bodies _____. -as structural molecules, such as hair and fingernails -for building genetic material -for membrane construction -as fuel

as fuel

glucose is to starch as ? a) a steroid is to a lipid b) a nucleotide is to a nucleic acid c) an amino acid is to a protein d) a polypeptide is to an amino acid

b) a nucleotide is to a nucleic acid

Which element is closely associated with the field of organic chemistry? -sulfur -potassium -nitrogen -carbon

carbon

What are some kinds of carbohydrate polymers?

cellulose, starch, glycogen, chitin

A ______ reaction builds polymers from monomers.

dehydration

The reaction that joins monomers to form a polymer is known as a _____ reaction. The molecule of water formed is due to the interaction between _____ and a hydrogen ion. -hydrolysis ... a carboxyl group -hydrolysis ... a hydroxyl group -dehydration ... a hydroxyl group -dehydration ... a carboxyl group

dehydration ... a hydroxyl group

A peptide bond is formed through a __________. -hydrolysis reaction between the two amino groups of two different amino acids -dehydration reaction between the amino groups of two different amino acids -dehydration reaction between the amino group of one amino acid and the carboxyl group of a second amino acid -hydrolysis reaction between the amino group of one amino acid and the carboxyl group of a second amino acid

dehydration reaction between the amino group of one amino acid and the carboxyl group of a second amino acid

A DNA nucleotide is composed of a __________. -deoxyribose sugar, which is bonded to a phosphate group and a nitrogenous base -deoxyribose sugar, which is attached to a phosphate group, which is bonded to a nitrogenous base -ribose sugar, which is attached to a phosphate group, which is bonded to a nitrogenous base -ribose sugar, which is bonded to both a phosphate group and a nitrogenous base

deoxyribose sugar, which is bonded to a phosphate group and a nitrogenous base

DNA has the appearance of a _____.

double helix

Of the following sugar molecules, which is not a disaccharide? -sucrose -fructose -lactose -maltose

fructose

A ______ reaction breaks down polymers into monomers.

hydrolysis

Dehydration reactions __________. They do so by __________. -link monomers to form a polymer; adding a water molecule -link monomers to form a polymer; removing a water molecule -remove monomers from polymers; adding a water molecule -remove monomers from polymers; removing a water molecule

link monomers to form a polymer; removing a water molecule

An individual subunit is called a ________ and many repeating subunits make up a ________.

monomer, polymer

A(n) ______ is a building block of polysaccharides such as starch.

monosaccharide

A(n) ______ is a building block of polynucleotides such as DNA.

nucleotide

DNA is composed of building blocks called _____.

nucleotides

Double bonds are present in the majority of the fats of which of the following foods? -lard -margarine -eggs -peanuts

peanuts

The lipids that form the main structural component of cell membranes are _____. -phospholipids -proteins -cholesterol -triglycerides

phospholipids

Cellulose is a _____ made of many _____. -carbohydrate ... fatty acids -protein ... amino acids -polypeptide ... monomers -polymer ... glucose molecules

polymer ... glucose molecules

A(n) ______ is a polymer of nucleotides.

polynucleotide

A(n) ______ is a polymer of amino acids.

polypeptide

DNA carries the instructions for building _____, and these instructions are found in informational units called _____. -steroids ... genes -carbohydrates ... libraries -polypeptides ... genes -lipids ... libraries

polypeptides ... genes

A(n) ______ is a polymer of monosaccharides.

polysaccharide

Which of the following foods would contain the most starch? -celery -potatoes -steak -liver

potatoes

A fatty acid containing at least one double bond is called _____.

unsaturated

When an RNA strand is constructed using DNA as a template, _____. -adenine pairs with cytosine and guanine pairs with thymine -uracil pairs with adenine and cytosine pairs with guanine -guanine pairs with adenine and thymine pairs with uracil -thymine pairs with cytosine and adenine pairs with guanine

uracil pairs with adenine and cytosine pairs with guanine

Polymers that contain sugars ... -(a) may store hereditary information. -(b) may store energy. -(c) may protect cells. -Both (b) and (c). -(a), (b), and (c).

(a), (b), and (c)