Bio 101: Macromolecules : Structure/Function Mastering

Lactase deficiency is more common in Asian, Native American, Mediterranean and some African populations than it is among people with northern or western European ancestry. How would you explain why this is so?

Although most mammals, including humans, are not able to digest the milk sugar, lactose, after infancy, the ancestors of northern and western Europeans relied on dairy products as an important part of their food supply. When other food sources were in low supply, mutations that allowed the expression of the enzyme lactase to persist past childhood conveyed an advantage to adults who were able to include dairy products in their diet. (The ability of adults to digest lactose is a result of a mutation related to the enzyme lactase. Lactose-tolerant adults make lactase. Lactose-intolerant adults do not make lactase.)

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 order in which the amino acids are arranged differs between the two proteins ( It is the sequence and arrangement of the 20 amino acids that determines the shape of a protein and thereby the function. Different sequences can yield different proteins.)

A glucose molecule is to starch as __________.

a nucleotide is to a nucleic acid (Nucleotides are the monomers that make nucleic acids, just as glucose is the monosaccharide from which starch is constructed.)

Glycogen is_____.

a polysaccharide found in animals ( animals store energy in the form of glycogen)

The oil and vinegar in your salad dressing remain separate from one another due to the _____ properties of the oil.

hydrophobic ( Oils and other fats are water-fearing or hydrophobic and will not dissolve in water-based solutions such as vinegar.)

Peptide bonds

link amino acids

Cholesterol belongs to which class of molecules?

lipids ( Steroids, such as cholesterol, are lipids characterized by a carbon skeleton consisting of four fused rings.)

glucose + glucose —> _____ by _____.

maltose + water ... dehydration synthesis ( Maltose is the disaccharide formed when two glucose molecules are linked by dehydration synthesis.)

Which of these is a source of lactose?

milk ( lactose is the sugar found in milk)

Which of the following characteristics of a protein will remain intact if the protein is denatured?

the number of amino acids in the protein

The tertiary structure of a polypeptide refers to

the overall three-dimensional structure

Part complete Lactose is a disaccharide (two monosaccharides joined together). To metabolize lactose, individuals require an enzyme known as lactase. What is true about this reaction?

the reaction hydrolyzes the sugar ( is hydrolyzed, or spilts, into two monosaccharide subunits)

Proteins differ from one another because

the sequence of amino acids in the polypeptide chain differs from protein to protein.

The partial charges in this water molecule occur because of _____.

the unequal sharing of electrons between hydrogen and oxygen(Because oxygen is more electronegative than hydrogen, electrons of the polar bond spend more time closer to the nucleus of the oxygen atom, resulting in a slight negative charge on the oxygen atom and slight positive charges on the hydrogen atoms.)

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

unsaturated ( an unsaturated fatty acid has one or more double bonds.)

Which of the following describes a covalent bond?

Two or more atoms share electron pairs ( occur when two or more atoms share one or more pairs of electrons.)

All proteins can be made from varying combinations of ___________amino acids.

20 ( all with different properties)

Many names for sugar end in the suffix

-ose

How are ionic bonds formed?

In ionic bonds, one atom gives up an electron to a second atom. ( For example, CaCl2 (calcium chloride) is formed by the give and take of electrons. Calcium gives up 2 electrons, and each chlorine atom absorbs an electron.)

Which of the following statements regarding lactose tolerance is true?

Lactose tolerance has evolved independently in multiple different human populations. ( Lactose tolerance arose independently in Europe, in multiple places in East Africa, and likely elsewhere.)

a hydrogen bond is ______.

a weak interaction between two molecules ( involve polarity, or polar interactions. they are weak chemical bonds that are very important in the chemistry of life)

This diagram shows a chemical reaction in which two glucose molecules combine to form a molecule of maltose.

a) monosaccharide b) dehydration reaction c) disaccharide d) OH e) H f) H2o

Can you label the atoms, partial charges, and types of bonds associated with these water molecules?

a)H atom b)O atom c ) H atom d) (+) charge e) (-) charge f)hydrogen bond g) polar covalent bond

Carbohydrates are mainly used in our bodies _____.

as fuel ( simple sugar molecules are major fuel for cellular work.)

_____ is the most abundant organic compound on Earth.

cellulose ( a component of plant cell walls, is the most abundant organic compound found on earth.)

Which of these is a polysaccharide?

cellulose ( is a carbohydrate composed)

Look at the table shown below. When referring to bonds, the symbol = means that the bond is a(n) _____.

double covalent bond ( The double line indicates that the atoms are sharing two pairs of electrons.)

of the following sugar molecules, which is not a disaccharide?

fructose ( is a monosaccharide, not a disaccharide)

The storage form of carbohydrates is ________ in animals and ________ in plants.

glycogen; starch

A diet high in animal products and hydrogenated vegetable margarine may increase the risk for heart disease. This is because

most animal fats are saturated and many hydrogenated vegetable margarines contain high levels of trans fats.

A hydrogen atom has one electron. How many covalent bonds can hydrogen form?

one

in a water molecule, hydrogen and oxygen are held together by a _____ bond

polar covalent

The atoms in the molecule of water shown below are held together by which type of bond? (slightly negative and slightly positive)

polar covalent bond (The hydrogen and oxygen atoms do not equally share their electrons, which results in the formation of electronegative oxygen atoms and electropositive hydrogen atoms. These are then able to interact with other water molecules to form hydrogen bonds.)

A protein containing more than one polypeptide chain exhibits the ________ level of protein structure.

primary, secondary, tertiary, and quaternary structure

Which meal is high in fiber, low in saturated fats, and high in unsaturated fats?

spaghetti noodles with olive oil and broccoli

When you eat a plant, you derive energy from the stored __________, but not from the __________ component.

starch... cellulose ( The starch is ultimately hydrolyzed into glucose, which can be used for energy, while the cellulose comprises the insoluble fiber passing through your digestive tract unchanged.)

The primary structure of a protein is

the amino acid sequence of the polypeptide chain

Amino acids can be distinguished from one another by

the chemical properties of their R groups.