BIO 111 ( First Test )

The mass number of an atom is 15 and its atomic number is 7. The atom probably has

8 neutrons

Propanol and isopropanol are isomers. This means that they have

Same molecular formulas but different chemical structures

What is the atomic difference between uranium-235 and uranium-238?

Uranium-235 has three fewer neutrons than uranium-238.

A(n) ______ forms when two atoms share electrons

covalent bond

Which of the following is a function that proteins routinely carry out in cells?

enzymatic activity transport of ions and molecules across membranes structural support and shape

The 'R' group in amino acids

is the variable among the 20 amino acids

What is the defining characteristic of an acid?

it donates hydrogen ions

Which property of the carbon atom makes it an ideal component of biological (organic) molecules.

it has a valence of 4

Which of the following is a carboxyl group?

-OH

An uncharged atom of phosphorus has an atomic number of 15 and an atomic mass of 31. How many electrons does phosphorus have?

15

What is the atomic mass of an atom that has 8 protons, 8 neutrons, and 8 electrons?

16

One strand of a DNA molecule includes a short sequence of bases 5'-ACCCGGTAC-3'. The complementary DNA strand would have the sequence

5'-TGGGCCATG-3'

Which of the following molecules would you expect to be hydrophilic?

A ionic compound, such as sodium chloride polysaccharide

What property of water molecules plays a role in water transport in plants?

Adhesion

Which of the following is true for all lipids?

At least some part of the molecule is hydrophobic

Which domains include only organisms with cells that do NOT contain a nucleus?

Bacteria and Archaea

A molecule with the chemical formula: C16 H32 O16 is probably

Carbohydrate

1. The smallest unit of life is a(n)

Cell

The two strands of a double-stranded DNA molecule are held together by

Hydrogen Bonds

What maintains the secondary structure of a protein?

Hydrogen bonds

What is the fundamental difference between covalent and ionic bonding?

In a covalent bond partners share electrons; in an ionic bond, one partner accepts electrons from the other

Which of these is not a lipid?

RNA

Glycogen is

a polysaccharide found in animals

A hypothesis is

a proposed explanation for a set of observations.

A nucleotide is composed of

a sugar, a phosphate and a base.

Partially charged atoms occur within large biological molecules only when

atoms within the molecule share electrons unevenly

Which of the two functional groups below are always found in amino acids?

carboxyl and amino groups

What is the term used for a change in a protein's three-dimensional shape or conformation which may occur when the protein experiences conditions (like temperature or pH) outside its tolerance rage?

denaturation

The short forms DNA and RNA stand for

deoxyribonucleic acid and ribonucleic acid respectively

Phospholipids are an important part of cell structure because they

form lipid bilayers such as the plasma membrane

Saturated fatty acids

have a higher ratio of hydrogen to carbon than do unsaturated fatty acids

Water molecules are bound weakly to other water molecules by __________bonds

hydrogen

The four main groups of biological molecules are

nucleic acids, proteins, carbohydrates and lipids

Which bonds are created during the formation of the primary structure of a protein?

peptide bonds

DNA is composed entirely of monomers referred to as _________, of which there are only ________ types that can appear in a DNA molecule.

phosphate groups, two

Which of the following is an example of an amphipathic molecule?

phospholipid

Within each water molecule, hydrogen and oxygen are held together by _____ covalent bonds

polar

The role of a control in an experiment is to

provide a basis of comparison to the experimental group.

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

quaternary

In order to be classified as an unsaturated fatty acid, a molecule must contain at least one___________________ between carbon atoms.

single covalent bond

What type of backbone structure is associated with nucleic acids, such as DNA?

sugar-phosphate