Module 2: Elements of life

Question 1

Atom

Answer 1

Smallest unit of matter that retains all of the chemical properties of an element.

Question 2

Matter

Answer 2

Has mass and occupies space

Question 3

Four elements common to all living organisms

Answer 3

Carbon, hydrogen, oxygen, nitrogen (CHON)

Question 4

Atomic nucleus

Answer 4

Center of an atom, made of protons and neutrons

Question 5

Proton

Answer 5

Positively charged particle at the center of an atom

Question 6

Neutron

Answer 6

Neutral particle at the center of an atom

Question 7

Electron

Answer 7

Negatively charged particle around the nucleus of an atom

Question 8

Dalton/atomic mass unit

Answer 8

A single proton or neutron weighs about 1 amu. An electron weighs about 1/1800th amu

Question 9

Isotope

Answer 9

Forms of the same element with different numbers of neutrons – differ in relative atomic mass but not in chemical properties

Question 10

Valence shell

Answer 10

Outermost shell of any atom

Question 11

Valence electrons

Answer 11

Electrons in the valence shell

Question 12

Free electrons

Answer 12

Electrons outside of the valence shell

Question 13

Octet rule

Answer 13

Atoms tend to feel more stable when they have, or can pretend to have, 8 electrons in their valence shell

Question 14

Organic molecule

Answer 14

Contains carbon

Question 15

Hydrocarbon

Answer 15

Molecule consisting entirely of hydrogen and carbon

Question 16

Tetrahedron

Answer 16

3-dimensional object where all sides are triangles, like a pyramid with a triangular base. Carbon forms tetrahedral shapes

Question 17

Functional groups

Answer 17

Groups of atoms in a molecule that have distinctive properties

Question 18

Hydroxyl group

Answer 18

Oxygen bonded to hydrogen. When attached to C, turns the molecule into an alcohol. Polar

Question 19

Sulfhydryl group

Answer 19

Sulfur bonded to hydrogen. Polar

Question 20

Carbonyl group

Answer 20

Carbon double-bonded to an oxygen. The carbon is slightly positive, which makes it subject to nucleophilic attack

Question 21

Carboxyl group

Answer 21

Carbon double-bonded to oxygen and single-bonded to hydroxyl group. Tends to be acidic. Charged at the pH of most biological systems

Question 22

Amino group

Answer 22

One nitrogen bonded to two hydrogens. Tends to be basic. Polar. Charged at the pH of most biological systems

Question 23

Amino acid

Answer 23

Contains a carboxyl group and an amino group. Building blocks of proteins

Question 24

Methyl group

Answer 24

One carbon bonded to three hydrogens. Nonpolar

Question 25

Phosphate group

Answer 25

One phosphorus single-bonded to three oxygens and double-bonded to one oxygen. Generally acidic. Charged at the pH of most biological systems