Exam 1 Concepts

Question 1

What is science?

Answer 1

The use of objective, verifiable evidence to answer questions about the natural world.

Question 2

Scientific Method

Answer 2

Process by which scientists formulate a hypothesis, gather data by observation and experimentation, and come to a conclusion.

Question 3

Characteristics of Life

Answer 3

Organization, acquiring materials and energy, reproducing, growing and developing, being homeostatic, responding to stimuli, adaptation

Question 4

Element

Answer 4

Substance that cannot be broken down into substances with different properties; composed of only one type of atom.

Question 5

Atom

Answer 5

Smallest particle of an element that displays the properties of the element

Question 6

Isotopes

Answer 6

Atoms with the same atomic number but a different atomic mass due to a different number of neutrons.

Question 7

Compound

Answer 7

Substance having two or more different elements united chemically in a fixed ratio.

Question 8

Ions

Answer 8

Charged particle that carries a negative or positive charge.

Question 9

Ionic bonds

Answer 9

Chemical bond in which ions are attracted to one another by opposite charges.

Question 10

Covalent bonds

Answer 10

Chemical bond in which atoms share one pair of electrons.

Question 11

Polar

Answer 11

Combination of atoms in which the electrical charge is not distributed symmetrically.

Question 12

Hydrogen bond

Answer 12

Weak bond that arises between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another, or between parts of the same molecule.

Question 13

pH Scale

Answer 13

Measurement scale for hydrogen ion concentration; logarithmic scale. 0 = most acidic and 14 = most basic.

Question 14

Acid

Answer 14

Substances that dissociate in water, releasing hydrogen ions (H+); they raise the hydrogen ion concentration in a solution and lower its pH numerically.

Question 15

Bases

Answer 15

Substances that take up H+ or release hydroxide ions (OH-); they lower the hydrogen ion concentration in a solution and raise the pH numerically.

Question 16

Functions of each organic molecule

Answer 16

Carb: quick and short-term energy storage
Lipids: energy storage
Protein: support, enzymes, transport, defense, hormones, motion
Nucleic acids: store genetic information

Question 17

Dehyration and Hydrolysis Reaction

Answer 17

Dehyrdration: Chemical reaction resulting in a covalent bond with the accompanying loss of a water molecule.
Hydrolysis: Splitting of a compound by the addition of water, with the H+ being incorporated in one fragment and the OH– in the other.

Question 18

Mono, Di, and Polysaccharides

Answer 18

Mono: Simple sugar; a carbohydrate that cannot be decomposed by hydrolysis (e.g., glucose).
Di: Two monosaccharides combined by dehydration reaction (e.g., maltose).
Poly: long chain of monosaccharides (glycogen, cellulose/fiber)

Question 19

Function of triglycerides

Answer 19

As fats and oils, they are used for energy storage, heat insulation, protective cushion around organs, and synthesize phospholipids and steriods

Question 20

Uses of phospholipids and steriods

Answer 20

Phospholipids: cellular membranes
Steriods: sex hormones, membrane components

Question 21

Why not all lipids should be avoided in diet?

Answer 21

Lipids are essential for functions in organisms (energy storage, protection, membranes), so they should still be consumed in a certain amount

Question 22

Functions of proteins

Answer 22

Support, enzymes, transport, defense, hormones, motion

Question 23

Structure of an amino acid

Answer 23

Central carbon bonded to a hydrogen, an amino group, and acid group, and an R group

Question 24

Four levels of protein structure

Answer 24

Primary: sequence of amino acids
Secondary: alpha helix/pleated sheet
Tertiary: final shape of polypeptide
Quaternary: two or more associated polypeptides

Question 25

Structure of a nucleotide

Answer 25

Made up of a phosphate, a 5-carbon sugar, and a nitrogen containing base

Question 26

DNA and RNA structure and function

Answer 26

DNA: deoxyribose sugar, phosphate, nitrogen-containing bases; used to store genetic information and is more stable
RNA: ribose sugar, phosphate, nitrogen-containing base; used to synthesize proteins but is short-lived in the cell

Question 27

ATP as an energy carrier

Answer 27

ATP has the base adenosine and three phosphate groups. The last two phosphate bonds are high-energy and unstable, and release energy when broken.