ch. 4

Question 1

98% of the mass of living organisms consists of just six elements:

The most abundant compound in cells is ?

Answer 1

hydrogen, oxygen, nitrogen, phosphorus, sulfur, carbon

water

Question 2

name the 4 organic macromolecules:

Answer 2

lipids, nucleic acids, proteins, carbs

Question 3

an ? consists of a ? charged nucleus that contains protons and neutrons surrounded by ? charged electrons; they make up molecules

Answer 3

atom, +, -

Question 4

an ? is the type of atom; it is a substance composed entirely of one specific type of atom

Answer 4

element

Question 5

the atomic number identifies the number of ?, which is the property that defines an element

Answer 5

protons

Question 6

the ? number = sum of protons & neutrons

Answer 6

mass

Question 7

the ? ? average mass number of the isotopes of an atom

Answer 7

atomic weight

Question 8

? are versions of the same element that have the same number of protons but different numbers of ? in their nuclei.

Answer 8

isotopes, neutrons

Question 9

?-? is the time it takes for half of a radioactive substance to decay into a different substance

Answer 9

Half-life

Question 10

? are regions around an atom’s nucleus where electrons are most likely to be found

Answer 10

orbitals

Question 11

Atoms that share electrons form a ?

Answer 11

molecule

Question 12

The sharing of ? between two atoms is called a covalent bond

Answer 12

electrons

Question 13

A molecular formula is a shorthand notation indicating the ? and ? of atoms present in a ?.

Answer 13

number, type, molecule

Question 14

A ? formula is a way of representing a molecule that shows how the atoms are arranged and ? to each other.

ex. H-O-H > gives water the name H₂O.

Answer 14

structural, bonded

Question 15

? are atoms or molecules that have gained or lost electrons, giving them an ? charge; charged particles

positive ions:
negative ions:

Answer 15

ions, electric, cations, anions

Question 16

? are charged particles (ions) that help conduct electricity in the body. They are vital for ?, nerve signals, and ? function.

Answer 16

electrolytes, hydration, muscle

Question 17

a bond or charge attraction between anions and cations is called an ? ?

Answer 17

ionic bond

Question 18

? bonds occur when two atoms share electrons equally

? bonds happen when electrons are shared unevenly, resulting in a partial positive charge on one atom and a partial negative charge on the other.

Answer 18

nonpolar, polar

Question 19

a ? bond is the weak partial attraction between the hydrogen atom of one water molecule and the ? atom of another water molecule, where the hydrogen has a slightly ? charge and the oxygen has a slightly ? charge, creating an ? attraction between them.

Answer 19

hydrogen, oxygen, +, -, electrostatic

Question 20

hydrophilic
hydrophobic

Answer 20

water loving
water fearing

Question 21

Cells are largely made of ? molecules, defined as molecules that contain a ?-carbon bond.

Answer 21

organic, carbon

Question 22

a large organic molecule is considered a

Answer 22

macromolecule

Question 23

A ? group is a specific group of ? in a molecule that gives the molecule its characteristic bonding, ?, properties, and reactivity.

Answer 23

functional, atoms, shape

Question 24

? are organic molecules that serve as ? components of membranes and other parts of cells. Lipids store lots of ? (as in “calories”) because their large number of C–H bonds release energy when metabolized with the ? we breathe

Answer 24

lipids, structural, energy, oxygen

Question 25

? fats have ? double bonds between carbon atoms, meaning they are "saturated" with hydrogen atoms, and are typically ? at room temperature

Answer 25

saturated, no, solid

Question 26

? fats have ? double bonds between carbon atoms, which creates kinks in the chain, and are usually ? at room temperature

Answer 26

unsaturated, 1+, liquid

Question 27

A ? reaction is a chemical reaction where two molecules ? to form a larger molecule, releasing a small molecule, like water, as a byproduct.

Answer 27

condensation, combine

Question 28

? are organic compounds made of ?, ?, and ?, and they are a primary source of ? for the body. They include sugars, starches, and fibers.

Answer 28

carbohydrates, C.H.O, energy

Question 29

A ? is the simplest form of ?, consisting of a single sugar molecule, such as glucose, fructose, or galactose. It serves as a basic building block for larger carbohydrates.

Answer 29

monosaccharide, carbs

Question 30

A carbohydrate composed of 2 simple sugars joined by a covalent bond is called a ?

Answer 30

disaccharide

Question 31

A ? (or glycan) is a complex carbohydrate made up of many monosaccharide units linked together; a carbohydrate ? composed of ? sugars.

Answer 31

polysaccharide, polymer, simple

Question 32

The complete genetic content of an organism is called the

Answer 32

genome

Question 33

A ? is the basic building block of ? ? (DNA and RNA), consisting of a 5-carbon-sugar, a phosphate group, and a nitrogenous base (A,T,G,C,U); the ? unit of nucleic acids

Answer 33

nucleotide, nucleic acids, monomer

Question 34

A ? is a nitrogenous base that pairs with other bases to form the structure of DNA or RNA.

Answer 34

nucleobase

Question 35

a ? is a macromolecule made of multiple ? subunits that work in a coordinated manner

Answer 35

complex, protein

Question 36

An ? ? is a building block of proteins, consisting of a central carbon atom bonded to an ? group, a ? group, a ? atom, and a variable side chain (R group) that determines its properties.

Answer 36

amino acid, amino, carboxyl, hydrogen

Question 37

? are molecules that have the same chemical formula but different structures or arrangements of atoms

Answer 37

isomers

Question 38

When discussing protein structure, "primary" refers to the ? ? sequence, "secondary" to local ? patterns like alpha helices, "tertiary" to the overall ? ? of a ? polypeptide chain, and "quaternary" to the ? of ? polypeptide chains within a protein complex.

Answer 38

amino acid, folding, 3D shape, single, arrangement, multiple

Question 39

The fully folded, functional form of a protein refers to ? ?

Answer 39

native conformation

Question 40

? means to greatly increase the rate of a reaction.

Answer 40

catalysis

Question 41

? ? ? is the difference in free energy between the reactants and products of a reaction. this change reflects the energy available to do work during a ? process.

Answer 41

free energy change, chemical

Question 42

? is the ability to do work.

Answer 42

energy

Question 43

First Law of Thermodynamics: Energy cannot be ? or ?, only ? or ?. The total energy in a system remains ?.

Answer 43

created, destroyed, transferred, transformed, constant

Question 44

Second Law of thermodynamics: In every transfer or transformation of energy, some energy is lost, and as a result, the ? of the system will ?. entropy means ? or randomness in a system

Answer 44

entropy, increase, disorder

Question 45

?: Reactions that release energy, with a negative free energy change. These reactions are ?.

Answer 45

exergonic, spontaneous

Question 46

?: Reactions that require energy input, with a positive free energy change. These reactions are ?.

Answer 46

endergonic, non-spontaneous

Question 47

Molarity is the measure of the ? of a ?, expressed as the number of ? of solute per liter of solution

Answer 47

concentration, solution, moles

Question 48

The energy needed for reactants to reach the transition state between reactants and products is called ? ?.

Answer 48

activation energy

Question 49

an ? biological catalyst; a protein or RNA molecule that can speed up the rate of a reaction without itself ? ?.

Answer 49

enzyme, being changed

Question 50

if a bacterium's enzyme becomes denatured, this means that the enzyme

Answer 50

loses its structure

Question 51

“LEO the lion says GER.” reduction is the ? ? ? oxidation is the ? ? ?

Answer 51

gain of electrons, loss of electrons

Question 52

The ? agent causes another substance to be oxidized. (gain) The ? agent causes another substance to be reduced. (loss)

Answer 52

oxidizing, reducing

Question 53

the ? ? is the phospholipid bilayer that encloses the ? which contains aqueous fluid.

Answer 53

cell membrane, cytoplasm

Question 54

? are a type of lipid molecule made up of a glycerol, two fatty acid tails (hydrophobic), and a ? group with a polar head (hydrophilic). They are the main components of cell membranes, forming a bilayer that separates the cell's interior from its ?.

Answer 54

phospholipids, phosphate, environment

Question 55

The phospholipid bilayer is a double layer of phospholipids that makes up the core structure of ? membranes. The ? tails (fatty acids) face inward, avoiding water. The ? heads (phosphate groups) face outward, interacting with water. This arrangement creates a flexible, semi-permeable barrier that regulates the ? of substances in and out of the cell.

Answer 55

cell, hydrophobic, hydrophilic, movement

Question 56

? proteins span (overlap) across the entire membrane, with parts exposed on both the inside and outside of the cell. They often function as channels or ? for molecules to pass through the membrane.

Answer 56

transmembrane, receptors

Question 57

? membrane proteins are attached to the outer or inner surface of the membrane, not embedded in it or overlapping. They help with cell ?, cell recognition, or maintaining the cell's shape.

Answer 57

peripheral, signaling

Question 58

Weak acids (e.g., aspirin) tend to be ? in ? environments (low pH), which allows them to cross cell membranes. In more ? environments (higher pH), they dissociate into a ? (H⁺) and a conjugate base, becoming charged and less likely to cross the membrane. Weak ? (e.g., nicotine) tend to be uncharged in ? environments (high pH), allowing them to pass through membranes. In ? environments (low pH), they can accept a proton (H⁺) and become charged, which prevents them from easily ? the membrane.

Answer 58

uncharged, acidic, basic, proton bases, basic, acidic, crossing

Question 59

? is the net movement of molecules from an area of high concentration to one of low concentration. ? is the diffusion of water across a selectively permeable membrane from regions of high water concentration (low solute) to regions of low water concentration (high solute).

Answer 59

diffusion, osmosis

Question 60

?: A solution where the concentration of solutes is the same inside and outside the cell, causing no net movement of water. ?: A solution with a higher concentration of solutes outside the cell, causing water to move out and the cell to shrink. ?: A solution with a lower concentration of solutes outside the cell, causing water to move in and the cell to swell.

Answer 60

isotonic, hypertonic, hypotonic or isosmotic, hyperosmotic, hypoosmotic

Question 61

?—a rupturing of the cell membrane and dispersal of cell contents. The sudden increase of osmotic pressure is called ? ?

Answer 61

lysis, osmotic shock

Question 62

? are specialized structures within a cell that perform specific functions. a hollow sphere is called a ? ? is the invagination of the cell membrane to form a vesicle that contains extracellular material An ? is a membrane-bound compartment within a cell that forms during the process of endocytosis

Answer 62

organelles, vesicle, endocytosis, endosome

Question 63

? are temporary extensions of the cell membrane used for movement or engulfing substances. ? is the process by which a cell engulfs and digests foreign particles or microorganisms. ? is the vesicle formed when a cell engulfs a particle during phagocytosis. ? are membrane-bound organelles in cells that contain digestive enzymes, responsible for breaking down ?, damaged organelles, and foreign substances. they are not found in ? cells.

Answer 63

pseudopods, phagocytosis, phagosome, lysosomes, waste, plant

Question 64

Reaction rates are affected by ? and ?.

Answer 64

temp, pH