Bio 2

Question 1

cell membrane

Answer 1

Barrier to the
outside, controls
flow in/out of cell

Question 2

DNA

Answer 2

Contains universal code of life –facilitates heredity

Question 3

Ribosomes

Answer 3

Where proteins are made – facilitates metabolism and cell function

Question 4

Molecules

Answer 4

are groups of atoms held together in a stable association

Question 5

Electronegativity determines an atom’s attraction for
the electrons

Answer 5

non-polar covalent bond: 0-0.4
polar covalent bond: 0.4-2
Ionic bond: >2

Question 6

Polar covalent bonds result from
uneven sharing of electrons

Answer 6

In a polar covalent bond, one atom is more electronegative.
– Unequal sharing of electrons causes a partial positive or
negative charge for each atom or molecule

Question 7

Water has four key properties

Answer 7

– Water is “sticky”
– Water is an excellent solvent
– Water moderates temperatures
– Ice (solid water) floats

Question 8

cohesion

Answer 8

Water molecules form hydrogen bonds with each other, resulting in an attractive force

Question 9

adhesion

Answer 9

Polarity also allows water to attract other polar molecules though

Question 10

Water is an excellent solvent because it is polar

Answer 10

Water is an excellent solvent for charged and polar
substances
- Charged and polar protein parts
- Small alcohols
- carbohydrates
Water is a poor solvent for nonpolar substances
- Non-polar gases
- Aromatic groups
- Long hydrocarbon chains

Question 11

PH scale

Answer 11

Acidic= 1-6
Neutral= 7
Base= 8-14

Question 12

Acids

Answer 12

are molecules that can split apart in water and release hydrogen ions (H+)

Question 13

Bases

Answer 13

are molecules that split apart in water and release hydroxide ions (OH-)

Question 14

Maintaining correct pH is important for organisms

Answer 14

• The pH of different cellular compartments, body fluids, and organs is tightly regulated in a process called acid-base homeostasis
• There must be a system in place to ensure pH is
  maintained at the desired level
• buffers are substances that resist extreme changes in pH
• take up excess hydrogen or hydroxide ions

Question 15

Buffers are essential for acid-base
homeostasis

Answer 15

• Keep the organism healthy and cellular
  components working properly
• if something goes wrong with the pH balance, organism can develop acidosis or alkalosis
• both are detrimental and potentially deadly
• The most common buffer system in humans is the bicarbonate/carbonic acid buffer system in blood

Question 16

Catabolic pathways

Answer 16

involve the breakdown of nutrient molecules into
usable forms (building blocks). In this process, energy is either stored in molecules for later use, or released as heat.

Question 17

Anabolic pathways

Answer 17

build new molecules out of the products of catabolism, and these pathways typically use energy. The new molecules built via anabolic pathways (macromolecules) are useful for building cell structures and maintaining the cell

Question 18

Lipids

Answer 18

• Energy storage
• protective membrane
• communication

Question 19

Carbohydrates

Answer 19

• Energy storage
• structural support
• communication

Question 20

Nucleic Acid

Answer 20

Contain genetic information

Question 21

Proteins

Answer 21

• communication
• transport
• chemical breakdown of substance
• structural support

Question 22

Most macromolecules are polymers

Answer 22

Polymers consist of many similar or identical building blocks linked by covalent bonds

Question 23

Biopolymers are made by condensation reactions (also known as dehydration reactions)

Answer 23

• Monomers connected together a covalent bond
• Water is lost in the process
• Energy is required
• Special enzymes are needed

Question 24

Biopolymers can be broken down via
hydrolysis

Answer 24

Hydrolysis adds a watermolecule, breaking a bond

Question 25

All cellular macromolecules are carbon-based because carbon atoms are the most versatile building blocks that combine together to form very diverse molecules

Answer 25

Carbon atoms can form 4 covalent
bonds with many elements, including H, O, P, S, N

Question 26

Carbon is also allotropic

Question 27

Structural isomers

Answer 27

Molecules with the same molecular formula have different bonding patterns and atomic organization

Question 28

Geometric isomers

Answer 28

cis isomer: The two Xs are on the same side.
trans isomer: The two Xs are on opposite sides.

Question 29

Enantiomers

Answer 29

• isomers that are mirror images of each other
  – to be an enantiomer, a molecule must have at least four different atoms or groups connected to a central carbon

Question 30

There are four essential macromolecules that build up cells

Answer 30

• polysaccharides
• Fats, lipids, membranes
• Protein
• Nucleic acid