Module 1.3: Review: Cellular Transport System

Question 1

The ___ separates the components of a cell
from its environment and is what surrounds the cell.

Answer 1

cell membrane

Question 2

The cell membrane is also referred to as the “gatekeeper” of the cell because ___.

Answer 2

it regulates the flow of materials into and out of cell, as it is selectively permeable

Question 3

___ is defined as the stable internal balance.

Answer 3

homeostasis

Question 4

What part of a cell is responsible for maintaining homeostasis within the cell?

Answer 4

cell membrane

Question 5

The cell membrane maintains homeostasis through balancing the ___. (4)

Answer 5

1. pH
2. temperature
3. glucose (sugar intake)
4. water balance

Question 6

True or False

The cell membrane maintains homeostasis within a cell only through active transport.

Answer 6

False

The cell membrane maintains homeostasis within a cell through active and passive transport.

Question 7

The ___ of a solution tells how acidic or basic it is.

Answer 7

pH

Question 8

What solutions are considered acidic, neutral, and basic?

Answer 8

acidic = solutions from 0-6 pH
basic = solutions from 8-14 pH
neutral = solutions with a 7 pH

Question 9

All cells have a cell membrane made of ___ ____, and ____. (3)

Answer 9

1. phosphate
2. proteins
3. lipids

Hence, it is called the phospholipid bilayer.

Question 10

True or False

The cell membrane both repels and attracts water through the membrane at the same.

Answer 10

True

Question 11

A single phospholipid has ___ heads and ____ fatty acid tails.

Answer 11

hydrophilic (water-loving) phosphate;
hydrophobic (water-hating)

Question 12

__ is a process that does not require energy to move molecules from a high to a low concentration.

Answer 12

passive transport

Question 13

What are three (3) types of passive transport?

Answer 13

1. diffusion or simple diffusion
2. facilitated diffusion
3. osmosis

Question 14

___ is the movement of small particles across the cell membrane until homeostasis is reached.

Answer 14

diffusion

Question 15

____ requires the help of carrier and channel proteins.

Answer 15

facilitated diffusion

Question 16

During diffusion, particles move from an area of ___ concentration to an area of ___ concentration.

Answer 16

high;
low

Question 17

____ is the movement of water through a selectively permeable membrane. This is in which water moves across the cell membrane from an area of high concentration to an area of low concentration.

Answer 17

osmosis

Question 18

What are the three (3) types of solutions in osmosis?

Answer 18

1. isotonic
2. hypotonic
3. hypertonic

Question 19

____ solutions contain the same concentration of solute as another solution.

Answer 19

isotonic

Question 20

When a cell is placed in an isotonic solution, the water ____ at the _____ rate.

Answer 20

diffuses into and out of the cell;
same

Question 21

___ solutions contain a low concentration of solute relative to another solution (e.g. cell cytoplasm).

Answer 21

hypotonic

Question 22

When a cell is placed in a hypotonic solution, the water diffuses ___ the
cell, causing the cell to ___ and ____.

Answer 22

into;
swell and possibly explode

Question 23

___ solutions contain a high concentration of solute relative to another solution (e.g. cell cytoplasm).

Answer 23

hypertonic

Question 24

When a cell is placed in a hypertonic solution, the water diffuses ___ of the cell, causing the cell to ____.

Answer 24

out;
shrivel

Question 25

In a hypertonic solution, the water or solution outside the cell is ___ than the inside of the cell. This will cause the cell to ___ and ___.

Answer 25

saltier; shrivel and shrink

Question 26

A hypotonic solution will cause the cell to take in water and ____.

Answer 26

swell

Question 27

True or False The water outside of the cell in an isotonic solution has an UNEQUAL amount of salt as the water inside the cell.

Answer 27

False EQUAL

Question 28

What are the four (4) types of active transport?

Answer 28

1. EXOcytosis 2. ENDOcytosis 3. PINOcytosis 4. PHAGOcytosis

Question 29

____, an active transport, refers to how materials EXIT the cell (or how the cell uses the bathroom).

Answer 29

EXOcytosis

Question 30

____, an active transport, refers to how materials ENTER the cell (cell eating or engulfing).

Answer 30

ENDOcytosis

Question 31

___, an active transport, refers to how SMALL materials enter the cell (cell eating/engulfing).

Answer 31

PINOcytosis

Question 32

____, an active transport, refers to how LARGER materials enter the cell (cell eating/engulfing).

Answer 32

PHAGOcytosis

Question 33

___ is a process that requires energy, the movement of molecules from low to high concentration.

Answer 33

active transport

Question 34

In active transport, why is energy required?

Answer 34

Energy is required as molecules must be pumped against the concentration gradient.

Question 35

What is one example of an active transport?

Answer 35

CO2 pumped out by body cells into the surrounding blood vessels to be carried to the lungs for exhale.

Question 36

Why does active transport need energy but passive transport does not?

Answer 36

Active transport needs energy because it moves molecules against their concentration gradient, from an area of low concentration to an area of high concentration. Passive transport does not need energy because it moves molecules along their concentration gradient, from an area of high concentration to an area of low concentration.

Question 37

____ refers to the distribution of charge across the cell membrane.

Answer 37

membrane potential

Question 38

Membrane potentials develop because of ____ between the inside and outside of the cell.

Answer 38

differing ion concentrations

Question 39

____ is the difference in electric potential between two points.

Answer 39

potential difference or voltage (V)

Question 40

What are the principles of electricity? (4)

Answer 40

1. voltage (V) - the difference in electrical potential between two points. 2. current - the flow of electric charge, in amperes (A). 3. resistance - the opposition to the flow of electric charge, ohms (Ω). 4. capacitance - the ability to store electrical charge, in farads (F).

Question 41

What are some principles of current? (3)

Answer 41

1. like charges repel, unlike attract. 2. ions tend to move from areas of GREATER concentration to areas of LOWER concentration. 3. the movement of a positive ion from one side of a membrane to the other implies a negative charge is left behind.

Question 42

According to ____, the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature, remain constant.

Answer 42

Ohm's law

Question 43

What is the formula of current flow?

Answer 43

I = E/R I = current flow E = electrical potential R = resistance

Question 44

____ membrane potential describes the steady state of the cell.

Answer 44

resting

Question 45

What are some of the principles of resting membrane potentials?

Answer 45

1. by convention - ECF (outside of the cell) is assigned a voltage of zero. 2. the polarity of the membrane is stated in terms of the sign of the excess charge inside of the cell.

Question 46

What are the two (2) types of membrane ion channels?

Answer 46

1. leak channels 2. Na+K+ATPase pump

Question 47

____ refers to a type of membrane ion channel that is open all of the time, the slow leak of ions. It is the simplest type of ion channel in that their permeability is more or less constant (neurons).

Answer 47

leak channels

Question 48

True or False Leak channels open and close at RANDOM, allowing ions to pass through when they are open.

Answer 48

True

Question 49

___ is an enzyme that actively transports sodium (Na+) ions out of the cell and potassium (K+) ions into the cell. It is essential for maintaining the resting membrane potential and for regulating nerve signaling.

Answer 49

Na+K+ATPase pump

Question 50

What are the complications of high potassium?

Answer 50

also referred to as hyperkalemia, some of its complications are: 1. muscle weakness/paralysis 2. arrhythmia (irregular heartbeat) 3. heart attack 4. cardiac arrest

Question 51

What are the two (2) forms of ion gradients?

Answer 51

1. chemical concentration gradient 2. electrical concentration gradient

Question 52

Together, the two forms of ion gradients are then known as the ____.

Answer 52

electrochemical agent

Question 53

A cell with a resting membrane potential is said to be ____ (polarized or nonpolarized).

Answer 53

polarized

Question 54

What are some of the factors that determine the resting membrane potential? (4)

Answer 54

1. selective permeability of the of the plasma membrane 2. leak channels 3. Na+K+ATPase pump 4. differences in ion concentrations

Question 55

What is the formula of equilibrium potential (Nernst potential)?

Answer 55

E(x) = RT/ZF log [x] inside/[x}] E(x) = gas constant T = temperature degrees (K) Z = charge on ion/s (valence) F = Faraday's constant

Question 56

An ____ is a globular protein that functions as a biological catalyst, speeding up a reaction rate.

Answer 56

enzyme

Question 57

How do enzymes speed up a reaction rate?

Answer 57

they lower the activation energy by the reaction it catalyze.

Question 58

Enzymes of the digestive tract and those found in blood are present in an inactive form called ____.

Answer 58

zymogen or proenzymes

Question 59

An ___ is a region on the surface of an enzyme to which substrates will bind and catalyze a chemical reaction.

Answer 59

active site

Question 60

True or False Enzymes are highly SPECIFIC for the type of reaction they catalyze and for their susbtrate.

Answer 60

True

Question 61

What are the types of specificity recognized by enzymes? (4)

Answer 61

1. absolute specificity 2. group specificity 3. reaction specificity 4. stereospecificity

Question 62

Conjugated proteins, also referred to as ____.

Answer 62

holoenzyme

Question 63

An enzyme without a non-protein part is known as ____.

Answer 63

apoenzyme

Question 64

The polymerization of deoxyribonucleotides into a DNA strand is catalyzed by the ____, a holoenzyme.

Answer 64

DNA polymerase

Question 65

The catalytic activity of DNA polymerase is catalyzed by the _____.

Answer 65

magnesium ion

Question 66

According to the IUBMB system of enzyme nomenclature, enzymes are grouped into 6 major classes: (6)

Answer 66

EC 1 OXIDOREDUCTASES EC 2 TRANSFERASES EC 3 HYDROLASES EC 4 LYASES EC 5 ISOMERASES EC 6 LIGASES

Question 67

What are some factors that affect the reaction velocity? (8)

Answer 67

1. temperature 1.2 hydrogen ion concentration (pH) 1.3 substrate concentration 1.4 enzyme concentration 1.5 products of the reaction 1.6 presence of an activator/inhibitor allosteric effect 1.7 time

Question 68

The study of reaction rate and how they change in response to changes in the experimental parameter is known as ____.

Answer 68

kinetics

Question 69

The mathematical equation that defines the quantitative relationship between the rate of anenzyme reaction and the substrate concentration is the ____.

Answer 69

Michaelis-Menten equation

Question 70

What is the equation of Michaelis-Menten?

Answer 70

V₀ = Vmax [S] / Km + [S] V₀ = observed velocity at the given [S] Km = Michaelis-Menten constant Km = (K-1 + K2) / K1 Vmax = maximum velocity at saturating [S] conc.

Question 71

According to the ____ plot, a linear representation is more accurate and convenient for determining Vmax and Km.

Answer 71

Lineweaver-Burk

Question 72

The ____ equation is obtained by taking the reciprocal of both sides of the Michaelis-Menten equation.

Answer 72

Lineweaver-Burk

Question 73

____ is the process of reducing the activity of an enzyme. It involves any substance that can diminish the velocity of an enzyme catalyzed.

Answer 73

enzyme inhibition

Question 74

True or False Enzyme inhibitors include drugs, antibiotics, poisons, and anti-metabolites.

Answer 74

True

Question 75

True or False Enzyme inhibition forms the basis of drug designing.

Answer 75

True

Question 76

What are the types of enzyme inhibitors? (2)

Answer 76

1. reversible 2. irreversible

Question 77

Reversible inhibitors can be classified into: (3)

Answer 77

1. competitive 2. non-competitive 3. un-competitive

Question 78

____ inhibitors are molecules that bind to the active site of an enzyme, preventing the substrate from binding.

Answer 78

competitive

Question 79

____ inhibitors bind to an allosteric site on the enzyme, which is a different site from the active site. Its binding changes the shape of the enzyme, making it less active.

Answer 79

noncompetitive

Question 80

____ inhibitors only bind to the enzyme-substrate complex, which means that they cannot bind to the enzyme alone.

Answer 80

uncompetitive

Question 81

True or False The rate of the reaction or velocity is directly proportional to the enzyme concentration when sufficient substrate is ABSENT.

Answer 81

False PRESENT

Question 82

The ____ in a reaction causes the inhibition of enzyme activity.

Answer 82

accumulation of a product