Unit 5-Cellular Function

Question 1

What are the 6 different types of functions of proteins in a plasma membrane

Answer 1

Attachment to the cytoskeleton and extracellular matrix 
Signal transduction 
Transport 
Intercellular junctions 
Cell-cell recognition 
Enzymatic activity

Question 2

Define diffusion

Answer 2

Molecules move down the concentration gradient

Does not require energy

Question 3

Define passive transport

Answer 3

A type of transport that does not require energy such as diffusion

Question 4

What is one of the most important substances that crosses membranes by passive transport

Answer 4

Water

Question 5

Define osmosis

Answer 5

The diffusion of water across a selectively permeable membrane

Question 6

Why are there a difference in water level but the concentration is equal

Answer 6

Because solutes attach to the water molecule so there are less free water molecules

Question 7

Define tonicity

Answer 7

The ability of a surrounding solution to cause a cell to gain or lose water

Question 8

What does the tonicity of a solution depend on

Answer 8

It’s concentration of solutes that cannot cross the plasma membrane relative to the concentration of solutes inside the cell

Question 9

Define isotonic

Answer 9

No net movement ; equal
Normal for animal cells
Flaccid for plant cells

Question 10

Define hypotonic

Answer 10

A solution with a solute concentration lower then that of the cell
The cell gains water and is lysed or bursts
Water moves into the cell
What plant cells like the best

Question 11

Define hypertonic

Answer 11

A solution with a higher solute concentration
The cell shrivels
Water moves out of the cell

Question 12

Define osmoregulation

Answer 12

The control of water balance

Question 13

What types of molecules can cross the membrane unassisted what can not

Answer 13

Polar or charged substances need help to move across the membrane
While nonpolar hydrophobic molecules can dissolve and pass through

Question 14

Define facilitated diffusion

Answer 14

The movement of substances across the membrane with the use of specific transport proteins
A type of passive transport because it does not require energy

Question 15

What substances use facilitated diffusion

Answer 15

Many sugars
Amino acids
Ions
And even water because water is polar

Question 16

Define an aquaporin

Answer 16

A type of protein channel used for water

Question 17

Define active transport

Answer 17

A cell must expend energy to move a solute against its concentration gradient
ATP is used for the energy

Question 18

Explain the process of active transport

Answer 18

Molecule attaches to specific binding sites on the transport protein ATP is used on the protein to change its shape so that the solute can be released on the other side the phosphate detaches and the transport protein returns to its original shape

Question 19

Does an animal cell have more K+ inside or outside of its cell

Answer 19

INSIDE OF THE CELL

Question 20

Is there a lower or higher concentration of sodium inside or outside of the cell

Answer 20

OUTSIDE

Question 21

What is the transport protein called used to regulate the NA and K levels

Answer 21

The sodium potassium pump

Works by moving Na and K against their concentration gradients

Question 22

How do large substances enter and exit a cell

Answer 22

Exocytosis and endocytosis

Question 23

Define exocytosis

Answer 23

How the cell exports bulky materials such as proteins or polysaccharides

Question 24

How does exocytosis work

Answer 24

A transport vesicle filled with macromolecules buds from the Golgi apparatus and moves to the plasma membrane once there it fuses and the contains spill out of the cell

Question 25

Define endocytosis

Answer 25

A transport process that is the opposite of exocytosis. A cell takes in large molecules

Question 26

Define phagocytosis

Answer 26

A type of endocytosis Cellular eating Engulfs a particle by wrapping the pseudopodia around it and packages it

Question 27

What are the three types of endocytosis

Answer 27

Phagocytosis Pinocytosis Receptor-mediated endocytosis

Question 28

Define pinocytosis

Answer 28

A type of endocytosis Cellular drinking Gulps little droplets of fluid into tiny vesicles Not specific takes in anything

Question 29

Define receptor mediated endocytosis

Answer 29

Highly selective Has receptor proteins for specific molecules embedded in regions of the membrane Coated protein Used for cholesterol

Question 30

Define thermodynamics

Answer 30

The study of energy transformations that occur in a collection of matter

Question 31

What is the first law of thermodynamics

Answer 31

Aka law of energy conservation Energy in the universe is constant Energy can be transferred and transformed but not created or destroyed

Question 32

Define the second law of thermodynamics

Answer 32

Energy conversions increase entropy (disorder/randomness) of the universe

Question 33

Define an exergonic reaction

Answer 33

A chemical reaction that releases energy

Question 34

Define an endergonic reaction

Answer 34

Yield products that are rich in potential energy

Question 35

Define energy coupling

Answer 35

The use of energy released from exergonic reactions to drive essential endergonic reactions

Question 36

What is the process called when a phosphate group is transferred to form ATP

Answer 36

Phosphorylation

Question 37

Define a substrate

Answer 37

The specific reactant that an enzyme acts on

Question 38

Define the active site

Answer 38

Where the substrate fits

Question 39

Define induced fit

Answer 39

The enzyme starts with an empty active site and the substrate attaches to the active site and the active site changes slightly to fit the substrate

Question 40

What describes the structure of a cell membrane

Answer 40

Proteins embedded in a bilayer of phospholipids

Question 41

Chemical bonds in the gasoline in a cars tank and the movement of the car along the road The first demonstrates what and what does the second part demonstrate

Answer 41

Potential energy | Kinetic energy

Question 42

A plant cell placed in distilled water will ___; an animal cell placed in distilled water will __

Answer 42

Become turgid | Burst

Question 43

The sodium concentration in a cell is 10 times less then the concentration in the surrounding fluid. How can the cell move sodium out of the cell

Answer 43

Active transport

Question 44

The synthesis of ATP from ADP and P

Answer 44

Stores energy in a form that can drive cellular work

Question 45

Facilitated diffusion across a membrane requires ___ and moves a solute ___ its concentration gradient

Answer 45

Transport proteins | Down

Question 46

When comparing an uncatalyzed reaction to the same reaction with an enzyme catalyst is true

Answer 46

The catalyzed reaction will have lower activation energy