Chapter 5- Cell Membrane Structure and Function

Question 1

All____ _________ have a double layer of phospholipids.

Answer 1

Cell Membranes

Question 2

Cell membranes are _____ mosaics or _________ with proteins within the ___________ bilayer that are constantly ________ with respect to one another.

Answer 2

Fluid
Patchwork
Phospholipid
Shifting

Question 3

The __________ phospholipid _________ are not ______ to one another, so the movement of certain ________ and lipids is possible within the bilayer.

Answer 3

Individual
Molecules
Bonded
Proteins

Question 4

A phospholipid consist of two different parts which are what?

Answer 4

A head that is polar and hydrophilic.

A pair of fatty acid tails that are non-polar and hydrophobic.

Question 5

Phospholipid heads face the _____ on the _______ and inside of the plasma membrane-_________ bonds form between water and the ___________ phospholipid heads.

Answer 5

Water
Outside
Hydrogen
Hydrophilic

Question 6

Phospholipid _____ cluster together within the bilayer because they are hydrophobic- they are ________ toward the interior of the ______ membrane.

Answer 6

Tails
Oriented
Plasma

Question 7

What are responsible for moving substances across the plasma membrane, communicating with other cells, and identifying the cell? Grouped in 5 major categories what are they?

Answer 7

Proteins
Enzymes
Receptor Proteins
Recognition Proteins
Connection Proteins
Transport Proteins

Question 8

What are Enzymes?

Answer 8

Proteins that promote chemical reactions that synthesize or break apart biological molecules

Question 9

_______ Proteins are proteins that allow cells to _______ to specific _________ molecules (such as hormones) carried in the _________

Answer 9

Recognition
Respond
Messenger
Bloodstream

Question 10

Define Recognition Proteins

Answer 10

Glycoproteins that sever as identification tags-identifies the cells as “self”

Question 11

Proteins that anchor cell membranes in various ways.

Answer 11

Connection Proteins

Question 12

________ Proteins- proteins that span the phospholipid bilayer and ________ the movement of hydrophilic _________ across the membrane- some form channels that can be ______ or ______ to allow specific substances to ____ across the membrane.

Answer 12

Transport
Regulate 
Molecules
Opened
Closed 
Pass

Question 13

How substance move across membranes: Define Solute and Solvent give examples.

Answer 13

Solute- Substance that can be dissolved in a solvent. EX: Sugar (sugar-water)
Solvent- A fluid capable of dissolving a solute. EX: Water (sugar-water)

Question 14

What is Diffusion?

Answer 14

A net movement to solutes from regions of high concentration to regions of low concentrations.

Question 15

______ Transport- involves diffusion of substances across cell membranes down their ____________ gradients, includes ______ Diffusion,__________ Diffusion, and _______- no ______ is required.

Answer 15

Passive
Concentration
Simple
Facilitated 
Osmosis
Energy

Question 16

Very small molecules with no net charge, such as water, oxygen. and carbon dioxide, con diffuse directly through the phospholipid bilayer of cell membranes. Lipid- Soluble molecules may also use this method. Give examples.

Answer 16

Simple Diffusion

EX: Ethyl alcohol, vitamins A,D, and E, and steroid hormones.

Question 17

Process used by specific proteins to move ions and polar molecules through cell membranes- two types of proteins allow facilitated diffusion- Carrier Proteins and Channel Proteins. Aquaporins- specialized water channel proteins- selective for water molecules.

Answer 17

Facilitated Diffusion

Question 18

The diffusion of water across a selectively permeable membrane in response to gradients of concentration, pressure, or temperature- we will focus on osmosis from a region of higher water concentration to a region of lower water concentration.

Answer 18

Osmosis

Question 19

What am I?

A solution with equal concentrations of solute and thus equal concentrations of water.

Answer 19

Isotonic (iso means same)

Question 20

What am I?
A solution that contains a greater concentration of solute when a membrane separates solutions with different concentrations.

Answer 20

Hypertonic (hyper means greater than)

Question 21

What am I?
A solution that contains a lesser concentration of solute when a membrane separates solutions with different concentrations.

Answer 21

Hypotonic (hypo means less than)

Question 22

___ _____ _____ retain their normal size in ________ solution ( they have numerous aquaporins) but in a ___________ solution, water leaves the cells by _______ causing the cells to shrivel; in a _________ solution, water enters the cells causing them to swell and eventually bust.

Answer 22

Red blood cells
Isotonic
Hypertonic
Osmosis
Hypotonic

Question 23

What am I?
Movement of molecules into or out of a cell against a concentration gradient- during active transport, membrane proteins use cellular energy to move molecules or ions across a plasma membrane against their concentration gradients-active transport proteins are often called pumps

Answer 23

Active Transport

Question 24

Energy requiring process that allows cells to engulf large particles or fluids- three forms: Pinocytosis, Receptor-mediated engocytosis, and Phagocytosis

Answer 24

Engocytosis

Question 25

Pinocytosis is when a small patch of ______ membrane dimples inward as it _________ interstitial fluid, and then the membrane buds off into the _______ as a tiny _______- moves a droplet of interstitial fluid into the cell (“___ ________”)

Answer 25

Plasma
Surrounds
Cytosol
Vesicle
Cell Drinking

Question 26

Receptor-mediated engocytosis- where the cell ___________ takes up specific molecules or complexes of molecules that ______ move through channels or diffuse through the plasma membrane- they ____ on specialized receptor proteins located on the plasma membrane in _________ depressions called ______ ____.

Answer 26

Selectively
Cannot
Rely
Thickened
Coated Pits

Question 27

Moves large particles-sometimes even whole organisms-into the cell ( from the Greek for “cell eating”)

Answer 27

Phagocytosis

Question 28

Define Exocytosis “Out of the Cell”

Answer 28

A process used by the cell to dispose of undigested particles of waste or to secrete substances such as hormones into the interstitial fluid- uses energy.

Question 29

Who am I?
Attach cell together
Join cells in tissues that are repeatedly stretched 
Prevent forces from pulling them apart.
Give examples.

Answer 29

Desmosomes

Ex: Skin, intestines, and heart cells

Question 30

Who am I?
Make cell attachments leak proof
Formed by proteins that span the plasma membranes at corresponding sites on adjacent cells.
Give examples.

Answer 30

Tight Junctions

Ex: In the bladder, prevents cellular wastes in urine from leaking back into blood.

Question 31

Who am I?
Allow direct communication between animals cells
Protein channels provide passage for hormones and nutrients as well as ions, sugars, and amino acids.
Give examples

Answer 31

Gap Junctions
Ex: They all electrical signals to pass rapidly among certain groups of nerve cells and synchronize contraction of heart muscle.

Question 32

Allow direct communication between plant cells- openings lined with plasma membrane and filled with cytosol, to the membranes and the cytosol of adjacent cells are continuous- cytoplasmic connections, serve similar function as Gap Junctions.

Answer 32

Plasmodesmata