Gen Bio Membrane Structure and function

Question 1

fluid mosaic, with protein molecules embedded in a phospholipid bilayer.

Answer 1

Membranes

Question 2

• Mosaic denotes

Answer 2

surface made of small pieces

Question 3

A membrane is a “mosaic” in having

Answer 3

diverse protein molecules embedded

Question 4

What keeps a membrane “fluid”?

Answer 4

-Kinks in the unsaturated fatty acid tails of some phospholipids
- cholesterol (in animal cells)

Question 5

a cell may alter the molecular composition of its membranes as an adaptation to changing ___________

Answer 5

temperature

Question 6

How do plants keeps the membranes from crystallizing during winter

Answer 6

increase their percentage of unsaturated phospholipids

Question 7

membranes of certain hibernating animals are enriched in ___________

Answer 7

cholesterol,

Question 8

Functions of Membrane Proteins

Answer 8

• Transport
• Enzymatic Activity
• Sigmal Transduction
• Cell-to-Cell recognition
• Intercellular Joining
• Attachment

Question 9

the concept that allows some substances to cross more easily than others.

Answer 9

selective permeability

Question 10

What are found in the ECM

Answer 10

• Cholesterol, Carbohydrates, Proteins, Lipids, Glycolipids, Glycoproteins

Question 11

2 Types of Proteins found in the Membrane

Answer 11

• Integral Protein
• Peripheral Protein

Question 12

Proteins embedded in the membrane

Answer 12

Integral Proteins

Question 13

proteins on the surface of membrane (on the cytoplasmic side)

Answer 13

peripheral proteins

Question 14

Protein that functions in attachment; found in ECM attached by intermediate filaments

Answer 14

integrin

Question 15

functions of membrane utilizing a signalling molecule attaching to receptor that will cause a change/response within cells

Answer 15

Sigmal Transduction

Question 16

“glyco” used as __________ for recognition

Answer 16

markers

Question 17

Function of Membrane that involves junctions and joining

Answer 17

Intercellular Joining

Question 18

Function of Membrane in which enzymes embedded react to substrates

Answer 18

Enzymatic Act.

Question 19

Reason for Selective Permeability of membranes

Answer 19

• hydrophobic interior

Question 20

___________, hydrophobic molecules can easily pass-through membranes.

Answer 20

Nonpolar

Question 21

_____ and ______ are not soluble in lipids (may require transport proteins to enter or leave the cell).

Answer 21

Polar molecules and ions

Question 22

DIFFUSION ACROSS A MEMBRANE WITH NO ENERGY INVESTMENT

Answer 22

PASSIVE TRANSPORT

Question 23

movement of molecules from an area where they are in high concentration to an area where the molecules are in low concentration

Answer 23

Diffusion

Question 24

Because a cell does not have to do work when molecules diffuse across its membrane, such movement is called ___________

Answer 24

passive transport.

Question 25

DIFFUSION OF WATER ACROSS A MEMBRANE

Answer 25

osmosis

Question 26

refers to the ability of a surrounding solution to cause a cell to gain or lose water.

Answer 26

tonicity

Question 27

The tonicity of a solution mainly depends on its concentration of________relative to the concentration of _________ inside the cell.

Answer 27

solutes ;solutes

Question 28

When an animal cell, is immersed in a solution that is __________ to the cell, the cell’s volume remains constant.

Answer 28

isotonic

Question 29

solute concentration of a cell and its isotonic environment are essentially equal, and the cell gains water at the same rate that it loses it.

Answer 29

isotonic

Question 30

What happens when an animal cell is placed in a hypotonic solution

Answer 30

gains water, swells, and may burst (lyse)

Question 31

an animal cell placed in a hypertonic solution will

Answer 31

shrivel and die from water loss

Question 32

an animal cell placed in a hypertonic solution will

Answer 32

shrivel and die from water loss

Question 33

solution that has lower solute concentration than a cell

Answer 33

hypotonic

Question 34

solution with higher solute concentration

Answer 34

hypertonic

Question 35

In a hypotonic environment, a plant cell is __________ which is the healthy state for most plant cells.

Answer 35

turgid (very firm),

Question 36

. Although the plant cell swells as water enters by osmosis, the cell wall exerts a back pressure, called ____________, which prevents the cell from taking in too much water and bursting.

Answer 36

turgor pressure

Question 37

When a plant cell is surrounded by an isotonic solution, what happens?

Answer 37

there is no net movement of water into the cell, and the cell is flaccid (limp).

Question 38

In a hypertonic environment, a plant cell is no better off than an animal cell. As a plant cell loses water, it __________

Answer 38

shrivels, and its plasma membrane pulls away from the cell wall.

Question 39

How do polar or charged substances make it past the hydrophobic center of a membrane?

Answer 39

the help of specific transport proteins in a process called facilitated diffusion

Question 40

In all passive transport, the driving force is the __________

Answer 40

concentration gradient.

Question 41

2 types of transport protein structure

Answer 41

- Channel proteins - Carrier Proteins

Question 42

After osmosis, water moves in equal rates which is called

Answer 42

dynamic equilibrium

Question 43

Another type of transport protein, that binds its passenger, changes shape, and releases the transported molecule on the other side.

Answer 43

carrier proteins

Question 44

Substances that use facilitated diffusion for crossing cell membranes include

Answer 44

sugars, amino acids, ions—and even water.

Question 45

the very rapid diffusion of water into and out of such cells is made possible by a protein channel called an ________

Answer 45

aquaporin

Question 46

cell must expend energy to move a solute against its concentration gradient—

Answer 46

active transport

Question 47

what supplies energy for most active transport

Answer 47

ATP

Question 48

Example of ACtive transport

Answer 48

Sodium-Potassium pump - higher potassium needed inside and lesser sodium

Question 49

A cell uses the process of __________to export bulky materials such as proteins or polysaccharides.

Answer 49

exocytosis (from the Greek exo, outside, and kytos, cell)

Question 50

A _________ buds from the Golgi apparatus and moves to the edge of the cell, where it fuses with the plasma membrane to transport substances.

Answer 50

transport vesicle

Question 51

a transport process through which a cell takes in large molecules or droplets of fluid.

Answer 51

Endocytosis

Question 52

What needs to be overcome before a chemical reaction can begin

Answer 52

Energy Barrier

Question 53

Energy must be absorbed to contort or weaken bonds in reactant molecules so that they can break and new bonds can form. We call this the __________

Answer 53

activation energy (because it activates the reactants).

Question 54

Bulk transport that increases cell's surface area

Answer 54

exocytosis

Question 55

what speeds up the cell’s chemical reactions by lowering energy barriers.

Answer 55

enzymes

Question 56

molecules that function as biological catalysts, increasing the rate of a reaction without being consumed by the reaction.

Answer 56

enzymes

Question 57

Structure of an enzyme

Answer 57

unique three-dimensional shape, and that shape determines the enzyme’s specificity

Question 58

The specific reactant that an enzyme acts on is called the

Answer 58

enzyme's substrate

Question 59

A substrate fits into a region of the enzyme called the ________

Answer 59

active site

Question 60

Enzymes are specific because _________

Answer 60

only specific substrate molecules fit into their active sites.

Question 61

Optimal Temp and pH of an enzyme

Answer 61

35-40 deg cel pH 6-8 9(except pepsin ph2)

Question 62

Many enzymes require nonprotein helpers called __________which bind to the active site and function in catalysis.

Answer 62

cofactors,

Question 63

T or F. The cofactors of some enzymes are organic

Answer 63

T coenzymes

Question 64

If the cofactor is an organic molecule, it is called a _________

Answer 64

coenzyme.

Question 65

___________ BLOCK ENZYME ACTION AND CAN REGULATE ENZYME ACTIVITY IN A CELL

Answer 65

ENZYME INHIBITORS

Question 66

chemical that interferes with an enzyme’s activity

Answer 66

inhibitors

Question 67

reduces an enzyme’s productivity by blocking substrate molecules

Answer 67

competitive inhibitor

Question 68

Competitive inhibition can be overcome by

Answer 68

increasing the concentration of the substrate

Question 69

does not enter the active site. Instead, it binds to a site elsewhere on the enzyme, and its binding changes the enzyme’s shape so that the active site no longer fits the substrate

Answer 69

noncompetitive inhibitor

Question 70

_FEEDBACK INHIBITION HELPS REGULATE ______

Answer 70

METABOLISM

Question 71

ToF the lower the activation energy the faster the reaction

Answer 71

T