chapter 5 structure and function of plasma membrane

Question 1

A cell’s plasma membrane is a barrier, allowing some molecules to pass its borders freely while excluding others from entry or exit.

Answer 1

Selective permeability

Question 2

It defines the borders of the cell

Answer 2

Function of the plasma membrane

Question 3

It regulates the passage of molecules entering or exiting the cell. Some molecules need help to cross the membrane and some even need energy to get across.

Answer 3

Functions of the Plasma membrane

Question 4

Flexibility allows the movement of some cells through narrow spaces (like red blood cells squeezing through tiny capillaries).

Answer 4

Function of plasma membrane

Question 5

Embedded in the membrane, there are also integral proteins that function as receptors. These proteins allow chemical messages like hormones and growth factors to bind to the cell, communicate their message, and may initiate a cascade of reactions inside.

Answer 5

Function of a plasma membrane

Question 6

proteins that allow chemical messages like hormones and growth factors to bind to the cell, communicate their message, and may initiate a cascade of reactions inside.

Answer 6

Receptors

Question 7

a phospholipid bilayer with embedded proteins

Answer 7

plasma membrane

Question 8

It is fluid because of the arrangement of two layers of phospholipids. It is a mosaic because it comprises components of proteins, cholesterol, carbohydrates, and phospholipids that give the membrane a fluid character.

Answer 8

Fluid mosaic model

Question 9

protein with carbohydrates attached. May serve as receptors for messenger molecules and are alsi important in cell adhesion and cell-to-cell recognition.

Answer 9

Glycoprotein

Question 10

lipid with a carbohydrate attached. May function like flags that tell our immune system not to attack.

Answer 10

glycolipid

Question 11

Does not span the entire membrane but rather are only present on one side, on the “periphery”.

Answer 11

Peripheral membrane protein

Question 12

Spans the entire plasma membranes and have a variety of functions.

Answer 12

Integral membrane protein

Question 13

Give cell membranes flexibility.

Answer 13

cytoskeletal filaments

Question 14

Is a hydrophobic molecule with a 4-ring structure that functions to stabilize membranes.

Answer 14

Cholesterol

Question 15

Helps large or polar/charged molecules across the membrane.

Answer 15

Protein channel

Question 16

Notice how there are two layers of phospholipids here. The water-loving phosphate heads point inwards towards the cytoplasm of the cell and outward towards the watery extracellular space. The water-hating fatty acids tails point inward, towards each other, to get away from water.

Answer 16

phospholipid bilayer

Question 17

hydrophobic and hydrophilic molecules
(loves and hates water)

Answer 17

Amphiphilic