Cell membrane

Question 1

Functions

Answer 1

Creates a boundary between the internal and external environment. Its functions include recognition of other cells, transportation of materials and transmission of neural impulses

Question 2

Amoeba

Answer 2

A unicellular organism that is consistently interacting with pond environment via the cell membrane. When feeding, can sense food and ignore indigestible molecules. (semipermiable0

Question 3

Extracellular fluid

Answer 3

Bodily fluid outside of the cell of any multicellular organism that bathes outside of the cell. Providing the liquid medium through which nutrients are supplied and wastes removed

Question 4

Int and ex parts of cell

Answer 4

99% is made up of C H O N CA P. Unicell organisms live in dynamic environments, like an amoeba living in freshwater can experience quick change, so must control substances movement to cope with rapid change. multi cell protected because extracellular fluid

Question 5

concs

Answer 5

Na (145 ex and 15 in), K (4.5 ex and 120 in), Cl (116 ex and 20 in), Ca (1.2 ex and 10 in). Cell membrane responsible for differences. Depending on the type of cell will need diff things, h levels low

Question 6

Fluid mosaic model

Answer 6

Describes membrane as double layer of lipids, lipid bilayer with the ability to flow and change shape. Proteins embedded like mosaic art

Question 7

Phospholipid bilayer

Answer 7

Composed of phospholipids which can be represented as hydrophilic head and hydrophobic tail

Question 8

Cholesterol

Answer 8

In animals, cholesterol is found, important to help maintain stability in varying temperatures. When temp changes, it will maintain right level of fluidity. In plants, its phytosterol. Able to be flexible and repair self and cell div

Question 9

Cell membrane proteins (transmembrane)

Answer 9

Transmembrane proteins extend across the entire membrane, they function as transport proteins, and they have evolved to enable interaction and comms between cells and exchange. Act as passageways allowing specific substances across

Question 10

Example (transmembrane)

Answer 10

Rapid movement of ions when a nerve is stimulated, causing a change in electric potential difference across the membrane and explains how electrical change of nerve impulses transmit along nerves

Question 11

Peripheral proteins

Answer 11

It extends across the middle region but on the surface.

Question 12

Channel Proteins (Ion channels)

Answer 12

Catalyse movement of specific ions and some simple molecules, down each substance’s electrochemical gradient. Help them via passive transport in facilitated diffusion. Eg is Ca channel, and ones for water are aquaporins.

Question 13

Carrier proteins

Answer 13

Change shape to pass molecules across the membrane. Some use Atp to transport specific small molecules or ions against conc gradient. (nak pump). Some do the passive movement of facilitate movement of ions or molecules conc gradient

Question 14

Adhension proteins

Answer 14

Link cells together to maintain 3D structure and normal functioning of the tissue

Question 15

Receptor Proteins

Answer 15

Bind hormones and other substances that cause changes in cells activities, diff cells diff receptor proteins, enabling them to only respond to certain signals and carry out specific funtions

Question 16

Recognition protein

Answer 16

Acts as a marker on membranes