Neurological System

Question 1

How many neurons are present in the human brain?

Answer 1

86 billion

Question 2

Place the following species in descending order

1) Chimpanzee
2) Gorilla
3) Human
4) Elephant

Answer 2

4-3-2-1

Question 3

What is the order of process of a nervous signal?

Answer 3

Reception -> treatment -> transmission

Question 4

What is the structure of a cell membrane?

Answer 4

thin, elastic structure composed entirely of:

• lipid barrier (bilayer)
• Proteins
• Carbohydrates

Question 5

What is the lipid bilayer impermeable to?

Answer 5

It is impermeable to water and the usual water-soluble substances but permeable to lipid-soluble substances

Question 6

What are the two types of membrane proteins?

Answer 6

Integral proteins & peripheral proteins

Question 7

Describe an integral protein.

Answer 7

Protrudes through the membrane, acts as pores and channels, substance carriers

Question 8

Describe peripheral proteins.

Answer 8

attached to only one surface of the membrane (often attached to the integral protein). Act as enzymes, controller of transport channels

Question 9

What are the two basic processes of transport?

Answer 9

Diffusion and active transport

Question 10

Describe simple diffusion.

Answer 10

it requires no energy, molecules move through interstices of lipid bilayer (lipid-soluble substances) and through protein channels for water and lipid-insoluble molecules

Question 11

Protein channels are selectively permeable to one or more specific ions or molecules based on:

Answer 11

• the diameter of the channel
• the diameter of the substance
• the shape of the channel
• the nature of electrical charges along the surface of the channel

Question 12

What are the two types of gates that regulate the opening and closing of protein channels?

Answer 12

Voltage-gated channels: gate responds to electrical potential, participates in the generation of AP
Chemical-gated (ligand-gated) channels: channel responds to the binding of another molecule with the channel, participates in the synaptic transmission (receptor)

Question 13

Describe the process of facilitated diffusion

Answer 13

Molecule diffuses by using a specific carrier protein, it enters the pore and binds to the binding point of the protein. A conformational change occurs so that the pore opens to the opposite side. At this position, the molecule is released.

Question 14

What is the role of facilitated diffusion?

Answer 14

Carrying large molecules like glucose and amino acids

Question 15

True or False. (simple diffusion) Diffusion rate speed is proportional to the concentration of the transported substance (i.e. the higher the concentration, the faster the rate of diffusion)

Answer 15

True, it is false for facilitated diffusion where the diffusion rate approaches a max when the concentration of the substance increases

Question 16

What are the factors that affect the net rate of diffusion?

Answer 16

• Concentration difference (concentration gradient): from high concentration to low concentration
• Electrical Potential Difference: electrical charges of ions causes them to move across the membrane even though there is no concentration gradient

Question 17

Define Active Transport

Answer 17

It requires energy. molecules or ions move across the membrane through a carrier protein against their concentration gradient and/or electrical gradient

Question 18

What are the two types of active transport according to the source of energy used?

Answer 18

Primary Active Transport (energy is directly driven from ATP) & Secondary Active Transport (2 different substances are transported, energy driven from concentration gradient of one of the transported substances)

Question 19

How many sodium and potassium ions are pumped in and out of the cell in the sodium-potassium pump?

Answer 19

3 Na+ pumped out

2 K+ pumped in

Question 20

What does the Sodium-potassium pump establish inside the cell?

Answer 20

it establishes a negative electrical potential

Question 21

What are the two substances transported in secondary active transport?

Answer 21

Principal & co-transported

Question 22

Where does the energy required to move the substances comes from?

Answer 22

It is from the concentration gradient of the principal transported substance (gradient energy)

Question 23

What are the two forms of secondary active transport according to the direction of diffusion of the two substances?

Answer 23

Symport (co-transport): the 2 substances move in the same direction
Antiport (countertransport): the 2 substances move in opposite direction

Question 24

What is the main goal of secondary active transport?

Answer 24

To maintain homeostasis in cell

Question 25

Example of Symport (glucose and sodium)

Answer 25

Na+ is the principal substance, glucose is the co-transported. Both substances move together into the cell

Question 26

Example of Antiport ( Sodium & Calcium or hydrogen)

Answer 26

the principal and co-transported are located on opposite sides of the membrane.
The principal moves from outside to inside while the co-transported goes from the inside to the outside

Question 27

True or False. Molecules are constantly kept with unequal concentrations inside and outside of the cell.

Answer 27

True