Lecture 8/9: Active and Passive Transport

Question 1

Active transport uses what kinds of molecules?

Answer 1

carrier- molecules

Question 2

What is active transport?

Answer 2

going from a low concentration to a high concentration

Question 3

What are the three characteristics that affect active transport?

Answer 3

• specificity
• saturation
• competition

Question 4

What drives active trasnport?

Answer 4

NOTHING

Question 5

What is affinity?

Answer 5

how strong a molecule can bind to the carrier molecules binding site

Question 6

How can we manipulate affinity for active transport?

Answer 6

we use ATPnase activity, by using the high energy phosphate group binded to the pumps and rearrange it shape

Question 7

What happens to the high energy phosphate after it is used for active trasnport?

Answer 7

• it becomes an organic phosphate that is then released

Question 8

What is the process of active transport called when using ATP directly?

Answer 8

Primary active transport

Question 9

What are the two examples of primary active transport?

Answer 9

• single molecule type: where one molecule is moved at a time
  ie. hydrogen or calcium
• multiple substance type: more molecules moving at the same time in either the same or different directions
  ie. sodium potassium pump

Question 10

How does the sodium potassium pump work?

Answer 10

• affinity for sodium inside the cell is high
• there are three binding spots for sodium
• ATP comes and the phosphate groups binds to the pump flipping it around for potassium to come bind

Question 11

is there more sodium inside the cell or outside the cell?

Answer 11

more sodium outside the cell!!

Question 12

Why do we concentrate ions on different sides of the membrane?

Answer 12

• to create a potential used for electric impulses

Question 13

Which cells go through the sodium potassium pumps the most?

Answer 13

neurons

Question 14

what is Secondary active transport?

Answer 14

Active transport with the indirect use of ATP
- still going from low to high concentration

Question 15

what are the two typed of secondary active transport?

Answer 15

type 1: cotransport/ symport = moving molecules in the same direction

type 2: counter/antiport = moving molecules in opposite directions

Question 16

whats an examples of secondary active transport counter?

Answer 16

moving glucose against it’s concentration gradient

Question 17

What is the use for vesicular trasnport?

Answer 17

to move big polar molecules across the membrane

ie. complex carbohydrates

Question 18

How do we use ATP in vesicular transports?

Answer 18

to make the vesicles itself

Question 19

What are the two types of vesicular transport?

Answer 19

type 1: endocytosis - brings molecules in
type 2: exocytosis - takes molecules out

Question 20

What are the three subtypes of endocytosis?

Answer 20

1. pinocytosis
   - non selective
   - drinks small amount of fluid from ECF
2. Receptor-mediated
   - selective
   - regulated by receptors
   - receptors bind to lygan
   ie. insulin, iron,B12
3. Phagocytosis
   - large molecules being eaten
   - selective process
   -only specialized cells can do this
   ie. good to get rid of pathogens

Question 21

True or false
once vesicles come into the cell they are fused with lysosomes majority of the time?

Answer 21

true

Question 22

True or false
viruses have found a way to take advantage of the receptor-mediated endocytosis to get access to the cell?

Answer 22

true

Question 23

How does exocytosis work?

Answer 23

• this takes molecules out of the cell
• using the Golgi body to sort the molecules in vesicles
• in the vesicles we make a protein called the docking marker acceptor
  (v-SNARE)
• this vesicle will then find the docking marker acceptor wherever it may be (t-SNARE)
• The lipids of the vesicle will then join the plasma membrane

Question 24

Is the endocytosis and exocytosis process always relatively in balance?

Answer 24

yes