lecture #07

Question 1

How many life processes occur in living organisms? list them.

Answer 1

the seven Life Processes that occur in Living Organisms are:

1) Cell replication
2) Nutrition
3) Respiration
4) Excretion
5) Respond to environment
6) Movement
7) Grow in number and size

Question 2

What are the means by which Cell to Cell Adhesion occurs?

Answer 2

Plasma membrane participates in cell to cell adhesions. But the three major means by which Cell to Cell Adhesion occurs are as follows:

i) Cell Adhesion Molecules (CAMs)
ii) Extracellular Matrix (ECM)
iii) Specialized cell Junctions

Question 3

Describe CAMS in two lines.

Answer 3

• Cell Adhesion Molecules (CAMs) join adjacent cells together.
• CAMS Belong to 4 major Protein families
a) Cadherins
b) Integrins
c) Ig Superfamily
d) Selectins

Question 4

give three salient features of Extracellular Matrix.

Answer 4

following are three salient features of Extracellular Matrix :
• Serves as biological glue
• Meshwork of fibrous proteins
• Secreted by fibroblasts

Question 5

how many types of protein fibers are there?

Name them.

Answer 5

there are 3 types of protein fibers:

i. Collagen
ii. Elastin
iii. Fibronectin

Question 6

what do cell junctions consist of ? and what are their types?

Answer 6

Cell Junctions consist of multiprotein complexes.
There are 3 types of cell junctions:
a) Desmosomes
b) Tight junctions
c)  Gap junctions

Question 7

which type of cell junction makes Strongest cell to cell connections?

Answer 7

Desmosomes are the type of cell junctions that make the strongest cell to cell connections.

Question 8

how many components do desmosomes have?

Answer 8

Desmosomes have 2 components , that are:
A) Plaque
B) Filaments

Question 9

In which parts of the body are desmosomes most abundant?

Answer 9

Desmosomes are most abundant in skin, uterus and heart.

Question 10

which type of cell junction binds adjacent cells firmly?

Answer 10

Tight Junctions are the type of cell junction bind adjacent cells firmly.

Question 11

where are tight Junctions found in the body?

Answer 11

Tight Junctions are found in sheets of epithelial tissue.

Question 12

Give two salient features of Tight Junctions.

Answer 12

tight junctions are:

1. impermeable
2. Prevent undesirable leaks

Question 13

Gap junctions exist between ___ cells.

Answer 13

Gap junctions exist between adjacent cells.

Question 14

how are the cells in Gap junctions linked?

Answer 14

Cells in Gap junctions are linked by connexons

Question 15

in Gap junctions, what do connexons consist of?

Answer 15

In Gap junctions, Connexon consist 6 protein subunits

Question 16

Gap junctions are ____ to small molecules.

Answer 16

Gap junctions are permeable to small molecules.

Question 17

In which part of the body are Gap junctions abundant?

Answer 17

Gap junctions are abundant in cardiac & smooth muscles.

Question 18

what are the (5) types of Membrane Permeability?

Answer 18

the (5) types of Membrane Permeability are:
1) Selective Permeability
2) Permeable to non-polar molecules
3) Impermeable to ions and large
molecules
4) Slightly permeable to small polar
molecules
5) Trans-membrane proteins increase
permeability

Question 19

what are the three types of Gradients across the Plasma Membrane ?

Answer 19

the three types of Gradients across the Plasma Membrane are:

a) Concentration gradient
b) Electrical gradient
c) Electrochemical gradient

Question 20

when does Membrane Potential occur?

Answer 20

Membrane Potential occurs when opposite charges separate across the plasma membrane.Separated charges have the potential to do work measured in millivolt (mV).

Question 21

in case of Membrane Potential, what does the magnitude of potential depend on?

Answer 21

In case of Membrane Potential, magnitude of potential depends on number of opposite charges separated.

Question 22

when membrane potential is generated, the membrane itself is not ____ .

Answer 22

when membrane potential is generated, the membrane itself is not charged.