Chapter 2: Functional Organization Of The Cell

Question 1

It is a digestive organelle.

Answer 1

Lysosome

Question 2

When a gene is expressed, it

Answer 2

serves as blueprint for coding of proteins

Notes: Central Dogma of Life
DNA - mRNA - proteins

Question 3

In the ribosome, the signal sequence is bound by the-

Answer 3

Signal recognition particle (SRP)

Question 4

What specific protein acts as conduits for passive exit and entry of molecules?

Answer 4

Channel

Notes:
Pumps use ATP, thus, active
Carriers facilitate transport across membrane or couple it with other molecule

Question 5

Clathrin-coated pits are used to:

Answer 5

Transport vesicle molecules to specific organelles.

Notes: Clathrin is used in endocytosis and exocytosis while Coatamers are used to transport between ER and Golgi (COP-1 and COP-II)

Question 6

One purpose of the lipid bilayer is:

Answer 6

To prevent water-soluble substances to cross the membrane.

Question 7

Proteins responsible for organ transplant rejection

Answer 7

Cell-recognition proteins

Question 8

Which of the following proteins are not embedded but are tightly attached to either cytoplasmic or extracellular surface of the plasma membrane?

Answer 8

Answer: Peripheral Membrane Proteins

Note: Peripheral proteins can be removed by high or low concentration of salts while Integral Membrane Proteins are removed by detergents

Question 9

The physical properties of the bilipid layer are dependent on its chemical makeup. The nature of the head groups of the lipid molecules would determine:

Answer 9

the density of the membrane

Question 10

Membrane proteins have several functions. Which of the following statements are true?

Answer 10

Integrins are adhesion molecules that attach the cells to the extracellular matrix.

Question 11

Phospholipids with long saturated fatty acids have ____ transition temperatures.

Answer 11

HIGH

Question 12

Which of the following best describes the function of rough ER in eukaryotic cells?

Answer 12

Protein synthesis

Question 13

Insulin is a protein that is produced by certain pancreatic cells and secreted into the bloodstream. Which of the following choices best describes the route of your insulin from its production and exit from the cell?

Answer 13

Rough ER > transport vesicles > Golgi > transport vesicles > cell membrane

Question 14

Which of the following signals directs the protein to the lysosomes?

Answer 14

Attachment of a terminal mannose-6-phosphate

Question 15

Protein glycosylation occurs where?

Answer 15

Lumen of RER

Notes: Also in formation of disulfide bonds, GPI-linkages, and hydroxylation

Question 16

Which of the following is NOT a characteristic of TIGHT JUNCTIONS?

Answer 16

Allow free-flow of cytoplasm between neighboring cells (It should NOT allow free-flow)

Question 17

Unlike other intercellular junctions, it only attaches the cell to its neighbors at potential stress points.

Answer 17

Desmosomes

Question 18

A transmembrane protein creates tiny pores through which small molecules and ions pass through between adjoining cells.

Answer 18

Gap junctions

Question 19

It allows proteins to be synthesized and secreted continuously.

Answer 19

Constitutive Pathway

(as compared to Regulated pathway which is controlled by hormonal or neural signals)

Question 20

Essential components of cillial mobility, flagella, centrioles, and spindle fibers

Answer 20

Microtubules

Question 21

Assume you have generated a recombinant cDNA encoding a chimeric protein that contains a signal sequence attached to the amino terminus of the nuclear protein. Where would you predict that this protein would be localized?

Answer 21

It will enter the ER and eventually will be secreted from the cell

Question 22

The location of the various synthetic pathway where lysosomal enzymes are segregated?

Answer 22

Trans-golgi network

Question 23

Which of the following is not a property of your SRP?

Answer 23

It contains a single peptidase activity

Notes: SRP is just a recognition particle. Its different from the Signal Peptidase protein

Question 24

Function of integral membrane proteins?

Answer 24

Adhesion
Receptor
Enzymes
Intracellular signaling.

Question 25

Loss in these substances is a hallmark in metastatic tumor cells

Answer 25

Adhesion Molecules

Note: if cells do not adhere, they can travel through blood, thus, metastasise.

Question 26

N-linked oligosaccharides are added in the:

Answer 26

ER

Notes: ER for N-linked glycosylation Golgi for O-linked glycosylation

Question 27

As they emerge from the ribosomes, signal sequences are recognized and bound by

Answer 27

Signal Recognition Protein (SRP)

Question 28

The cell membrane is primarily made up of

Answer 28

phospholipids

Question 29

What happens to Membrane Fluidity when there’s:

1. Insertion of cholesterol in between phospholipids.
2. Low temperature.
3. Presence of high temperature and cholesterol. Decrease
4. Presence of saturated fatty acids.

Answer 29

1. Cholesterol inserted between phospholipids > increases fluidity
2. Low temperature > phospolipids stay in place > decrease fluidity
3. High temperature with cholesterol > decrease fluidity (idk, mo ni sa RC pero murag wala ga make-sense)
4. High saturated fatty acid > phospholipids are more compact > decrease fluidity

Question 30

Destruction of the chemical bonds that link proteins to membranes may occur. Which of the following tend to be disrupted with treatment of high salt concentrations?

Answer 30

Ionic bonds (because salts are ions themselves)

Question 31

Which of the following peripheral membrane protein that ANCHORS fibrils directly to integral membrane proteins.

Answer 31

Ankyrin

Question 32

T/F: All communication functions are done through cell membrane proteins.

Answer 32

False.

Note: For example, steroid hormones can freely diffuse the cell membrane, so they don’t need membrane proteins

Question 33

T/F: The phospholipid bilayer is the fluid structure where phospholipid molecules can freely diffuse within the entire leaflet which it resides.

Answer 33

True

Note: What a phospholipid molecule cannot freely do is to “flip-flop” from one leaflet to the other.

Question 34

A transmembrane protein create tiny pores through which small molecules and ions pass through between adjoining cells.

Answer 34

Gap junctions

Question 35

Which of the following events would happen to a protein in a secretory pathway? 
A. It’s signal sequence is cleaved
B. Acquire carbohydrate residues
C. Acquire intra-chained disulfide
bond

Answer 35

all of the above

Question 36

Location where mRNA and ribosome associate

Answer 36

Cytoplasm

Question 37

For proteins being synthesized on ribosomes attached to rough ER, all of the following takes place in the lumen, except:

Answer 37

Sulfation (Sulfation occurs in the Golgi)

Question 38

The cell membrane is impermeable to which of the following:

Answer 38

proteins and nucleic acids (both should be kept inside cell)