10/6 Recitation Quiz (Lectures #8-9)

Question 1

Exocytosis

Answer 1

The process by which material is exported out of the cell
(Ex: insulin secretion)

Question 2

Endocytosis

Answer 2

The plasma membrane surrounds material from outside the cell, trapping it in an endocytic vesicle
- Material can be taken into a cell
(Ex: Macrophage cell)

Question 3

What are the two types of endocytosis processes?

Answer 3

specific process and non-specific process

Question 4

Specific process (endocytosis)

Answer 4

uses receptors

Question 5

Non-specific process (endocytosis)

Answer 5

takes up water and nutrients

Question 6

Lysosomes

Answer 6

Membrane-bound vesicles that contain digestive enzymes
Function: to digest material (inside or outside the cell)

Question 7

What are new lysosomes called?

Answer 7

Primary Lysosomes

Question 8

How are secondary lysosomes formed?

Answer 8

when primary lysosomes fuse with an endocytic vesicle or a cellular organelle; creates secondary lysosomes

Question 9

How is Tuberculosis Bacteria dangerous?

Answer 9

• TB bacteria can prevent fusion of the endocytic vesicle and primary lysosome
• TB avoids digestion, and lives in the cell
• easily spreadable

Question 10

Mitochondria

Answer 10

Structure: double lipid bilayer membrane

Function: energy metabolism (ATP production)

Question 11

What does the outer and inner membrane of the mitchondria do?

Answer 11

Outer membrane covers entire organelle

Inner membrane is extensively enfolded, called cristae

Question 12

What is the lipid center of the mitochondria called?

Answer 12

The Matrix

Question 13

What is the Endosymbiotic Theory?

Answer 13

Mitochondria are similar to prokaryotes so it is believed mitochondria at once point were free-living prokaryotes

Question 14

Chloroplasts

Answer 14

Structure: double lipid bilayer (DLB) membrane

Function: site of photosynthesis in plant cells

Question 15

Thylakoid

Answer 15

single membrane disk of a chloroplast

Question 16

Granum

Answer 16

a stack of thylakoids

Question 17

Stroma

Answer 17

lipid substance surrounding the grana

Question 18

What is binary fission?

Answer 18

asexual reproduction by a separation of the body into new bodies

Question 19

What are two examples of structures that aren’t organelles?

Answer 19

Cytoskeleton

Extracellular Matrix

Question 20

Cytoskeleton (CS)

Answer 20

Structure: Network of multiple types of proteins inside of cells
Functions:
- Provides structural support within cells
- Has a role in transport within cells
- Helps mobile cells move

Question 21

Extracellular Matrix

Answer 21

Structure: the extracellular matrix (ECM) is a network of multiple types of proteins outside of cells
Functions:
- Provides structural support outside of cells
- “glues” cells into higher order structures (organs)
- Has a role in cell-cell communication

Question 22

Plasma Membrane (PM)

Answer 22

defines the inside and outside of a cell; it’s a barrier
- selective barrier

Question 23

What can cells adjust in the Plasma Membrane (PM)?

Answer 23

The chemistry of the PM

The molecules associated with the PM

Question 24

Who discovered the structure of the phospholipid bilayer in membranes?

Answer 24

Evert Gorter

Question 25

Why did Gorter use red blood cells in his experiment?

Answer 25

They are easy to obtain

They are easy to count

They are of uniform size

Question 26

What was Gorter’s experimental method?

Answer 26

1. Counted the # of Red Blood Cells (RBCs) and calculated the total surface area (SA) of the RBCs
   - the SA of 1 cell X the total # of cells
2. Destroyed the cells and collected the membrane phospholipids
3. Placed the phospholipids into a chamber of buffer where they would form a floating monolayer
4. Measured the total SA of the phospholipids in the chamber, and compared it to the total SA of the RBCs

Question 27

Monolayer

Answer 27

Surface area (S.A) of the monolayer equals the surface area of the cells

1:1 ratio for surface area

Question 28

Bilayer

Answer 28

Surface area (S.A) of the bilayer is double the surface area of the cells

2:1 ration for surface area

Question 29

What was the conclusion of Gorter’s experiment?

Answer 29

Cell membranes are a phospholipid bilayer
- the surface area of the phospholipids is 2x the calculated surface area of the cells

Question 30

What would have been the conclusion if Gorter used nuclear envelopes?

Answer 30

the ratio of surface area in the would have been 4:1 ratio because the nucleus has a double bilayer membrane

Question 31

What are the other parts in the Plasma Membrane?

Answer 31

Peripheral proteins

Cholesterol

Cytoplasm

Integral (transmembrane) proteins

Polysaccharides

Extracellular environment

Question 32

What type of structure is the plasma membrane?

Answer 32

fluid structure

Question 33

Fluid mosaic model

Answer 33

plasma membranes are fluid structures
(Ex: Phospholipid bilayer is like a “lake” where molecules are “floating” around in it )

Question 34

What was the conclusion of the cell fusion experiment?

Answer 34

proteins are laterally diffusing around the membrane so the membrane is fluid
- red dye from human cell proteins mixed with the green dye from mouse cell proteins