BIO 360 - Exam 1 - Chapter 3 SP 2023 PowerPoint

Question 1

An increase in insulin to reduce glucose levels
is an example of?

Answer 1

Negative feedback

Question 2

Membranous tissues separate _______ _______.

Answer 2

body cavities

Question 3

Cell plasma membranes (plasmalemma) ______ cells.

Answer 3

enclose
* nuclear membranes enclose cell nucleus
* Composed of lipids, proteins, carbohydrates

Question 4

What do plasma membranes do? (4 things)

Answer 4

1. Impermeable membranes serve as barriers to isolate cell
2. Semi-permeable membranes regulate exchange between extracellular and intracellular fluid.
3. Cell-to-cell communication
4. Provide cell structure and support

Question 5

What are the major components comprising the
cell membrane?

Answer 5

Lipids (phospholipids and sphingolipids) cholesterol, proteins, and carbohydrate groups.

Question 6

Fluid Mosaic Model

• ______ arranged in ______ - composed of 2 fatty acid chains bound to ______ with phosphate group.
• At higher (body) temperatures, the bilayer actually
  ‘melts’ and the interior is fluid allowing the lipid
  molecules to move around, rotate, exchange places.
  This also allows movement of other components of
  the membrane.
• ______ can move in the membrane (i.e. the membrane is “fluid.”
• ______ is needed to stabilize the membrane (i.e. make it ______ “fluid”).

Answer 6

Phospholipids / bilayer / glycerol

Phosphlipids / Cholesterol / less

Question 7

Cholesterol in the Fluid Mosaic Model

Approx. ____ cholesterol per ______ molecule.
* Inserted into membrane with same orientation as PL
* ____ head of cholesterol oriented with ____ head of PL
Two-dimensional fluid of freely diffusing lipids w/embedded proteins.
* Proteins are ______, ______ & ______ for extracellular signals.
* Approx 1/3rd of our DNA encodes membrane proteins.

Answer 7

one / phospholipid

Polar / polar

channels, transporters & receptors

Question 8

Cholesterol ______ the first few ______ ______ of the PL. This makes the lipid ______ ______ and ______ ______ to small water-soluble molecules.

Answer 8

Immobilizes / hydrocarbon groups

less deformable / decreases permeability

Question 9

Fluid Mosaic Model - _______ ______ are loosely attached to integral proteins.

Answer 9

peripheral proteins

Question 10

Fluid Mosaic Model - membrane spanning ______ ______ are tightly bound to the membrane.

Answer 10

integral proteins

Question 11

Organization of polar and nonpolar regions in the plasma membrane important for understanding…

Answer 11

movement into and out of cells

Question 12

Transmembrane proteins that span plasma membrane seven times are called?

Answer 12

G protein-coupled receptors
* amino acids in transmembrane region likely to have non-polar side chains.
* cytoplasmic loops: linear sequence of amino acids often have
phosphorylation sites.

Question 13

What is the difference between channel and carrier transmembrane proteins?

Answer 13

Open channels create a water-filled pore between the ECF and ICF.
Carriers never form an open channel between the two sides of the membrane.

Question 14

What is the cell composed of?

Answer 14

Figure 3.4 - the nucleus, cytoplasm and cell membrane. The cytoplasm then spreads to cytosol, membranous organelles, inclusions, and protein fibers.

Question 15

Describe the role of Mitochondria of a cell - Figure 3.4.

Answer 15

ATP synthesis in the cell.

Question 16

Describe the role of the rough and smooth endoplasmic reticulum (ER) of a cell - Figure 3.4.

Answer 16

• The rough ER is the main site of protein synthesis.
• The smooth ER synthesizes lipids and, in some cells, concentrates and stores calcium ions.

Question 17

Describe the role of the Golgi apparatus of a cell - Figure 3.4.

Answer 17

protein modification and packaging.

Question 18

Figure 3.7 - Protein synthesis demonstrates ____-______ ______.

Answer 18

sub-cellular compartmentation.

Question 19

What are the three cytoplasmic Protein Fibers? AIM

Answer 19

1. Actin (micro-filaments)
2. Intermediate filaments - Keratin & Neurofilaments
3. Micro-tubules - centrioles, cilia, flagella

Question 20

What are the functions of the cytoplasmic Protein Fibers?

Answer 20

• Cell shape
• Internal organization
• Intracellular transport
• Assembly of cells into tissues
• Movement

Question 21

What are the parts and their function(s) of the cytoskeleton in cytoplasmic Protein Fibers?

Answer 21

• Microvilli: increase cell surface area. Supported by micro-filaments.
• Micro-filaments: form a network just inside the cell membrane.
• Micro-tubules: are the largest cytoskeleton fiber.
• Intermediate filaments: include myosin and keratin.

Question 22

Figure 3.6 Microtubules and Motor proteins

What is the function of Myosins, Kinesins and Dyneins?

Answer 22

Myosins - muscle contraction

Kinesins / dyneins - movement of vesicles along microtubules

Dyneins - movement of cilia and flagella

Question 23

Figure 3.8a what are the four types of cell junctions and their associated membrane protein?

Answer 23

Cell to Cell junctions - Gap junctions - Connexin
Cell to Cell junctions - Tight junctions - Claudin, Occludin
Cell-matrix junctions - Focal adhesion - Integrin
Cell-matrix junctions - Hemi-desmosome - Integrin

Question 24

Gap junctions are ______ junctions.
Tight junctions are ______ junctions.
A ______ is a cell-to-cell ______ junction.

Answer 24

communicating / occluding (obstruct) / desmosome / anchoring

Question 25

Again, what are some functions of cell plasma membrane?

Answer 25

• Organization of polar and nonpolar regions of lipid bilayer
  makes plasma membrane a barrier to free movement of
  many substances.
• Exchange or transport of substances into and out of cell is
  critical.
• H2O, nutrients, ions, proteins, gases, wastes, chemical
  signals, etc.
• Respond to chemical signals in extracellular fluid.
• Maintain tissue integrity via tight junctions - cell adhesion molecules

Question 26

Simplest type of movement though membranes is ______.

Answer 26

diffusion