Cell Organelles (S&f)

Front 1

Describe the phospholipid molecules in the cytoplasmic bi-layer:

Back 1

-polar head (hydrophilic)
-non-polar tail (hydrophobic)
-nitrogenous head linked to glycerol via phosphate bridge
-tail has 2 long chain fatty acids attached

Front 2

What is the role of the fatty acid chains linked to the phospholipid molecule in the cytoplasmic membrane?

Back 2

Keep the membranes fluid-like and flexible

Front 3

What is the role of cholesterol molecules in the cytoplasmic bi-layer membrane?

Back 3

stabilize and regulate the fluidity of the phospholipid bilayer.

Front 4

What percentage of weight do the proteins included in the cytoplasmic bilayer membrane make up?

Back 4

make up almost half of the total mass of a typical membrane, although the proportion varies depending on the type of membrane

Front 5

Where is an integral or intrinsic protein located?

Back 5

incorporated within the cytoplasmic membrane

Front 6

What are the constituents of a transmembrane protein?

Back 6

- Integral or intrinsic protein that span the entire thickness of the membrane

Front 7

What is a lipid raft?

Back 7

Specialized areas of integral proteins and phospholipids that allow regional functions.

Front 8

What is a glycocalyx?

Back 8

After certain proteins and lipids are synthesized, carbohydrates are attached. When these glycoproteins and glycolipids are inserted into the plasma membrane, the carbohydrate portion ends up on the extracellular surface. These molecules constitute a layer at the surface of a cell

Front 9

Why do gap junctions form?

Back 9

to allow intercellular communication through the cytoplasmic membrane

Front 10

Within the gap junction there are many _______ composed of 6 circularly arranged integral membrane proteins of each cell, forming a watery channel that allows passage of ions and small organic molecules

Back 10

connexons

Front 11

Where are connexons found?

Back 11

gap junctions

Front 12

How is the opening of a gap junction regulated? (2 ways)

Back 12

Electrical or chemical (Ca++, H+) changes within the cell

Front 13

What 4 types of tissues are gap junctions found?

Back 13

1 Epithelia
2 Smooth Muscle
3 Cardiac Muscle
4 Nerve cells

Front 14

For what purpose does a tunneling nanotubule serve?

Back 14

to allow intercellular communication, (like synnapses and gap junctions)

Front 15

In what situation would a tunneling nanotubule be more useful than a gap junction?

Back 15

tunneling nanotubules are effective at greater differences between cells by send out very long, thin extensions of plasma membrane

Front 16

The rER contains of a network of flattened membrane-limited sacs called ________

Back 16

cisternae

Front 17

rER has _________ attached and studding the exterior surface of the membrane.

Back 17

ribosomes

Front 18

rER can interconnect in some cells with what other organelle structures? (3)

Back 18

1. Plasma membrane
-or-
2. Outer membrane of the nuclear envelope
-or-
3. smooth ER

Front 19

rER's primary purpose is to:

Back 19

synthesize proteins

Front 20

What is the principle function of Smooth ER? (2)

Back 20

lipid biosynthesis
Membrane repair & synthesis

Front 21

What types of cells are prolific in sER?

Back 21

1. cells that secrete and synthesize steroids (adrenal/testes)
2. Detoxification (liver)
3. cells involved in glycogen metabolism

Front 22

What is sER called in skeletal muscle?

Back 22

sarcoplasmic reticulum

Front 23

The sarcoplasmic reticulum is contiguous with which organelle in other types of cells?

Back 23

sER

Front 24

Is the side of the golgi facing the rER concave or convex? cis-golgi or trans-golgi?

Back 24

convex, cis-golgi

Front 25

Is the outer or exit face of the golgi concave or convex? cis-golgi or trans-golgi?

Back 25

concave, trans-golgi

Front 26

What structures hold together the membrane sacs of the golgi apparatus? (2)

Back 26

Microtubules and microfilaments

Front 27

What processes is the Golgi Apparatus involved in? (4)

Back 27

1. Terminal Glycosylation (adding a carbohydrate to protein)
2. Carbohydrate packaging
3. Carbohydrate transport and secretion from the cell
4. Production of lysosomes

Front 28

What are the folds in mitochondria called?

Back 28

christae

Front 29

What is the space between the two layers of mitochondria called?

Back 29

matrix

Front 30

Mitochondrial DNA, RNA, ribosomes, enzymes for mitochondria protein and lipid & steroid synthesis and Krebs cycle enzymes are also located in the:

Back 30

matrix

Front 31

What is the mitochondria's signficant role in apoptosis?

Back 31

cellular stresses cause release of cytochrome c and other proteins that initiate one of the apoptotic pathways

Front 32

Newly formed lysosomes pinch off what organelle are which class of lysosome?

Back 32

Golgi cisternae; primary

Front 33

What molecules keep the lysosome contents acidic? (pH-5)

Back 33

H+ ATPase

Front 34

When does a primary lysosome become a secondary lysosome?

Back 34

At fusion with cellular contents to be destroyed and after discharge of hydrolytic enzymes.

Front 35

What good molecules come from lysosomal destruction of organelles?

Back 35

sugars, amino acids, & nucleic acids transported to cytoplasm via transporter molecules on lysosome.

Front 36

What is a residual body?

Back 36

Residue left over after incomplete hydrolysis by a lysosome.

Front 37

What are lipofuscin granules?

Back 37

residual bodies left over in nervous tissue.

Front 38

Name the three mechanisms of endocytosis: (Endosomes)

Back 38

1. Pinocytosis
2. Phagocytosis
3. Receptor-mediated endocytosis

Front 39

Peroxisomes closely resemble lysosomes but contain ________ and _________.

Back 39

Catalases & Oxidases

Front 40

What is a peroxisomes main target for degradation? (2)

Back 40

1. Long chain fatty acids
2. Other toxic foreign molecules

Front 41

A peroxisomes' catabolic pathway results in the formation of what molecule?

Back 41

H2O2 (Hydrogen peroxide)

Front 42

Hydrogen peroxide is produced where?

Back 42

peroxisome

Front 43

What destroys hydrogen peroxide to prevent over-production by peroxisomes?

Back 43

Catalases

Front 44

Peroxisome disorders generally result in what problems?

Back 44

disrupt lipid metabolism, often affecting myelin membranes of nerves, leading to neurological symptoms

Front 45

Name the 7 membrane bound organelles:

Back 45

1. Golgi Apparatus
2. rER
3. sER
4. Mitochondria
5. Lysosomes
6. Endosomes
7. Peroxisomes

Front 46

What do the larger ribosomal subunits have that the smaller ones do not? (both contain proteins)

Back 46

A strand of rRNA

Front 47

Besides attachment to rER, ribosomes can form in clusters in the cytoplasm called________.

Back 47

polysomes

Front 48

Barrel-shaped organelles

Back 48

Vaults

Front 49

Vaults are composed of what structures

Back 49

a ribosome and 3 proteins found in the cytoplasm.

Front 50

These are the nonliving components of the cell that may be of endogenous or exogenous origin, and they do not participate in energy-requiring reactions.

Back 50

Inclusions