Quiz 1 Flashcards
1
Q
What are other names for a plasma membrane?
A
Plasmalemma or cell membrane
2
Q
Major components of a cell (3)
A
Plasma membrane (outer) , cytoplasm, nucleus
3
Q
Functions of plasma membrane (6)
A
- Envelope of the cell
- Perform as a semipermeable membrane
- Place for membrane receptors
- Signal transduction into intracellular environment
- Cell to cell integration
- Maintain electrical gradient between intra & extracellular (capacitance)
4
Q
Components of a plasma membrane
A
Phospholipids,
cholesterol,
proteins,
oligosaccharide chains (linked to phospholipids and proteins)
5
Q
What makes up the phospholipid-bilayer structure?
A
- P-Face
- E-Face
6
Q
The inner layer that faces the cytoplasm in a phospholipid-bilayer structure
A
P-Face
7
Q
The Outer layer that faces the extracellular compartment in a phospholipid-bilayer structure
A
E-face
8
Q
Nonpolar fatty acid chains, can be _________ or _________
A
- Saturated; Straight
- Unsaturated; Kinked
9
Q
Structural components of a phospholipid (2)
A
- Polar head group
- Nonpolar (long chain) fatty acid chains
10
Q
What kind of fatty acid allows the phospholipid structure to be straight?
A
Saturated
11
Q
What kind of fatty acid allows the phospholipid structure to be bent?
A
Unsaturated
12
Q
Membrane __________ is present in about the same amount as phospholipid?
A
Cholesterol
13
Q
Phospholipids are most stable when organized into a double layer with the _______ fatty acid chains located in a middle region away from water and the _________ polar head groups contacting the water?
A
Hydrophobic, hydrophilic
14
Q
Phospholipids are _________, consisting of two _______ long-chain fatty acid’s liked to a charged _________ head that bears a phosphate group.
A
Amphipathic, non-polar, polar
15
Q
The polar hydrophobic head of a phospholipid gets attracted to water on the __________, turn and that chain will automatically face __________.
A
Outside, inside
16
Q
Fluidity is crucial for the purpose of: (4)
A
-Exocytosis, endocytosis, membrane trafficking and membrane biogenesis
17
Q
Fluidity increases with:
A
- Increased temperature
- Increased number of unsaturated bonds of the fatty acyl tails
18
Q
Fluidity decreases with:
A
Decrease in temperature
19
Q
Function of Cholesterol in the plasma membrane
A
-Acts as a fluidity buffer with changes in temperature
20
Q
Function of Cholesterol in the plasma membrane (Depending on temperature)
A
- Cold temperatures: prevents the membrane from becoming rigid
- Hot temperatures: Acts as an interfering molecule and lowers fluidity
21
Q
Membrane Proteins constitute around ____% of plasma membrane
A
50
22
Q
Types of Integral Protein
A
Transmembrane and multi pass proteins
23
Q
___________ proteins are firmly embedded in the lipid layers; those that completely span the bilayer are called _________ proteins
A
Integral, transmembrane
24
Q
Protein to lipid ratio in a plasma membrane is more or less _______
A
1:1
25
Multipass proteins can either move _______, or held static in place by part of the cytoskeleton
Laterally
26
List the 6 integral protein categories (6)
| *Know These
Pumps, Channels, Receptors, Linkers, Enzymes, Structural proteins
27
____________ transport certain ions like Na+, amino acids and sugars. (Sodium potassium)
Pumps
28
_____________ allow for passive diffusion of small ions, molecules and water. (Aquaporin)
Channels
29
_________________ allow the ligands to bind to such as hormones, antibodies, coated vesicle endocytosis
Receptor Proteins
30
_____________ anchor the intracellular cytoskeleton to the extracellular matrix
Linker proteins
31
Example of Enzymes for Integral Proteins:
| __________ for ion pumping
ATPases
32
Function of Structural Proteins
Forming junction with neighboring cells
33
What does Spectrin do?
Stabilizes cell membranes or erythrocytes
34
Mutations in spectrin causes hereditary defects of the erythrocyte such as: (2)
*Know these
Hereditary elliptocytosis, hereditary spherocytosis
35
Oligosaccharide chains constitute the _____________
Glycocalyx
36
What are glycolipids?
Phospholipids and membrane proteins that have the oligosaccharide chains attached
37
Types of transport across the plasma membrane (3)
-Passive, active, vesicular
38
What is passive transport?
Transport where no energy is requires and materials move from higher to lower concentrations
39
Types of passive transport
- Simple diffusion
| - Facilitated Diffusion: Channel, carrier/pump
40
What are some characteristics of simple diffusion?
-lipophilic, diffuse easily, exchange oxygen and CO2 though the lung blood air barrier
41
What is aquaporin?
A protein channel that allows water to come in
42
What is active transport?
Transport where energy (ATP) is required to transport molecules against electrochemical gradient via carrier protein
43
Forms of active transport
-Primary active transport, secondary active transport
44
Primary Active Transport uses __________
ATP
45
Forms of secondary active transport
- Symporter (Same directions)
| - Antiporter (Opposite directions)
46
How does secondary active transport work?
Harnessing energy while moving substances up the concentration gradient while pushing Na down the gradient
47
Forms of Endocytosis (Vesicular Transport)
Phagocytosis, pinocytosis, receptor mediated endocytosis
48
Definition/Process of Phagocytosis
“Cell Eating”
| -Bacteria/Dead cells are engulfed and those materials are internalized and broken down (cytoplasmic vacuole/phagosome)
49
What blood-derived cells are specialized for phagocytosis?
Macrophages and neutrophils
50
Definition/Process of Pinocytosis
- “Cell Drinking”
| - Involves smaller invaginations of the cell membrane which fuse and entrap extracellular fluid (looking like fluid)
51
What is the difference between phagocytosis and receptor mediated endocytosis
- RME: Involves receptors that will bind to a specific molecule and only take that in
- Phagocytosis: Uses cells like macrophages/neutrophil to keep area free of debris
52
What is an example of receptor mediated endocytosis?
Developing RBC’s in bone marrow (RBCs need Iron)
53
What is exocytosis?
Movement of large molecules from the cell by vesicular transport
-Move from P Face to E Face
54
What do secretory vesicles/secretory granules contain
Enzymes accumulated in the apical portion of cells that are ready to be released into lumen
55
What is membrane trafficking?
Process of membrane movement and recycling through the process of endocytosis and exocytosis
56
What are cells characteristically involved in endocytosis/absorption in the GI tract?
Simple epithelia
57
What are cells characteristically involved in exocytosis/secretion?
Glandular epithelium
58
What are types of glandular epithelium? (3)
Serous gland, mucus gland and demilune
59
What do microvilli do?
Increase surface area
60
What is the purpose of the serous gland?
Secreting mainly proteins and enzymes
61
What is the purpose of the mucus gland?
Secreting mucous
62
What is the purpose of the demilune?
Secretes both serous and mucous products
63
Cells communicate with one another to: (3)
1. Regulate tissue and organ development
2. To control their growth and division
3. To coordinate their functions
64
Types of cell signalling (5)
Endocrine, paracrine, synaptic, autocrine, juxtacrine
65
In ____________ signaling, the signal molecules (hormones) are carried in the blood from their sources to target cells throughout the body
Endocrine
66
In _________ signaling, the chemical ligand diffuses in extracellular fluid but is rapidly metabolized so that its effect is only local on target cells near its source.
Paracrine
67
In _________signaling, a special kind of paracrine interaction, neurotransmitters act on adjacent cells through special contact areas called ____________
Synaptic, synapses
68
In ___________ signaling, signals bind receptors on the same cells that produced the messenger molecule.
Autocrine
69
In ___________ signaling, important in early embryonic tissue interactions, the signaling molecules are cell membrane-bound proteins which bind surface receptors of the target cell when the two cells make direct physical contact.
Juxtacrine
70
The cytoplasm consists of: (4)
Cytosol (fluid component), organelles, inclusion, cytoskeleton
71
Organelles in the cytoplasm (5)
```
Ribosomes
rER & sER
Golgi apparatus
Lysosome
Mitochondria
```
72
Inclusions in the cytoplasm
Glycogen
Lipid droplets
Lipofuscin & melanin
73
Cytoskeleton components in the cytoplasm
Microtubules & Centrosome
Microfilaments (= actin filaments)
Intermediate filaments
74
Characteristics/Functions of a Ribosome
- Very large enzyme systems
- Create the place for amino acid arrangement
- Catalyze the peptide bond formation in the process of protein synthesis
75
Each ribosome has two subunits of unequal sizes ____S & _____S. Combined they equal _____S
76
What does S stand for in a ribosome
Svedberg units: A measure of sedimentation of coefficients
77
Types of ribosomal arrangements (2)
1) free or polyribosomes (polysomes)
| 2) ribosomes which are fixed to the endoplasmic reticulum forming the rough ER
78
Translation requires: (3)
RRNA, mRNA, tRNA
79
What role does rRNA play in Translation?
-Forms the ribosomes when bound to other ribosomal proteins
80
What role does mRNA play in translation?
Carries the genetic codes as codons to determine what amino acids will be added
81
The __________ will transfer a certain amino acid molecule, to be added in a proper sequence to the growing polypeptide chain, as dictated by the sequence of codon on mRNA.
TRNA
82
What would be considered a start codon
AUG
83
What would be considered Stop Codons
UAA, UAG, UGA
84
The tRNA contains about _____ nucleotides with an amino acid attached to its terminal
80
85
Characteristics of Free Ribosomes
- Floating around in the cytoplasm
- May form polyribosomes or polysomes
- Products are destined for self-use (nucleus, cytoplasm and mitcochondria)
86
Where are membrane-bound ribosomes attached?
On the surface of the ER (to become rER)
87
Where are membrane-bound ribosomes destined for? (3)
- Export out of the cell (cell secretion)
- For the lysosomal proteins
- The integral membrane proteins
88
What is the Endoplasmic reticulum (ER)?
An interconnecting network of membranous tissues, flattened sacs (with lumen)
89
What are the differences between rER and sER?
```
Structure
Ribosome formation on the surface
(rER has this, making the surface rough)
Functions
-Lipid Biosynthesis (sER)
-Metabolism of glycogen and detoxification of very noxious metabolic by-products (sER)
-Storage and release of calcium ions
```
90
What happens to the raw material that is endocytosed by a cell?
It will be processed to become the amino acids, which will be recycled to participate in the process of protein synthesis again
91
The 4 main types of phospholipids are:
Phosphatidylcholine
Phosphatidylserine
Phosphatidylethanolamine
Sphingomyelin
92
Membrane fluidity is dependent on cholesterol and temperature (T/F)
True
93
What is amphipathic
2 hydrophobic long chain fatty acids linked to a hydrophilic head that bears a phosphate group.
94
Types of Membrane Proteins
Integral and Peripheral Proteins
95
What is the hydrophilic component of the phospholipid
Polar head group
96
What is the hydrophobic component of the phospholipid
non polar fatty acid chains
97
What is the role of peripheral proteins?
Assist the integral proteins
98
What does the word oligosaccharide mean?
Sugar molecule chains
99
What are examples of pumps
Sodium-Potassium Pump
| -can also be used for amino acids and sugars
100
What are examples of channels
Aquaporin
101
What are examples of receptor proteins
Endocrine system: Hormones, antibodies, coated vesicle endocytosis
102
What is an example of a linker protein
Integrin family: links cytoplasmic actin filaments to an extra cellular matrix protein (fibronectin)
103
Example of enzyme
ATP Synthase
104
Example of Structural proteins
Epithelial tissue
105
What is hereditary elliptocytosis?
RBCs are mis-shaped, going from a concave shape to an elliptical (oval) shape
106
What is hereditary spherocytosis?
RBCs are mis-shaped from their normal concave shape into a sphere (circle) shape
107
What can hereditary ellipto\spherocytosis cause?
Issues in overall blood circulation and enlarged spleen (which filters out blood)
108
What are glycocalyx made of
Saccharides
109
What forms the glycocalyx
Oligosaccharide chains
110
Where is the glycocalyx found?
E-Face Only
111
What is the function of the glycocalyx?
Provides cells with a specific identity for things like cell interactions
112
What does the glycocalyx look like
Outer fuzzy layer
113
How do carriers/pumps work with facilitated diffusion?
Proteins bind to the molecule, can transport them by undergoing a series of conformational changes (ie. change shape)
114
What is pseudopodia?
Surface folds that occur in phagocytosis that look like feet
115
Explain the process of receptor mediated endocytosis
- Ligands bind to specific receptors
- A depression is formed
- Clathrin and adaptor protein help bind to the ligands
- Dynamin: separates the cell from the surface
116
Example of receptor mediated endocytosis
Developing RBCs (Found in Bone Marrow)
117
Explain RME in developing RBCs
Engulf Fe-transferrin in order to produce hemoglobin
118
What are examples of exocytosis
-Salivary gland, pancreas, endocrine glands
119
How do you identify acids and bases in exocytosis
Hematoxylin (Basic): Stains acidic substances (eg. DNA) purple or blue
Eosin (Acidic): Stains basic substances pink (ie. vesicles with basic proteins)
120
What does endocytosis do in regards to membrane trafficking?
Reduces plasma membrane on the surface
121
What is the difference between exocytosis and endocytosis
Endocytosis: Absorption
Exocytosis: Secretion
122
Microvilli decrease when we are fasting and come back to normal levels when we eat (T/F)
True
123
What is the “brush border”?
Very small, tight folds of the membrane collectively
124
How are different cells displayed in a salivary gland?
Serum: Watery, protein rich material enzymes (pink)
| -Mucus: Viscous substance, very little water, less protein and more sugary substances (lighter pink)
125
What are receptors?
Proteins on the surface of the cell (plasma membrane)
126
What are examples of endocrine signalling
Hormones (Pituitary, Reproductive, Thyroid)
127
What is endocrine signalling
Secretory cell secretes a hormone and the hormone is thrown into the bloodstream. Blood acts as a medium, moving the hormone to the target cell
128
What is paracrine signalling?
- Localized
- The chemical ligand diffused in extracellular fluid but is rapidly metabolized so that it’s effect is only on target cells near its source (localized)
129
What is synaptic signalling?
- Seen with Neurons
- A special type of paracrine interaction, neurotransmitters act on adjacent cells through special contact areas called synapses
130
What is autocrine signalling?
- Self-Signalling
| - Signals bind receptors on the same cells that produced the messenger molecule
131
What is juxtacrine signalling?
- Use of direct contact between cells
- Important in early embryonic tissue interactions, the signalling molecules are cell membrane bound proteins which bind surface receptors of the target cell when the two cells make direct physical contact
132
Clinical application of how receptors are important in physiological functioning in the body?
Pseudohypoparathyroidism
133
Explain pseudohypoparathyroidism
- Caused by nonfunctioning parathyroid hormone receptors
- PTH work to increase plasma in the blood
- Target cells fail to respond to PTH because they lack normal receptors to this hormone
- Sufficient PTH is made but there is a peripheral resistance because receptors cannot respond
- This causes blood Ca levels to stay low and phosphate retention by the kidneys
- Form of endocrine signalling
134
Other issues that pseudohypoparathyroidism can create
-Bones ossify very quickly
135
What are organelles?
Machineries that help the cell do it’s functions
136
What are inclusions?
Pockets of storage material or metabolic byproducts
137
What is cytoskeleton?
Parts of the cell that give the the cell it’s shape
| -Also transport materials
138
What is a ribosome?
-Very large enzyme systems whose job is to create a place for amino acid arrangement and to catalyze the peptide bind formation in the process of protein synthesis
139
Ribosomes are made of:
- Ribosomal RNA (rRNA)
| - Ribosomal proteins
140
Function of the Ribosome
Translate mRNA into a polypeptide chain (Translation)
141
rRNA is present in
The ribosome
142
mRNA is produced in the
Nucleus by transcription
143
tRNA do what in translation
Bind to amino acids
144
What are cisternae
Flat, disc like structures that look like a little strip
145
Functions of the smooth endoplasmic reticulum (sER)
- Storage of calcium in skeletal and cardiac muscle
- Storage of glycogen in liver cells (hepatocytes)
- Transport of protein bits from the rER to the golgi
- Steroid hormone synthesis (Adrenal/Leydig)
146
Clinical Application to the development of sER
Neonatal Jaundice
147
Explain the clinical application of neonatal jaundice
-Baby look yellowish
Causes
-Normal breakdown of RBCs produces a pigment compound bilirubin (usually cleared by the liver and excreted in bile)
-When the liver is not well developed, specifically in sER in the heptatocytes is underdeveloped, the bilirubin is not cleared from the blood
-Condition usually improves within 2-3 weeks once the liver develops
-Sometimes phototherapy is used to clear this up
148
What is the golgi complex/golgi apparatus
- composed of a stack of flattened, slightly curved membrane-bound cisternae
- slightly dilated along the periphery
- One cell may have more than one golgi
149
Forming face (golgi)
Where golgi is receiving vesicles via the sER
| -also called the cis face
150
Maturing face (golgi)
- Also called the trans face
- Has a lot of vesicles
- Has the trans golgi network
151
Trans Golgi network sorts proteins into: (3)
- Sectetory vesicles/granules
- Plasma membrane
- Lysosomes
152
Secretory Vesicles/Granules
- Found in secretory cells
| - Function: Make their way toward the duct in materials like acinus
153
Lysosome
- Dense membrane-bound organelles containing an amorphous granular material
- Hold onto alot of lysosomal enzymes like proteases, nucleuses, photophatase, sulfatases which are optimal at a ph of 5.0
- Formed or found in the cytoplasm until they are used
- Used in autophagy and heterophagy
154
What is autophagy
Process in which the cell uses lysosomes to dispose of excess or non-functioning organelles or membranes
155
Heterophagy
- A defence mechanism in the cell
| - Degrades harmful materials outside of the cell
156
Differences between secretory vesicles and lysosomes
- Secretory vesicles: outside cell/extracellular
| - Lysosome: inside cell/stays within cell
157
Mitrochondrion
- Produces ATP
- Vary in shape/number
- Very mobile, transported along microtubules
- Increase in number by division, reduce by fusion
- Bi-membrane: has an inner and outer membrane
158
Components of a mitochondrion
Inner membrane, Cristae, matrix, outer membrane, ribosomes, DNA
159
Inclusions (Defintions/Examples)
```
Cytoplasmic inclusions contain accumulated metabolites or other substances
-Glycogen (ex cardiac muscle/liver)
-Lipid Droplets (ex adipocytes)
-Lipofuscin and melanin (ex.neurons)
-
```
160
General Function of Cytoskeleton
- Structural: Provides structural support to cell (Gives it shape)
- Movement: Assists with cytosol streaming and cell motility
161
Components of Cytoskeleton
- Microfilaments (Actin)
- Intermediate Filaments
- Microtubules (tubulin)
162
Microtubules
- Hollow, spiral shape arrangement
- 2 tubulins: alpha and beta
- 13 dimers can make 1 circle
- Vary in length
- Good at serving as pathways
163
Motor proteins
- use ATP to function
| - Kinesin and dynein
164
Cilia Structure
- Cell appendages
- Core structures are made of microtubules (9+2 arrangement)
- 9 dimers
- 2 monomers
165
Movement of cilia can be called
Kinocilia
166
Cilia vs Microvilli
Cilia (Long wavy)
| Microvilli (short)
167
Microfilaments (shape/function)
-Made up of actin
-globular protein (circular)
-g-actin (globular) form in a strand intertwined creating an f-actin (fiber)
Function
-Found in the core of the Microvilli
-The actin play and important role in cell movement
-important for cytokinesis (cell division), forming the contractile ring
168
Intermediate filaments
- Do not tend to grow long or large
- stable
- examples: cytokeratin, Vincentian, Desmond, lamin, neuro-filament proteins
