Cells and Organelles Flashcards
FOM 1, Exam 1, Lectures 5, 6, 19
1
Q
What are primary functions of the plasma membrane?
A
selective permeability
exocytosis/endocytosis
cell-to-cell communication
2
Q
What are the three types of endocytosis?
A
phagocytosis
pinocytosis
receptor-mediated endocytosis
3
Q
What is phagocytosis?
A
engulf a large amount of material
4
Q
What is pinocytosis?
A
engulf a small amount of extracellular fluid/ content to help with cellular processes or rebuilding cell membrane
5
Q
What is receptor-meditated endocytosis?
A
requires binding to a receptor
needs coded proteins
6
Q
What is the function of clathrin?
A
clathrin is a protein that is under the cell membrane and helps the ligand-bound receptors engulf the ligand from the surface
7
Q
What is the function of clathrin?
A
clathrin is a protein that is under the cell membrane and helps the ligand-bound receptors engulf the ligand from the surface
8
Q
What is the distribution of cholesterol in the cell membrane bilayer?
A
evenly distributed in both leaflets of bilayer
9
Q
What is the distribution of phospholipids in the cell membrane bilayer?
A
asymmetric
10
Q
What is the distribution of glycolipids in the cell membrane bilayer?
A
exclusively on outer leaflet of bilayer
11
Q
What are the two faces on an electron micrograph image of a cell membrane?
A
E - face
P - face
12
Q
What is the E-face on an electron micrograph image of a cell membrane?
A
inner surface of outer leaflet
closer to extracellular space
13
Q
What is the P-face on an electron micrograph image of a cell membrane?
A
outer surface of inner leaflet
closer to protoplasm
14
Q
What is the protoplasm?
A
all living parts of the cell on the inside (organelles)
15
Q
What two types of proteins are found in the cell membrane?
A
integral proteins
peripheral proteins
16
Q
What are integral proteins?
A
span across the whole membrane (ex. receptors, ion channels)
17
Q
What is the glycocalyx?
A
a coating on the cell membrane that helps cells adhere to and recognize one another
18
Q
What is the fluid mosaic model?
A
proteins are clustered in the lipid bilayer but they can move around
19
Q
What does the membrane asymmetry of the fluid mosaic model refer to?
A
proteins usually stay on their own sides of the membrane
20
Q
What does the membrane mobility of the fluid mosaic model refer to?
A
proteins can either move rapidly around the membrane or be held stable by intracellular structural elements
21
Q
What are the most common type of membrane receptors?
A
integral membrane glycoproteins
22
Q
What are the three domains of glycoproteins?
A
extracellular, transmembrane, and intracellular
23
Q
What are the three main functions of membrane receptors?
A
- control membrane permeability
- bind extracellular matrix molecules to cytoskeleton via integrins
- relay messages to respond to extracellular events
24
Q
What are venoms?
A
inactivate acetylcholine receptors of skeletal muscle sarcolemma at neuromuscular junctions
25
What is the function of channel-linked receptors?
open when a ligand bind to allow molecules/ions to move across membrane
26
What is the function of enzymatic (catalytic) receptors?
ligand (usually protein kinases) that bind the receptor induces catalytic activity in associated peripheral proteins
27
What is the function of G-protein coupled receptors?
ion channels/enzyme bound to the cytoplasmic surface of the cell membrane;
bind ligands that change the shape of its G-protein subunit, activating intracellular second messengers
28
What is the most common G-protein coupled receptor pathway?
cyclic adenosine monophosphate (cAMP), Ca2+, and inositol phospholipid-signaling pathway
29
What is familial hypercholesterolemia?
inability to take in cholesterol normally ingested by receptor-mediated endocytosis of LDLs
30
What are venoms?
inactivate acetylcholine receptors of skeletal muscle sarcolemma at neuromuscular junction
31
What is the cause of autoimmune diseases?
self-antibodies that bind to and activate plasma membrane receptors
32
What are two diseases that result from a damaged G-protein?
```
Cholera toxin (diarrhea)
Pertussis toxin (whooping cough)
```
33
What organelles are at the root of all protein synthesis?
nucleus and ribosomes
34
What is the process to make vesicle-packaged proteins?
Nucleus → Ribosomes associated with rough ER → Golgi complex → vesicle packaging of proteins
35
What is the process to make cytoplasmic proteins?
Nucleus → Free ribosomes → Cytoplasmic proteins
36
What are cristae in the mitochondria?
folds in the inner membrane
37
What is the mitochondrial intercristae/matrix space enclosed in?
inner membrane
38
What ion granules are found in the mitochondrial matrix?
calcium
39
What are the three functions of the mitochondria?
1. citric acid and ATP synthesis
2. buffering of intracellular calcium (organelle of last resort)
3. induce apoptosis
40
How does hypoxia affect the mitochondria?
1. destroy proteins for oxidative phosphorylation
2. swells
3. ETC will be damaged
41
What tissues do mitochondrial defects affect the most?
tissues that use large amounts of ATP (ex. muscle cells and neurons)
42
What is the cause of myoclonic epilepsy with ragged-red fibers?
aggregation of abnormal mitochondria that look like red fibers due to mutation in mitochondrial DNA
43
What is myoclonus?
muscle spasms
44
What are the symptoms of myoclonic epilepsy?
muscle weakness
ataxia
seizures
cardiac and respiratory failure
45
What is ataxia?
impaired coordination
46
What are the components of ribosomes?
two subunits and rRNA
47
What is the function of ribosomes?
synthesize proteins
48
What is the template that ribosomes use to synthesize proteins?
mRNA
49
What is rough endoplasmic reticulum comprised of?
tubular system of membranes that is continuous with the nuclear membrane
50
What is the function of endoplasmic reticulum?
synthesize proteins
- secretion
- form other organelles
- package to transport to Golgi
51
What are the six functions of the smooth endoplasmic reticulum?
- detox
- steroid hormone synthesis
- cholesterol metabolism
- buffering of intracellular calcium (organelle of first resort)
- break down glycogen in liver
- lipid synthesis
52
What is the Golgi apparatus comprised of?
stacked cisternae with vesicles budding off
53
What are the three functions of the Golgi apparatus?
- receives proteins and lipids from rough ER
| - package proteins and send out
54
What enzymes do lysosomes contain?
hydrolytic (acid hydrolases)
55
In what cells are lysosomes abundantly present?
phagocytic cells (ex. macrophages)
56
What is the difference between primary and secondary lysosomes?
primary - brand-new assembled by Golgi complex
| secondary - activated when fused with phagosomes
57
What are phagosomes?
vesicles containing phagocytic materials
58
What are residual bodies?
works on breaking down debris that lysosomes have a hard time digesting
59
What do residual bodies contain?
lipofuscin - a yellowish fat soluble pigment
60
What do proteasomes break down?
cellular proteins that have been tagged by ubiquitin
61
What is the function of ubiquitin ligase?
connect proteins with ubiquitin
62
What are the four functions of peroxisomes (microbodies)?
- production and breakdown of hydrogen peroxide (bactericidal)
- lipid metabolism
- bile salt synthesis
- detox
63
What oxidative enzymes do peroxisomes contain?
amino acid oxidases
| hydroxyacid oxidase
64
What do peroxisomes use to break down hydrogen peroxide?
catalase
65
What are secretory granules?
small granules that release things outside of the cell (ex. neurotransmitters, hormones, enzymes, etc.)
66
What are three types of inclusions in the cell?
- fat droplets
- glycogen granules
- pigment deposits
67
What are the four different types of pigment deposits?
- melanin
- hemosiderin
- lipofuscin
- bilirubin
68
What are the three components of the cytoskeleton?
microtubules
actin filaments
intermediate filaments
69
How are microtubules formed?
alpha and beta subunits that grow off the "leading edge" into a cylinder
70
What are the four specialized types of microtubules?
centrioles
cilia + flagella
mitotic spindles
basal bodies
71
What are centrioles?
center for microtubule formation in cells
72
What is the arrangement of microtubules for centrioles?
9 sets of 3 with no central microtubules (9+0 arrangement)
73
What is the function of cilia and flagella?
propulsion
74
What is the arrangement of microtubules for cilia and flagella?
9 sets of 2 with 2 central microtubules (9+2 arrangement)
75
What is a basal body?
microtubule anchor at base of cilia and flagella
76
What are mitotic spindles?
centrioles that organize meiosis
77
List the three components in the cytoskeleton from smallest to largest diameter
microfilaments
intermediate filaments
microtubules
78
What is the function of intermediate filaments?
structural support
79
What is the specific intermediate filament for epithelial cells?
cytokeratins
80
What is the specific intermediate filament for muscle cells?
desmin
81
What is the specific intermediate filament for astrocytes?
GFAP (glial fibrillary acidic protein)
82
What is the specific intermediate filament for nuclei?
lamins
83
What is the specific intermediate filament for neurons?
peripherin
84
What is the specific intermediate filament for mesenchymal cells?
vimentin
85
What is the function of microfilaments (actin filaments)?
cell movement
86
What is the cause of jaundice?
accumulation in extracellular fluid of bilirubin and other pigmented compounds
87
What organ usually metabolizes bilirubin?
smooth endoplasmic reticulum enzymes in liver cells
88
What are lysosomal storage disorders?
deficiency in specific lysosomal acid hydrolases
| compounds accumulate and interfere with cell function
89
What are the two peroxisomal diseases?
Zellweger syndrome
| Neonatal adrenoleukodystrophy
90
What is Zellweger syndrome?
normal peroxisomes are absent
91
How are microtubule dynamics used to treat cancer?
inhibitory compounds prevent cancerous cells from forming the mitotic spindle
92
What is neonatal adrenoleukodystrophy?
inability of peroxisomes to metabolize fatty acids
93
How are tumors diagnosed?
looking at intermediate filaments
94
How big is the nucleus?
5-10 micrometers
95
What is the nuclear envelope comprised of?
```
two membranes
perinuclear cisternae (space) in between
```
96
What allows for transport of macromolecules in the nuclear envelope?
nuclear pores
97
What organelle is the nuclear envelope continuous with?
rough ER
98
What are the two types of chromatin?
euchromatin
| heterochromatin
99
What are the locations of euchromatin vs. heterochromatin?
euchromatin - medially located
| heterochromatin - eccentric in location
100
What are the densities of euchromatin vs. heterochromatin?
euchromatin - light
| heterochromatin - dense
101
What are the transcriptional activities of euchromatin vs. heterochromatin?
euchromatin - transcriptionally active
| heterochromatin - metabolically inactive
102
What is a nucleosome?
smallest structural unit of chromatin
103
What is the nuclear lamina?
internal to inner nuclear membrane to which chromatin is attached
104
What is the function of the nucleolus?
assembles ribosomes
105
What does the nucleolus use to assemble ribosomes?
ribosomal proteins (from cytoplasm) and mature rRNA
106
What is karyokinesis?
division of the nucleus
107
What is cytokinesis?
division of the cell
108
What happens during the S phase?
replicates DNA and centrioles
109
What happens during prophase?
nucleolus disappears
dispersed chromosomes
nuclear envelope fragments
110
What happens during metaphase?
chromosomes line up
111
What happens during anaphase?
sister chromatids separate
112
What happens during telophase?
nuclear envelope reforms
| cytokinesis
113
What kinase controls mitosis?
cyclin-dependent kinases (associated proteins are cyclins)
114
What is p53?
tumor suppressant protein
115
What are the two divisions of meiosis called?
reductional
| equatorial
116
What is non-disjunction?
failure to separate - can lead to trisomies
117
What are the three types of cell death?
necrosis (after trauma)
apoptosis (natural cell turnover)
autophagy (controlled signaling process)
118
What is the process of necrosis?
1. cell membrane lyses
2. organelles swell
3. extracellular environment mixes with cytoplasm
4. debris is consumed by macrophages
119
What is the process of apoptosis?
1. cell condenses
2. membrane bulges
3. cytoskeleton breaks down
4. mitochondria activates death proteins
5. nucleus breaks down
6. rest of the cell breaks down
120
What is the process of autophagy?
cell uses lysosomes to destroy itself
121
What are the two determinants of membrane permeability?
hydrophobicity
| size
122
What are the two types of potential gradients?
electrical
| chemical
123
What is primary active transport?
when the ATP energy source is directly coupled to the transport process
124
What is the function of cardiac glycosides?
drugs that inhibit Na+ K+ ATP-ase
125
What is the function of a plasma-membrane Ca2+ ATPase (PMCA)?
extrude Ca2+ from the cell against an electrochemical gradient
126
What is the Ca : ATP ratio for PMCA?
1:1
127
What is the Ca : ATP ratio for SERCA?
2:1
128
What is secondary active transport?
when the transport of two or more solutes are coupled
| indirect use of ATP for energy
129
What are the two types of secondary active transport?
cotransport (symport)
| countertransport (antiport)
130
What is an example of cotransport (symport)?
Na+ and glucose
131
What is an example of countertransport (antiport)?
3 Na+ and 1 Ca+
132
What are the two solutions to an osmotic pressure difference?
increase osmotic pressure of surrounding fluid
| reduce molecules in the cell
133
What is the Na+ K+ ATPase stoichiometry?
3 Na+ out
2 K+ in
1 ATP
134
What happens to a RBC in hypertonic fluid?
shrivels (crenated)
135
What happens to a RBC in hypotonic fluid?
swells
136
What happens to a RBC in very hypotonic fluid?
lyses
137
What feature of the cell membrane is used for high rates of water transport?
aquaporins
138
What organs have high rates of water transport?
kidney
lungs
salivary glands
139
What is a channel vs. a carrier?
channel - simple hole, selective, gated
| carrier - conformational changes after binding
140
What is the order of "channel" "carrier" and "pump" from most to least specific?
pump
carrier
channel
141
What is the function of ATP binding cassettes?
convert the energy gained from ATP hydrolysis into movement of substrates either into the cytoplasm (import) or out of the cytoplasm (export)
142
What is the function of multi-drug resistant proteins?
ABC transporters
| pump out hydrophobic molecules
143
What is the cause of cystic fibrosis?
inhibition of Cl- membrane permeability which leads to increased viscosity of body secretions
144
What is the ABC associated with cystic fibrosis?
cystic fibrosis transmembrane regulator (CFTR)
145
What are the two properties that impact ion channels?
gating
| ion selectivity
146
What are the four different types of ion-gated channels?
voltage
ligand (extracellular)
ligand (intracellular)
mechanical
147
What is the purpose of patch clamping?
to study ionic currents
148
What three features do all forms of carrier-mediated transport share?
saturation
stereospecificity
competition
149
What are the steps for a stem cell to become a mature cell?
stem cell
transit-amplifying cell/colony forming units
blast cells
mature cells
150
Where are totipotent stem cells found?
zygote or early embryo
151
What do totipotent stem cells become?
pluripotent embryonic stem cells
152
Where are pluripotent embryonic stem cells found?
blastocyst
153
What do pluripotent embryonic stem cells become?
multipotent adult stem cells
154
What are multipotent adult stem cells found in?
every tissue and organ in adults
155
What are induced pluripotent stem cells?
somatic (adult) cells reprogrammed to enter an embryonic stem cell–like state
156
What are blast cells?
more restricted developmental choices than stem cells
157
What are the hematopoietic blast cells?
myeloblast
| erythroblast
158
What are the neural blast cells?
neuroblast
159
What are the osteogenic blast cells?
osteoblasts
160
What is the relationship between daughter and parent blast cells?
Daughter cells are often more mature than the parent
| cell.
161
What are mature cells?
Final commitment to a specific cell fate
162
What are transit-amplifying cells?
can proliferate and self-renew to produce more mature daughter cells
163
What is parenchyma?
functional cells of that organ
164
What is stroma?
supporting cells and tissues
165
What is the general organization of solid tissues?
parenchyma and stroma
166
What is the general organization of tubular tissues?
epithelium
basement membrane
lamina propria
tissue-specific lamina
167
What is the basement membrane?
an acellular barrier
168
What is the lamina propria?
connective tissue support
169
What is adventitia?
loose connective tissue that connects the organ to the surrounding tissues
170
What is serosa?
thin membrane lining the closed cavities of the body; has two layers with a space between that is filled with serous fluid
171
What three components does the formation of an organ require?
cells
programming and growth factors
extracellular matrix
172
What two components of and organ interact to influence its shape?
cell and matrix
173
What is chemotaxis?
chemical signals that tell cells where to go
174
How does notch influence the fate of tissue?
differentiates arterial and venous tissue
