Cell biology Flashcards
1
Q
Light microscope use _____ as source of radiation
A
light
2
Q
Electron microscope use ____ as source of radiation
A
electrons
3
Q
Similarities b/w plant cells and animal cells
A
-cell membrane
-nucleus—->chromatin—->DNA—->nucleolus
-cytoplasm
-organelles(mitochondria & Golgi)
4
Q
The organelle that contains in only animal cells but lacks in plant cells is
A
Centriole-cell division mhr pr
5
Q
Organelles that contains in only in plants cells
A
1)cell wall
2)plasmodesmata(plant cellမှာ neighboring cellsတွေကိုlinkလုပ်ပေး)
3)vacuoles (animal cellsမှာပါပေမဲ့ it’s not permanent)
4)Chloroplasts-chlorophyll
6
Q
In plant cell,vacuole is surrounded by a membrane called____
A
tonoplast
7
Q
Which cell is bigger?
plant cell or animal cell?
A
plant cells
8
Q
Cell walls are ______ permeable and cell membrane is ______ permeable
A
cell wall-freely permeable
cell membrane-partially permeable
9
Q
Image obtained by electron microscope are true-colour.
True or false?
A
false
they’re false-colour (stainလုပ်ထားတဲ့အပိုင်းတွေကပိုdarkဖြစ်)
10
Q
Only _____ material is examined by electron microscope.
A
dead
11
Q
Glycogen are present in cytoplasm.
True or false?
A
True
12
Q
Why electron microscope have better resolution?
A
b/c electrons has very short wavelength
13
Q
The _____ membrane of nucleus is continuous with ______
A
outer
ER
14
Q
Nucleus is _____ organelle and it is surrounded by ______
A
Largest organelles
double membrane called nuclear envelope
15
Q
What are nuclear pores and their function?
A
nuclear pores are small pores on nuclear envelope
func-exchange of material b/w cytoplasm and nucleus
16
Q
in nucleus,chromosomes are loosely coiled into _____
A
chromatin
17
Q
Function of nucleolus
A
ribosome synthesis (esp: rRNA)
18
Q
Chromosome contain ____
A
DNA
19
Q
Difference b/w rough ER and Smooth ER
A
Rough ER contains ribosomes in its membrane and smooth ER lacks ribosome
20
Q
Function of ribosome
A
Protein synthesis
21
Q
Structure of ribosome
A
large and small subunit
22
Q
Ribosome is made of _____ and _____
A
rRNA and protein
rRNA-ribosomal RNA
23
Q
Functions of smooth ER
A
synthesis of lipids and steroids. (cholesterol,and reproductive hormones like testosterone and estrogen)
24
Q
Function of Golgi body
A
Protein modification and transport
(eg.Golgi vesicles are also used to make lysosomes)
25
Structure of lysosome
spherical sac surrounded by a single membrane and no internal structure
26
Lysosome contains_____
digestive (hydrolytic) ensymes
27
Function of lysosome
-breakdown of macromolecules
-autophagy of organelles
-autolysis of damaged cells or organelles
-breakdown of unwanted organelles such as old ones or whole cells
eg.mammary glands after lactation
28
In WBC, lysosomes are used to digest____
bacteria by PHAGOCYTOSIS
phagocytosis-cell eating
29
Heads of sperm contains____ for ____
acrosome (specialized lysosome)
for digesting path to egg
30
Cell structure that are surrounded by double membrane
1)nucleus
2)mitochondria
3)Chloroplasts
31
The inner membrane of mitochondria is folded into _____
cristae
32
The outer membrane of mitochondria contains ______
transport protein called porin
33
Membrane permeability of mitochondria
Outer membrane-less selective
Inner membrane-more selective
34
Which cells contains many mitochondria?
Cell with high demand of energy
(eg.liver and muscle cells)
***RBC do not contains mitochondria ***
35
Function of mitochondria
-ATP synthesis
-lipid synthesis
36
ATP is _____ molecule found in all living cells
energy-carrying
37
Aerobic respiration takes place in _____ of mitochondria
inner membrane and matrix
38
Mitochondria contains ribosomes.
True or false?
True
The chloroplast and mitochondria contains smaller(70S) ribosomes while cytoplasmic ribosomes is larger (80S).
****Bacteria contain 70S ribosomes****
39
Mitochondria and chloroplasts contains DNA.
True or false?
True
It contains small circular DNA like bacteria
(mitochondrial DNA-maternal DNA)
40
Microtubule structures
long, rigid , hollow tubes found in cytoplasm
(microtubule+actin+intermediate filament—->cytoskeleton)
cytoskeleton maintain cell shape.
41
Microtubules is made up of _____ protein.
Tubulin- alpha and beta tubulin
(alpha+beta—>dimer)
dimerတွေအများကြီးပေါင်းထား—->protofilaments
Microtubulesကိုcross sectionဖြတ်ရင် 13 protofilamentsရှိ
42
Centrioles contains _____ of microtubules
nine triplets
43
Centrioles are found at base of _____
cilia and flagella
acts as microtubule organizing centres
44
Chloroplasts are surrounded by _____
double membrane
45
Chloroplasts and mitochondria replicate independently during cell division.
True or false?
True
46
Main function of chloroplast and shape
photosynthesis
shape-lens-shaped
47
Mitochondria and chloroplasts contains their own protein synthetic machinery.
True or False?
True
They contains circular DNA and 70S ribosome
48
Prokaryotic cells lacks ____ and _____contains ____ ribosomes.
Their DNA structure
Lacks nucleus
lacks membrane bound organelles
70S ribosomes
DNA (circular & lies naked in cytoplasm)
49
Eukaryotic cells contains ____ and _____contains ____ ribosomes.
Their DNA structure
-Nucleus
-membrane bound organelles
-80S ribosomes
-DNA(linear and lied within the nucleus (protein bound DNA)
50
Source of radiation for light microscope and electron microscope
L- light
E- electron
51
Lenses that used in light microscope and electron microscope
L-glass
E-electromagnets
52
Specimen for light microscope and electron microscope
L-living, nonliving or dead
E-nonliving or dead
53
Stains used for light microscope and electron microscope
L-colored dyes
E-heavy metals
54
Images of light microscope and electron microscope
L-colored
E-B & W
55
Organelles with no membrane
1)Nucleolus
2)ribosome
3)centrioles
4)centrosomes
5)microtubules
56
Organelles with a single membrane
1)RER
2)SER
3)Lysosomes
4)Golgi
5)Peroxisome
6)Vacuoles
57
SEM shows ______
3D image of surface of specimen
58
TEM shows______
internal structure of the cell
59
What is cell fractionation?
separation of cell’s major organelles and other sub-cellular structures
is carried out by CENTRIFUGE
60
Which type of microscope is used to study
1)internal structure of plant cells and
2)fluorescently labeled nervous tissue?
1)Transmission electron microscope
2)Light microscope
61
Prokaryotes and Eukaryotes
Prokaryotes
1)Bacteria
2)Archaea
Eukaryotes
1)Animal
2)Plants
3)Fungi
4)Protists (unicellular eukaryotes)
62
Similarities b/w prokaryotes and eukaryotes
1)cell membrane
2)cytosol
3)DNA
4)Ribosomes
63
Difference b/w prokaryotes and eukaryotes
1)Location of DNA
Pro-nucleoid (circular DNA)
Eu-Nucleus (linear DNA)
2)size Eu>pro
3)Organelles
Pro-no
Eu-yes
64
Size of smallest bacteria, typical bacteria and eukaryotic cells
Smallest bacteria: 0.1-1 micrometers
Typical bacteria: 1-5 micrometers
Eukaryotic cells: 10-100 micrometers
65
All human cells have nucleus. True or false?
False
RBC do not have nucleus but skeletal muscle have multinucleus
66
Function of Nucleus
-stores genetic information
-controls and coordinates the cell
67
Nucleus is surrounded by _____
double membrane called nuclear envelope
68
The outer membrane of nuclear envelope contains ____ and inner membrane contain_____
Ribosome
Protein Lamina
69
Function of Nuclear Lamina
Nuclear lamina aka intermediate filament
Func:maintain the shape of nucleus &
breakdown and assembly of nuclear envelope
70
Nucleoplasm is_____
cytoplasm inside nucleus and site of metabolic reactions
71
Chromatin is complex of ____ and _____
DNA and histone protein
72
Types of chromatin
1)Euchromatin(loose)- centre of the nucleus
2)Heterochromatin(tight)- near inner membrane
73
Ribosomes are synthesized in _____ but only functions in _____
Nucleus
Cytoplasm
74
What is 70S ribosome?
ribosome found in prokaryotes (as well as in mitochondria and chloroplasts)
50S subunit+ 30S subunit
75
What is 80S ribosome?
ribosome contains in eukaryotes
rRNA(60%) + protein (40%)—-> 80S
76
What are 4 binding site for ribosome?
one for mRNA
and three for tRNA(A,P,E)
77
Types of ribosome
1)Free ribosomes-cytosol
2)Bound ribosomes-bound to RER and nuclear envelope
3)Polyribosomes
4)70S in mitochondria and chloroplasts
78
Proteins synthesized from free ribosomes are used ______
mainly within the cytosol
79
Proteins synthesized from bound ribosomes are used ______
for secretion and for lysosomes
80
RER member is continuous with______ and _______
outer membrane of nuclear envelope
SER
81
ER membrane is physically interconnected.True or False?
True
82
Golgi membranes are physically interconnected.True or False?
False
83
Structure of RER
sac-like structures (cristernae)
contains ribosomes on surface
84
Structure of SER
tubular structure
no ribosomes on surface
85
Function of RER
1)Protein synthesis
2)Protein Folding
3)Glycosylation( glycoproteinပေါင်း)
4)Packaging (transport vesicles နဲ့ RERဆီပို့)
86
Why pancreatic cells contains many ribosomes?
b/c the pancreatic cells produces many proteins
87
Function of SER
1)Glucose metabolism
2)Lipid synthesis____steroid hormones synthesis sites
3)Detoxification of drugs and poisons___liver cells
4)Stores Ca2+__muscle cells
88
Region of Golgi
1)cis face-receive vesicles from RER and SER products
2)modification and sorting
3)trans face-transport vesicles
89
Golgi manufactures ______
some polysaccharides
90
Lysosomes contains
HYDROLYTIC ENZYMES
1)Proteases-protein breakdown
2)Lipases-Lipid breakdown
3)Nucleases-Nucleic acid breakdown
4)Glycosidases-Carbohydrates breakdown
91
enzymes of lysosomes show greatest performance in ____
acidic environment
92
Both hydrolytic enzymes and lysosome membranes are synthesized by
RER—>Golgi—>lysosome
93
Types of vacuoles
1)Food vacuoles
2)Contractile vacuoles
3)Sap vacuole
4)Air vacuole
94
Function of vacuole
Stores water and mineral
Maintain hydrostatic pressure (turgor)
in plant,central vacuole plays major role in growth of plant cells
95
In plant,solution inside the central vacuole is called
cell sap
96
Why is endosymbiont theory?
eukaryotic cells engulfing an oxygen-using nonphotosynthetic prokaryotic cells
(cells living within another cell)
97
Why mitochondria and chloroplasts are considered as endosymbiosis organelles?
1)They are bound by double membrane
2)They contain circular DNA and 70S DNA like prokaryotes
3)They are autonomous (independently grow and reproduce within the cell)
98
Mitochondrial matrix contain_____ and _____
enzymes
mitochondrial DNA and ribosomes
99
In chloroplast, DNA and ribosomes are contained in_____
stroma, the fluid inside chloroplats
100
What is thylakoid?
Interconnected disc-shaped sacs within the chloroplast
101
Thylakoids are stacked into ____ and are suspended in_____
Grana
Stroma
102
Structure of peroxisome
spherical shaped organelle surrounded by a single membrane
103
Peroxisomes contains _____ enzymes
oxidative enzymes (eg.oxidases and catalases)
104
How H2O2 is produced in peroxisomes?
enzymes removes H2 from substances and transfers it to O2 to form H2O2 as byproduct
But H2O2 is toxic and it is then converted into water by catalases
105
Function of peroxisomes
1)oxidation
2)fatty acid oxidation (esp:beta)
3)Lipid synthesis
4)Alcohol breakdown in liver
106
Enzymes contained in peroxisomes are made from_____
free ribosome
(because peroxisomes is not a part of the endomembrane system)
107
Lysosomal enzymes are made from _____
bound ribosomes of RER
Because lysosome are part of the endomembrane system
108
What is cytoskeleton?
a network of fibers in cytoplasm
109
Types of cytoskeleton
Microtubules-thickest
Microfilament-thinnest
Intermediate filament
110
Function of cytoskeleton
Support-mechanical support and maintenance of cell shape
Cell motility-change in cell location and movements of cell parts
111
Cell motility can be carried by interaction b/w ____ and _____
cytoskeleton
motor proteins
112
Structure and Proteins that made up microtubules
Structure-hollow tube
Globular protein called Tubulin
Tubulin-a dimer containing 2 subunits (alpha and beta)
113
Structure and Proteins that made up microfilaments
Structure-thin solid strands
Globular proteins called actin(2 strands ပါ)
strands are twisted
114
Structure and Proteins that made up Intermediate filaments
Structure-cable shaped
Fibrous proteins (Keratin)
115
Is all 3 types of filaments are found in all eukaryotic cells
No
Microtubules and microfilaments are found in all eukaryotic cells
but intermediate filament are found in some animal cells(vertebrates)
116
Microtubules contains 2 ends, which ends can accumulate or release dimer at higher rate than other end?
Plus end
117
Microtubules grow in length by adding_____
tubulin dimer at plus end
118
Function of microtubule
1)maintain cell shape and intracellular movement (compression bearing)
2)Separation of chromatids in cell division(centriolesကလုပ်)
3)Cell extension(eg.cilia and flagella)
119
Microtubules grow from _____
centrosome(near nucleus)
*animal cells only*
120
Centrosomes contains____
a pair of centrioles
121
Flagella and cilia is differ in ____
beating pattern
122
What is motile cilia and non motile cilia?
Motile cilia-present many in cell surface
Non motile cilia-present as a signal receiving antenna and contains only one
123
What is difference b/w cilia and flagella ?
flagella -longer than cilia, only one
Cilia-short,many on surface
124
Structure of microtubules in motile cilia and flagella
9+2 arrangement——>9 doublet arranged in ring and 2 single at center
(9 outer and 2 centre is joined by cross-linking proteins)
(9 is interconnection by dyneins motor proteins)
125
Structure of microtubules in nonmotile cilia
9+0
9 doublet outer microtubules + 0 at center
126
Function of microfilaments
1)support cell shape(tension bearing)
2)Cell motility(actin+myosin->contraction)
3)Cytoplasmic streaming(plant cells,circular flow of cytoplasm within cells)
4)cytokinesis of mitosis
5)Phagocytosis of WBC
127
After cell die ,is all filaments remains in the cells?
No
only intermediate filament remains
128
Function of intermediate filament
1)Formation of Nuclear lamina
2)Support cell shape(tension)
3)anchorage
cell-cell
cell-ECF
cell-organelles
nucleus-organelles
129
Function of cell wall
Protects cells
maintain cell shape
prevents excess water intake
130
which is thicker?
plant cell wall or plasma membrane
cell wall
131
Cell wall is made up of ______
microfibrils synthesized from cellulose (cellulose synthase)
132
A young plant cells secretes thin and flexible ______
primary cell wall
133
B/w primary wall of adjacent cells is called ____ and contains sticky polysaccharide called_____
middle lamella
pectins(glue adjacent cells)
134
When plants mature and stops growing,it secretes _______
secondary cell wall(more strength)
135
Extracellular matrix mainly contains_____
glycoproteins (proteins with short chains carbohydrates)
136
Most abundant glycoprotein in ECM of animal cells is_____
Collagen
137
Collagen are embedded in network of _____
proteoglycans
138
What is proteoglycan complex?
core proteinsမှာshort carbohydrates တွေအများကြီးပေါင်းနေ_____အဲ့core proteinsတွေအကုန်လုံးကsingle polysaccharide strandတခုမှာသွားပေါင်း
139
What is fibronectin?
glycoproteins which are attached to ECM
140
Fibronectin and other cell surface receptors are attached to ______ protein
intergrin proteins-cell surface receptor proteins built in plasma membrane
141
Cytoplasm of adjacent cells in plant calls are connected by ______
plasmodesmata
142
Types of cell junctions in animal cells
1)Tight junctions
2)Desmosomes
3)Gap Junctions
143
All 3 types of cells junctions are common in_____
epithelial tissue
144
What are tight junctions?
impermeable junctions
(prevent molecules from passing through intercellular space)
145
What are desmosomes?
anchoring junctions that binds adjacent cells
146
What are Gap junctions?
allows for intercellular communication (membrane ကနေဖြစ်တာမဟုတ် contains channels)
147
Prokaryotic cell wall is composed of
peptidoglycan
148
Eukaryotic cell wall is composed of
cellulose
149
Which is bigger animal cells or plant cells
Plant cells- 10 to 100 micrometer Animal cells- 5 to 30 micrometer
150
Cell size prokaryotic and eukaryotic which is bigger
Eukaryotic cells
151
From the largest to lowest
Nucleus mitochondria chloroplast Golgi ER lysosome virus E coli plasma membrane ribosomes egg sperm RBC
Egg——> sperm——>RBC——>nucleus——>chloroplasts—— >mitochondria ——>ER——>Golgi——>Ecoli——> lysosome—>virus ——>ribosomes——> plasma membrane———> width of DNA molecules
Mitochondria’s size is 1 to 5 Micrometer
Some bacteria are larger than mitochondria
152
Why do cells need to divide?
Surface area growth is slower than the volume growth
Insufficient plasma membrane not enough materials at the center therefore cells divide
153
Do light microscopes and electron microscope kill cells?
Yes. Light microscope- stains kill cells Electron microscope-kill cells too
154
Structures that are contained in both eukaryotes and prokaryotes
1. Plasma membrane
2. DNA
3. Cytoplasm
4.Ribosomes
Can carry out protein synthesis
155
In bacteria where is genetic materials stored?
Stored in nucleiod-membraneless organelles
Also stored in plasmids- floating in cytoplasm
156
Does bacteria contain cell wall?
Yes made of peptidoglycans, also contain cilli and flagella
157
Extent in which light microscope can view and its magnification?
0.2 micrometer or 200 nanometer and its magnification 1000 times actual size
158
What kinds of lens both light and electron microscopes use?
LM-Glass
EM-Electromagnets lens
159
The image under microscope is———
Inverted. Left——> right
Right——>left
160
What is resolving power
The ability to see two separate points clearly
161
Difference between prokaryotes and eukaryotes
Eukaryotes
- Membrane bound organelles present
- DNA- multiple linear chromosome
- Multicellular
-DNA is protein bound
-Reproduced by sexual repiration
Prokaryotes
- Membrane bound organelles absent -DNA - single circular chromosomes -Unicellular
- DNA is naked
- Binary fission reproduction
162
What are membrane bound organelles
1. Nucleus
2. Mitochondria
3. ER
4. Golgi
5. Vacuoles and vesicles
6. Lysosome
7. Plastids -chloroplasts and small organelles in plants
163
Both DNA of eukaryotes and prokaryotes are double stranded. T or F
T
164
Smallest bacteria named mycoplasma size and largest bacteria size
Smallest- 0.1 to 1 micrometer
Largest - 1 micrometer
Some bacteria are larger than mitochondria Some are smaller v]
165
Larger organisms have larger cells than smaller ones . T or F
F.
They only have more cells.
166
Protists eu or pro?
Eu
167
What types of organism are prokaryotes
Bacteria and archaea
168
Components of bacteria
1. DNA in nucleoid
2. Cytoplasm
3. Cell wall
4. Plasma membrane
5. Pilli
6. Flagella
7. Ribosomes
8. Capsules
9. Plasmids
169
Largest organelles in a plant
Central vacuole——> nucleus——> chloroplasts
170
Largest organelles in an animal
Nucleus—-> centrioles——> mitochondria
171
Cytoplasm also contain ———- in addition to water
Enzymes, proteins, macromolecules and ions
172
Nucleus components
Nucleolus- synthesize rRNA for ribosome synthesis
Nuclear pores- allow entry of proteins and RNA, rRNA leaves the nucleus to the cytoplasm through the pores
Nuclear lamina- filaments maintain the shape of the nucleus
Nuclear envelope
Nucleoplasm - cytoplasm
173
Under what conditions , is the chromatin visible under the light microscope ?
Chromosomes coil and become thick enough to be seen as the cell prepare to divide
When a cell is not dividing, chromosomes cannot be distinguished
174
Subunits of eukaryotic and prokaryotic ribosomes
Eu- 40 S subunit+ 60 S subunits
Pro- 30S subunit+ 50 S subunits
175
Func of free and attached ribosomes
Free- enz to catalyze in the cytoplasm such as first step of sugar breakdown
Attached - destined proteins into membrane and packaging by endomembrane system
176
Ribosomes are present in pro. T or F
T
177
Where is mitochondrial DNA inherited?
From the mother’s side
178
What types of organelles have their own ribosomes?
Nucleus
Mitochondria
Chloroplasts
MT and CP also have DNA similar to bacterial DNA, small and circular. Endosymbiosis
179
Cellular respiration takes place in the ———
Inner membrane cristae of the mitochondria
180
Mitochondria has ——- membranes
Outer and inner / double layer
181
What organelles reduce H202
Perioxisomes
Have enzymes to remove H2 from substrates and trensfer them to O2 to produce H2O2. But the organelles also contain enzymes h2o2 to water and oxygen or other molecules
182
Describes the structures that are not present in plants cells
Lysosomes and centrioles
Digestion take place in the vacuoles of the plant cells
183
Describe the sturctures present in the plant cells but not in animal cells
Cell wall
Plastids and chloroplasts
Central vacuole
184
Lysosome pH is ——— than that of the cytoplasm
Lower. More acidic
Large burst of many lysosomes ——> cell self digestion
185
How many types of vacuoles are there?
Contractile vacuole-pump excess water out of the cell thereby maintaining a suitable conc of ions and molecules inside the cell.
Food vacuole- phagocytosis and pinocytosis
Lysosome vacuole- enzymatic hydrolysis
Some plant vacuoles contain pigments
186
Autophagy
An enzyme to recycle the cell’s own materials , a damaged organelles or molecule get surrounded by lysosome , and fuse and the resulting small organic molecules are used for reuse
187
Tay sach disease is due to the lack of ———
Lipid digesting enzyme present in lysosome
The brain becomes impaired by an accumulation of lipids in the cells
188
Chloroplast structure
Double layer membrane
Thylakoid - membranous system fluid filled Stacks of thylakoids - granum
Light dependent reaction of photosynthesis takes place in the thylakoid membrane
Stroma- remaining fluid membrane other than the thylakoid
Light independent reaction of = photosynthesis takes place in the stroma
Also contain small, circular DNA and ribosomes
189
Which organelles are developed from endosymbiosis?
Scientists believe mitochondria and chloroplasts are once used to be microbiomes, that enter the organisms and survive as they are not destroyed by the host cells.
They contain
1. Double layer membrane
2. Small, circular DNA like the bacteria
3. Its own ribosomes to synthesize proteins
4. They both are autonomous , organelles that grow and reproduce within the cells
190
Func of central vacuole
Present in plants only Osmoregulation.
No water for days——> soil water less than plant cells water—-> water down to the soil—-> wit
Water——> soil water greater——> water travel up the cell——> expansion
191
Difference between vacuoles and vesicles
Vesicles fuse with plasma membrane , vacuoles do not Vacuoles are larger than vesicles
192
Cellular respiration stages where they take place
Glycolysis- cytoplasm
CAC- matrix
Oxidative phosphorylation - inner mitochondria membrane
193
Numbers of mitochondria depends on the type of cells
Yes.
194
———— cells do not have mitochondria
Rbc
195
Components of endomembrane system
1. Plasma membrane
2. Nucleus
3. ER
4. Golgi
5. Vesicles and vacuoles
Endomembrane system do not contain membranes of mitochondria and chloroplasts
196
——— accounts for more than half of the total membrane in eukaryotes
ER
197
Func of rough ER
Ribosomes- protein
Proteins and lipids of plasma membrane synthesis
Modification of proteins
198
Func of smooth ER
1. Detoxification in liver cells
2. Sarcoplasmic reticulum stores Ca ions
3. Produce lipids such as oil, steroids hormones and plasma membrane
199
Cells that secrete steroid hormones such as adrenal glands are rich in ———
Smooth ER
200
Detoxification in the liver in done by———
Addition of hydroxyl group to make the molecule polar easier to flush from the body
201
Cells that engage in a great deal of secretion presents ——
Golgi body
Cis surface——> cisternae——> trans surface
Modification of proteins such as phosphorylation to direct to the destined areas.
ER also has cisternae
202
Bacteria cell wall is made of .....
Murein peptidoglycan
203
Cytoskeleton can also support cell motility.
Yes or no
Yes cytoskeleton with the motor proteins
204
Shape of the microtubules, size and func
Shape- tube like
Func- resist compression, cell motiliy Size- thickest in three cytoskeleton
205
Cytoskeletons can be seen with a light microscope. True or flase
True
206
Microtubules are ———
Polar because they contain alpha and beta tubulin, two subunits one positive charge and the other negative charge
207
Eukaryotes can be unicellular
T or F
True
208
Cilia and flagella contain ————
Microtubules , special arrangement of microtubules is responsible for beating of the cilia and flagella
Though different in length, number per cell, and beating pattern, motile cilia and flagella share a common structure. Each motile cilium or flagellum has a group of microtu- bules sheathed in an extension of the plasma membrane. Nine doublets of microtubules are arranged in a ring with two single microtubules in its center. This arrangement, referred to as the “9 + 2” pattern, is found in nearly all eukaryotic flagella and motile cilia. (Nonmotile primary cilia have a “9 + 0” pattern, lacking the central pair of microtubules.)
Microtubules is anchored in the cilia and flagella by basal body.
209
Microfilament func
Also called actin filament, muscle contraction, resist tension, cell motility
210
Intermediate filaments is found in all plants and animals. T or F
False. Only found in cells of some animals , including vertebrates
211
Intermediate filaments func
Shape of the cell , fixing the position of organelles, make up nuclear lamina
212
Keratin filaments are——
Intermediate filaments, more permanent fixtures do cells than are microfilaments and microtubules , which are often disassembled and reassembled in various parts of a cell
213
Signaling cells secrete——— that bind——to initiate a change of events in the cell/
Ligands molecule/ receptors
214
What is the action of epinephrine ?
Epinephrine is used in anti inflammatory response
But when glucose level is low, epinephrine is released, they covert glycogen to glucose in the liver.
215
What kinds of cellular junctions allow the passage of signaling molecules between neighboring cells?
Gap junction and plasmodesmata
216
Stages involved in cellular pathway
Reception——>signal transduction——>cellular response
217
How does ligands such as steroids bind to receptor?
They fuse into the cell and bind with the internal receptor. Ligand- receptor complex moves to the nucleus and interacts with the cellular DNA and influenced the genes it expressed.
218
How does polar ligands interact with the receptors?
By binding to the membrane receptor. Some membrane receptors change conformation so that certain ions such Na+ and K+ can pass through the membrane. Other membrane receptors interact with the G protein on the cytoplasmic part of the membrane, which causes series f reactions inside the c ell.
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Some receptors can bind several ligands true or false?
Yes. Smell receptors
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A specific ligands only bind to a specific receptor/ true or false
True
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How many types of signaling are there?
There are four categories of chemical signaling found in multicellular organisms: paracrine signaling, endocrine signaling, autocrine signaling, and direct signaling across gap junctions
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What are paracrine signals?
Signals that act locally between cells that are close together are called paracrine signals. Paracrine signals move by diffusion through the extracellular matrix
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Paracrine cells are quickly removed or degraded by enzymes or neighboring cells. Why?
To restablish the conc gradient for the signals
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Endocrine signals originate from———
Endocrine cells
Hypothalamus, pituitary and thyroid gland
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The response from endocrine gland is ——
Slow but long lasting
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The ligands of the endocrine glands are—— and they travel via ——
Hormones And blood
Because of their form of transport, hormones get diluted and are present in low concentrations when they act on their target cells. This is different from paracrine signaling, in which local concentrations of ligands can be very high.
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When do autocrine signalling take place ?
This type of signaling often occurs during the early development of an organism to ensure that cells develop into the correct tissues and take on the proper function
this process of stimulating a group of neighboring cells may help to direct the differentiation of identical cells into the same cell type, thus ensuring the proper developmental outcome.
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Where do paracrine signals act on?
On the same cell or a similar cell.
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What does autocrine signalling also regulate?
Regulates the pain sensation and inflammatory responses. Further if a cell is infected with a virus , can signal itself to programmed cell death apoptosis.
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Direct signalling through cell junction interact between what type of cells
Adjacent cells.
The transfer of signaling molecules communicates the current state of the cell that is directly next to the target cell; this allows a group of cells to coordinate their response to a signal that only one of them may have received. In plants, plasmodesmata are ubiquitous, making the entire plant into a giant communication network.
Gap junction allow small signaling molecules called intracellalar mediators to diffuse between two cells.
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Two types of receptors are—— and ——
Internal receptor and cell surface receptor
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Intracellular receptors are located in the——- and respond to —— molecules
Cytoplasm a of the cell and hydrophobic molecules that can travel across the membrane
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When the intracellular receptor binds to ligand, what happens next?
Conformational change in the receptor protein and exposes DNA binding site and interfere with the gene expression.
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What type of cell signaling influence the green expression without having to pass the signals on to the other receptors or messengers?
Intercellular receptor+non polar ligands
Directly interfere with the gene expression
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Cell surface-receptors are ———or——- proteins
Transmembrane receptor or integral proteins
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What happened when the receptors proteins are defect?
Lead to many diseases such as hypertension, asthma and heart disease
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What are the components of the cell surface receptor?
Three components
1. Extracellular domain (external ligand binding domain)
2. Hydrophobic membrane spanning region
3. Intracellular domain
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What are the three categories of the cell surface receptor?
Ion-channel linked receptor
G protein linked receptor
Enzyme linked receptor
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Ion channel linked receptor mechanisms
Allow the passage of ions through the membranes . When a ligand binds to the extracellular domain of the channel, conformational changes occur and allow ions such as sodium, calcium, magnesium to pass through
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