cells Flashcards
(225 cards)
1
Q
wt can flip in the membrane ?
A
cholestrol but phospholipids dont
2
Q
which protein is a part of cytoskeleton ?
A
peripheral protein
3
Q
which protein works as a receptor ?
A
integral
4
Q
functions of plasma membrane ?
A
1- physical barrier
2- selective
3- communication
4- cell recognition
5
Q
which protein interacts with both nonpolar and the water ?
A
intergral proteinss
6
Q
how do we connect two cells together ?
A
cell junctions
7
Q
which junction is impermeable junction ?
A
tight junction
8
Q
which junction forms continous deals around the cell ?
A
tight junction
9
Q
which junction prevents molecules from passing bw cells ?
A
tight junctions
10
Q
which junction are anchoring junctions ?
A
desmosomes
11
Q
which junction bind cells together like molecular velcro ?
A
desmosomes
12
Q
which cell junction help keep cells from tearing apart ?
A
desmosomes
13
Q
which junction is responsible for communicating ?
A
gap junctions
14
Q
which junction allows ions and small molecules to pass from CELL TO CELL ?
A
gap junctions
15
Q
which junction is important in heart cells and embryonic cells ?
A
gap junctions
16
Q
which gap junction keeps everything going in hermony ?
A
gap junctions
17
Q
how do the subs move through the plasma membrane ?
A
passive or active processes
18
Q
whate are the three types of passive transport ?
A
simple diffusion , facilitated diffusion and osmosis
19
Q
the speed of diffusion is influenced by three factors
A
concentration - molecular size and temp
20
Q
wt determines whether a subs can cross the plasma mambrane ?
A
lipid solubility ( so the more lipid ) the faster it will diffuse , the smaller the molecule
21
Q
wt is the other name of simple difffusion ?
A
unassisted diffusion
22
Q
wt is the other name of facilitated diffusion ?
A
assisted diffusion
23
Q
which diffusion does the subs diffuse directly ?
A
simple diffusion
24
Q
how are the subs transported in facilatated diffusion ?
A
either bind to a carrier proteins in the membrane or moves through water filled channel proteins
25
wt are the two ypes of facilitated diffusion ?
carrier mediated faciliated diffusion or channel mediated facilitated diffusion
26
wdym by carrier facilitated diffusion ?
transmembrane proteins that are specific for transporting certain polar molecules
27
give me an example of what carrier mediated facilitated diffusion
sugars and amino acids , too large to pass through the membrane
28
wdym by carrier mediated transport is limited and wt is the other name for it ?
when all glucose carriers are engaged they are said to be SATURATED
29
wt do channel mediated facilitated diffusion transport ?
ions or water
30
wdym by osmosis
diffusion of a
solvent such as water
through a specific
channel protein
31
when does osmosis happen ?
it occurs whenever the water concentration differs on the two sides of a membrane
32
wdym by osmolarity ?
a way of measuring how concentrated a solution is with solutes
33
solutes and solution has a what kind of relationship ?
indirect propotional
34
osmatic pressure is high when ?
the amount of solutes is grater than solution
35
what do we mean by hydrostatic pressure ?
pressure exerted by the water inside the cell against cell wall
36
what do we mean by isotonic solution ?
same concentration and their shape dosent change
37
what do you mean by hyoertonic solutions ?
it has a high concentration of solutes outside than the inside
38
wt happens to the cell in hypertonic solutions ?
they shrink and loses water
39
wt happens to the hypotonic solutions?
concentration of solutes is higher inside than the outside
40
wt happens to the hypotonic solution cells ?
cell gains water it swells and bursts
41
wt is the diff bw osmolarity and tonicity ?
osmolarity is based on its total solute concentration and tonicity is based on how the solution affects the cell volume
42
wdym by active process ?
whenever a cell uses energy to move solutes across the membrane
43
wt is a known example for primary active transport
Na - K pumu is an important example of primary active transport
44
how does the na k pump works ?
1- three cytoplasmic Na binds to the pump protein 2- Na binding promotes hydrolysis of atp the enrgy released causes the phosphorylates the pump 3- phosphorylation causes the pump to change shape expelling na to the outside 4-two extracellular k binds to the pump 5- k binding triggers release of the phosphate 6- the pump protein boiinds atp and releases k to the inside and Na sites are ready to bind Na + again
45
how does the Na - k Pump helps the cell ?
it insures the concentration of Na is low inside and k+ high inside and prevents the cell from swelling and bursting
46
wts the biggest diff bw active transport and passive ?
active from low to high concentration , passive from high to low concentration
47
what do we mean by primary active transport ?
the energy to do work comes directly from hydrolysis of atp by transport protein called pump
48
secondary can move more than one subs at a time true or false ?
true using a cotransport protein
49
wt is the other name for secondary active transport
cotransport
50
what do we mean by symport system ?
two substances move in the same direction across the membrane using the same transport protein
51
what do we mean by antiport system ?
two subs moves in opposite directions across the membrane
52
for what is the vesicular transport used ?
fluids containing large particles
53
does vesicular transport requires atp or gtp ?
yes
54
what do we mean by transcytosis ?
a subs is brought into the cell , transported across , and released on the other side so THROUGH THE CELL
55
what do we mean by vesicular trafficking ?
moves subs bw different areas within the cell like between organelles r
56
The proteins that are transported from endoplasmic reticulum to golgi apparatus is which way is it transported ?
vesicular trafficking
57
wt are the three types of endocytosis ?
phagocytosis , pinocytosis and receptor - mediated endocytosis
58
wdym by phagocytosis ?
the cell engulfs large or solid material
59
who is responsible for phagocytosis ?
macrophages and white blood cells
60
how do macrophages and white blood cells move to chase their target ?
like an amoeba
61
wdym by pinocytosis ?
a type of endocytosis where the cell takes in small droplets of extracellular fluid
62
wts the difference bw phagocytosis and and pinocytosis ?
phagocytosis engulfs large particles , pinocytosis absorbs fluid and dissolved substances
63
why is pinocytosis important ?
helps cells take in nutrients dissolved in fluids
64
which endocytosis is highly selective ?
receptor mediated endocytosis
65
wt is a receptor mediated endocytosis ?
a highly specific way for cells to take in important molecules from their surroundings
66
in receptor mediated wt happens to the contents after the vesicle moves into the cell
either used by the cell , passsed through the cell or broken down
67
wt is the downside of receptor mediated ?
some virsues and toxins trick this system to enter cells and cause infections
68
exocytosis is a type of which transsport ?
vesicular
68
wt are the subs taken up by the receptor mediated ?
enzymes , insulin and low density lipoproteins and iron
69
what is exocytosis used for ?
hormone secretion , neurotransmitter release , mucus secretion and waste removal
70
the inside of the cell is more negative than the outisde true or false ?
true
71
why is the inside negative ?
more k+ ion leak out of the cell so the inside of the cell looses positive charge which causes it to be more negative
72
why is membrane potential important ?
allows nerve cells to send signals and helps muscles contract and regulates ion movement across the membrane
73
what do we mean by cell adhesion ?
the act of cells sticking together
74
CAMS play a key role in wt ?
embryonic development and wound repair and immunity
75
wt are the functions of CAMs ?
- help cells stick to each other
- help migrating cells move past eash other during development
- SOS signals - cams send signals to wbc
-detect changes in the extracellular enviroment
76
wt are the roles of plasma membrane ?
contact signaling , chemical signaling
77
wdym by contact signaling ?
cells come together and touch and they recognize one another
78
wdym by chemical signaling ?
the process in which ligand binds a specifc receptor and initiates a response
79
why do diff cells respond so differently ?
each receptor is connected to a diff intracellular signaling networks
80
go through g protein
81
where can we find cytoplasm ?
between the plasma membrane and the nucleus
82
what does the cytoplasm consist of ?
cytosol , organelles and inclusions
83
wt is a cytosol ?
viscous , semitransparent fluid
84
wt can we find in the cytosol ?
largely water , proteins , salts and sugars
85
true or false inclusions are considered as non membrane bound
true
86
function of inclusions ?
serve as storage units
87
which organelles lack a membrane ?
ribosomes and centeioles
88
which organelle has a double membrane ?
mitochondria
89
which organelle is lozenge-shaped membranous?
mitochondria
90
which organelle provides most of the atp ?
mitochondria
91
which organelle contains their own DNA and RNA and ribosomes
mitochondria
92
which organelle can divide when the cell needs more atp ?
mitochondira
93
which organelle is responsible for protein synthesis ?
ribosomes
94
who is responsible for synthesizing ribosomes ?
nucleoulus
95
wt are the two main types of ribosomes
free ribosomes and membrane bound ribosomes
96
membrane bound ribosomes are attachedd to which endoplasmic ?
rough endoplasmic
97
main function of endoplasmic reticulum ?
stores calcium and forms lipids
98
which endoplasmic is responsible for the protein synthesis ?
rough endoplasmic
99
which organelle is involved in protein based ?
rough endoplasmic
100
after the proteins are made in rough endoplasmic they are sent to which organelle ?
golgi apparatus
101
wt are the functions of rough ER ?
1- cell membrane factory 2- synthesising proteins
3- folding proteins
4- glycosylation
102
main function of smothh er ?
-synthesis of lipid
-calcium storage
-involved in detoxifying harmful subs
-synthesize steroid based hormones
- breaks down stored glycogen into glucose
103
from where does the ribosomes synthesize proteins ?
amino acids
104
consists of stacked and flattened
membranous sacs, shaped like hollow dinner plates, associated
with swarms of tiny membranous vesicles , which organelle ?
golgi
105
wt does the golgi do to the proteins ?
golgi takes proteins and lipids that are made in the rough Er modifies them and then sorts and packages them into vesicles for delivering
106
golgi is made from what ?
cisternea
107
the cisternea usually faces which organelle ?
ER
108
spherical membranous sacs containing
a variety of powerful enzymes which organelle ?
peroxisomes
109
wt are the two powerful enzymes in peroxisomes ?
oxidases and catalases
110
for wt is the oxidases used in pero ?
to detoxify harmdul subs
111
wt is the function of oxidases ?
neutralising free radicals
112
Oxidases convert free radicals to hydrogen peroxide, which the ...................... quickly convert to water.
catalases
113
where can we find peroxisomes in our body ?
liver and kidney cells
114
true or false . pero can pinch in half ( fission )
true
115
how are new peroxi are formed ?
by budding off the endoplasmic reticulum
116
which organelle contains hydrolytic enzyme ?
lysosomes
117
wt is lysosomes responsible of ?
breaking down and digesting waste material and involved in autophagy
118
wdwm by autophagy ?
recycling damaged cellular parts
119
functionsss of lysosomes ?
1- digesting particles taken by endocytosis
2- breaking down old or damaged parts of the cell
3-performing metabolic functions
4- breaking down bone to release calcium ions into the blood
120
what do we call the process when the cell digest itself ?
autolysis
121
wdwm by endomembrane system ?
system of organelles that work together
122
wt do the endomembrane do ?
1- produce , degrade , storee and export biological molecules
2-degrade harmfull subs
123
wt is a cytoskeleton ?
network of rods running through the cytosol
124
wt are the three types of rods in the cytoskeleton ?
microfilaments , intermediate filaments and microtubules
125
what is the thinnest elements of the cytoskeleton ?
microfilaments
126
function of microfilaments ?
involved in cell motility
127
microfilament is made from wt ?
actin
128
which filament is tough ?
intermediate
129
which filament is made from twisted unites of tetramer fibrils
intermediate
130
intermediate filaments is attached to wt ?
desmosomes
131
main job of intermediate filaments ?
to act as internal cables to resist pulling forces
132
wt do we call intermediate filaments in nerve cells and epithelial cells
neurofilaments in nerve cells and keratin filaments in epithelial cells
133
which filament has the largest diameter
microtubules
134
are hollow tubes made of spherical protein
subunits called tubulin wt are we talking about ?
microtubules
135
microtubules is made from ?
centrosome
136
wt gives the movement to mitochondria , lysoso and secretory veicles ?
microtubules
137
wt does the centrosome do to the microtubules ?
organizes it
138
ech centriole consists of how many microtubules ?
nine triplets
139
who forms the bases of cillia and flagella ?
centrioles
140
are whiplike, motile cellular
extensions who ?
cilia
141
function of cilia ?
moves subs in one direction across cell surfaces
142
cilia are made from which filament ?
microtubules
143
flagella is formed by who ?
centrioles
144
microvili are involved in wt ?
absorption and increasing the surface area
145
where can we find microvilli ?
intestinal and kidney tubule cells
146
which cells are multinucleate ?
skeletal muscle cells , bone destruction cells and some liver cells
147
which cell looses its nucleus when it matures
red blood cells
148
why is nucleus important in cells ?
because without a nucleus a cell cannot reproduce mrna to make proteins and when the enzymes and cell structures break down they cannot be replaced
149
wt are the three structures of nucleus ?
nuclear envelope , nucleoli and chromatin
150
wt do we call the protective layer of the nucleus ?
nuclear envelope
151
wt is a nucleoplasm ?
the subs that fills the inside of the nucleus
152
who is responsible for making ribosomal subunits ?
nucleoli
153
is nucleoli a membrane bound ?
no
154
wt is a chromatin
mix of DNA , proteins and RNA
155
who provides a physical means for packing the very long DNA molecules in a compact ?
histones
156
who plays an important role in gene regulation ?
histones
157
wt does the methyl group on histone proteins do to the DNA ?
THEY SHUT IT DOWN , they turn of the gene
158
wt does the acetyl group do to the histones when added ?
exposes diff DNA segments , so turns on the gene
159
the dark staining and more easily detetcted is which chromatin ?
inactive condensed chromatin
160
How is the chromosomes formed ?
chromatin condenses
161
163
Which period id the cell formation to cell division ?
Interphase
164
Interphase is divided ito subphases
G1 , s and G2
165
Which subphase is the slowest and why ?
G1 because it could take years
166
Which subphase is the fastest ?
G2
167
Wdwm by G0
At rest
168
Who is at G0 ?
Neurons stay at G0 so u cant replace neurons
169
As G1 ends wt happens ?
Centrioles start to replicate in preparation for cell division
170
Wt happens in S phase ?
Dna is replicated , new histones are made and assembled into chromatin
171
Wt happens in G2 ?
Enzymes and other proteins needed for division are synthesized and moved to their proper sites
172
When is the centrioles replication complete in the subphases ?
G2 phase
173
How does the dna replicate?
1- Uncoiling enzymes unwind the Dna molecule , forming a replication bubble
2- the two strands separate as the hydrogen bonds are beoken
3- assembly - the enzyme Dna polymerase positions complementary free nucleotides forming two new strands
4- Restoration ligase enzymes splice short segment of dna together restoring the double helix structure
174
175
Wt do we call the mechanism of having an old and one new nucleotide strand ?
Semi conservative replication
176
M phase consists of two distinct events
Mitosis and cytokinesis
177
Wdwm by mitosis
Division of nucleus
178
How many phases do we have in mitosis and wt are they ?
4 prophase , metaphase , anaphase and telophase . PMAT
179
Wdwm by cytokinesis ?
Division of the cytoplasm
180
When does chtokinesis takes place ?
Begins during late anaphase
181
When does cytokinesis end ?
When mitosis ends
182
Who forms the cleavage furrow ?
A contractile rings made from actin filaments
183
Wdwm by centromere ?
Each chromosome has a centromere where the two sisters are held together
184
Wdwm by contact inhibtion ?
Prevents cells from dividing when there is no space for them to grow
185
What are the two proteins crucial to a cells ability to finish the s Phase and enter mitosis
Cyclins and cyclindependent kinases (CDKS)
186
AAA calls for wt ?
Amino acids
187
CCT calls for wt ?
Glycine
188
Wt do we call the coding regions
Exons
189
Who carries the coded information to the cytoplasm where protein synthesis occurs ?
MRNA
190
Which rna forms functionals ribosomes
RRNA
191
Which rna is L shaped that ferry amino acids to the ribosomes
TRNA
192
What does polypeptide synthesis involves ?
Transcription and translation
193
Wdwm by transcription ?
DNAS INFORMATION IS encoded in mRNA
194
wdwm by translation?
where tRNA matches codons on the mRNA with the correct amino acids
195
Where does transcription takes place ?
Nucleus
196
wt happens in transcription ?
DNA code is copied into mRNA using RNA polymerase
197
where does translation takes place ?
ribosome
198
what happens in mitosis and does it affect the cytoplasm ?
dividing the nucleus into two not the cytoplasm
199
wt do we call the process of the division of cytoplasm
cytokinesis
200
wt do we call the first phase of mitosis ?
prophase
201
wt happens in early prophase ?
1- the chromatin coils and condenses ,
2- centrosomes separate from one another
202
when does the nuclear envelope starts to disapear in mitosis ?
late prophase
203
wt happens in the late prophase ?
1- nuclear envelope breaks up
2- growing spindle microtubules attach to kinetochores
3-the microtubules slide past each other forcing the poles apart
204
wt do we call the second phase in mitosis ?
metaphase
205
wt happens in metaphase ?
1- two centrosomes are at opposite poles of the cells
2- the chromosomes cluster at the midline of the cell
3- at the end of metaphase , enzymes that will separate the chromatids from each other
206
when does the chromosomes cluster at the midline of the cell ?
metaphase
207
wt do we call the third phase of mitosis ?
anaphase
208
wt happens in anaphase ?
centromeres of the chromosomes start to split
- kinetchore microtubules shortens
209
which phase is the shortest in mitosis ?
anaphase
210
which phase is the final phase ?
telophase
211
wt happens in telophase ?
1- A new nuclear envelope forms around each chromatin and the spindle breaks down and disappears
2- mitosis ends
212
when does the cytokinesis starts ?
late anaphase
213
how does the cytoplasm divides , who helps ?
microfilaments
214
who pries apart the two dna strands during transcription and at which phase does it happen ?
RNA polymerase and during initiation
215
wt happens at elongatiion ?
rna poly moves along the template strand joining together rna nucleotides complem to the dna
216
wt happens in the termination ?
mrna synthesis ends when the polymerase reaches a special nucleotide sequence called termination signal
217
where does the polypeptide elongation and synthesis takes place ?
p site
218
which transport is used to transport sodium towards the cell and potassium outwards ?
antiport system
219
give me an example of symport system ?
glucose and sodium or hydrogen
220
wt happens to the hypertonic solution ?
shrinks
221
which membrane proteins helps maintain the resting memebrane potential in the steady state ?
potassium leakage channel
222
how is CO2 transported ?
phospholipids
223
how do polypeptide enters and exits ?
through vesicles
224
who activates the dna ?
acytilation
225
who shuts the dna down ?
methyliation
