Which cell-cell connection allows for the formation of a
gradient of 2nd messengers, small molecules or...
Which cell-cell connection allows for the formation of a
gradient of 2nd messengers, small molecules or ions in the cytosol
of neighboring animal cells?
a Plasmodesmata
b Adherens junction
c Gap junction
Solutions
Expert Solution
Ans.
Cellular structures which are responsible for providing
association between neighbouring cells or between materials of
extracellular space and a cell, are known as cell junctions (or,
intercellular bridges).
These structures comprise of complexes of multiple
proteins.
These structures support many functions in plant and animal
cells such as, communication between neighbouring cells, reducing
stressed placed upon cells and transfer of small molecules across
cells.
Structures (or, channels) between neighbouring cells in animals
responsible for the transfer of ions, water and other substances
are called as gap junctions.
Gap junctions form the cell-cell connection allowing
for the formation of a gradient of 2nd messengers, small molecules
or ions in the cytosol of neighboring animal cells.
These gap junctions are structurally similar to plasmodesmata
in plant cells.
Transformation of connexins, a six membrane proteins, into
connexon which is a donut like structure, results in the
development of gap junctions.
A channel is formed between the cells upon alignment of the
pores of connexons.
Which of the following molecules is a B cell co-receptor that
brings antibody to the cell surface and participates in signal
transduction.
CR2
Ig alpha and beta
CD81
CD19
CD3
Which of the following is a serial killer:
B cells
mast cells
macrophages
T cells
dendritic cells
Which of the following is one of the signals centrocytes need to
survive?
Bind to an Ag on a follicular macrophage
Present Ag to a T-follicular helper cell and receive
co-stimulator "T-cell help"...
Cells require a constant exchange of solutes (ions and small molecules) with the outside of the cell. Many of these solutes undergo passive transport across the membrane. Passive transport occurs without the input of cellular energy. Some solutes are transported into the cell while others are transported out of the cell.
Part A - Diffusion
All molecules have energy that causes thermal motion. One result of thermal motion is diffusion: the tendency of substances to spread out evenly in the...
Amino acid are micro molecules which are associated with the
formation of a
macromolecule called protein. When an amino acid is kept in a
solution it exists in the
ionic state. Answer the questions below related to amino acids
a. Draw the structure of amino acid and explain how the
migration of groups in the amino
acid leads to formation of a structure with neutral ions.
Define what ions are these;
(2.5 marks)
b. When an amino acid with equal...
1)Cell walls are rigid and resist expansion, which allows the
pressure to build inside a cell when it absorbs water. The force
exerted by pressing water against the cell wall is called [BLANK1],
which is a key feature that allows plants to stand upright.
2)Prokaryotes concentrate DNA in a discrete region of the cell
interior known as the BLANK . They often contain additional small
circular molecules of DNA known as BLANK that carry a small number
of genes that...
Which of the following alterations would likely contribute to
the formation of a cancerous somatic cell?
A.Mutations in cyclin-dependent kinase genes that made the
catalytic activity of the kinases cyclin-independent.
B. A mutation in the Mdm2 gene that eliminated the ability of
the MDM2 protein to bind to p53.
C.A mutation that inactivated expression of the gene that
encoded the protein that de-phosphorylated the RB protein.
D. A mutation in the Ras gene that eliminated the GTPase
activity of the...
Which of the following alterations would likely contribute to
the formation of a cancerous somatic cell? Fill in all correct
answers if there are more than one.
A.Mutations in cyclin-dependent kinase genes that made the
catalytic activity of the kinases cyclin-independent.
B.A mutation that inactivated expression of the gene that
encoded the protein that de-phosphorylated the RB protein
C.A mutation in the p53 transcription factor binding site near
the Bax gene promoter that eliminated p53 binding.
D.A mutation in the...
Which of the following molecules, when taken up by the cell,
binds to the repressor allowing it to bind to the operator?
-Inducer
-Corepressor
-Repressor
-Promoter
You are observing a cell process in which small vesicles
continually merge with the cell membrane. A number of different
treatments known to influence the secretion of specific materials
seems to have no effect on the process. What type of
secretion appears to be occurring and why do different treatments
have no effect on process?
Which two molecules, an regulatory protein and enzyme regulate cell
division in mitosis?
How does the cell stop division?
What controls the breakdown of bonds between sister chromatids
so they can seperate in anaphase?