Most bacteria live in a solution that is hypotonic relative to the cytoplasm of the bacteria. This means that the bacterial cell is constantly taking in water. The cell wall of a bacterium is a peptidoglycan polymer that is tightly cross-linked. This would therefore function to:_________-.
A. regulate the flow of most molecules into and out of the bacterial cell.
B. provide a rigid wall that prevents the cell from swelling.
C. provide a rigid wall that prevents the cell from shrinking.
D. confirm a close relationship to plant cells that have a similar structure and live in hypotonic solutions.
E. make all bacteria fairly uniform in metabolic chemistry.
Answer:
B. provide a rigid wall that prevents the cell from swelling.
Explanation:
When organisms are present in hypotonic surroundings, their cells that are in contact with the surroundings tend to gain water. Bacteria present in hypotonic solution would gain water as their cells are hypertonic than the surroundings. The entry of water would increase the volume of cytoplasm and could lead to the bursting of the cell. However, the presence of a cell wall made up of cross-linked peptidoglycan prevents the swelling of the bacterial cell and allow them to survive in hypotonic surroundings.
Answer:
1. Acetylcholine binds to receptors on the motor end plate
2. Ligand-gated channels open leading to depolarization
3. End plate potential triggers an action potential
4. Transverse tubules convey action potentials into the interior of the muscle fiber
5. Calcium is released from the sarcoplasmic reticulum
6. Calcium ions bind to troponin, which then moves tropomyosin
Explanation:
Acetylcholine (ACh) is a signaling molecule (neurotransmitter) that binds to receptors on muscle cells. This binding triggers the opening of ligand-gated sodium channels, thereby ions enter into muscle cells, which causes the depolarization of the sarcolemma and thus promotes the release of Ca2+ ions from the sarcoplasmic reticulum. The myoneural junction, also known as the motor endplate, is the site of synaptic contact between a motor axon and a skeletal muscle fiber. The endplate potential is the voltage that produces the depolarization of muscle fibers when ACh molecules bind to their receptors in the cell membrane. This depolarization spreads in the sarcolemma through transverse tubules (T tubules) and thus generates an action potential. Finally, this action potential induces the release of Ca2+ in the sarcoplasmic reticulum, which activates troponin protein and induces muscle contraction.
im not sure if this is what the class is considerd but i know that it avians,aka birds
Answer: C
Has about 95% water in It
Answer:
carbon, hydrogen, oxygen, nitrogen, and phosphorous
Explanation:
The phosphate groups allow the nucleotides to link together, creating the sugar-phosphate backbone of the nucleic acid while the nitrogenous bases provide the letters of the genetic alphabet. These components of nucleic acids are constructed from five elements.
