GRE Subject Test: Biochemistry, Cell, and Molecular Biology › Cellular Signals and Communication
The sodium-potassium pump works by bringing sodium __________ cells and potassium __________ cells through the use of ATP.
out of . . . into
into . . . out of
into . . . into
out of . . . out of
None of these
The sodium-potassium pump is a type of active transport that brings sodium out of the cell and potassium into the cell. This is in the opposite direction of their natural gradient. The fact that it is going in the opposite direction requires this pump to need energy, or, ATP.
The sodium-potassium pump works by bringing sodium __________ cells and potassium __________ cells through the use of ATP.
out of . . . into
into . . . out of
into . . . into
out of . . . out of
None of these
The sodium-potassium pump is a type of active transport that brings sodium out of the cell and potassium into the cell. This is in the opposite direction of their natural gradient. The fact that it is going in the opposite direction requires this pump to need energy, or, ATP.
Which of the following events occur when the MAP Kinase pathway is activated?
ATP is used to phosphorylate transcription factors
Ras blocks the activation of MAP kinases
The phosphorylated receptor facilitates the binding of GDP to Ras
The receptor is phosphorylated by G-coupled proteins
When MAP Kinase signaling is activated, the receptors auto-phosphorylate to activate the signal transduction, which leads to the binding of GTP to Ras. Ras is activated when bound to GTP. Ras then activates downstream MAP Kinases, which lead to a phosphorylate cascade that eventually uses ATP to phosphorylate transcription factors. The phosphorylated transcription factors then go on to alter gene expression in the cell.
Therefore, the correct answer in this question is that transcription factors are phosphorylated using ATP molecules.
Which of the following events occur when the MAP Kinase pathway is activated?
ATP is used to phosphorylate transcription factors
Ras blocks the activation of MAP kinases
The phosphorylated receptor facilitates the binding of GDP to Ras
The receptor is phosphorylated by G-coupled proteins
When MAP Kinase signaling is activated, the receptors auto-phosphorylate to activate the signal transduction, which leads to the binding of GTP to Ras. Ras is activated when bound to GTP. Ras then activates downstream MAP Kinases, which lead to a phosphorylate cascade that eventually uses ATP to phosphorylate transcription factors. The phosphorylated transcription factors then go on to alter gene expression in the cell.
Therefore, the correct answer in this question is that transcription factors are phosphorylated using ATP molecules.
What protein is responsible for maintaining the resting potential across a neuronal plasma membrane?
Sodium-potassium pump
Sodium-chlorine pump
Potassium-ATP transporter
Proton pump
Ligand-gated sodium channels
The sodium-potassium pump maintains the resting membrane potential by utilizing 1 ATP to transport 2 potassium ions into the cell, and pumping 3 sodium ions out, which makes the inside of the cell negative relative to the outside of the cell.
What protein is responsible for maintaining the resting potential across a neuronal plasma membrane?
Sodium-potassium pump
Sodium-chlorine pump
Potassium-ATP transporter
Proton pump
Ligand-gated sodium channels
The sodium-potassium pump maintains the resting membrane potential by utilizing 1 ATP to transport 2 potassium ions into the cell, and pumping 3 sodium ions out, which makes the inside of the cell negative relative to the outside of the cell.
An action potential occurs in an axon that synapses at a muscle; this specific type of synapse is called a neuromuscular junction. During the action potential, the membrane potential of the axon sharply depolarizes as the signal moves towards the terminal. Upon reaching the synaptic terminal, neurotransmitters are released and interact with receptors on the muscle. Which of the following best summarizes the changes that occur in the post-synaptic muscle after a neurotransmission event?
Activation of receptors causes opening of ion channels on the muscle, and the muscle depolarizes.
Activation of receptors causes closing of ion channels on the muscle, and the muscle hyperpolarizes.
Activation of receptors causes opening of ion channels on the muscle, and the muscle hyperpolarizes.
Activation of receptors depletes the muscle of intracellular calcium stores and the muscle depolarizes.
Activation of receptors opens ion channels, but the membrane potential is unchanged.
Neurotransmitters will bind their respective receptors on the post-synaptic membrane, which is a muscle in this case. This binding causes changes to other proteins on that membrane, which results in an opening of ion channels. The muscle then depolarizes due to the influx of positively charged ions, and this can be measured as a positive change in the muscle membrane potential.
An action potential occurs in an axon that synapses at a muscle; this specific type of synapse is called a neuromuscular junction. During the action potential, the membrane potential of the axon sharply depolarizes as the signal moves towards the terminal. Upon reaching the synaptic terminal, neurotransmitters are released and interact with receptors on the muscle. Which of the following best summarizes the changes that occur in the post-synaptic muscle after a neurotransmission event?
Activation of receptors causes opening of ion channels on the muscle, and the muscle depolarizes.
Activation of receptors causes closing of ion channels on the muscle, and the muscle hyperpolarizes.
Activation of receptors causes opening of ion channels on the muscle, and the muscle hyperpolarizes.
Activation of receptors depletes the muscle of intracellular calcium stores and the muscle depolarizes.
Activation of receptors opens ion channels, but the membrane potential is unchanged.
Neurotransmitters will bind their respective receptors on the post-synaptic membrane, which is a muscle in this case. This binding causes changes to other proteins on that membrane, which results in an opening of ion channels. The muscle then depolarizes due to the influx of positively charged ions, and this can be measured as a positive change in the muscle membrane potential.
Which of the following hormones will elicit a response in cells by attaching to a membrane bound receptor?
Insulin
Testosterone
Estrogen
Cortisol
Before answering this question, consider what types of hormones would not attach to a membrane bound receptor. Steroid hormones can simply diffuse through the plasma membrane, so they do not need to attach to a receptor there. Cortisol, testosterone, and estrogen are all steroid hormones. This leaves insulin as the only acceptable answer. In fact, insulin attaches to a receptor tyrosine kinase on the outside of cells.
Which of the following hormones will elicit a response in cells by attaching to a membrane bound receptor?
Insulin
Testosterone
Estrogen
Cortisol
Before answering this question, consider what types of hormones would not attach to a membrane bound receptor. Steroid hormones can simply diffuse through the plasma membrane, so they do not need to attach to a receptor there. Cortisol, testosterone, and estrogen are all steroid hormones. This leaves insulin as the only acceptable answer. In fact, insulin attaches to a receptor tyrosine kinase on the outside of cells.