UNIT 2 - QUIZZES Flashcards
(19 cards)
The adrenal medulla will release norepinephrine when the sympathetic nervous system activates it. The release is triggered by the activation of the sympathetic nervous system.
neural stimulation
The pancreas releases insulin when glucose molecules in the blood are at high concentration. The release is triggered by the activation of the sympathetic nervous system.
humoral stimulation
When the hormone TSH (thyroid-stimulating hormone) is released into the blood it stimulates the release of the hormone thyroxine. The release of thyroxine is triggered by another hormone (TSH).
hormonal stimulation
The endocrine system is a means by which organs/tissues communicate with other organs/tissues.
* True
* False
True.
It uses hormones, which are chemical messengers released into the bloodstream, to coordinate various bodily functions and maintain homeostasis.
Thyroxine can only bind to thyroxine receptors. If it bounces into an insulin receptor, it will have no effect because it does not have the correct shape to fit.
This paragraph is an illustration of what concept?
__ dynamic equilibrium
__ specificity
__ refractory period
__ affinity
specificity
The idea that thyroxine can only bind to thyroxine receptors.and not insulin receptors due to its specific shape highlights the principle of specificity in biological systems.
Specificity refers to the ability of a molecule, such as a hormone, to interact only with its corresponding receptor due to a precise fit, much like a lock and key mechanism.
Endocrine Communication
A chemical message is transported through the blood to a target cell.
Paracrine Communication
A chemical message diffuses into local tissue to affect neighboring cells.
Autocrine Communication
A chemical message diffuses its local tissue and affects the cell that released it.
Neural Communication
A neuron releases neurotransmitters into a synapse.
When inhalers were first used by patients to treat asthma, the patient had to inhale several doses throughout the day because the medication would not bind well to the receptors in the lungs. Newer medications, however, only require the patient to inhale the medication once in the morning to be treated all day because the medication can bind to a receptor and stay there for some time.
This paragraph is an example of which concept?
__ Phanou’s principle
__ specificity
__ affinity
__ dynamic equillibrium
This paragraph is an example of the concept of affinity.
The text describes how newer asthma medications can bind to receptors in the lungs and remain there for an extended period, improving their effectiveness compared to older medications that required multiple doses due to poor binding. Affinity refers to the strength of the binding between a ligand (such as a medication) and its receptor, which directly relates to how well and how long the medication can stay bound to the receptor, thus affecting the duration of its therapeutic effect.
Why are second messengers needed?
__ because hydrophobic molecules will not dissolve in the blood plasma
__ because chaperones carry cholesterol as well as steroids
__ because steroid hormones can enter a cell
__ because amino acid based hormones cannot enter a cell
The correct answer is: because steroid hormones can enter a cell because amino acid-based hormones cannot enter a cell.
Second messengers are necessary because steroid hormones, which are lipid-soluble can pass through the cell membrane and bind to intracellular receptors to directly influence gene expression. In contrast, amino acid-based hormones (e.g., peptide or protein hormones) are hydrophilic and cannot enter the cell. Instead, they bind to receptors on the cell surface, triggering the release of second messengers (such as cyclic AMP or calcium ions) to relay the signal inside the cell and elicit a response.
Place the events of the cAMP second messenger pathway in the correct sequence:
__ adenylate cyclase converts ATP into CAMP
__ protein kinase activates specific proteins by phosphorylation
__ G-protein is activated
__ hormone binds to receptor
The CAMP second messenger pathway involves a series of events triggered by a hormone binding to a receptor, ultimately leading to cellular responses.
Here is the correct sequence of the provided events:
- Hormone binds to receptor: A hormone (first messenger) binds to a specific G-protein-coupled receptor (GPCR) on the cell membrane, initiating the signaling cascade.
- G-protein is activated: The receptor’s conformational change activates an associated G-protein, which exchanges GDP for GTP, becoming active.
- Adenylate cyclase converts ATP into cAMP: The activated G-protein stimulates adenylate cyclase, an enzyme that catalyzes the conversion of ATP into cyclic AMP (CAMP), the second messenger.
- Protein kinase activates specific proteins by phosphorylation: CAMP activates protein kinase A (PKA), which then phosphorylates specific target proteins, altering their function and eliciting cellular responses.
This sequence reflects the standard flow of the cAMP signaling pathway.
Match the term with the descriptor: hydrophobic
Steroid hormones are lipid-soluble and ____________, allowing them to pass through cell membranes.
Match the term with the descriptor: interact with DNA to alter cell function
Steroid hormones enter cells and bind to receptors that interact with DNA to regulate gene expression.
Match the term with the descriptor: require a second messenger
Amino acid based hormones typically bind to cell surface receptors and use second messengers, like CAMP, to transmit signals inside the cell.
Match the term with the descriptor: can enter a cell
Due to their hydrophobic nature, steroid hormones can diffuse through the cell membrane and enter the cell.)
Match the term with the descriptor: broken down by the liver and kidneys
Amino acid-based hormones are metabolized and broken down by the liver and kidneys after their action.
Place the events of steroid hormone cell interaction in the correct sequence:
__ specific genes on DNA are activated or inhibited
__ receptor-hormone complex enters the nucleus
__ steroid hormone crosses the cell membrane
__ steroid binds to an intracellular receptor
Steroid hormones, being lipid-soluble, follow a specific mechanism to influence cell function.
Based on their biological action, the correct sequence of the provided events is:
1. Steroid hormone crosses the cell membrane: As steroid hormones are hydrophobic, they can diffuse through the lipid bilayer of the cell membrane.
2. Steroid binds to an intracellular receptor: Inside the cell, the steroid hormone binds to a specific intracellular receptor, forming a hormone-receptor complex.
3. Receptor-hormone complex enters the nucleus: The hormone-receptor complex translocates to the nucleus if it isn’t already there.
4. Specific genes on DNA are activated or inhibited: The receptor-hormone complex interacts with DNA to regulate gene expression, leading to the activation or inhibition of specific genes, which alters cell function.
This sequence reflects the typical mechanism by which steroid hormones, such as cortisol or estrogen, exert their effects on target cells.
Why are chaperone molecules necessary?
__ they allow hydrophobic molecules to be transported through the blood
__ they break down steroids so they won’t reach toxic concentrations
__ they enter the nucleus to activate/deactivate DNA
__ they carry the message from a membrane bound receptor to the protein kinase molecules
Chaperone molecules are necessary because they allow hydrophobic molecules to be transported through the blood by binding to them and preventing aggregation or degradation.
