Shared Flashcard Set

Details

BIO FINAL
Final Exam
37
Biology
Undergraduate 1
12/16/2008

Additional Biology Flashcards

 


 

Cards

Term
What is a paracrine signal?
Definition
A paracrine signal is one that acts on cells near the secreting cell.
Term
What is an autocrine signal?
Definition
An autocrine signal acts on the secreting cell itself.
Term
What is a general endocrine signal?
Definition
An endocrine signal is one that travels through the bloodstream and creates a response in any target cell within the body.
Term
What is a pheromone?
Definition
A pheromone is a chemical signal that is released from the body and communicates with other individuals in a species.
Term
What are the three main class of of molecules that function as hormones in vertebrates?
Definition
Polypeptides (water soluble), Amines (water soluble), and Steroids (lipid soluble)
Term
What is the difference between the way that water soluble and lipid soluble hormones travel?
Definition
Water soluble hormones travel in the bloodstream, and lipid soluble hormones diffuse across cell membranes.
Term
What are the three key events induced by a hormone?
Definition
Reception, Signal Transduction, and Response.
Term
What are a couple things that hormone responses can induce?
Definition
Enzyme activation or a change in gene expression.
Term
Where does epinephrine come from, and how does it help you with a burst of energy?
Definition
Epinephrine comes from the adrenal glands. It reaches the liver and binds to a GPCR, which then releases cAMP (second messenger) that induces an enzyme to speed up glycogen synthesis, which gives you glucose in your bloodstream for energy.
Term
Describe the secretin response pathway.
Definition
Low pH in the small intestine causes "S cells" from the duodenum to release the hormone "secretin" which targets the pancreas to release bicarbonate and increase pH in the duodenum.
Term
What are two antagonistic hormones that regulate blood glucose concentration?
Definition
Insulin and glucagon. Insulin decreases glucose concentration, whereas glucagon increases glucose concentration. Insulin promotes fat storage, whereas glucagon breaks down fat and protein.
Term
What is an islet of Langerhans?
Definition
An islet of Langerhans is a pancreatic cluster of cells that make insulin and glucagon.
Term
What is diabetes and what is it marked by?
Definition
Diabetes is a deficiency of insulin and is marked by elevated glucose levels.
Term
What does the anterior pituitary gland do?
Definition
The anterior pituitary gland releases hormones under regulation of the hypothalamus.
Term
What does the posterior pituitary gland do?
Definition
The posterior pituitary gland stores hormones made in the hypothalamus.
Term
What is oxytocin and where is it stored?
Definition
Oxytocin is a neurotransmitter that is stored in the posterior pituitary gland and stimulates milk release in mammary glands. This is an example of a positive feedback loop: suckling induces milk production, which causes more suckling.
Term
What kind of feedback do hormone cascade pathways involve?
Definition
They involve negative feedback.

Hypothalamus --> anterior pituitary ---> endocrine tissue
Term
What is a tropic hormone and what are four examples?
Definition
A tropic hormone regulates endocrine cells and glands. Four tropic hormones: Thyroid-stimulating hormone (TSH), Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), and Adrenocorticotropic hormone (ACTH)
Term
What are examples of two nontropic hormones?
Definition
Prolactin (PRL) which stimulates lactation, and Melanocyte-stimulating hormone (MSH) which influences skin pigmentation and metabolism
Term
What are examples of two nontropic hormones?
Definition
Prolactin (PRL) which stimulates lactation, and Melanocyte-stimulating hormone (MSH) which influences skin pigmentation and metabolism
Term
What two iodine-containing hormones does the thyroid gland produce?
Definition
Triodothyronine and thyroxine, which stimulate metabolism and influence maturation.
Term
What does parathyroid hormone (PTH) do?
Definition
Parathyroid hormone raises calcium levels in the blood. It targets bones and calcium reabsorption in the kidney. Calcitonin has the opposite effect.
Term
What is hyperthyroidism? Hypothyroidism?
Definition
Hyperthyroidism is excessive secretion of hormones resulting in weight loss and high blood pressure. Hypothyroidism is low secretion of thyroid hormones causing lethargy and weight gain.
Term
What are corticosteroids? Where are they released? What are two examples?
Definition
These are released in response to stress from the adrenal cortex of the adrenal gland. Glucocorticoids influence glucose metabolism, and Mineralocorticoids affect salt and water balance.
Term
What is the difference between type 1 and type 2 diabetes?
Definition
Type 1 is insulin dependent in which the immune system kills pancreatic beta cells. Type 2 diabetes involves insulin deficiency or degradation of insulin receptors.
Term
What are the names of cell junctions in animal cells and plant cells?
Definition
Animals = Gap Junctions, Plants = Plasmodesmata
Term
What is the difference between Conformation and Configuration?
Definition
Conformation is the folding shape that depends on weak forces, Configuration depends on covalent bonds.
Term
How is a GPCR activated?
Definition
The GPCR undergoes some extracellular activation, which activates a G-protein within a cell by displacing GDP with GTP. The activated G-protein dissociates from the receptor and binds to an enzyme, which sends out a cellular response. The enzyme then cleaves the G-protein, turning its GTP back into GDP and releasing a phosphate.
Term
How do receptor tyrosine kinases work?
Definition
They attach phosphates to tyrosine. When a signaling molecule binds to the receptors, the two polypeptides join together to make a dimer. This dimer then uses ATP to phosphorylate another kinase that changes the conformation of relay proteins which make a cellular response.
Term
How does a ligand-gated ion channel work?
Definition
A signaling molecule binds to a receptor as a ligand and then opens the gate to allow ions in or out.
Term
What does a protein phosphatase do?
Definition
A protein phosphatase remove phosphates from proteins.
Term
What is a second messenger? Give 2 examples.
Definition
A second messenger is a non-protein water soluble molecule or ion that diffuses throughout a cell. Examples: cAMP and Calcium.
Term
What does Adenylyl Cyclase do?
Definition
It converts ATP to cAMP in response to an extracellular signal.
Term
How do you regulate cell metabolism?
Definition
You inhibit adenylyl cyclase in GPCRs.
Term
Where does signal transduction occur, and where does the response part of cellular signaling occur?
Definition
Signal transduction occurs in the cytoplasm, and the response occurs in the nucleus.
Term
Why are multistep pathways helpful?
Definition
Multistep pathways can amplify a single and coordinate second messengers for more effective signaling.
Term
Cell division is responsible for:
Definition
reproduction, development, growth, repair
Supporting users have an ad free experience!