Biochemistry + Cell Bio
These amphipathic membrane molecules have hydrophilic heads and hydrophobic tails, allowing them to spontaneously assemble into bilayers in water.
What are phospholipids?
At resting membrane potential, neuronal membranes are especially permeable to this ion through leak channels.
What is potassium (K+)?
Upon activation and differentiation, these lymphocytes give rise to plasma cells that secrete antibodies.
What are B lymphocytes (B cells)?
This pancreatic hormone lowers blood glucose by promoting cellular glucose uptake and storage of glucose as glycogen.
What is insulin?
Which side of the heart pumps oxygenated blood to the rest of the body?
What is the left side?
Increasing substrate concentration can overcome competitive inhibition because the inhibitor and substrate compete for this region of an enzyme.
What is the active site?
The rapid rising phase of a typical neuronal action potential occurs when these channels open, allowing positive ions to enter.
What are voltage-gated sodium channels?
Cytotoxic CD8+ T cells recognize antigenic peptides presented by this class of MHC molecule, expressed by nearly all nucleated human cells.
What is MHC class I?
These gastric cells secrete hydrochloric acid, creating a low-pH environment that supports the conversion of pepsinogen to pepsin.
What are parietal cells?
These two valves prevent blood from flowing backward from the ventricles into the atria during ventricular contraction.
What are the atrioventricular (tricuspid and mitral) valves?
A pancreatic beta cell synthesizes insulin in the rough ER, modifies and sorts it in the Golgi, and then releases it through this vesicle-mediated process.
What is exocytosis?
An action potential reaches the presynaptic terminal, opening voltage-gated channels. Influx of this ion triggers synaptic vesicle fusion.
What is calcium (Ca2+)?
What is the functional unit of the kidney responsible for filtering blood and producing urine?
The nephron.
When acidic chyme enters the duodenum, this intestinal hormone stimulates the pancreas to release bicarbonate-rich fluid.
What is secretin?
This cardiovascular measurement equals heart rate multiplied by stroke volume and represents the volume of blood pumped by one ventricle each minute.
What is cardiac output?
DNA damage activates p53, which induces a CDK inhibitor called p21. This prevents a cell from passing which major cell-cycle checkpoint?
What is the G1 checkpoint (G1/S transition)?
Multiple sclerosis damages insulating structures surrounding CNS axons, slowing or blocking the rapid node-to-node propagation of action potentials. Name this form of conduction.
What is saltatory conduction?
A patient secretes abundant ADH, but their collecting ducts cannot respond to it. These water-channel proteins fail to be inserted into the apical membrane, producing large quantities of dilute urine.
What are aquaporin-2 (AQP2) channels?
A peptide hormone produces a cellular response within seconds despite inhibition of transcription. Unlike many steroid hormones, its receptor is most likely located in this part of the cell.
What is the plasma membrane?
In exercising muscle, increasing CO2 and decreasing pH reduce hemoglobin's affinity for oxygen, increasing oxygen delivery to tissues. Name this physiological phenomenon.
What is the Bohr effect (Bohr shift)?
A poison blocks the final protein complex in the mitochondrial electron transport chain. What happens to oxygen consumption and ATP production?
Both decrease dramatically.
A drug blocks voltage-gated potassium channels in a neuron. Which phase of the action potential becomes slower?
What is Repolarization.
A person becomes severely dehydrated, causing increased ADH secretion. What happens to their urine volume and urine concentration?
Urine volume decreases, while urine concentration increases.
Following a carbohydrate-rich meal, insulin levels rise. Name one effect of insulin in the liver and one in skeletal muscle.
Liver: increased glycogen synthesis. Skeletal muscle: increased glucose uptake.
When a person stands up quickly, blood pressure may temporarily fall. What does the baroreceptor reflex do to heart rate and blood vessel diameter?
Heart rate increases, and many arterioles constrict.