Test #1 Flashcards
For an action potential to occur:
a. The stimulus must reach or exceed threshold
b. Sodium movement into the cell must exceed potassium movement out of the cell
c. The membrane must be out of the absolute refractory period
The hormone insulin causes the transport of glucose into body cells. Its secretion is controlled by a negative feedback system. Which of the following is most likely to be correct?
An increase in blood glucose concentration will stimulate insulin secretion, which will in turn lower the blood glucose concentration.
Homeostasis
Depends upon the interaction of receptors, integrating centers, and effectors
Depends primarily upon negative feedback
The way in which the nervous system can detect the intensity of a stimulus is
The frequency of action potentials
Which of the following statements applies to paracrine regulation?
Prostaglandins are paracrine chemicals
Paracrine chemicals are released by cells in a tissue and act on cells in the same vicinity
Which of the following would be likely to alter a cells resting membrane potential?
a. Loss of Na+ through dehydration
b. Opening chemical-gated Na+ channels
c. Stopping the Na+/K+ pump
d. An excess of K+ in the ECF
A protein is found in blood that is produced by the pituitary gland and acts on the testes, the protein is classified as an
Hormone
The process of breaking down glucose to form ATP energy
Glycolysis
Enzymes
Are shape-specific proteins
Which of the following can be used to produce ATP by cellular respiration?
a. Carbohydrates
b. Lipids
c. Proteins
Ammonia is
Processed by the liver to less toxic compound
A waste product of protein metabolism
Simple diffusion across a membrane
Does not require a carrier protein
Is influenced by the surface area of the membrane
Which of the following could most easily cross the lipid portion of the plasma membrane?
Fatty acids
Which of the following statements regarding the active transport of substances across cell membranes is correct?
a. Both primary and secondary active transport will eventually use ATP energy
b. Active transport requires a carrier protein
c. Active transport moves molecules from their low concentration to their high concentration
Which of the following statements about the Na+/K+ pump is false?
It transports Na+ and K+ in a 3:1 ratio
Which of the following examples of transport requires a carrier protein?
Facilitated diffusion of glucose down its concentration gradient
The Na+/K+ pump
Which of the following statements regarding endocytosis and exocytosis is correct?
Endocytosis is a method by which large molecules may be brought into the cell
Exocytosis is a method by which large molecules may be excreted from the cell
A chemical messenger is released by a cell within the thyroid gland and binds to receptors on other thyroid cells and to receptors on itself. The chemical messenger would be considered
Paracrine factor
Autocrine factor
The concentration gradient for Na+
Is maintained by the Na+/K+ pump
In response to falling blood pressure, the nercous system will stimulate the heart to pump harder and increase blood pressure. This is an example of:
Extrinsic regulation to accomplish negative feedback
If a cell is placed in a hypertonic solution
The cell will crenate
The solution has a higher concentration of solutes than the cell
Which of the following types of transport does not rely on a concentration gradient?
Filtration
Increasing the concentration of a substrate for an enzyme-catalyzed reaction will increase the rate of that reaction until the point of____________ is reached.
Saturation
Which of the following types of transport is involved in trans epithelial transport of sodium?
Active transport of Na+
Diffusion of Na+ through a channel
Which of the following would generally cause an increased (enzyme-catalyzed) reaction rate?
Increased substrate concentration
Increased enzyme concentration
Which of the following examples of transport does not require a carrier protein?
Diffusion of K+ down its concentration gradient
The movement of water into a cell
Place the numbers of theses components of a reflex arc in the correct order:
- Effector
- Receptor
- Afferent pathway
- Stimulus
- Integration center
- Efferent pathway
4,2,3,5,6,1
Which of the following is responsible for restoring the resting electrical gradient (polarized nature) of the plasma membrane after an action potential?
The opening of voltage-gated K+ channels
The absolute refactory period of a cell has primarily to do with
The status of the voltage-gated Na+ channels
Opening gated Na+ channels in a cell membrane would result in
Depolarization
The inside and the outside of the cell membrane becoming more similar
The process of making glucose fro amino acids is
Gluconeogenesis
When a molecule temporarily binding somewhere other than the active site controls an enzyme activity, it is called?
Allosteric regulation
Which of the following statements about transepithelial transport of glucose with sodium is true?
Glucose and sodium both move into the apical surface of the cell
What type of ion channels is responsible for establishing the resting membrane potential of a cell?
Leak channels
During which of the following states are the majority of voltage-gated sodium channels closed and incapable of opening?
During the absolute refactory period
Which of the following would decrease the rate of an enzyme-catalyzed reaction?
Increasing the concentration of product
A protein kinase catalyzes which of the following types of chemical reactions?
Phosphorylation
The organ that stores glucose as glycogen and then provides glucose to the blood when needed is the:
Liver
Which of the following pairs of characteristics is more likely to make a substance diffuse through the lipid portion of the cell membrane?
Small, non-polar molecule
Hypocalcaemia explains the basis for stopping the heartbeat during lethal injection.
False
Action potentials can be either depolarizing or hyperpolarizing
False
A strong stimulus produces a strong action potential
False
The primary source of negative charges in the intracellular fluid is the presence of chloride ions
False
Increasing the concentration of substrate for an enzyme-catalyzed reaction will increase the saturation rate
False
Filtration moves solutes from areas of high concentration to areas of low concentration
False
