AP Bio Chapter 4 & 5 Test

In a plant cell, DNA may be found where?

chloroplasts, nucleus, mitochondria

Integrins

membrane proteins; they transmit signals between the ECM and cytoskeleton

When a potassium ion (K+) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures. Which of the following correctly describes the order in which these structures will be encountered by the ion?

primary cell wall --> plasma membrane --> cytoplasm --> vacuole

when plant cells are in a hypotonic solution, they become ___

turgid

second messenger

A small, nonprotein, water-soluble molecule or ion, such as calcium ion or cyclic AMP, that relays a signal to a cell's interior in response to a signal received by a signal receptor protein.

endocrine (hormonal) signaling

A type of long-distance signaling in animals that utilizes hormones.

protein phosphatases

An enzyme that removes phosphate groups from proteins, often functioning to reverse the effect of a protein kinase, process is dephosphorylation

T/F diffusion is a process that doesn't require energy in which solutes go from a lower concentration to a higher concentration across a membrane

False (diffusion is higher to lower)

T/F Both a proton pump and a potassium channel will increase the electrochemical gradient across a membrane

False (only proton pump)

Why is it advantageous to have multiple steps in a transduction pathway

Having multiple steps allows for greater possible signal amplification

A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, a volume of distilled water equal to that of lost blood is directly transferred into one of his veins. What is the most likely result

His cells are will be hypotonic compared to the water; they will lyse

The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cels, ATP is synthesized primarily on the inner membrane of the mitochondria. Where are the corresponding reactions likely to occur in prokaryotic cells?

On the plasma membrane

paracrine signaling

Signal released from a cell has an effect on neighboring cells.

T/F Familial hypercholesterolemia is characterized by defective or deficient LDL receptors on the membrane

True

T/F GTPase is associated with the conversion of GTP to GDP

True

T/F carrier proteins in the membrane exhibit specificity for a particular type of molecule

True

T/F water always moves toward the lowest water potential

True

ligand-gated ion channel

Type of membrane receptor that has a region that can act as a "gate" when the receptor changes shape. The gate allows for specific ions to pass through the membrane

G-protein coupled receptors

a membrane receptor that works with the help of a G protein. G proteins bind to GTP, an energy rich molecule, if GTP is bound to the protein, it is inactive

signal molecule

a molecule that activates an activator protein or represses a repressor protein

When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway?

a signal molecule

synaptic signaling

a type of local signaling specific to neurotransmitters in nerve cells

the presence of cholesterol in the plasma membrane of some animal cells does what?

allows for the viscosity of the membrane to fluctuate depending on the temperature

In order for a protein to be an integral membrane protein it would have to be

amphipathic, that is having both a hydrophobic and hydrophilic region

why would unsaturated fatty acids keep cells more fluid at lower temperatures?

because they do not stack well, IMFs cannot form as easily and they cannot become solids.

Glycolipids

carbohydrates covalently bonded to lipids

autocrine signaling

cells respond to signaling substances that they themselves secrete

In what way do membranes of a eukaryotic cell vary?

certain proteins are unique to each kind of membrane

when animal cells are in a hypertonic solution they become ___

crenated

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?

estrogen binds to specific receptors in many cells, each with a different response to its binding

Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells?

facilitated diffusion

when plant cells are in an isotonic solution, they become ___

flaccid

chemical used in long distance signaling

hormones

Where are steroid receptors typically located

in the nuclear membrane

the extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information outside the cell to inside the cell via which cellular structure?

integrins

when animal cells are in a hypotonic solution they become ___

lysed

a bacterium engulfed by a white blood cell via phagocytosis will be digested by ___ enzymes (an organelle)

lysosomal

Cynanide binds to at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the ____

mitochondria

Which organelle is the primary site of ATP synthesis in eukaryotic cells?

mitochondria

when plant cells are in a hypertonic solution, they become ___

plasmolyzed

Singer and Nicholson's fluid mosaic model of the membrane proposed that membranes consist of _____

protein molecule embedded on a fluid layer of membrane

peripheral proteins

proteins bound to the surface of the membrane

integral proteins

proteins embedded in the phospholipid bilayer.

Proton pumps are used in various ways by members of every domain of organisms: Bacteria, Archaea, and Eukarya. What does this most probably mean?

proton gradients across a membrane were used by cells that were common ancestors of all three domains of life

You are working on a team that is designing a new drug. For this drug to work, it must enter the cytoplasm of specific target cells. What is a factor that determines whether the molecule selectively enters the target cells?

similarity of the drug molecule to other molecules transported by the target cells

the movement of gas nitrous oxide (N2O) is an example of what type of diffusion

simple diffusion, as N2O is small and nonpolar (refer to lewis structure)

When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that

the hydrophobic interactions that hold the membrane together are weakest at this point

protein kinases

transfer phosphates from ATP to protein, a process called phosphorylation