AP Biology Body systems

When the body temperature decreases, hypothalamus sends out signals to constrict blood vessels to reduce heat loss and to shiver muscles to generate heat. This is an example of

• positive feedback

• negative feedback

• feedback inhibition

• allosteric inhibition

Tags

NGSS.HS-LS1-3

When baby starts pushing against the cervix, hypothalamus releases oxytocin to further contract the uterine walls. This is an example of

• positive feedback

• negative feedback

Tags

NGSS.HS-LS1-3

When a person is dehydrated, pituitary gland releases antidiuretic hormone (ADH) to allow reabsorption of water into blood to reduce water loss. This is an example of

• positive feedback

• negative feedback

Tags

NGSS.HS-LS1-3

When blood glucose level rises, the pancreas releases insulin to allow glucose to enter into livers for storage. This is an example of

• positive feedback

• negative feedback

Tags

NGSS.HS-LS1-3

When human tissue is damaged, the cells near the wound site send out a signal to activate platelets. This recruits more platelets to the wound to form a plug. This is an example of

• positive feedback

• negative feedback

Tags

NGSS.HS-LS1-3

Which part of neuron receives an incoming signal?

• dendrite

• cell body

• axon

• myeline sheath

The diagram shows the propagation of an action potential in neurons. What occurs in phase 3 in the diagram?

• the cell is at resting potential

• voltage-gated K+ channels open, repolarizing the membrane.

• Na+-K+ pump restores the original ion and charge distribution across the membrane.

• voltage-gated Na+ channels open, depolarizing the membrane.

Which of the following is INCORRECT regarding the communication at the synapse?

• Ca⁺² channels open, allowing Ca⁺² ions to rush into pre-synaptic neuron

• neurotransmitters packaged in vesicles fuse with the membrane to release neurotransmitters into the synapse

• neurotransmitters bind to the receptors on post-synaptic neuron

• After a signal has been transmitted, neurotransmitters get quickly degraded

A pufferfish's liver produces TTX which is a neurotoxin that inactivates the voltage-gated Na+ channels in the neurons. Which of the following will be the most immediate effect of TTX poisoning?

• membrane cannot be depolarized and cannot initiate an action potential

• membrane is depolarized but it cannot be repolarized to return to the resting potential

• vesicles cannot fuse with the membrane and no neurotransmitter is released to the synapse

• no signal is transmitted to motor neurons, paralyzing the muscles

Bacteria uses quorum sensing to determine the population density of their species in their surrounding. Each bacterium produces a ligand. Once the concentration of that ligand reaches a critical level, all bacteria respond simultaneously. This is an example of

• autocrine signaling

• juxtacrine signaling

• paracrine signaling

• endocrine signaling