BIO CHEM EXAM 3 MULTIPLE CHOICE

Which equation is used to calculate the resting membrane potential considering multiple ions and their permeability?

 

Einstein equation

 

Nernst equation

 

Newton's law

 

Goldman equation

Goldman equation

The _____________ equation is used to calculate the equilibrium potential of a single ion.

Nernst

A ______________-gated ion channel opens when a molecule binds to it.

ligand

The _______________ is the part of the neuron responsible for carrying out DNA replication and protein synthesis.

soma or cell body

In synaptic transmission, neurotransmitters are released from _______________ at the end of the axon.

vesicles

synaptic vesicles

The small gaps in the myelin sheath where ion channels are concentrated are called ________________.

nodes of Ranvier

The _______________ pump moves three sodium ions out and two potassium ions in for every ATP used.

sodium potassium

What is the function of dendrites in a neuron?

 

Send signals to muscles

 

Store calcium

 

Receive information from other cells

 

Wrap the axon in insulation

Receive information from other cells

What triggers the release of neurotransmitters at the synapse?

 

Sodium influx

 

Potassium outflow

 

ATP synthesis

 

Calcium entry

Calcium

What is the function of arrestins in GPCR signaling?

 

Activate secondary messengers

 

Promote GTP hydrolysis

 

Amplify kinase activity

 

Terminate receptor signaling

Terminate receptor signaling

The lipid molecule _________ is cleaved by phospholipase C into DAG and IP₃.

PIP2

Which class of G-protein stimulates adenylyl cyclase?

 

Gi

 

Ga

 

Gs

 

Gq

Gs

Which of the following best describes a second messenger?

 

A small molecule that transmits signals within the cytoplasm

 

A hormone that binds to an extracellular receptor

 

A molecule that initiates transcription in the nucleus

 

A membrane-bound protein that activates receptors

A small molecule that transmits signals within the cytoplasm

Protein _________ add phosphate groups to proteins, altering their activity.

kinase

Which type of enzyme removes phosphate groups from proteins?

 

Phosphatase

 

Cyclase

 

Kinase

 

Protease

phosphate

Which second messenger is responsible for activating protein kinase A (PKA)?

 

IP₃

 

cAMP

 

DAG

 

Calcium

cAMP

The final and most complex sugar modifications on proteins occur in the __________ complex.

Golgi

What type of enzyme is responsible for adding sugars to proteins in the ER and Golgi?

 

Kinases

 

Oxygenases

 

Proteases

 

Glycosyltransferases

Glycosyltransferases

Vesicle coats help __________ the membrane and select cargo.

shape

Which region of the Golgi apparatus acts as the sorting station?

 

Medial Golgi

 

Cis Golgi

 

ERGIC

 

Trans Golgi

Cis Golgi

Proteins destined for secretion are synthesized into the ER by a process called __________ translocation.

co translational

A sequence of amino acids at the N-terminus of a protein, directing it to the ER, is called the __________ sequence.

signal

The process by which proteins are made in the ER and transported out of the cell is called:

 

Endocytosis

 

Secretory pathway

 

Exocytosis

 

Co-translational transport

Secretory pathway

The plus end of a microtubule is primarily composed of:

 

Beta-tubulin subunits

 

Delta-tubulin subunits

 

Gamma-tubulin subunits

 

Alpha-tubulin subunits

Beta-tubulin subunits

The dynamic instability of microtubules is due to:

 

Hydrolysis of GTP

 

The action of myosin motors

 

Hydrolysis of ATP

 

Covalent bonds between subunits

Hydrolysis of GTP

Microtubules are composed of how many protofilaments arranged in a circular pattern?

 

13

 

9

 

11

 

15

13

The process in which actin filaments simultaneously add subunits at one end and lose them at the other is called __________.

Treadmilling

During actin filament treadmilling, subunits are added at the _______ end and lost from the _______ end. 

 

Barbed; pointed

 

Minus; plus

 

Plus; minus

 

Pointed; barbed

Barbed; pointed

Microtubules are long, hollow tubes composed of the protein __________.

Tubulin

The enzyme activity associated with tubulin is __________ hydrolysis.

GTP

The motor protein that carries cargo toward the plus end of microtubules is __________.

kinesin

Which of the following motor proteins moves toward the minus end of a microtubule?

 

Dynein

 

Myosin II

 

Myosin I

 

Kinesin

 

Dynein

The large motor protein that moves cargo toward the minus end of microtubules is __________.

dynein

Which part of a neuron primarily receives signals from other neurons?

Dendrite

What is the primary function of the myelin sheath?

Speed up electrical signal transmission along the axon

In the biosynthetic pathway, where are proteins first synthesized?

Rough endoplasmic reticulum (Rough ER)

What is the main role of the Golgi apparatus in protein transport?

Modify and package proteins for transport

Which type of secretion occurs continuously without needing a stimulus?

Constitutive secretion

The endocytic pathway moves materials in which direction?

From the cell surface into the cytoplasm

What activates a G-protein coupled receptor (GPCR)?

Binding of a ligand

What three subunits make up heterotrimeric G-proteins?

Alpha, Beta, Gamma

Which ion enters the neuron to trigger neurotransmitter vesicle release?

Calcium (Ca2+)

Neurotransmitters bind to what type of channels on the next neuron?

Ligand-gated ion channels

What is the monomer that forms microtubules?

Tubulin

Which motor proteins move along microtubules?

Kinesin and Dynein

Which cytoskeleton component provides strong structural support and has no motor proteins?

Intermediate filaments

Which cytoskeletal component is mainly responsible for cell movement?

Actin filaments

What structure carries proteins from the ER to the Golgi?

Vesicles

Which side of the Golgi receives proteins from the ER?

Cis face

How many sodium ions are pumped out of the cell by the sodium-potassium pump per cycle?

3 sodium ions

How many potassium ions are pumped into the cell by the sodium-potassium pump per cycle?

2 potassium ions

What molecule provides energy for the sodium-potassium pump?

ATP

Which extracellular matrix component forms strong triple-helix fibers?

Collagen

What is the main function of proteoglycans in the extracellular matrix?

Attract water and provide cushioning for tissues

What is the main function of fibronectin in the extracellular matrix?

Connect ECM components to the cell surface

Which disease is associated with defective collagen?

Scurvy

In lipid-derived signaling pathways, which enzyme is activated by Gαq?

Phospholipase C (PLC)

What second messenger is produced by adenylyl cyclase in nucleic-acid derived signaling?

cAMP

What is a key similarity between lipid-derived and nucleic-acid derived signaling pathways?

Both use GPCR signaling cascades and second messenger amplification