Regarding signaling by steroid hormones, which of the following statements is NOT true:
Hormone receptors need to be transmembrane proteins because hormones cannot diffuse through the plasma membrane
Protein tyrosine kinase signaling pathways control cell growth and migration. FGF secreted by fibroblast binds to FGFR which eventually activates Ras (monomeric G protein). Which is the correct order of kinase cascades that happens next?
RAF -> MEK -> ERK
Transautophosphorylation occurs on
receptor tyrosine kinases
Which of these are NOT signal termination mechanisms?
Second messenger release
GTP-binding proteins switch from an active to an inactive state when
they hydrolyze GTP to GDP
Dominant negative mutations produce proteins that antagonize the activity of wild type proteins when the mutant protein and wild type protein are coexpressed. Which of the following mutations would be considered a dominant negative mutation for a receptor
a mutation which eliminates expression of the intracellular domain of an RTK without affecting its ability to dimerize
Which 2nd messenger is not involved in the activation of protein kinase C (PKC)?
cAMP
The study of a newly discovered protein on the surface of endothelial cells indicates that it dimerizes, undergoes transautophosphorylation, activates monomeric G proteins, and stimulates a MAPK pathway. This protein must therefore be a(n)
receptor tyrosine kinase
A particular drug inhibits protein kinase A (PKA), the protein kinase that is responsible for phosphorylating cAMP response element binding protein (CREB). This drug should negatively affect which of the following events?
The ability of the CREB protein to stimulate transcription
Cortisol receptors contain nuclear localization sequences, yet they are commonly found in the cytosol of cells. What is the most likely explanation for this observation?
Binding to cortisol induces a change in the receptor's shape and unmasks a nuclear localization sequence that allows it to enter the nucleus.
How do ion channel receptors transmit signal information?
They bind to a signaling ligand
They permit ions to flow from one side of the plasma membrane to another
Which of the following proteins would tend to increase or prolong the amount of signal produced by a GTP-binding protein in its active state?
A protein that decreases the GTPase activity of the protein
A protein that increases the release of GDP
Which regulatory regions are far away from the regulated gene?
Enhancer
The following are motifs transcriptions factors use to bind DNA
Zinc finger
Leucine zipper
Helix-turn-helix
Which of these is NOT a motif transcription factors use to bind DNA?
Tudor
Which of these elements are NOT part of the core promoter?
CCAAT
Regarding histone modifiers, the following statements is true:
They are large ATP-consuming complexes
Histone methylation is associated with chromatin condensation
Histone acetylation can promote transcription of genes
the following sequences are in the core promoter?
TATA box
BRE (TFIIB recognition element)
DPE (downstream core promoter element)
the following molecules is considered to be signaling effector:
Cohesins
Histone modifiers
Transcription factors
Which of the following mutant proteins might cause cancer due to hyperactive (increased) signaling through a receptor tyrosine kinase (RTK) pathway?
A Ras protein which cannot hydrolyze GTP to form GDP and inorganic phosphate.
the following general statements about GPCRs is true?
They are cell surface receptors.
They contain seven transmembrane domains.
They are also known as serpentine receptors.
The study of a newly discovered protein on the surface of endothelial cells indicates that it dimerizes, undergoes transautophosphorylation, activates monomeric G proteins, and stimulates a MAPK pathway. This protein must therefore be a(n)
Receptor tyrosine kinase
In histone modification, which of the following amino acids can be both acetylated and ubiquitinated by histone acetyltransferases and ubiquitin ligases, respectively?
Lysine
types of signaling pathways do converge on ERK?
GPCRs
RTKs
Integrines
At which of the following steps would a signal typically be amplified in a signal transduction pathway?
Activated adenylyl cyclase produces cAMP.
The cell cycle are the events that control the growth and division of a eukaryotic cell. Select the correct statement:
G2 phase always happens after S phase, but only if the events in the S phase are complete
The cell cycle are the events that control the growth and division of a eukaryotic cell. Select the correct statement:
Synthesis of new membranes, and new proteins necessary for cell division takes place in G1 and G2 phases
ATM and ATR
Bring the DNA repair machinery to DNA break points
The cell cycle progression can be inhibited. Which of the following events lead to inhibition of the cell cycle progression?
Mutation in the cyclin B gene that prevents it from being transcribed
Regarding apoptosis, the following statements are true:
Bak and Bax can move to the outer mitochondrial membrane, where they form channel-like structures that permits proteins in the intermembrane space of the mitochondrion to leak out into the cytosol (mitochondrial outer membrane permeabilization or MOMP)
Cy
Growth factors induce mitosis in cells by binding to receptor tyrosine kinases. Which of the following events must be triggered by the growth factor-associated signaling pathways?
expression of cyclin genes
Which type of protein is often called the "tipping point" of the cell cycle and can promote either cell growth or cell death?
E2F proteins
The apoptosome is composed of __.
caspase 9, APAF-1, cytochrome C
Place the different phases of the cell cycle in a correct order. Since the cell cycle is circular, the starting point is arbitrary (we can start with any phase)
G2, M, G1, S
(1) triggers the degradation of (2), and this degradation activates __(3) to degrade cohesins during mitosis.
Anaphase-promoting complex (APC)(1), securin (2), separase (3)
Which of the following is not a characteristic of apoptosis?
cell lysis
During the action potential the cell depolarizes and goes back to to the resting potential after a little depolarization, caused by:
The exit of K+ through voltage-gated K+ channels
The contacts between muscle and neurons are called:
Neuromuscular junction
The cells that secrete the ECM in cartilage are called
Chondrocytes
What best describes a unique feature of keratinized epithelium?
The topmost cells undergo cornification
In the gastrointestinal system:
In the stomach, cell polarization permits secretion of mucus in the lumen surface to protect epithelial cells from being digested
In the stomach, the cells are organized in gastric pits
Food is absorbed by active transport, while water absorption occurs b
The refractory period is the time where channels cannot open, even if the electrical potential is favorable for opening. Which channels could NOT be opened immediately after closing?
Voltage-gated Na+ channels
the following is characteristic of the skeletal muscle
The cells are multinucleated
The sarcomere is the functional unit
Contraction is triggered by calcium
the following is true of chemical synapses
neurotransmitters are used as signals
chemical synapses have synaptic clefts
chemical synapses are formed by pre and post-synaptic cells
the following is a connective tissue
blood
adipose
bone
cartilage
When channelrhodopsin used for an optogenetic experiments is activated, it causes neurons to eventually generate action potentials by
moving Na+ into the cell
In the Na+/K+ pump, the energy required to move Na+ ions against its gradient is coupled to the__.
hydrolysis of ATP