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TLS Online TPP Program

#Question id: 7270

According to this figure which of the following option is incorrect?

#Unit 5. Developmental Biology
  1. OTX is a general transcription factor, and B-catenin from the maternal cytoplasm is concentrated at the vegetal pole of the egg.
  2. These transcriptional regulators are inherited by the micromeres and activate the Pmar1 gene. Pmar1 encodes a repressor of HesC.
  3. In the veg2 macromeres, where activated Pmar1 protein represses the HesC repressor, the macromere specification and signaling genes are active.
  4. In the veg2 cells, Pmar1 is not activated and the HesC gene product shuts down the skeletogenic genes; however, those cells containing Notch can respond to the Delta signal from the skeletogenic mesenchyme.
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TLS Online TPP Program

#Question id: 2239

#Unit 2. Cellular Organization

Consider the transport of K+ from the blood (where its concentration is about 4 mM) into an erythrocyte that contains 150 mM K+.  The transmembrane potential is about 60 mV, inside negative relative to outside.  The free-energy change for this transport process is:  (These values may be of use to you:  R = 8.315 J/mol.K; T = 298 K; 9 (Faraday constant) = 96,480 J/V; N = 6.022×10²³ /mol.)
TLS Online TPP Program

#Question id: 2240

#Unit 2. Cellular Organization

 In which of the following cases is energy NOT needed for transmembrane transport?

a. Lysine moves into the cell against its concentration gradient via the Na+/lysine symporter.

b. Potassium ions (K+) move out of the cell down the K+ concentration gradient via potassium channels.

c. Glucose moves into the cell down its concentration gradient via a glucose uniporter.

d. Sodium ions (Na+) move out of the cell down the Na+ concentration gradient via sodium channels.

Which of the following are correct?
TLS Online TPP Program

#Question id: 2241

#Unit 2. Cellular Organization

Which of the following statement(s) is (are) true of V-class proton pumps?
TLS Online TPP Program

#Question id: 2242

#Unit 2. Cellular Organization

What two features of the structure of cholesterol make it somewhat amphipathic?
TLS Online TPP Program

#Question id: 2243

#Unit 2. Cellular Organization

Features of the fluid mosaic model of membrane structure include:

A. a lipid bilayer.

B. dynamic motion of both membrane lipids and proteins.

C. proteins that may either rest on the surface or penetrate the membrane.

D. the hydrophobic core of the bilayer prevents the unassisted movement of water-soluble substances from one side to the other.

E. Covalent interactions between phospholipids, and between phospholipids and proteins, lend strength and resilience to the membrane.

Which of the following is correct?
TLS Online TPP Program

#Question id: 2244

#Unit 2. Cellular Organization

Arrange the statements below in the proper sequence of events that occur in an action potential:

I. The resting potential is re-established.

II. A stimulus depolarizes the membrane to threshold.

III. Na+ gates open and Na+ rushes into the cell.

IV. K+ gates open and K+ rushes out of the cell.