LS7A PAL questions

Three carbon atoms are linked by single covalent bonds such that those carbon atoms and bonds together form the shape of a V. All of the unshared electrons form covalent bonds with hydrogen. How many hydrogen atoms does this molecule contain?

8 Carbon is able to form 4 single bonds.

Which molecule would most likely require a transport protein to cross the plasma membrane of a red blood cell?

C6H12O6 Glucose is both polar and a large molecule, so it would require the most help passing through the cell membrane.

Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X could form a hydrogen bond with another Molecule X:

False Hydrophilic molecules are able to form hydrogen bonds in water, not necessarily with one another. Hydrogen bonds form between Hydrogen and an atom with high electronegativity.

Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X could form an ionic bond with Cl-

False Ionic bonds only form between arms of opposite charges.

Three different molecules are shown below. The electronegativity of sulfur (S) is similar to the electronegativity of carbon (C) and the electronegativity of nitrogen (N) is similar to the electronegativity of oxygen (O). T/F: Molecule 1 only contains nonpolar covalent bonds.

False Since oxygen is high in electronegativity, it usually forms polar covalent bonds.

Three different molecules are shown below. The electronegativity of sulfur (S) is similar to the electronegativity of carbon (C) and the electronegativity of nitrogen (N) is similar to the electronegativity of oxygen (O). T/F: Molecule 2 is hydrophilic.

False This atom is non-polar and therefore hydrophobic.

Three different molecules are shown below. The electronegativity of sulfur (S) is similar to the electronegativity of carbon (C) and the electronegativity of nitrogen (N) is similar to the electronegativity of oxygen (O). T/F: Molecule 3 could form a hydrogen bond with water.

False This molecule is non-polar and hydrophobic. Hydrophobic molecules do not form hydrogen bonds in water.

The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. What will happen to the net movement of Waste molecules if the Na+/K+ Pump stops working?

If the Na+/K+ pump stops working, the net movement of waste molecules stops. In order for the waste to come out of the cell, sodium must come into the cell.

The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. The concentration of Waste molecules is ________ inside the cell compared to the outside.

Lower

Although the phospholipid molecules can be in constant lateral movement, they very rarely flip from one side of the bilayer to the other. Which of the answer choices could explain this?

The phospholipid molecule heads are repelled by the hydrophobic interior of the cell membrane. Since the outside and inside of the cell are aqueous and the phospholipid tails are hydrophobic, they will avoid water. The heads of the phospholipid molecules are hydrophilic and are repelled by the hydrophobic interior.

The beaker in the illustration contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to water but not to salt. What will occur in this container?

There will be a diffusion of water from side A to side B. Since the solute will move from a high to a low concentration, and only water can pass through the membrane, the water will move from the side with a high concentration to the side with a low concentration.

A beaker contains two solutions of salt dissolved in water. The two solutions have different concentrations of salt (measured by molarity, M) and are separated by a membrane that is permeable to both salt and water. The salt and water will move through the membrane by diffusion. Which statement is true about the diffusion of these solutions?

There will be a net diffusion of salt from side B to side A and of water from side A to side B. In diffusion, solutes move from areas of high concentration to low concentration.

The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. What will happen when the Na+ channel is open?

There will be net movement of Na+ into the cell through the channel

Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X could form a hydrogen bond with water:

True Hydrophilic, or polar, molecules can form hydrogen bonds when dissolved in water.

Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X could form an ionic bond with Na+:

True Ionic bonds are able to form between atoms with opposite charges. Sodium (Na+) has a positive 1 charge and Chlorine (Cl-) has a negative charge of 1.

Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. T/F: Molecule X contains at least one nonpolar covalent bond.

True Non-polar bonds occur when atoms equally share electrons, usually between atoms with lower electronegativity.

Three different molecules are shown below. The electronegativity of sulfur (S) is similar to the electronegativity of carbon (C) and the electronegativity of nitrogen (N) is similar to the electronegativity of oxygen (O). T/F: Molecule 1 could form a hydrogen bond with another Molecule 1.

True Since Oxygen is high in electronegativity, this molecule is able to form hydrogen bonds.