Question 1

Which of the following best describes the first, inner-most energy shell of an atom?

Accepted Answer

It can have a maximum of 2 electrons.

Question 2

The atomic number of an atom is defined as:

Accepted Answer

The number of protons in the atom.

Question 3

Nitrogen has 7 electrons. How many covalent bonds can it form with other elements?

Accepted Answer

3

Question 4

Starch and cellulose are both polysaccharides. The key structural difference that supports their functional differences is:

Accepted Answer

Starch has some branching and is poorly soluble, whereas cellulose is unbranched, insoluble, and very stable.

Question 5

A semi-permeable bag contains 0.3 M maltose, 0.1 M galactose, and 0.5 M mannose. It is placed in a beaker with 0.5 M maltose, 0.4 M galactose, and 0.2 M mannose. The membrane is permeable to galactose and mannose, but not maltose. What initial change will occur?

Accepted Answer

The bag would become more turgid.

Question 6

When sodium ions cross a cell membrane, how do they move?

Accepted Answer

They are helped across by proteins.

Question 7

A liposome is filled with acidic solution and placed in a basic solution. Both inside and outside have equal osmolarity. What will happen to protons?

Accepted Answer

There will be no movement across the membrane.

Question 8

The term 'phospholipid' can best be described as:

Accepted Answer

A nonpolar lipid molecule that is made amphipathic by the addition of a phosphate.

Question 9

Under what circumstances does membrane transport always require energy?

Accepted Answer

Whenever a solute needs to be moved from low concentration to high concentration through a phospholipid bilayer membrane.

Question 10

A can of Monster X-presso has 221 mg of caffeine. The LD$_{50}$ of caffeine is 170 mg/kg. If a student weighs 54 kg, approximately how many cans would reach the LD$_{50}$?

Accepted Answer

5

Question 11

Why have most enzymes not evolved to have super high affinity (very low $K_m$) for their substrates?

Accepted Answer

Enzymes would always be saturated, always at $V_{max}$, and thus regulation via changing $[substrate]$ would be lost.

Question 12

Highly specific protein-protein interactions play important roles in:

Accepted Answer

Cell-receptor interaction with ligands.

Question 13

Pumping hydrogen ions across the inner mitochondrial membrane via the electron transport chain facilitates ATP production. This is known as:

Accepted Answer

Chemiosmosis.

Question 14

Which statement is FALSE? Lactate production from pyruvate during oxygen deprivation is:

Accepted Answer

A proton-consuming reaction.

Question 15

If a cell has only protein available as an energy source and no glucose, how might metabolism be impacted?

Accepted Answer

Proteins will be broken down to carbon skeletons from amino acids and used to enter at the end of glycolysis and run the Krebs cycle and electron transport chain.

Question 16

The main regulatory point in glycolysis (in animals) is:

Accepted Answer

Feedback regulation of PFK (phosphofructokinase).

Question 17

ATP production during glycolysis occurs via:

Accepted Answer

Substrate-level phosphorylation.

Question 18

The TCA cycle (Krebs cycle) occurs in the:

Accepted Answer

Matrix of mitochondria.

Question 19

An enzyme that has high affinity for its substrate and catalyzes a reaction very rapidly would display:

Accepted Answer

Low $K_m$ and high $V_{max}$.

Question 20

Which of the following would least likely be found in a molecule of DNA?

Accepted Answer

Uracil.

General Biology: Atomic Structure, Macromolecules, Membranes, and Cellular Processes

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