Question

Choose the FALSE statement:

A) The products formed in a catabolic reaction would probably have lower energy than the reactants from which they are formed.

B) Coenzymes, or vitamins, are organic molecules that are required by many enzymes in order to carry out their catalytic functions.

C) The limit of cell size is partly determined by the surface area to volume ratio, which favors larger cells having a higher surface area to volume ratio than smaller cells.

Choose the FALSE statement:

A) According to the principles of diffusion, molecules will move down their concentration gradient from high to low by relying on entropy, and without requiring any input of energy.

B) Sugars and amino acids are examples of molecules that can easily diffuse across the phospholipid bilayer.

C) Active transport requires ATP and is used in those instances where substances are to be moved across the cell membrane against their concentration gradient.

Choose the FALSE statement:

A) Complex cell structure, is inclusive of all multicellular organisms, including plants, animals, and fungi; simple cell structure is inclusive of all unicellular organisms, including amoeba, paramecium, bacteria and cyanobacteria.

B) In contrast to bacterial cells, which have only one piece of DNA, animal and plant cells have much more DNA; in these cells it is organized as many separate linear pieces.

C) Prokaryotic cells are much smaller than eukaryotic cells because they lack the internal organization provided by organelles, they are also much more primitive in terms of their evolutionary history.

Answer 1

Ans 1- The limit of cell size is partly determined by the surface area to volume ratio, which favors larger cells having a higher surface area to volume ratio than smaller cells. is false statement.

area to volume ratio is the ratio of  surface area divided by the volume. This indicates how much surface area is available compared to how big the cell is. If the surface area to volume ratio is small, the cell is very big. If the ratio is big, the surface area is greater than the volume, and the cell is small.As cells increase in size, the surface area and volume do not usually increase proportionally to length. The greater the diameter of a single-celled organism, the lower the surface area to volume ratio. It is this relationship that restricts the size of a particular cell.

Ans 2- ) Sugars and amino acids are examples of molecules that can easily diffuse across the phospholipid bilayer. This statement is false.

The simplest mechanism by which molecules can cross the plasma membrane is passive diffusion. During passive diffusion, a molecule simply dissolves in the phospholipid bilayer, diffuses across it, and then dissolves in the aqueous solution at the other side of the membrane. Passive diffusion is thus a nonselective process by which any molecule able to dissolve in the phospholipid bilayer is able to cross the plasma membrane and equilibrate between the inside and outside of the cell. Importantly, only small, relatively hydrophobic molecules are able to diffuse across a phospholipid bilayer at significant rates. Thus, gases (such as O2 and CO2), hydrophobic molecules (such as benzene), and small polar but uncharged molecules (such as H2O and ethanol) are able to diffuse across the plasma membrane. Other biological molecules like amino acid and sugars  however, are unable to dissolve in the hydrophobic interior of the phospholipid bilayer.

Facilitated diffusion allows polar and charged molecules, such as carbohydrates, amino acids, nucleosides, and ions, to cross the plasma membrane.

Facilitated diffusion  is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins.

Ans 3- In contrast to bacterial cells, which have only one piece of DNA, animal and plant cells have much more DNA; in these cells it is organized as many separate linear pieces. is a wrong statement.

bacteria may have one or more smaller circular DNA molecules, called plasmids, that contain (usually) non-essential genes.