Question 1

What is the role of cholesterol in plasma membrane structure?

Accepted Answer

Cholesterol is a lipid molecule that is found in the plasma membrane of cells. It helps to regulate the fluidity of the membrane, which is important for the proper function of the cell.

Question 2

Proteins attached to the membrane through hydrophobic interactions and embedded in the membrane are called _____.

Accepted Answer

Integral proteins are embedded in the membrane and interact with the hydrophobic core of the lipid bilayer.

Question 3

What is the major route for ATP production?

Accepted Answer

Oxidative phosphorylation is the major route for ATP production in cells, which occurs in the mitochondrial inner membrane. This process involves the electron transport chain, where electrons are passed from one carrier to another, generating a proton gradient that is used by ATP synthase to produce ATP. Hydrolysis, peroxidation, and transformation are not major pathways for ATP production in cells.

Question 4

Which of the following nitrogenous bases is unique to RNA?

Accepted Answer

Uracil is a nitrogenous base that is unique to RNA. It is similar to thymine, which is found in DNA, but it has a different chemical structure. Uracil is one of the four nitrogenous bases that make up the genetic code, along with adenine, guanine, and cytosine.

Question 5

What type of cell depends solely on energy produced through anaerobic mechanisms?

Accepted Answer

Erythrocytes (red blood cells) rely solely on anaerobic glycolysis for energy because they lack mitochondria, which are necessary for aerobic respiration.

Question 6

Which of the following is NOT an attribute common to all membranes?

Accepted Answer

Biological membranes are generally asymmetrical, meaning the two leaflets of the bilayer have different compositions and functions.

Question 7

The cell organelle responsible for most of the initiation and regulation of cellular activity is the _____.

Accepted Answer

The nucleus is the control center of the cell and is responsible for most of the initiation and regulation of cellular activity.

Question 8

The carbohydrate moieties of the plasma membrane glycoproteins and glycolipids are oriented _____.

Accepted Answer

The carbohydrate moieties of the plasma membrane glycoproteins and glycolipids are oriented outwardly, away from the cytoplasmic matrix. This orientation allows for interactions with other molecules outside of the cell and plays a role in cell recognition and signaling.

Question 9

What structural body made up of flattened cisternae flanked by tubular networks is thought to be an extension of the endoplasmic reticulum?

Accepted Answer

The Golgi apparatus is composed of flattened cisternae and is involved in modifying, sorting, and packaging proteins and lipids, functioning as an extension of the endoplasmic reticulum.

Question 10

Encoded within the nuclear DNA of each cell is

Accepted Answer

The nuclear DNA in each cell contains the entire genome for that organism, which includes all the genes necessary for the function and development of the organism.

Question 11

In the cell structure the _____ provides support and controls the movement of cell organelles.

Accepted Answer

The cytoskeleton is responsible for providing support to the cell and also for controlling the movement of cell organelles. The endoplasmic reticulum and mitochondria have specific functions related to protein synthesis and energy production, respectively. The matrix space is a term used to describe the space inside the mitochondria where ATP is produced.

Question 12

Genes contained in mitochondrial DNA are inherited only from the mother and code for

Accepted Answer

Genes contained in mitochondrial DNA code for proteins vital to the production of ATP. Mitochondria are the powerhouse of the cell, responsible for generating energy in the form of ATP through oxidative phosphorylation. Genes within the mitochondrial DNA encode for some of the proteins involved in this process.

Question 13

In which organelle do the TCA cycle and fatty acid oxidation occur?

Accepted Answer

The TCA cycle and fatty acid oxidation both occur in the mitochondrion.

Question 14

Membrane proteins serve as all of the following EXCEPT _____.

Accepted Answer

Membrane proteins do not typically function as detoxifiers. They primarily act as pumps, receptors, and enzymes, facilitating transport, signal transduction, and catalyzing reactions.

Question 15

All components of the electron transport chain are embedded in the _____.

Accepted Answer

The electron transport chain is located in the inner membrane of mitochondria.

Question 16

Enzymes of metabolic pathways that are associated with the cytoplasmic matrix so that the product of one enzyme is released in close proximity to the next enzyme for which it is a substrate to facilitate velocity of the overall pathway include enzymes of _____.

Accepted Answer

Glycolysis is a metabolic pathway that occurs in the cytoplasm, where enzymes are organized in a way that allows the product of one enzyme to be readily available as a substrate for the next enzyme, facilitating the pathway's efficiency.

Question 17

The organelle responsible for production of most of the metabolic energy (ATP) is the _____.

Accepted Answer

Mitochondria are responsible for producing ATP through cellular respiration, making them the organelle that produces most of the metabolic energy. The Golgi apparatus is responsible for packaging and modifying proteins, the endoplasmic reticulum is involved in protein and lipid synthesis, and the nucleus stores genetic information.

Question 18

The smooth endoplasmic reticulum (SER) is associated with

Accepted Answer

The smooth endoplasmic reticulum (SER) is primarily associated with lipid synthesis. It is also involved in detoxification reactions and storage of calcium ions. It does not have ribosomes for protein synthesis, unlike the rough endoplasmic reticulum (RER). The calcium ion pump necessary for the contractile process is associated with the sarcoplasmic reticulum in muscle cells, not the smooth endoplasmic reticulum. The cytochrome P450 enzymes are involved in drug metabolism and are found in the smooth endoplasmic reticulum.

Question 19

Membrane lipid bilayers consist primarily of _____.

Accepted Answer

Membrane lipid bilayers consist primarily of phospholipids, which are amphipathic molecules that have both hydrophobic and hydrophilic regions. Cholesterol and proteins are also found in membranes, but in smaller amounts than phospholipids. Saturated fatty acids can be components of phospholipids, but they are not the main constituent of membrane bilayers.

Question 20

Translation is the process by which

Accepted Answer

Translation is the process where genetic information in the form of mRNA molecules is used to specify the sequence of amino acids in a protein product. This process occurs in ribosomes, where the mRNA is read and tRNAs carrying specific amino acids are brought in to form a polypeptide chain. Therefore, option D is the correct choice.

Quiz 1: The Cell: a Microcosm of Life