Question 1

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

Accepted Answer

The nucleus is the control center of the cell and contains the genetic material that regulates most cellular activities. It is responsible for controlling gene expression, DNA replication, and cell division, among other important functions. The other options - cytoplast, mitochondrion, and nucleolus - are important organelles, but they do not have the same level of control over cellular activity as the nucleus.

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 lipid bilayer of the membrane and held in place by hydrophobic interactions between the nonpolar regions of the protein and the hydrophobic tails of the phospholipids in the membrane. Peripheral proteins, on the other hand, are attached to the membrane through weaker, electrostatic interactions and are not embedded in the lipid bilayer. Rough endoplasmic reticula and Golgi apparatuses are organelles within the cell and not membrane proteins.

Question 3

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, towards the external environment. This orientation allows for interactions with other molecules, such as cell-to-cell recognition and signaling.

Question 4

DNA in the nucleus is wrapped around ____.

Accepted Answer

DNA in the nucleus is wrapped around proteins called histones to form structures called nucleosomes.

Question 5

Which organelle is capable of performing both fission and fusion?

Accepted Answer

Mitochondria are capable of performing both fission, which is the process of the organelle dividing into two or more smaller units, and fusion, which is the process of two or more organelles merging to form a larger unit. This allows for the mitochondria to adapt to the changing energy needs of the cell. The other organelles listed do not have the ability to perform fission and fusion.

Question 6

In addition to the mitochondria,which organelle possesses an inner and outer membrane?

Accepted Answer

The nucleus possesses an inner and outer membrane called the nuclear envelope, which separates the contents of the nucleus from the cytoplasm.

Question 7

Encoded within the nuclear DNA of each cell is ____.

Accepted Answer

The nuclear DNA of each cell contains the entire genome for that organism, which includes all the genes necessary for the development and function of the entire organism, not just for a particular cell type.

Question 8

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

Accepted Answer

The cytoskeleton is a network of protein fibers that provide structural support and help to move cell organelles within the cell. The endoplasmic reticulum is responsible for protein synthesis and lipid metabolism, while the mitochondrion generates energy for the cell. The matrix space is found within the mitochondrion and is involved in cellular respiration. Therefore, the best choice for this question is C, the cytoskeleton.

Question 9

What is the major route for ATP production?

Accepted Answer

Oxidative phosphorylation is the major route for ATP production in cells, where energy derived from the oxidation of nutrients such as glucose, fatty acids, and amino acids is used to generate a proton gradient across the inner mitochondrial membrane, which is then used by the ATP synthase to produce ATP. Hydrolysis, peroxidation, and transformation are not the major routes for ATP production in cells.

Question 10

Membrane proteins do not serve as ____.

Accepted Answer

Membrane proteins can act as pumps, receptors, and enzymes, but they do not serve as detoxifiers. This is typically the role of enzymes found within the cell's cytoplasm or specialized organs such as the liver.

Question 11

The fluid portion of the cytoplasmic matrix does not contain ____.

Accepted Answer

The fluid portion of the cytoplasmic matrix, also known as the cytosol, typically contains amino acids, glucose, and carbon dioxide as they are involved in cellular metabolism and processes. Urea, however, is primarily a waste product of protein metabolism and is not typically found in the cytosol.

Question 12

Membrane lipid bilayers consist primarily of ____.

Accepted Answer

Membrane lipid bilayers consists primarily of phospholipids which are composed of a polar hydrophilic head (usually containing a phosphate group) and two nonpolar hydrophobic fatty acid tails.

Question 13

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

Accepted Answer

The electron transport chain is located in the mitochondrial inner membrane. This is where the thylakoid membranes in the mitochondria are located, which is where the electron transport chain occurs. The other choices are not correct, as the outer membrane of the mitochondria does not contain the electron transport chain, the matrix is the location of the citric acid cycle, and the cytoplasmic matrix is not part of the mitochondria.

Question 14

Signals generated at one part of a cell are transmitted quickly to other parts of the cell due to the interconnection of the cytosol and ____.

Accepted Answer

Filaments, such as microtubules and microfilaments, provide a network of interconnected fibers within the cytosol of the cell. This allows signals to quickly and efficiently travel from one part of the cell to another. Glycoproteins, glycolipids, and integral proteins are all important components of cellular membranes, but do not directly contribute to the transmission of signals within the cytosol.

Question 15

Microtubule organization centers (MTOCs)on the outer nuclear membrane are associated with which cellular process?

Accepted Answer

Microtubule organization centers (MTOCs) on the outer nuclear membrane are associated with organizing and nucleating microtubules during mitosis.

Question 16

Enzymes of metabolic pathways within the cytoplasmic matrix are often oriented so that the product of one enzyme is released in close proximity to the next enzyme for which it is a substrate,to facilitate the velocity of the overall pathway.This arrangement includes enzymes of ____.

Accepted Answer

Enzymes of glycolysis are oriented in a way that products of one enzyme are released near the next enzyme for which it is a substrate. This facilitates the velocity of the pathway and is known as channeling. This type of organization is not found in beta-oxidation, ketone production, or the Krebs cycle.

Question 17

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

Accepted Answer

The TCA (tricarboxylic acid) cycle and fatty acid oxidation occur in the mitochondrion. The mitochondria are the primary site for cellular respiration and energy production, which involves both TCA cycle and fatty acid oxidation. The other organelles listed, such as the Golgi apparatus, nucleus, and microsomes, do not play a direct role in these metabolic pathways.

Question 18

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

Accepted Answer

The organelle responsible for most of the metabolic energy (ATP) production is the mitochondrion. It contains enzymes needed for the electron transport chain, which ultimately produces ATP via oxidative phosphorylation. The Golgi apparatus and endoplasmic reticulum are both involved in protein and lipid processing and trafficking, while the nucleus is responsible for storing and protecting genetic information.

Question 19

What is the role of cholesterol in plasma membrane structure?

Accepted Answer

Cholesterol plays a crucial role in maintaining the fluidity and permeability of the plasma membrane. It helps regulate the packing of phospholipid molecules in the membrane by inserting itself in between them. This reduces the membrane's fluidity and prevents excessive movement of the phospholipids, thus maintaining a stable structure. Additionally, cholesterol also helps in reducing the membrane's permeability to ions and polar molecules, thus controlling the flow of substances in and out of the cell.

Question 20

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. ATP is the energy currency of the cell and occurs within the mitochondria. These genes are inherited only from the mother in a maternal inheritance pattern.

Quiz 1: The Cell: A Microcosm of Life