Question 1

Protein molecules are most likely to be actively folded and cross-linked in which of the following structures?&#10;A)Granular endoplasmic reticulum&#10;B)Lysosome&#10;C)Ribosome&#10;D)Golgi apparatus&#10;E)Secretory granule

Accepted Answer

The granular endoplasmic reticulum, also known as the rough endoplasmic reticulum, is where protein synthesis occurs, and it is involved in the folding and modification of proteins, including the formation of disulfide bonds (cross-linking).

Question 2

The citric acid cycle (Krebs cycle) takes place in which of the following?&#10;A)Mitochondrial matrix&#10;B)Inner mitochondrial membrane&#10;C)Outer mitochondrial membrane&#10;D)Inner mitochondrial space

Accepted Answer

The citric acid cycle (Krebs cycle) takes place in the mitochondrial matrix, where the enzymes and cofactors necessary for the cycle are located. The inner mitochondrial membrane and inner mitochondrial space are involved in oxidative phosphorylation, which uses the energy generated by the citric acid cycle to produce ATP. The outer mitochondrial membrane is involved in regulating the passage of molecules in and out of the mitochondria.

Question 3

Cholesterol in the cell membrane most likely serves which of the following functions?&#10;A)Increases membrane permeability&#10;B)Increases membrane turnover&#10;C)Decreases membrane fluidity&#10;D)Decreases membrane stability

Accepted Answer

Cholesterol decreases membrane fluidity by preventing phospholipids from packing too closely and inhibiting movement of phospholipid tails. This allows for a stable membrane structure.

Question 4

Lipid synthesis occurs in which of the following locations?&#10;A)Trans-Golgi network&#10;B)Granular, or &#34;rough,&#34; endoplasmic reticulum&#10;C)Agranular, or &#34;smooth,&#34; endoplasmic reticulum&#10;D)Nucleus&#10;E)Lysosome

Accepted Answer

Lipid synthesis primarily occurs in the smooth endoplasmic reticulum, which lacks ribosomes (agranular). The Golgi complex is involved in the modification and sorting of lipids and proteins synthesized in the ER but is not directly involved in lipid synthesis. The nucleus contains genetic material and is primarily involved in transcription and replication, not lipid synthesis. Lysosomes are organelles involved in the breakdown of cellular waste, not lipid synthesis. Rough endoplasmic reticulum is responsible for protein synthesis and does not have a primary role in lipid synthesis.

Question 5

Ubiquinone, an electron acceptor in the electron transport chain (oxidative phosphorylation), is found in which of the following?&#10;A)Inner mitochondrial membrane&#10;B)Mitochondrial matrix&#10;C)Outer mitochondrial membrane&#10;D)Nucleus

Accepted Answer

Ubiquinone (also known as coenzyme Q) is a component of the inner mitochondrial membrane where it plays a role in transferring electrons within the electron transport chain. It is not found in the mitochondrial matrix, outer mitochondrial membrane, or nucleus.

Question 6

The cell membrane is least permeable to which of the following substances?&#10;A)Sodium&#10;B)Oxygen&#10;C)Ethanol&#10;D)Carbon dioxide&#10;E)Water

Accepted Answer

The cell membrane is least permeable to ions such as sodium due to its hydrophobic core, which repels ions and other polar molecules. Oxygen, ethanol, carbon dioxide, and water can all pass through the cell membrane to some degree.

Question 7

All the following processes depend on adenosine triphosphate except which of the following?&#10;A)Ciliary movement&#10;B)Positive chemotaxis&#10;C)Movement of oxygen across lipid bilayer&#10;D)Endocytosis&#10;E)Smooth muscle contraction

Accepted Answer

Movement of oxygen across the lipid bilayer is a passive process that does not require the use of ATP. The other processes listed all require ATP for energy.

Question 8

A pure phospholipid bilayer is most permeable to which of the following?&#10;A)Sodium&#10;B)Calcium&#10;C)Chloride&#10;D)Water&#10;E)Oxygen

Accepted Answer

A pure phospholipid bilayer is most permeable to small, nonpolar molecules like oxygen, which can easily diffuse through the hydrophobic core of the bilayer.

Question 9

Which of the following substances in most likely to represent the highest percent of cell mass in a typical cell of the body?&#10;A)Carbohydrates&#10;B)Ions&#10;C)Lipids&#10;D)Proteins&#10;E)Water

Accepted Answer

Water typically represents the highest percent of cell mass in a typical cell, often making up about 70% or more of the cell's total mass.

Question 10

The observation that abnormal cleavage of mannose residues from glycoproteins causes an autoimmune disease in mice is most consistent with the role of which of the following structures in the normal immune response?

A)Cytoskeleton
B)Glycocalyx
C)Peroxisomes
D)Lysosomes
E)Microtubules

Accepted Answer

The glycocalyx is a sugar-rich layer that surrounds cells and plays a role in cell-cell recognition and communication. It also contains glycoproteins that can trigger an immune response. Abnormal cleavage of mannose residues from glycoproteins suggests that the normal immune response involves recognition and response to specific glycoproteins, making option B the most consistent choice. The other structures listed, such as peroxisomes or microtubules, do not have a direct relationship with the immune response.

Question 11

Proteins are sorted for their delivery to lysosomes, secretory vesicles, and the plasma membrane in which of the following?&#10;A)Golgi apparatus&#10;B)Smooth endoplasmic reticulum&#10;C)Nucleus&#10;D)Endocytotic vesicle

Accepted Answer

The answer of Proteins are sorted for their delivery to...

Question 12

This cytoskeletal element plays a role in certain forms of cell movement and is an essential component of the mitotic spindle ____________.&#10;A)Phospholipids&#10;B)Glycocalyx&#10;C)F-actin&#10;D)Microtubules&#10;E)Clathrin

Accepted Answer

The answer of This cytoskeletal element plays a role in...

Question 13

Which of the following is true for both pinocytosis and phagocytosis?&#10;A)Involves recruitment of actin filaments&#10;B)Occurs spontaneously and nonselectively&#10;C)Permits uptake of bacterium into cytosol&#10;D)Is only observed in macrophages and neutrophils&#10;E)Does not require adenosine triphosphate

Accepted Answer

The answer of Which of the following is true for...

Question 14

The abnormal cleavage of mannose residues during the posttranslational processing of glycoproteins has been shown to result in the development of a lupus-like autoimmune disease in mice. The abnormal cleavage is due to a mutation of the enzyme $\alpha$ -mannosidase II. Based on your understanding of the processing of membrane proteins, you would predict this enzyme to be localized to which of the following?

A)Nucleus
B)Cytosol
C)Golgi apparatus
D)Lysosomes
E)Peroxisomes

Accepted Answer

The answer of The abnormal cleavage of mannose residues during...

Question 15

Which of the following best describes the glycocalyx of a cell?&#10;A)Negatively charged carbohydrate chains that protrude into cytosol&#10;B)Negatively charged carbohydrate layer on cell surface&#10;C)Layer of anions aligned on the cytosolic surface of plasma membrane&#10;D)Large glycogen stores found in &#34;fast&#34; muscles&#10;E)A mechanism of cell-cell attachment

Accepted Answer

The answer of Which of the following best describes the...

Deck 2: The Cell and Its Functions