Question 1

A gap junction is a channel that connects adjacent cells. Which one of the following cannot pass through a gap junction?

Accepted Answer

A)  ions that can regulate heartbeat 
B)  amino acids 
C)  nucleotides 
D)  ribosomes 
A)  ions that can regulate heartbeat 
B)  amino acids 
C)  nucleotides 
D)  ribosomes

Question 2

In plant cells, the middle lamella ________.

Accepted Answer

A)  allows adjacent cells to adhere to one another 
B)  prevents dehydration of adjacent cells 
C)  maintains the plant's circulatory system 
D)  allows for gas and nutrient exchange among adjacent cells 
A)  allows adjacent cells to adhere to one another 
B)  prevents dehydration of adjacent cells 
C)  maintains the plant's circulatory system 
D)  allows for gas and nutrient exchange among adjacent cells

Question 3

What is a major difference between the extracellular matrix (ECM) of a plant cell and the ECM of an animal cell?

Accepted Answer

A)  Plant ECM is composed primarily of proteins, whereas animal ECM is mainly carbohydrates. 
B)  Plant ECM is primarily carbohydrate in nature, whereas animal ECM is mainly proteins. 
C)  Plant and animal ECMs are quite similar in structure and function. 
D)  ECM components in plant cells are released extracellularly by the Golgi stacks, whereas lysosomes do this in animal cells. 
A)  Plant ECM is composed primarily of proteins, whereas animal ECM is mainly carbohydrates. 
B)  Plant ECM is primarily carbohydrate in nature, whereas animal ECM is mainly proteins. 
C)  Plant and animal ECMs are quite similar in structure and function. 
D)  ECM components in plant cells are released extracellularly by the Golgi stacks, whereas lysosomes do this in animal cells.

Question 4

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?

Accepted Answer

A)  Estrogen is produced in very large concentration by nearly every tissue of the body. 
B)  Each cell responds in the same way when steroids bind to the cell surface. 
C)  Estrogen is kept away from the surface of any cells not able to bind it at the surface. 
D)  Estrogen binds to specific receptors inside many kinds of cells, each with different responses. 
E)  Cells metabolize steroids in different ways, producing by-products that stimulate tRNA production. 
A)  Estrogen is produced in very large concentration by nearly every tissue of the body. 
B)  Each cell responds in the same way when steroids bind to the cell surface. 
C)  Estrogen is kept away from the surface of any cells not able to bind it at the surface. 
D)  Estrogen binds to specific receptors inside many kinds of cells, each with different responses. 
E)  Cells metabolize steroids in different ways, producing by-products that stimulate tRNA production.

Question 5

The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a characteristic common to all of these extracellular structures?

Accepted Answer

A)  They must block water and small molecules to regulate the exchange of matter and energy with their environment. 
B)  They must permit information transfer between the cell's cytoplasm and the nucleus. 
C)  They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. 
D)  They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell. 
E)  They are composed of a mixture of lipids and nucleotides. 
A)  They must block water and small molecules to regulate the exchange of matter and energy with their environment. 
B)  They must permit information transfer between the cell's cytoplasm and the nucleus. 
C)  They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. 
D)  They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell. 
E)  They are composed of a mixture of lipids and nucleotides.

Question 6

The cancer-causing forms of the Ras protein are involved in which of the following processes?

Accepted Answer

A)  relaying a signal from a growth-factor receptor 
B)  DNA replication 
C)  DNA repair 
D)  cell-cell adhesion 
E)  cell division 
A)  relaying a signal from a growth-factor receptor 
B)  DNA replication 
C)  DNA repair 
D)  cell-cell adhesion 
E)  cell division

Question 7

Plasmodesmata are cell-cell junctions that are found between ________.

Accepted Answer

A)  individual cardiac cells in heart muscle tissue 
B)  adjacent plant cells 
C)  adjacent animal cells in the same tissue type 
D)  the plasma membrane of actively dividing prokaryotes 
A)  individual cardiac cells in heart muscle tissue 
B)  adjacent plant cells 
C)  adjacent animal cells in the same tissue type 
D)  the plasma membrane of actively dividing prokaryotes

Question 8

Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because they ________.

Accepted Answer

A)  are species specific 
B)  always lead to the same cellular response 
C)  amplify the original signal many times 
D)  counter the harmful effects of phosphatases 
E)  use a small and fixed number of molecules 
A)  are species specific 
B)  always lead to the same cellular response 
C)  amplify the original signal many times 
D)  counter the harmful effects of phosphatases 
E)  use a small and fixed number of molecules

Question 9

One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?

Accepted Answer

A)  G-protein-coupled receptors 
B)  ligand-gated ion channels 
C)  steroid receptors 
D)  receptor tyrosine kinases 
A)  G-protein-coupled receptors 
B)  ligand-gated ion channels 
C)  steroid receptors 
D)  receptor tyrosine kinases

Question 10

Which observation suggested the involvement of a second messenger in epinephrine's effect on liver cells?

Accepted Answer

A)  Enzymatic activity was proportional to the amount of calcium added to a cell-free extract. 
B)  Receptor studies indicated that epinephrine was a ligand. 
C)  Glycogen breakdown was observed only when epinephrine was administered to intact cells. 
D)  Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined. 
E)  Epinephrine was known to have different effects on different types of cells. 
A)  Enzymatic activity was proportional to the amount of calcium added to a cell-free extract. 
B)  Receptor studies indicated that epinephrine was a ligand. 
C)  Glycogen breakdown was observed only when epinephrine was administered to intact cells. 
D)  Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined. 
E)  Epinephrine was known to have different effects on different types of cells.

Question 11

Not all intercellular signals require transduction. Which one of the following signals would be processed without transduction?

Accepted Answer

A)  a lipid-soluble signal 
B)  a signal that is weakly bound to a nucleotide 
C)  a signal that binds to a receptor in the cell membrane 
D)  a signal that binds to the ECM 
A)  a lipid-soluble signal 
B)  a signal that is weakly bound to a nucleotide 
C)  a signal that binds to a receptor in the cell membrane 
D)  a signal that binds to the ECM

Question 12

For a tissue or an organ to function as a unit, ________.

Accepted Answer

A)  there must be a signal molecule recognized by all cells in the tissue or organ 
B)  there must be cell-cell communication among the cells within a tissue or organ 
C)  the tissue or organ must perform similar functions 
D)  the tissue or organ must be composed of all of the same type of cells 
A)  there must be a signal molecule recognized by all cells in the tissue or organ 
B)  there must be cell-cell communication among the cells within a tissue or organ 
C)  the tissue or organ must perform similar functions 
D)  the tissue or organ must be composed of all of the same type of cells

Exam 11: Cellcell Interactions

A gap junction is a channel that connects adjacent cells. Which one of the following cannot pass through a gap junction?

In plant cells, the middle lamella ________.

What is a major difference between the extracellular matrix (ECM) of a plant cell and the ECM of an animal cell?

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?

The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a characteristic common to all of these extracellular structures?

The cancer-causing forms of the Ras protein are involved in which of the following processes?

Plasmodesmata are cell-cell junctions that are found between ________.

Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because they ________.

One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?

Which observation suggested the involvement of a second messenger in epinephrine's effect on liver cells?

Not all intercellular signals require transduction. Which one of the following signals would be processed without transduction?

For a tissue or an organ to function as a unit, ________.

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Ecosystems and Global Ecology

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes: an Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Genes, Development, and Evolution

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

Population Ecology

Community Ecology

Biodiversity and Conservation Biology

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