EKB-Lecture 2

•L-Canavanine is an amino acid produced by some species of plant. The figure shows that it is structurally similar to arginine.

•How does the production of canavanine protect a plant from infection?

It prepares plant cells for future infections by the same pathogen.
It breaks down toxins that have been released by pathogens.
It is toxic to herbivores because it is incorporated into their proteins.
It causes the cell walls of epidermal cells to swell, preventing pathogen entry.
It promotes the lignification of cell walls, preventing pathogen entry.

•How do receptors present in plant cells act as a defense mechanism?

They act as an insulator to stop the pathogen from spreading to other parts.
They bind to antimicrobial chemicals produced by the plant to increase their effectiveness.
They increase the exchange of materials between neighboring plant cells.
They bind to chemicals in the plant cell to make the cell walls stronger.
They bind to common molecules present on pathogens and initiate defense responses.

•Which of the following is not an example of a biochemical defense used by plants?

Secretion of antimicrobials
Production of canavanine
Formation of tyloses
Production of phenols

•fill in the blank: The release of proteins with antitoxin properties in response to an infection is an example of .

a preexisting structural defense
an induced structural defense
a biochemical defense

•Some pathogens produce toxins that harm the plant. What chemicals does the plant produce to break down these toxins and limit the damage that they cause?

Glycosides
Nonprotein amino acids
Phenols
Enzymes
Protein receptors

•Farmers use different approaches to reduce crop damage caused by a pathogen:

•Selective breeding

•Spraying chemicals that are toxic to the pathogen

•Genetic engineering

•Which approaches lead to an increase in the immunity of the crop plant against disease?

Selective breeding only
Selective breeding and genetic engineering
Selective breeding and spraying toxic chemicals
Spraying toxic chemicals only
Genetic engineering and spraying toxic chemicals

•Which of the following is not an example of an antimicrobial chemical released by plants?

Glycoside
Cellulose
phenol

•Where do all white blood cells originate?

Thymus
Spleen
Lymph nodes
Liver
Bone marrow

•Peyer’s patches are important structures within the human lymphatic system. Where are they found in the body?

In the tonsils
In the small intestine
In the spleen
in the bone marrow

•The organs of the immune system are scattered throughout the body, as shown in the figure.

•What is the name of organ X?

Spleen
Adenoid
Tonsils
Bone marrow
Thymus

•Where do precursor T lymphocytes go to complete their maturation?

Thymus
Liver
Bone marrow
Lymph nodes
Spleen

•Which of the following is not a function of the spleen in the human immune system?

To act as a store of some macrophages
To act as the site of T lymphocyte maturation
To filter out microbes and pathogens from the blood

•The figure shows a cross section of a lymph node.

•What cells can be found inside the structure?

Lymphocytes, macrophages, and other white blood cells
Only T lymphocytes in their final stages of maturation
Stem cells that develop into all types of blood cells
Aging red blood cells and their breakdown products

•What is the primary function of bone marrow in the human immune system?

To produce blood cells, including white blood cells (leukocytes) and platelets
To act as the site of T lymphocyte maturation
To produce macrophages that target and destroy pathogens within the bone marrow
To act as a store of plasma and help filter out pathogens from the lymph

•What is the primary function of the thymus gland in the human immune system

to act as the site of T lymphocyte maturation
To act as a store of white blood cells and help filter out pathogens from the lymph
To help prevent the entry of pathogens carried on food, drink, or air into the body
To act as the site of B lymphocyte maturation

•Where are all lymphocytes initially produced?

Peyer’s patches
The tonsils
The bone marrow
The spleen

•The organs of the immune system are scattered through the body, as shown in the figure. Which organ is the spleen?

A
D
B
E
C

•What is the primary function of the tonsils in the human immune system?

To act as the site of T lymphocyte maturation
To act as a store of white blood cells and help filter out pathogens from the lymph
To help prevent the entry of pathogens carried on food, drink, or air into the body
To break down and digest dead or damaged immune cells

•What is the primary function of lymph nodes in the lymphatic system?

To act as the site of T lymphocyte production and maturation
To store lymphocytes and help filter out pathogens from lymph
To initiate the inflammatory response when the skin is punctured or wounded
To act as the site of B lymphocyte production and maturation

•Which of the following is not a component of the lymphatic system?

Lymph nodes
Bone marrow
The gonads
The tonsils
The spleen

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