Classification of Proteins by Biological Value

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Which organ is responsible for secreting a proenzyme called pepsinogen to begin protein digestion?

Stomach (correct)

Small intestine

Liver

Pancreas

What is the primary cause of negative nitrogen balance in older adults according to the text?

Lack of essential fatty acids

Inadequate dietary protein (correct)

Lack of essential vitamins

Inadequate dietary carbohydrates

Which hormone is responsible for causing the gall bladder contraction during protein digestion?

Secretin

Glucagon

Cholecystokinin (CCK) (correct)

Insulin

What is the function of enteropeptidase in protein digestion?

Activates trypsinogen to produce trypsin Signup and view all the answers

In which phase of life is negative nitrogen balance most commonly associated according to the text?

Old age Signup and view all the answers

Which organ secretes peptide hormones called cholecystokinin (CCK) and secretin into the circulatory system for protein digestion?

Small intestine Signup and view all the answers

What is the main difference between proteins of high biological value and proteins of low biological value?

High biological value proteins are more digestible and contain high essential amino acids, while low biological value proteins are less digestible and contain inadequate essential amino acids. Signup and view all the answers

When two or more fair proteins are taken together, what can happen?

They may become of good value due to complementing amino acids. Signup and view all the answers

Why is it important to supplement animals not only with essential amino acids but also with nonessential amino acids?

To spare the essential amino acids lost in their synthesis. Signup and view all the answers

Which nonprotein nitrogenous compound is excreted by humans in the largest amount?

Urea Signup and view all the answers

What does positive nitrogen balance indicate?

N input exceeds N output during growth. Signup and view all the answers

Why is it crucial for animal nutrition to provide adequate essential amino acids?

To ensure proper growth and health. Signup and view all the answers

What modification is made to Glu to form pyroglutamic acid in Thyrotropin releasing hormone (TRH)?

It is modified to pyroglutamic acid Signup and view all the answers

Which peptide is involved in erythrocyte membrane integrity and enzyme activity?

Glutathione Signup and view all the answers

How many amino acids are present in Vasopressin (ADH)?

9 Signup and view all the answers

What differentiates Angiotensin I from Angiotensin II in terms of amino acid count?

Angiotensin I has 10 and Angiotensin II has 8 amino acids Signup and view all the answers

Which antibiotic contains D-phenyl alanine instead of L-amino acids?

Gramicidin S Signup and view all the answers

What are the precursors for the biosynthesis of catecholamines like dopamine?

Thyrotropin releasing hormone (TRH) Signup and view all the answers

Which molecule is synthesized from tryptophan?

Serotonin Signup and view all the answers

Where is the largest amount of serotonin found in the body?

Intestinal mucosa cells Signup and view all the answers

What is the function of nitric oxide in macrophages?

Killing bacteria and tumor cells Signup and view all the answers

In what form is nitric oxide synthase present in brain and endothelial cells?

Constitutive calcium-dependent form Signup and view all the answers

What physiological roles does serotonin play?

Regulation of mood and cognitive functions Signup and view all the answers

How does nitric oxide affect blood pressure?

It lowers blood pressure by causing vasodilation Signup and view all the answers

What is the consequence of abnormally high levels of nitric oxide during a stroke?

Killing neurons similar to how macrophages kill bacteria. Signup and view all the answers

What is the role of nitroglycerin in the treatment of angina pectoris?

It converts into nitric oxide, which helps dilate coronary arteries. Signup and view all the answers

How does administering an inhibitor of nitric oxide synthase affect stroke damage in animals?

Provides some protection from stroke damage. Signup and view all the answers

What is one role of nitric oxide as a neurotransmitter?

Facilitating penile erection. Signup and view all the answers

Which compound functions in brain tissue as an inhibitory neurotransmitter by altering transmembrane potential differences?

$ ext{GABA} (γ-Aminobutyrate)$ Signup and view all the answers

What is the function of glutamate in the central nervous system?

Acting as an excitatory neurotransmitter. Signup and view all the answers