Proteins Composition and Properties

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Questions and Answers

What are proteins composed of?

Vitamins and minerals

Amino acids (correct)

Nucleic acids

Fats and carbohydrates

What is the principal constituent of the organs and soft structures of the animal body?

Minerals

Proteins (correct)

Fats

Carbohydrates

What distinguishes the various proteins from a nutritional standpoint?

Physical properties

Biological functions

Molecular weight

Amino acids makeup (correct)

What additional elements do proteins contain, apart from carbon, hydrogen, and oxygen?

Nitrogen and sulfur Signup and view all the answers

What are amino acids?

A and B Signup and view all the answers

Which of the following amino acids cannot be synthesized in the body at all or can only be synthesized in low amounts not sufficient to meet body requirements?

Histidine Signup and view all the answers

For which animals are the 10 essential amino acids + glycine or serine and proline required in their diets?

Poultry Signup and view all the answers

Which type of amino acid is used metabolically in the synthesis of proteins?

L-isomers Signup and view all the answers

Which amino acids are most likely to be deficient in rations when primary energy feeds such as corn are low in these amino acids?

Lysine, methionine, tryptophan Signup and view all the answers

Which category of amino acids forms about 44% of the body protein and can be synthesized in the animal body?

Non-essential (dispensable) amino acids Signup and view all the answers

Which type of protein contains all the essential amino acids in proper amount and proportion?

Proteins of animal origin Signup and view all the answers

Which proteins are considered to be of poor quality due to their lack of one or more essential amino acids?

Proteins of plant origin Signup and view all the answers

What is the process by which intact dietary protein is broken down in the gastrointestinal tract?

Hydrolysis Signup and view all the answers

Which part of the body is responsible for the synthesis of enzymes & hormones and the creation of an amino acid pool?

Tissues Signup and view all the answers

What is the primary method of protein digestion in nonruminants?

Enzymatic digestion in the stomach Signup and view all the answers

What happens to the ingested oligopeptides in the intestines?

They are absorbed directly into the intestinal mucosa and hydrolyzed by peptidases to amino acids. Signup and view all the answers

Which type of feed is best for the rapid growth of ruminal microorganisms?

Cereals high in starch Signup and view all the answers

What is the effect of high protein rations on the utilization of urea?

The utilization of urea decreases on high protein rations. Signup and view all the answers

What is the relationship between the fiber content in feed and protein digestibility?

Increase in fiber content decreases the protein digestibility. Signup and view all the answers

What stimulates microbial growth according to the text?

Energy-rich rations Signup and view all the answers

Study Notes

Proteins and Their Composition

Proteins are composed of amino acids linked by peptide bonds.
Principal constituents of organs and soft structures in the animal body include proteins.
Nutritional differentiation of proteins is based on their amino acid composition.

Elements in Proteins

Aside from carbon, hydrogen, and oxygen, proteins also contain nitrogen, sulfur, and sometimes phosphorus and iron.

Amino Acids

Amino acids are organic compounds serving as the building blocks of proteins.
Essential amino acids cannot be synthesized by the body or are synthesized in insufficient amounts to meet needs.

Essential Amino Acids

In animal diets, ten essential amino acids, along with glycine or serine and proline, are crucial.
These essential amino acids are necessary for all mammals and certain other animals.

Amino Acid Synthesis and Deficiency

Metabolically, amino acids are used for protein synthesis.
When primary energy feeds like corn are low, amino acids such as lysine and tryptophan are most likely to be deficient.

Categories of Amino Acids

Approximately 44% of body protein comprises non-essential amino acids, which can be synthesized by the body.
Complete proteins contain all essential amino acids in adequate amounts and proportions.

Protein Quality

Incomplete proteins lack one or more essential amino acids, resulting in lower nutritional quality.

Protein Digestion Process

Dietary proteins are broken down in the gastrointestinal tract through a process called proteolysis.
The stomach and pancreas play key roles in this process by secreting enzymes.

Synthesis of Enzymes and Hormones

The liver is responsible for the synthesis of enzymes, hormones, and creating an amino acid pool in the body.

Protein Digestion in Nonruminants

Primary protein digestion in nonruminants occurs through enzymatic action in the stomach and small intestine.

Oligopeptide Processing

Ingested oligopeptides are further degraded into amino acids in the intestines.

Feed Types and Microbial Growth

High-quality feeds rich in fermentable carbohydrates support rapid growth of ruminal microorganisms.

Effects of High Protein Rations

High protein rations can enhance the utilization of urea, improving nitrogen available for microbial protein synthesis.

Fiber and Protein Digestibility

There is an inverse relationship between fiber content in feed and protein digestibility; higher fiber may lower digestibility.

Microbial Growth Stimulation

The availability of energy sources, such as starch or sugars, stimulates microbial growth.

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Description

Learn about the composition, physical properties, biological functions, and dietary importance of proteins as presented by Professor Dr. Mohammed Taher Ibrahim, a renowned expert in Nutrition and Clinical Nutrition at Suez Canal University, Egypt.