Loading in 2 Seconds...
Loading in 2 Seconds...
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Pharos universityFaculty of Allied Medical SCIENCEBiochemistry 1(MGBC-101) Dr. Tarek El Sewedy Department of Medical Laboratory Technology Faculty of Allied Medical Sciences
Lecture 5 Amino acids and proteins Part 2
Intended Learning Outcomes By the end of this lecture, students will learn: Amino Acids classification.
Classification of amino acids Amino Acids and proteins nutritional facts Lecture Content
Structure of amino acids The basic structure of an amino-acid molecule consists of a carbon atom bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a fourth group that differs from one amino acid to another and often is referred to as the-R group or the side chain. The-R group, which can vary widely, is responsible for the differences in chemical properties.
α, β, or γ Amino Acids • Amino acids may be characterized as α, β , or γ depending on the location of the amino group on the carbon chain. • α are on the carbon adjacent to the carboxyl group. • β are on the 2ndcarbon • γ on the 3rdcarbon from the carboxyl group.
α− amino acids • Amino acids found in proteins are α− amino acids. • The amino group is always found on the carbon adjacent to the carboxyl group
Metabolic Classification of theAmino Acids • Essential and Non-essential • Glucogenicand Ketogenic
Essential Amino Acids • Only 11Of the 20 amino acids that make up proteins can be synthesized by the human body • The other 9 amino acids must be acquired from food sources. These amino acids are known as essential amino acids
Glucogenicor ketogenic Amino acids • Glucogenicaminoacids are degradedto compounds that can be used as carbon skeletons for glucose synthesis via gluconeogenesis. • Ketogenic amino acids are degraded to compounds that can only be used to generate the ketonebodies.
Ketogenic Amino Acids • Metabolized to acetyl CoA or acetoacetylCoA then to ketone bodies • Leucine • Lysine
Amino Acid Functions 1. Amino acids are the building blocks of proteins. 2. Some amino acids and their derivatives function as neurotransmittershormones. 3. It may supply the carbohydrates pool with glucose ?????????.
Protein functions • - Catalytic functions [enzymes] • - Receptor [insulin receptor] • - Structural function [collagen] • - Transport [hemoglobin] • - Protective functions [Antibodies]
Protein function (cont…) • - Hemostasis [clotting factors] • - Hormonal functions [insulin, glucagon, GH] • - Control of gene expression [transcription factors] • - DNA packing [histones] • - Act as buffers.
Spirulina quinoa soybeans Almond
Amino Acid nutrition Our body doesn’t use proteins in a direct way; first proteins are decomposed into amino acids and then amino acids are used for the resynthesize of muscular proteins
Protein and diet • An individual's daily protein requirement depends on several factors, including: • Age - a growing child's needs will not be the same as an individual aged 80 years • Sex - males generally require more protein than (non-pregnant or non-breastfeeding) females • Weight - an individual who weighs 100 Kg will require more protein compared to somebody who weighs 50 Kg. • Muscular exertion - an individual who earns his living delivering pianos will require more protein than a computer programmer of the same age and height. • Muscle mass - a muscle-bound weight trainer will need more dietary protein than a marathon runner • Health - a person who is recovering after an illness or medical procedure may need more dietary protein than other people.
Percentage of energy that should come from protein: • Children aged 1 to 3 years - 5% to 20% • Children aged 4 to 18 years - 10% to 30% • Adults - 10% to 35% • According to the US Department of Agriculture, our protein intake should be: • Infants - 10 grams per day • Teenage boys - up to 52 grams per day • Teenage girls - up to 46 grams per day • Adult men- approximately 56 grams per day • Adult women - approximately 46 grams per day • Pregnant or lactating (breastfeeding) women - about 71 grams per day
Protein deficiency • Mental retardation and reduced IQ. • Growth problems • Wasting and shrinkage of muscle tissue • Apathy • Swollen belly • Anemia • Weaker immune system
Protein Excess • Weight gain. • Intestinal irritation. • Risk of heart disease • Kidney problems • Gout disease
ASSIGNMENTS • Selected students are requested to prepare slides about one of the following topics (To be delivered before next lecture): • Digestion of proteins • Essential amino acids. • Non essential amino acids • Physical properties of amino acids. • Chemical properties of amino acids. • Disease resulting from disturbance in amino acid metabolism. • Ketone bodies and amino acids • Translation of RNA
Study Question • Write three points about : Classification of amino acids • 1- • 2- • 3-
Suggested readings: • Principles of Biochemistry, Donald J. Voet, Judith G. Voet, Charlotte W. pratt; Willey, 3rded.