Protein - Chapter 5 Flashcards
Protos
- Greek for “first”
- origin of the word protein
What distinguishes protein from the other macronutrients?
- the presence of the element nitrogen
Nitrogen
- One of the most abundant elements in the earth’s atmosphere and biosphere, essential to the structure of an amino acid.
Fertile soil
- supports lush foliage because it is rich in nitrogen
Legumes
- member of a plant family capable of fixing nitrogen from the air and thus not dependent on soil fertility to produce a high protein seed
Fix nitrogen
- to remove nitrogen from the atmosphere and render it into a chemical form usable by plants
Herbivore
- Animal that subsists on foods of plant origin
Amino Acid
- Basic unit from which protein is made
- Consists of an amine group, a carboxyl group, and various side chains
Carnivore
- Animal that subsists on foods of animal origin
How much of the air does nitrogen compose?
78 percent of the air
How many amino acids are there to create proteins?
20
What are amino acids composed of?
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
- Sometimes, sulfur
Amine
- an -NH2 chemical group
- nitrogen is present in this chemical group
Carboxyl
- a -COOH chemical group
- involved in amino acids
essential amino acid
- One which cannot be synthesized by the body and must therefore be consumed in the diet
Urea
- a nitrogen-containing compoud found in urine and created as a byproduct of the use of protein for energy
- when nitrogen is left over and must be disposed of
High protein diets:
- tax the kidneys
- cause water loss through urination
All amino acids consist of:
- Amine
- Carboxyl
- A side chain
- the amino acid is named for the side chain, which gives it distinct chemical properties
Peptide bond
- a chemical bond joining two amino acids
Peptide
- a short chain of amino acids
- range from dipeptides (2 amino acids) to polypeptides
Insulin
- A peptide hormone responsible for regulation of blood sugar
- composed of 51 amino acids
Hormone
- a regulatory compound capable of affecting cells throughout the body
- hormones are also peptides
Proteins
- A very long chain of amino acids
Collagen
- the primary protein in connective tissue
Amylase
- Digestive enzyme which breaks down starch
- a protein
Sequence
- Order in which amino acids appear in a protein, affecting its physical and chemical properties
DNA
- the genetic material of a cell
- inherited traits are carried
- carries a sequence
Genes
- unit of genetic information
- the sequence of amino acids in that protein is carried by genes
Cooking analogy for proteins
- each gene = recipe for a protein
- DNA = cookbook
THE process
- DNA contains the information necessary to produce proteins
- Transcription or copying of a segment of DNA results in mRNA, a copy of the information in DNA needed to make a protein
- the mRNA leaves the nucleus and goes to a ribosome
- Amino acids are carried to the ribosome by tRNAs containing the code that matches that on the mRNA
- Translation - the information contained in mRNA is used to determine the arrangement, number, and types of amino acids in the protein
Denature
- change the physical and chemical properties of a protein through the action of heat, acid, or other factors
- began in the stomach
- strong hydrochloric acid
Protease
- digestive enzyme which breaks protein down
- break the peptide bonds between amino acids
- stomach produces protease to start it, the small intestine produces it to finish it
What structure does protein provide?
- muscle and connective tissue (ligaments, tendons, and cartilage) consist of protein
- strength, elasticiy, and contractive power - protein provides this
Protein-sparing
- the action of carbohydrate in preserving muscle
- If inadequate carbohydrate is consumed, muscle is broken down to supply blood glucose
Blood transport proteins
- carry nutrients and other substances in the blood
- sequester them in such a way that they remain inactive until they get where they are needed
Hemoglobin
- a transport protein
- carries oxygen and carbon dioxide
Lipoprotein
- transport protein for lipids
- since lipids are not water soluble, they are encapsulated by lipoproteins to travel the water-based bloodstream
Homeostasis
- means “same state”
- the physiological principle that the bodoy tries to maintain constant conditions
- ex.
- state of temperature
- acidity
- solute concentration
- oxygen
solute
Substance disolved in a solvent
Acid-base balance
- the degree of acidity or alkalinity in a fluid, caused by an imbalance of hydrogen ions
acidity
excess of hydrogen ions
basic
deficiency of hydrogen ions
ions
- a charged particular formed when a molecule splits in two
- electrically charged hydrogen particles
Buffer
- A substance which maintains a constant pH in a solution by absorbing or releasing hydrogen ions as needed
Osmosis
- the movement of water from an area of low solute concentration to an area of high solute concentration through a membrane
Osmotic pressure
- the fore generated by the attraction of the solute on the solvent
- causes osmosis
Kwashiorkor
- a type of Protein Energy Malnutrition characterized by emanciation and abdominal edema
- movement of fluid out of the blood stream into the abdominal cavity
Enzyme
- protein that controls and facilitates a chemical reaction
- catalyze biochemical reactions
- ex. digestion, making fat, releasing energy from nutrients, synthesizing body constituents
Catalyst
- Substance that participates in and controls a chemical reaction without itself being consumed
Substrate
- the material acted on by an enzyme
Precursors
A substance from which another substance is formed
Neurotransmitters
- Substance used to bridge the gap of the nerve synapse and transmit nerve impulses
Typtophan and Tyrosine
Two amino acids that are precursors of three neurotransmitters
Synapse
- A gap between nerve cells
Antigen
- Foreign protein which triggers response by immune system (antibody)
Antibody
- immune protein used to attack foreign proteins (antigens)
Gluconeogensis
Production of glucose from amino acids (body protein)
Used when carbohydrate stores are depleted
RDA of protein
- 0.8 grams per kg of body weight
- 58-63 grams for males
- 46-50 grams for females
- 12-15 percent of total calories
How many essential amino acids exist?
9
Essential amino acid (indispensable)
- One which cannot be synthesized by the body and must therefore be consumed in the diet
Conditionally essential amino acid
- One which cannot be synthesized only under certain conditions, and must be consumed in the diet under these conditions
essential
- not merely necessary, but we cannot manufacture it ourselves
Nutrient balance
- The net flow of a nutrient into an orgnism, resulting in gain or loss of the nutrient
Limiting amino acid
- The amino acid in the shortest supply during protein synthesis, resulting in cessation of synthesis
Biological Value
- A measure of the degree to which an absorbed nitrogen is retained.
- Nitrogen is here used as a surrogate for protein
Nitrogen retained
Nitrogen absorbed
Chemical score
- A comparison of the amino acid composition of a particular protein with a reference protein (egg)
Protein digestibility-corrected amino acid score
- a form of chemical score of protein quality that also accounts for the digestibility of the protein
- Gives a realistic measure of a protein’s contribution to meeting needs
Lacto-vegetarian
- One who eats only plant foods and dairy products
Lacto-ovo-vegetarian
- One who eats only plant foods, eggs, and dairy products
Vegan
- one who eats only foods of plant origin
Complementarity
- Practice of combining two proteins to improve their amino acids proportions through mutual aupplementation
Protein Energy Malnutrition (PEM)
A deficiency of both protein and energy
ex. Marasmus and Kwashiokor
Two types of PEM
- Marasmus
- Kwashiorkor
- Both characterized by fatigue, exhaustion, and reduced work capacity
Edema
- buildup of fluid in the abdominal cavity
- bloated bellies as a result of Kwashiorkor
Diuresis
- Urine formation by the kidney as a result of high intakes of protein