Chapter 6: Proteins Flashcards Preview

Nutrition 120 > Chapter 6: Proteins > Flashcards

Flashcards in Chapter 6: Proteins Deck (47):
1

amino acids

The building blocks of proteins. Each contains central carbon atom, an amino group, an acid group, and a side chain.

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essential amino acids

Cannot be synthesized by the body in sufficient amounts to meet the needs and therefore must be included in the diet.

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nonessential amino acids

Can be synthesized y the human body in sufficient amounts to meet their needs.

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Transamination

The process by which an amino group from one amino acid is transferred to a carbon compound to form a new amino acid.

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conditionally essential amino acids

amino acids that are essential in the diet only under certain conditions or a certain times of life. (ex. only if there is enough phenylalanine in the diet is there going to be enough tyrosine)

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dipeptide

Two amino acids linked by a peptide bonds.

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tripeptide

3 amino acids linked by peptide bonds

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polypeptide

A chain of 3+ amino acids linked by peptide bonds

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primary structure

Linear sequence of amino acids

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secondary structure

Shapes within parts of a protein (e.g. beta-pleated sheet, helical, linear)

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tertiary structure

Final 3D Structure
-Multiple polypeptide chains linked together (a protein) create a specific 3D shape to perform a specific task. If the shape is altered in any way the protein will NOT work the same way.

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denaturation

the alteration of protein's 3D structure. This can be caused by certain changes in the environment such as an increased temperature of pH.

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Why is protein important? (5)

1. Regulating body processes
2. Growth and Repair of Tissues
3. Immune Deficiency
4. Transportation
5. Energy (as a last resort if the body has not fat or CHO

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amino acid pool

All of the amino acids in body tissues and fluids that are available for use by the body.

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deamination

the removal of the amino acid group from an amino acid

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amino acid pool allows for... (3)

1. Energy production
2. Synthesis of glucose or fatty acids
3. Synthesis of nonprotein molecules that contain nitrogen

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protein turnover

the continuous synthesis and breakdown of body proteins

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gene

a length of DNA containing the information need to synthesize RNA or a polypeptide

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transcription

the process of copying the information in DNA to a molecule of mRNA

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translation

the process of translation mRNA code into the amino acid sequence of a polypeptide chain

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limiting amino acid

the essential amino acid that is available in the lowest concentration in relation to the body's needs

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gene expression

the events of protein synthesis in which the information coded in a gene is used to synthesize a product, either a protein or a molecule of RNA

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neurotransmitters

molecules that function to transfer signals between the cells of the nervous system and can stimulate or inhibit a signal

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urea

a nitrogen-containing waste product formed from the breakdown of amino acids that is excreted in the urine

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antibodies

proteins produced by the bodes immune system that recognize foreign substances in the body and help to destroy them

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protein-energy malnutrition (PEM)

a condition characterized by wasting and an increased susceptibility to infection that results from the long-term consumption of insufficient amounts of energy and protein to meet needs

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kwashiorkor

a form of protein-energy malnutrition in which only protein is deficient

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marasmus

a form of protein-energy malnutrition in which a deficiency of energy in the diet causes severe body wasting

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protein excess causes (4)

1. Hydration and kidney function (if kidneys do not work well already extra stress is added to them)
2. Bone health (excess calcium is lost in the urine)
3. Kidney stones (in creased risk)
4. Heart disease and cancer risk (high protein = high animal products = high risk CHD)

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phenylketonuria (PKU)

an inherited disease in which the body cannot metabolize the amino acid phenylalanine. If the disease is untreated, toxic by-products called phenylketones accumulate in the blood and interfere with brain development

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celiac disease

a disorder that causes damage to the intestines when the protein gluten is eaten

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nitrogen balance

the amount of nitrogen consumed in the diet compared with the amount excreted by the body over a given period of time

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negative nitrogen balance

nitrogen intake < nitrogen output
the total body protein decreases
e.g. when severely burned

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positive nitrogen balance

nitrogen intake > nitrogen output
total body protein increases
e.g. when pregnant

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High protein needs

pregnant and lactating women, the ill, those who exercise, and children

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protein quality

a measure of how efficiently a protein in the diet can be used to make body proteins

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complete dietary protein

protein that provides essential amino acids in the proportions needed to support protein synthesis

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incomplete dietary protein

protein that is deficient in one or more essential amino acids relative to body needs

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chemical or amino acid score

a measure of protein quality determined by comparing the essential amino acid content of the protein in a food with that in a reference protein. The lowest amino acid ratio calculated is the chemical score

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protein digestibility-corrected amino acid score (PDCAAS)

a measure of protein quality that reflects a protein's digestibility as well as the proportions of amnio acids it provides

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protein efficiency ratio

A measure of protein quality determined by comparing the weight gain of a laboratory animal fed a test protein wit the wight gain of an animal fed a reference protein

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net protein utilization

a measure of protein quality determined by comparing the amount of nitrogen retained in the body with the amount eaten in the diet

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biological value

a measure of protein quality determined by comparing the amount of nitrogen retained in the body with the amount absorbed from the diet

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protein complementation

the process of combining proteins from different sources so that they collectively provide the proportions of amino acids required to meet needs

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vegetarianism

a pattern of food intake that eliminates some or all animal products

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vegan

a pattern of food intake that eliminates all animal products

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risks of missing animal products

lack of B vitamins, calcium, vitamin D, iron, zinc, DHA, and EPA