unit 1 nutrition

carbohydrates

Organic compounds consisting of carbon, hydrogen, and oxygen, typically in a ratio of 1:2:1.

monosaccharides

The simplest form of carbohydrates, consisting of single sugar molecules like glucose, fructose, and galactose.

disaccharides

Carbohydrates formed from two monosaccharide monomers linked through glycosidic linkage.

glycosidic linkage

The bond that connects monosaccharides to form disaccharides or polysaccharides.

maltose

A disaccharide composed of two glucose units linked by an alpha 1,4 glycosidic linkage.

lactose

A disaccharide composed of galactose and glucose, linked by a beta 1,4 glycosidic bond.

sucrose

Common table sugar, composed of glucose and fructose, linked by an alpha 1-beta 2 glycosidic linkage.

lactose intolerance

A condition where individuals lack the enzyme lactase, leading to difficulty in digesting lactose.

reducing end

The end of a sugar molecule that has a free anomeric carbon that can undergo oxidation.

non-reducing end

The end of the sugar molecule that does not have a free anomeric carbon.

glycosidic bonds

Linkages between sugar molecules formed through dehydration reactions.

polymerization

The process of combining small sugar units (monomers) to form larger molecules (polymers) like starch and glycogen.

amylose

A linear polymer made of alpha 1,4 linked glucose units.

amylopectin

A branched polymer made of alpha 1,4 and alpha 1,6 linked glucose units.

glycogen

The storage form of glucose in animals, highly branched and found in liver and muscle.

oligosaccharides

Carbohydrates composed of 3-10 monosaccharides, often found in legumes.

dietary fiber

Plant-based carbohydrates that are not digestible by human enzymes.

cellulose

A type of dietary fiber made of beta-glucose units and found in plant cell walls.

pectins

Plant polysaccharides used for gelling and thickening.

soluble fiber

Fiber that dissolves in water to form a gel-like substance, slowing digestion.

insoluble fiber

Fiber that does not dissolve in water, aiding in bowel movement.

lignins

Complex polymers that provide structural rigidity in plant cell walls.

chylomicrons

Lipoproteins that transport dietary lipids from the intestines to other locations in the body.

lipoproteins

Molecular complexes that transport lipids in the blood.

saturation

The presence or absence of double bonds in fatty acid chains.

essential fatty acids

Fatty acids that cannot be synthesized by the body and must be obtained from the diet.

lipids

A diverse group of hydrophobic organic compounds, including fats, oils, waxes, and steroids.

triglycerides

The main form of stored fat in the body, consisting of glycerol and three fatty acids.

phospholipids

Lipids that contain two fatty acids and a phosphate group, important in membrane structure.

sterols

Cholesterol and cholesterol derivatives with a multi-ring structure.

RDA for protein

Recommended dietary allowance, which is 0.8 g/kg of body weight for healthy adults.

amino acids

Building blocks of proteins, characterized by the presence of an amino group and a carboxylic acid group.

transamination

The process of transferring an amino group from one amino acid to a keto acid to form another amino acid.

deamination

The removal of an amino group from an amino acid, leading to ammonia production.

denaturation

The structural alteration of proteins by physical or chemical means, rendering them inactive.

nitrogen balance

The comparison between nitrogen intake and nitrogen excretion in the body.

complete protein

Protein that contains all nine essential amino acids in sufficient quantities.

incomplete protein

Protein that lacks one or more essential amino acids.

food microbiome

The community of microorganisms residing in the digestive tract.

digestion

The process of breaking down food into its molecular components for absorption.

peristalsis

The wave-like muscle contractions that move food through the digestive tract.

segmentation

A localized contraction of the intestine that enhances digestion and absorption by mixing the chyme.

mass movement

A powerful contraction that pushes the contents of the colon toward the rectum.

salivary amylase

An enzyme in saliva that begins the digestion of carbohydrates.

protein digestion

The process of breaking down proteins into peptides and amino acids.

lipid absorption

The uptake of lipids in the intestine after digestion.

micelles

Small clusters of lipids formed during digestion that aid in lipid absorption.

enterohepatic circulation

The recycling process of bile acids from the intestine back to the liver.

glycemic index

A measure of how quickly a food causes blood sugar levels to rise.

oral bacteria

Microorganisms in the mouth that can ferment sugars and produce acid.

insulin

A hormone that regulates blood glucose levels by facilitating cellular uptake of glucose.

CHO

Abbreviation for carbohydrates.

exocrine pancreas

The part of the pancreas that secretes digestive enzymes into the small intestine.

insufficient lactase

A condition that leads to lactose intolerance due to low levels of the enzyme lactase.

nutrient absorption

The process by which nutrients from food are taken up by the cells lining the digestive tract.

gut microbiome

The community of microorganisms residing in the gastrointestinal tract.

cancer and fiber

Evidence suggesting a protective effect of fiber against colorectal cancers.

adjusted protein quality

The measure of protein quality taking digestion and absorption into account.