Flashcards in Nutrition Deck (37):
what is a calorie?
the amount of energy needed to raise the temperature of 1 kilogram of water 1 degree celsius
what are the six fundamental nutrients and which ones generate energy when consumed?
proteins, lipids, carbohydrates, vitamins, minerals, and water are the six fundamental nutrients; proteins, lipids, and carbohydrates generate energy when consumed
why is water so vital to the survival of an animal?
- major component of blood
- found inside and outside all cells
- lubricant for body tissues
- transportation medium
- temperature regulation
- maintains homeostasis
what are the three categories of carbohydrates?
sugars, starches, and cellulose
what are the four major categories of lipids?
neutral fats, phospholipids, steroids, and other lipoid substances
what is the difference between a saturated and an unsaturated fat? why is this difference important nutritionally?
saturated fatty acids have single bonds between the carbon atoms and can accommodate the greatest number of hydrogen atoms attached to the chain of carbon atoms, they also tend to have long chains and are primarily found in meat and dairy foods such as milk, cream, cheese, lard, and butter; unsaturated fatty acids have one or more double bonds between the carbon atoms and can accommodate fewer hydrogen atoms, these are found in seeds, nuts, and most vegetables
what is an essential fatty acid?
essential fatty acids are ones that the body cannot manufacture and must be provided in the diet.
what are steroids?
lipids that are dramatically different from neutral fats, made of four interlocking rings of hydrocarbons; they include cholesterol, bile salts, sex hormones, and hormones released in the cortex of the adrenal gland
what is the principal building block unit of proteins and how are they arranged?
amino acids are the principal building blocks of proteins, they are arrange by one amino acid links to the basic group on the next, forming a peptide bond
what are the four basic components of amino acids?
amino acids are composed of a central carbon atom, an amino group (NH2), a carboxyl group (COOH), and a variety of side chains (“R” group); differences in the “R” group make each amino acid unique
what are the amino acids called that can not be made in the body so they must be found in the diet?
essential amino acids cannot be synthesized in the body; taurine is an essential amino acid for cats, and glycine is essential for birds
what is cellular metabolism?
it is all the biochemical events involved in building molecules and breaking down nutrients, manufacturing, packaging, and excreting; making proteins is one very important example of cellular metabolism
what are the two categories of cellular metabolism?
anabolism and catabolism
what is the first stage of cellular metabolism called?
the first stage of catabolism is called hydrolysis, it is when energy is produced
is energy produced or consumed during anabolic process?
energy is consumed during the anabolic process; examples include the production of fat molecules by combining glycerol and fatty acid molecules, and the creation of proteins by joining amino acids
what cellular process represents the largest demand for protein and enzymes?
why are enzymatic reactions considered highly specific?
enzymatic reactions are highly specific because one enzyme reacts only with one substrate or combination of substrates.
what is a substrate and what is a product?
each enzyme reacts with a particular molecule called a substrate to produce a new molecule called a product
why is the total number of enzymes present in the body relatively low when compared with the number of metabolic reactions?
enzymes are recycled and used over and over again, so once an enzyme has catalyzed one reaction, it is free to catalyze another reaction, in this way, a few enzymes can carry out many metabolic reactions
what is the energy of activation in a biochemical reaction?
the energy of activation is the energy needed to initiate a biochemical reaction
what is a catalyst?
a catalyst is a substance that speeds up a reaction; enzymes are catalysts because they speed up reactions by lowering the activation energy
what are the characteristics of an enzyme?
- an enzyme’s name ends with the suffix -ase
- the enzyme is usually named for the substrate on which it acts
- the name of the enzyme may also indicate the kind of reaction that the enzyme initiates
what is a cofactor?
elements such as iron, zinc, or copper, that are needed to complete the shape of a binding site; magnesium ion is a cofactor in reactions that involve the transfer of a phosphate group and is therefore found in virtually all cells
how might vitamins play a role in enzyme driven reactions?
vitamins are nonprotein organic substances whose derivatives may act as cofactors, specifically called coenzymes; they may be bound temporarily or permanently to the enzyme and are usually located near the active site
how is energy stored in molecules and when is it released?
energy is stored in the atomic bonds of molecules such as ATP, NADH, and FADH2, energy is released when part of the molecule is broken off
where does carbohydrate metabolism begin in non-ruminant animals?
with the breakdown of glycogen or glycerol in the liver
what part of carbohydrate metabolism occurs in the cytoplasm?
glycolysis breaks down glucose to form pyruvate in the cytoplasm
under what conditions is lactic acid formed in muscle cells?
when oxygen is depleted
how many biochemical steps are involved in glycolysis and does it require oxygen?
glycolysis involves 10 steps, no, it does not require oxygen
cellular respiration is composed of what two parts?
anaerobic (glycolysis) and aerobic respiration (krebs cycle and the electron transport chain)
how does the membrane structure of the mitochondria assist in the process of cellular respiration?
the inner membrane of the mitochondrion houses a series of cytochrome molecules, which make up the electron transport system, as electrons are passed from one cytochrome molecule to another, energy is released and used to transport protons from the mitochondrial matrix across the inner membrane to the intermembrane space, because protons are positive, this establishes a positive charge on the outside of the inner membrane relative to the matrix side, the electrical gradient that is established is a form of stored (potential) energy, energy is released when protons rush back into the mitochondrial matrix
what role does oxygen play in the electron transport system?
at the end of the electron transport chain, oxygen accepts the low-energy electrons, joins with hydrogen ions, and forms water (H2O); oxygen is the final acceptor of the electrons
what is oxidative phosphorylation?
the process in which ATP is produced as electrons are transferred from NADH or FADH2 to O2 by a series of electron carriers in the electron transport chain; this is the major source of ATP in aerobic organisms
what is the maximum number of ATP molecules the can be formed from the catabolism of one molecule of glucose?
what is transamination?
when the amine group from an amino acid is transferred to a different keto acid; in the process, a new and different amino acid is made
what is the most common carbohydrate found in blood?