Physiology Ch. 2

Using chemical equations, explain how bicarbonate ion and carbonic acid function as a buffer pair.

If an acid releases H+ into the blood, the bicarbonate ion takes up the H+ to make carbonic acid. HCO3- + H+ ---> H2CO3 Excessive vomiting results in loss of gastric acid causing the concentration of H+ in the blood to fall causing carbonic acid to loss H+ ions to the blood and make bicarbonate ions. H2CO3 ---> H+ + HCO3- These two function as a buffer pair to keep the blood pH between 7.35 and 7.45.

Why are ions and polar molecules soluble in water?

Ions are soluble in water because they are positively and negatively charged, and the partially positive hydrogens in water are attracted to the negative ions while the partially negative oxygens in water are attracted to the positive ions. Polar molecules are soluble in water because they have partially positive and negative regions just like water so that the partially positive hydrogens of water attract to the partially negative atom of the other molecule and the partially negative oxygen of water attracts to the partially positive atom of the other molecule.

List the types of RNA, and explain how the structure of RNA differs from the structure of DNA.

The types of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). RNA uses ribose as the pentose sugar and DNA uses deoxyribose as the pentose sugar. RNA uses uracil as a nitrogenous base instead of thymine that DNA uses. RNA is single stranded and DNA is double stranded. RNA is used in participation in genetic regulation whereas DNA contains the genetic code and genome of the individual.

Define pH and describe the relationship between pH and the H+ concentration of a solution.

The unit used to indicate the H+ concentration of a solution. The pH is inversely related to the H+ concentration in the solution. For example, solutions with a higher concentration of H+ has a lower pH and vice versa.

Explain why different atoms are able to form characteristic numbers of chemical bonds.

The valence shell, or outside shell, of the atom needs to be full for the atom to be stable. If the valence shell has 4 valence electrons, it needs 4 more to complete the orbital.

polysaccharide

a carbohydrate formed by covalent bonding of numerous monosaccharides. Examples are glycogen and starch.

polypeptide

a chain of amino acids connected by covalent bonds called peptide bonds. A very large polypeptide is called a protein.

micelle

a colloidal particle formed by the aggregation of numerous molecules

phospholipid

a lipid containing a phosphate group. Phospholipid molecules (such as lecithin) are polar on one end and nonpolar on the other end. They make up a large part of the cell membrane and function in the lung alveoli as surfactants.

steroid

a lipid derived from cholesterol that has three six-sided carbon rings and one five-sided carbon ring. These form the steroid hormones of the adrenal cortex and gonads

polar molecule

a molecule in which the shared electrons are not evenly distributed, so that one side of the molecule is negatively (or positively) charged in comparison with the other side. Polar molecules are soluble in polar solvents such as water

nonpolar molecule

a molecule lacking positive and negative charges and therefore not soluble in water

buffer

a molecule that serves to prevent large changes in pH by either combining with H+ or by releasing H+ into solution

RNA (ribonucleic acid)

a nucleic acid consisting of the nitrogenous bases adenine, guanine, cytosine, and uracil; the sugar ribose; and phosphate groups. There are three types of RNA found in cytoplasm: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).

glycogen

a polysaccharide of glucose-also called animal starch-produced primarily in the liver and skeletal muscles. Similar to plant starch in composition, glycogen contains more highly branched chains of glucose subunits that does plant starch.

surface tension

a property of water wherein the hydrogen bonding between water molecules produces a tension at the water surface

enzyme

a protein catalyst that increases the rate of specific chemical reactions

cholesterol

a twenty-seven-carbon steroid that serves as the precursor for steroid hormones

messenger RNA (mRNA)

a type of RNA that contains a base sequence complementary to a part of the DNA that specifies the synthesis of a particular protein

ketoacidosis

a type of metabolic acidosis resulting from the excessive production of ketone bodies, as in diabetes mellitus

proton

a unit of positive charge in the nucleus of atoms

atomic number

a whole number representing the number of positively charged protons in the nucleus of an atom

ketosis

an abnormal elevation in the blood concentration of ketone bodies. This condition does not necessarily produce acidosis.

acidosis

an abnormal increase in the H+ concentration of the blood that lowers the arterial pH below 7.35

alkalosis

an abnormally high alkalinity of the blood and body fluids (blood pH > 7.45)

ion

an atom or a group of atoms that has a net positive or a net negative charge because of a loss or gain of electrons

neutron

an electrically neutral particle that exists together with positively charged protons in the nucleus of atoms

anion

an ion that is negatively charged, such as chloride, bicarbonate, or phosphate

carbohydrate

an organic molecule containing carbon, hydrogen, and oxygen in a ratio of 1:2:1. The carbohydrate class of molecules is subdivided into monosaccharides, disaccharides, and polysaccharides.

lipid

an organic molecule that is nonpolar, and thus insoluble in water. Lipids include triglycerides, steroids, and phospholipids

disaccharide

any of a class of double sugars; carbohydrates that yield two simple sugars, or monosaccharides, upon hydrolysis

corticosteroid

any of a class of steroid hormones of the adrenal cortex, consisting of glucocorticoids (such as hydrocortisone) and mineralocorticoids (such as aldosterone)

prostaglandin

any of a family of fatty acids that serve numerous autocrine regulatory functions, including the stimulation of uterine contractions and of gastric acid secretion and the promotion of inflammation

molar

pertaining to the number of moles of solute per liter of solution

cations

positively charged ions, such as sodium, potassium, calcium, and magnesium

receptor proteins

proteins in target cells for regulatory molecules that are each specific for a particular regulatory molecule, and that bind to it with a high affinity and limited capacity. A regulatory molecule must bind to receptor proteins in its target cells in order to regulate those cells.

DNA (deoxyribonucleic acid)

A nucleic acid composed of nucleotide bases and deoxyribose sugar that contains the genetic code.

describe the structural characteristics of all carbohydrates, and distinguish between monosaccharides, disaccharides, and polysaccharides.

All carbohydrates have 2 hydrogens to every 1 carbon and oxygen. it is a 1:2:1 ration of carbon, hydrogen, and oxygen. Monosaccharides are the simple sugars or building blocks of carbohydrates. Disaccharides are two monosaccharides bonded together. Polysaccharides are multiple monosaccharides bonded together.

Describe the characteristics of a lipid, and discuss the different subcategories of lipids.

All lipids are insoluble in polar solvents such as water because they consist primarily of hydrocarbon chains and rings which are nonpolar or hydrophobic. Lipids can therefore dissolve in nonpolar solvents such as ether, benzene, and related compounds. Triglycerides are fats and oils. They are made up of a molecule of glycerol and 3 fatty acids covalently bonded together. Phospholipids are lipids with a phosphate group. The most common type is one with in which glycerol is attached to two fatty acids and a phosphate group which can be bound to other molecules. Phospholipids are the major component of cell membranes. Steroids are made up of 3 6-carbon rings joined to one 5-carbon ring. Steroids can be cholesterol or steroids secreted from the gonads or the adrenal cortex. Prostaglandins are a type of fatty acid with a cyclic hydrocarbon group. They are produced in almost all organs and serve a variety of regulatory functions.

extracellular compartment

All of the material outside of cells, including the extracellular fluid fluid with all of its solutes, insoluble protein fibers, and, in some cases, crystals. Also called the extracellular matrix

Explain how carbon atoms can bond with each other and with atoms of hydrogen, oxygen, and nitrogen.

Carbon atoms can bond to one another with single, double, or triple bonds. Each carbon is allowed to have 4 bonds. Each hydrogen is allowed to have 1 single bond. Each oxygen is allowed to have 2 single bonds or one double bond. Each nitrogen is allowed to have 3 single bonds or one triple bond

Explain, in terms of dehydration synthesis and hydrolysis reactions, how disaccharides and monosaccharides can be interconverted and how triglycerides can be formed and broken down.

Disaccharides are formed from monosaccharides by dehydration synthesis. A water molecule is formed when two monosaccharides are covalently bonded together. Monosaccharides are formed from disaccharides by hydrolysis. A water molecule is used to form two monosaccharides from a disaccharide. When triglycerides are formed dehydration synthesis occurs because the covalent bonds between the glycerol and fatty acids releases 3 water molecules. When triglycerides are broken down hydrolysis occurs because 3 water molecules are used to form glycerol and 3 fatty acids.

Describe the nature of nonpolar and polar covalent bonds, ionic bonds, and hydrogen bonds.

Nonpolar covalent bonds-the atoms share electrons, but atom contains a partially negative charge and one atom contains a partially positive charge polar covalent bonds-the atoms share electrons evenly with no charges ionic bonds-atoms release and gain electrons. The electrons are not shared with gives rise to one negative ion and one positive ion hydrogen bonds-are bonds between polar molecules containing hydrogen. For example the partially positive hydrogens in water are attracted to the partially negative oxygens.

What are nucleotides, and of what are they composed?

Nucleotides are subunits of nucleic acids. They are composed of a pentose sugar (deoxyribose or ribose), a nitrogenous base (adenine, cytosine, guanine, and thymine or uracil), and a phosphate group.

Relate the functions of phospholipids to their structure, and explain the significance of the prostaglandins.

Phospholipids are the major component of cell membranes. This is because they are amphipathic meaning part polar part nonpolar. The membrane is on the outside of the cell. The membrane would have to be exposed to water from inside the cell and outside the cell; therefore the polar regions of the phospholipid face toward the aqueous regions and the nonpolar regions of the phospholipid face each other. Prostaglandins are produced in almost all organs where they serve a variety of regulatory functions. They are implicated in the regulation of blood vessel diameter, ovulation, uterine contraction during labor, inflammation reactions, blood clotting, and many other functions.

Describe and account for the different levels of protein structure.

Primary structure is the amino acid sequence. Secondary structure is the particular shape the protein takes because of hydrogen bonding between the amino group and oxygens near by. Tertiary structure is the folding of the polypeptide chain into a three-dimensional complex. This happens by chemical interactions between R groups in amino acids. Quaternary structure is the bonding of two or more polypeptides.

Describe the different categories of protein function in the body, and explain why proteins can serve functions that are diverse.

Proteins can be categorized as structural, enzymes, antibodies, receptors, and carriers. Proteins have tremendous structural diversity which allows them to serve a wider variety of functions than other types of molecules in the body.

List the components of an atom and explain how they are organized.

Proton-centrally located in the nucleus Neutrons-centrally located in the nucleus Electrons-orbit the nucleus of an atom. the first orbit has two electrons and the others have 8.

Define the terms acidic, basic, acid, and base.

acidic-a solution that has a higher H+ concentration than that of water basic-a solution that has a lower H+ concentration that that of water acid-a molecule that can release H+ (protons) into a solution base-a molecule that can combine with H+

genome

all of the genes of an individual or in a particular species

Write the general formula for an amino acid, and describe how amino acids differ from one another.

amino group-C-carboxylic acid Above the C is an R group and below is an H atom. The R group is different in each amino acid. The R groups differ in functional groups and can be grouped into polar and nonpolar categories.

hydrophilic

denoting a substance that readily absorbs water; literally, "water loving"

hydrophobic

denoting a substance that repels, and that is repelled by, water; literally "water fearing"

triglyceride

fats and oils. Also known as triacylglycerol.

surfactant

in the lungs, a mixture of phospholipids and proteins produced by alveolar cells that reduces the surface tension of the alveoli and contributes to the elastic properties of the lungs

antibodies

immunoglobulin proteins secreted by B lymphocytes that have been transformed into plasma cells. Antibodies are responsible for humoral immunity. Their synthesis is induced by specific antigens, and they combine with these specific antigens but not with unrelated antigens

lactose

milk sugar; a disaccharide of glucose and galactose

stereoisomers

molecules with the same atoms in the same sequence, but which differ in the three-dimensional arrangement of their atoms

dehydration synthesis

the bonding together of subunits to form a longer molecule, in a reaction that also results in the production of a molecule of water

phosphatidylcholine

the chemical name for the molecule also called lecithin

protein

the class of organic molecules composed of large polypeptides in which over a hundred amino acids are bonded together by peptide bonds

monosaccharide

the monomer of the more complex carbohydrate. Examples of monomers are glucose, fructose, and galactose. Also called a simple sugar.

hydrolysis

the splitting of a larger molecule into its subunits, in a reaction that also results in the breaking of a water molecule

ketone bodies

the substance derived from fatty acids via acetyl coenzyme A in the liver; namely, acetone, acetoacetic acid, and beta-hydroxybutic acid. Ketone bodies are oxidized by skeletal muscles for energy.

nucleotide

the subunit of DNA and RNA macromolecules. Each nucleotide is composed of a nitrogenous base (adenine, guanine, cytosine, and thymine or uracil); a sugar (deoxyribose or ribose); and a phosphate group.