Chapter 2 - Chemicals in the Human Body Flashcards
Define atoms
Smallest unit of chemical elements
Covalent vs. Ionic bonds
Covalent bonds share valence electrons
Ionic bonds give away valence electrons (ion want it)
Non-polar Covalent Bonds
Electrons are shared equally
Lipid molecules have fatty acid tails
- not water soluble
Polar covalent bonds
Electrons are not shared equally; they have positive and negative ends
ex. Water
Cation + anions
In an ionic bond, one atom gives elections to another so that both have filled electrons
The electron donor is positively charged, now is called the cation
The electron receiver is positively charged, now is called the anion
Hydrophilic vs hydrophobic
Hydrophilic: molecules that can dissolve in water
Hydrophobic: molecule’s that repel water
Ionic bonds are much weaker than covalent, they easily dissociate when dissolved in H2O
pH
Water molecules break to form free hydrogen ions and hydroxide ions
(below 7 = acidic, above 7 = basic)
Buffers
Buffers stabilize H+ concentration in a solution.
In blood, 2 molecules stabilize pH:
1) bicarbonate (HCO3-) und carbonic acid (H2CO3)
Acidosis vs alkalosis
- if blood falls below 7.35 pH, it is called acidosis
- if blood rises above 7.45 pH, it is called alkalosis
Carbohydrates
Organic molecules containing carbon, hydrogen, and oxygen, ring shaped
CnH2nOn
Monosaccharide vs disaccharide vs polysaccharide
Monosaccharide: simple sugar, single ring
Disaccharide: 2 monosaccharides covalently bonded together
Polysaccharide: numerous monosaccharides
jointed together
Lipids
Consist of non-polar hydrocarbon chains and rings
Hydrophobic = lipophilic
Categories: Triglycerides, phospholipids, steroids
Triglycerides
Include fat and oil (diet), stored in adipose tissue
1 glycerol molecule joined with three fatty acids
Fatty acids: C and H chains
saturated vs unsaturated fats
saturated fats = single bond (solid at room temp)
unsaturated fats = double bond (liquid at room temp)
phospholipids
major component of cell membrane
polar head made up of phosphate
nonpolar tails made up of fatty acid
micelles
groups of phospholipids
(polar head faces water)
steroids
*only lipid with a ring structure
*cholesterol, sex etc.
*nonpolar and insoluble in water
*able to pass through cell membranes
*easy access to our DNA
anabolic steroids
*mimic testosterone
*increase protein synthesis and cellular tissue (muscle)
*increase cholesterol, blood pressure
*more blood flow to tissues, higher BP
*cancer too
what determines the function of the protein
the structure determines the function of the protein
how many different amino acids are there?
20 different amino acids
what is the functional group of protein
*Amino Acid
*an amine group (carboxyl group and a functional group)
what kind of bonds hold together the tertiary structure of a protein
weak bonds hold the tertiary structure together. It is easily denatured (unfolded) due to changes in pH or temperature
What are amino acids linked with
Peptide bonds
What is a glycoprotein composed of?
Protein + carbohydrate
What is a lipoprotein composed of?
Protein + lipid
What are the 3 macromolecules that make up the cell?
Lipids, Carbohydrates, and Proteins
define enzymes
enzymes are biological catalysts:
1. increase rate of rxn
2. are not changed by the rxn (so it can be used again)
3. do not change the nature of the reaction (the rxn can ouccur without the enzyme, just slower rxn rate)
activation energy
the energy required for the reactancts to engage in a reaction
adding heat to a rxn
adding heat increases the likelihood of a rxn occuring = increases rxn rate
catalysts
help the rxn occur at lower temperatures by lowering the required activation energy
describe how enzymes work with conformation and active sites
- each enzyme has a specifc conformation, with pockets that serve as active sites in the enzyme
- the reactants are called substates, and they fit into the active site
describe the 2 models of enzyme activity
lock and key model
Induced fit model: enzyme structural change (wraps around substrate)
enzyme-substrate complex
temporary bonds form creating the enyzme-substrate complex
enzyme activity
measured by the rate at which substrate is converted to product
conditions that influence enzyme activity
- temperature
- pH
- concentration of cofactors and coenzymes
- concentration of enzyme and substrate
effects of temperature on enzymes
an increase in temp will increase rate of rxn until the temp reaches above body temp. At this point the enzyme is denatured.
Sustained high fever = denatured proteins
effects of pH on enzymes
enzymes exhibit peak activity within a narrow pH range = pH optimum
optimium pH reflects the pH of the fluid the enzyme is found in (stomach vs saliva)
coenzymes
- an additional small molecule to aid in the rxn
- they transport hydrogen atoms and other small molecules between enzymes
cofactors
- metal ions (Ca2+, Mg2+, Mn2+, Zn2+)
- help form the active site through a conformational change of enzyme or help in enzyme-substrate binding.
substrate concentrations
as substrate concentration increases, rate of rxn increases until the enzymes become saturated.
metabolic pathway
- formed by many enzymes
- most rxns are linked together in a chain or web
allosteric inhibition
- negative feedback
- what is turned on must be turned off
- main goal of allosteric inhibition: keep a specific final product from accumulating
branch point
- are often inhibited by a form of negative feedback in which one of the final products inhibits the branch point enzyme
- a divergent pathway becomes favored (chocolate chip cookies to PB cookies)
