quiz 10

monomers

A chemical subunit that serves as a building block of a polymer. linked together by dehydration synthesisin which a water molecule is removed, covalently bonding the two subunits. the bond between monomers can be removed by hydrolysis (removing a water molecule)

control variable

A factor that is held constant to test the relative impact of an independent variable

projected blood spatter

created when an exposed blood source is subjected to an action or force greater than force of gravity

positive controls in Benedicts Reagent Test

deep red (most reducing sugars present) e.g glucose and reducing sugars, yellow (some reducing sugars), green (a little reducing sugars) e.g onion juice

fiber evidence

fibers are frequently left behind through cross transfer from the suspect to the victim and/or surrounding area. natural fibers=those derived from animal or plant sources. ex: cashmere, wool, fur. manufactured fibers: natural or synthetic polymers ex: polyester, acrylic, spandex

Sudan IV test

hydrophobic bond (fat soluble dye) lipids. high proportion of non-polar carbon hydrogen bonds and can only dissolve in non-polar solvents such as ether, ethanol and acetone.

nucleic acids

important class of macromolecules because they comprise our genes, regulate cell function, and are a major component in cellular respiration

nucleic acids

(DNA and RNA) the info center of the cell comprise our genes regukate cell function and are involved in energy transfer. both participate in cellular replication.

polymerase chain reaction (PCR)

A method of producing thousands of copies of DNA segment using the enzyme DNA polymerase

purines (double-ring structure)

Adenine and Guanine

proteins

Amino acids are the monomer state for Proteins, they are held together by peptide bonds. structural elements within the cell and aid in the transport of molecules across membranes. regulate cellular activities (enzymes and hormones) and are important components of the immune system. properties of proteins (amino acids) vary in accordance to these properties.

Kastle-Meyer Test

Based on fact that hemoglobin has perioxidase-like activity; Capable of oxidizing compounds; Phenolphtalein is in reduced form (pale yellow) becomes oxidized by blood and turns pink; very sensitive but also yields false positive from potatoes and horseradish

Phenolphthalein assay (Kastle-Meyer test)

Based on fact that hemoglobin has perioxidase-like activity; Capable of oxidizing compounds; Phenolphtalein is in reduced form (pale yellow) becomes oxidized by blood and turns pink; very sensitive but also yields false positive from potatoes and horseradish. Color based assay relies on the redox reaction of the phenolphthalein indicator with hydrogen peroxide and heme, iron-containg portion of hemoglobin molecule. Not confirmatory since vegetable peroxidase, household cleaners, bleach and salts also act as oxidants, giving a false positive result.

carbohydrates

Building Block: Monosaccharaide. (glucose, ribose, deoxyribose) made up of simple sugars Carbon, Hydrogen and Oxygen in a 1:2:1 ratio. monosaccharide contains aldehyde (-CHO) or hetone (-C=O) these two processes are referred to as redox reactions. function as the primary source of fuel in cells and are used to support cell walls

negative control

Control group where conditions produce a negative outcome. Negative control groups help identify outside influences which may be present that were not accounted for when the procedure was created.

positive control

Group expected to have a positive result, allowing the researcher to show that the experimental set up was capable of producting results.

polymers

Large compound formed from combinations of many monomers.

pyrimidines (single ring structure)

Thymine and Cytosine

monosaccharide

a single sugar molecule

Dische Diphenylamine Reagent Test

acidic conditions convert deoxyribose to a molecule that binds with diphenylamine to form a blue complex. form hydrogen bonds between bases. A-T AND C-G

passive blood spatter

blood drops created or formed by the force of gravity alone. ex: blood dripping from murder weapon

negative control in Benedicts Reagent Test

blue (distilled water)

positive control in Dische Diphenylamine Reagent Test

blue DNA is presnt

positive control in Starch-Iodine Test

blue-black

phosphodiester bond

both DNA and RNA long polymers composed of nucleotide subunits, connected end to end by this bond. each nucleotide consisting of a phosphate group, a pentose sugar (deoxyribose in DNA vs. ribose in RNA) and a nitrogenous base

microscopy

can be used to rule out potential suspects

biological organisms utilize four major classes of macromolecules in every biochemical reaction

carbohydrates, proteins, lipids and nucleic acids. these organic compounds are important for proper cellular functioning

all molecules are held together by a

carbon backbone

proteinase K

cellular proteins present in are enzymatically digested with proteasome enzyme

negative control in Dische Diphenylamine Reagent Test

clear blue no DNA is present, maybe RNA or other macromolecules

Biuret Test

composed of amino acids covalently linked by peptide bonds. Peptide bonds form when the amino group of one amino acid reacts with the carboxyl group of another (C--N)

disaccharide, polysaccharide

composed of two or more sugar molecules. di - (sucrose and maltose) poly- (starch, glycogen, cellulose, chitin)

gel electrophoresis

in this process following the PCR, the amplified products are seperated by gel electrophoresis where DNA, RNA or protein molecules are seperated in a gel matrix based on size and charge. an electric current is applied to the gel and creates a charge seperation across the gel matrix, i.e one side becomes positively charged (anode) and the other negatively charged (cathode). Because opposite charges attract, negatively charged molecules move toward the anode while positively charged molecules migrate toward the cathode. amplified products of smaller molecular weight have a tendency to move through the gel faster than larger products, which are retained near the wells. once this process is complete the products can be viewed through the use of ethidium bromide in conjuction with a UV irradiation system or staining the gel with a safe stain

arterial spurt

injury occured at victims neck resulting in breached artery

impact spatter

massive force or blow resulting in random dispersion of blood droplets. can be characterized by low velocity (5 ft/sec or less) (stabbed or hit with a hammer). medium velocity spatters (intense beating with a bat) 5-100ft/sec. high velocity resulst from forces traveling at speeds greater than 100ft/sec.

transfer blood splatter

occurs when a wet bloody surface , hand or shoe, comes into contact with another surface

sodium dodecylsulfate

once cells have lysed after DNA isolation this detergent functions to remove lipids present in the cell membrane so that DNA can be released into the solution.

negative control in Starch-Iodine Test

orange

DNA isolation

procedure done to examine the genetic material of the cell, DNA must first be removed from the confines of the cell through this process. Procedure involves dissolving the cell membrane and then removing proteins that are not part of the DNA structure. to break down the cell membrane the cells are subjected to physical abrasion such as bead beating or vortexing.

negative control in Sudan IV Test

red altogether (no lipids)

benedicts reagent

redox reaction results in a tractable color change from light blue to green reddish orange. the instensity of the color change is indicative of the of the amount of reducing sugars present.

positive control in Sudan IV test

seperated layers one red the other blue means there are lipids present

Benedicts Reagent Test

test for reducing sugars. aldehyde bonds with copper. 1st carbon produced aldehyde. In the test the benedicts reagent is reduced while the reducing sugar is oxidized resulting in a redox reaction. difference between aldehyde (-CHO) and ketone (-C=O) ketone side groups reduce oxidizing compounds.

Starch-Iodine Test

tests for polysaccharides

hair morphology

three properties that can be used to link a potential suspect to a crime scene are --resistance to chemcial decomposition, maintenance of its structural features over long periods of time and presence of DNA. cortex layer located immediately beneath the cuticle. medulla=inner most layer of the hair shaft. root=terminal end of hair located within the hair follicle. contains the cells necessary for hair growth.

lipids

used for "storage" of excess fuel and are an integral structure part of cell memebranes. made of fatty acids, are nonpolar (hydrophobic)

molecular biology

uses cellular chemistry and genetics to study molecules critical to life. Emplying techniques such as DNA isolatation, Polymerase Chain Reaction, and gel electrophoresis

fingerprints can be classified into one of five categories

visible, plastic, latent, patent or examplar prints. visible prints are those that can be visualized with the naked eye and are usually formed when the fingerprint ridges are in contact with colored material. plastic prints are ridge impressions left behind in a soft substance such as a soap or wax. Latent prints are left behind on most objects that have been touched but are invisible to the naked eye. require the use of special tools for vizualization. examplar prints are prints collected purposefully from an individual. loop fingerprint