Post on 14-Feb-2016
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Good Morning! Please sit at your lab table with you lab notebook.
BiologyStudy of life
Is it ALIVE? Biology is the study of life, but how can you tell if something is alive?
All living organisms exhibit certain properties that biologists look for to classify it as alive.
Properties of Life
Cells Reproduction
HomeostasisMetabolismHeredityEvolutionInterdependen
ce
All living organisms have the following properties present at some point in their life:
Lets start small…What are we made of?
WaterWater is essential for life
◦ Living organisms are made mostly of water 70%-90%
Resistant to temperature change◦ Homeostasis
Expands when frozen◦Less density than l form◦Turnover in lakes
WaterAdhesive (adhere to surfaces)Cohesive (adhere to each other)The universal solvent
Water can dissolve ions and polar molecules. Non-polar
molecules do not dissolve well in water (oil, fats). Remember like dissolves like (polar dissolves
polar, non-polar dissolves non-polar).
Adhesion• Because water
molecules are polar, they have a tendency to stick to other polar substances. • Glass may carry a
partial charge along its surface. • That’s why rain
droplets stick to windows.
Why does water have these special properties???
…because water is POLAR!Polar molecules have uneven charges.
This attracts ions and other polar moleculesIt is also the reason water is a universal
solvent
Capillary ActionPolarity
◦water uses cohesive and adhesive properties to climb up capillaries in plants
This makes it possible for the tops of the trees to obtain water
Chemistry of Life
The Essential Ingredients for Life
Ingredients for Life
1. Water2. Carbohydrates3. Lipids4. Proteins5. Nucleic Acids
Carbon Compounds Organic (carbon) compounds are found in
living things Carbon has four valence electrons ready for
bonding Carbon can form chains, chains with
branches or rings
What does it all mean???
Carbon can bond with itself and with many other elements
Form large organic molecules called biomolecules◦Small chains are called monomers
◦Large chains made of monomers are called polymers
Carbon forms:
1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acid
1.Carbohydrates - made of Carbon, Hydrogen and Oxygen in
1:2:1 ratio (C6H12O6) - major source of energy found in most foods - monosaccharides are simple sugars and the
building block of carbohydrates (glucose and fructose)
- polysaccharides are large molecules made of many sugars that store energy.
plants – starch animals - glycogen
Carbohydrate - Sugar
Monosaccharide– glucose
polysaccharide- starch
Lipids- non-polar molecules
- Is it soluble in H2O?- fats, phospholipids,
steroids, oils, waxes…
- important part of cell membranes
- lipids are used by cells for energy storage
- Insulation
Lipids Saturated fatty acid – no double bonds
between carbon- carbon bonds, straight molecule, solid at room temperature
Unsaturated fatty acid – double bonds that make the molecule kinked, liquid at room temperature
Proteins - Amino Acids There are 20 different amino acidsAmino Acids bonded together form a chain called a polypeptide chain.
Amine Group: -NH2A polypeptide chain folds into a protein
The way a protein folds is important to its function
Mad Cow Disease
Functions of ProtiensTransport: hemoglobin in red
blood cellsMovement: musclesStructural: membranes, hair,
nailsEnzymes: cellular reactions
EnzymesEnzymes are proteins Speed up chemical reactionsLower activation energyThey work on a specific substrate
Some reactions in your body would not occur without enzymes.
4.Nucleic Acids –- Long chains of nucleotides (sugar,
phosphate, base)- Contain genetic/heredity information
in code
- DNA- (deoxyribonucleic acid) found in nucleus of cells. Have genes that contain hereditary info (traits). 2 strands
- RNA – (ribonucleic acid) can act as an enzyme or help in protein synthesis. 1 strand
Nucleic acids – Genetic Material
Nucleic acids are composed of long chains of nucleotides
Identifying Organic Compounds Lab
IntroductionThe most common organic compounds found
in living organisms are lipids, carbohydrates, proteins, and nucleic
acids. Substances called indicators can be used to test for the presence of organic compounds. An indicator is a substance that changes color in the presence of a particular compound. In this investigation, you will use several indicators to test for the presence of lipids, carbohydrates and proteins in various foods.
Materials
8 Test tubes
Test tube holder
Test tube rack
Hot plate
Brown paper towel
Labeling tape
For each organic compound test you need:
5 drops egg white 5 drops lettuce/water 5 drops apple juice 5 drops corn oil 5 drops Spinach/water 5 drops peanut butter 5 drops potato/water 5 drops water Starch test: Iodine
solution Sugar test: Benedicts
solution Protein: Biuret solution
Lipid Test1. Divide a piece of brown paper towel into 8 equal sections. In each section, write the name of one test substances, as shown.
2. In each section, place a small drop of the identified food onto the brown paper towel. With another paper towel, wipe off any excess pieces of food that may stick to the paper. Set aside for 10-15 minutes3. Hold paper to light or window. If food sample produces a translucent or see-through spot, there is a presence of a LIPID.
1.Distilled Water
2.Egg White 3.Corn Oil 4. Spinach
5.Peanut Butter
6.Apple Juice
7.Potato & Water
8.Fish
Carbohydrate Test - Starch
1. Label test tubes: water, egg, oil, Spinach, peanut, apple, potato, fish2. Add 5 drops of each food sample to its proper test tube. 3.Add 5 drops of iodine solution to each test tube and shake. *Iodine will change color from yellow brown →blue black in presence of STARCH.4. Record data on table.5. Wash test tubes thoroughly!
Carbohydrate Test - Sugar1. Set up hot water bath: Fill half the beaker with tap water and heat to a gentle boil. 2. While water bath is heating, fill each cleaned test tube with 5 full drops of the appropriate food sample.3. Add 10 drops of Benedicts solution and shake.4. Place test tubes in hot water bath and heat for 3-5 minutes.5. Caution: Remove test tubes from water bath with test tube holder! *When heated, Benedicts solution will change color from blue → green, yellow, orange, or red in the presence of SUGAR.6. Record any color changes on data table. 7. Wash test tubes thoroughly!
Protein Test1. Put 5 drops of appropriate food samples in each labeled test tube. 2. Add 5 drops of Biuret solution to each test tube and gently shake.Caution: Biuret contains NaOH, a strong base. If you splash any on yourself, wash with water and notify your teacher immediately!*Biuret changes color from light blue→blue-violet in the presence of PROTEIN.3. Record any color change on data table.4. Wash test tubes thoroughly!
Data chartAll should have before and after descriptions!
Food Sample LipidTest
StarchTest
SugarTest
AA or Protein Test
Egg white
Corn Oil
Potato
Peanut Butter
Water
Apple Juice
Fish
Spinach