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

CarbonMonomer Polymer

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