Chemistry in Biology

A VERY Brief Overview of Chemistry

Chapter 3

15 Clicker Questions!

Words in Bold Pink

Those are your vocabulary words…

Please high-light them!!!

ElementElement: Substance consisting

entirely of one type of atom.

Examples: Carbon, Hydrogen, Oxygen

SubscriptA subscript is a small lowered

number after a symbol for an element.

H2O– the 2 is lowered and considered

a subscript.

The 2 indicates how many atoms of the element are present in that compound.

Chemical Compounds

Compound: A substance formed by the chemical combination of 2 or more elements in definite proportions.

Examples: H2O (water) NaCl (Salt)

C6 H12 O6 (Sugar)

Chemical Formula States how many atoms are in each molecule.

How many carbon atoms are in C6 H12 O6?

How many hydrogen atoms?

How many oxygen atoms?

66

1212

66

Click for answers

Chemical Equations Let’s say I give you a chemical equation like—

CO2 + H2O -------- C6 H12 O6 + O2

What are the names of these compounds?

Could you tell me which side are the reactants and which side are the products?

REACTANTS PRODUCTS

Carbon

dioxideWater Sugar/glucose Oxygen

Click for answers

Click for answers

Elements in the Human Body

Oxygen – 65% Carbon – 18.5% Hydrogen – 9.5% Nitrogen – 3.3% All of these equal 96.3%. The other 4% are

trace elements: Calcium (1.5), Phosphorous (1.0), Potassium (0.4), & others.

Water

Most abundant element in our body

Most abundant compound in our body

Click for animation

Clicker Question #1

Which of the following is an element?

a. Carbon dioxide

b. Methane

c. Oxygen

d. Water

Clicker Question #2

How many atoms are in: NH3

a. 1

b. 2

c. 3

d. 4

Clicker Question #3

Which of the following are the reactants?

CH4 + 2 O2 CO2 + 2 H2O

a. CH4 + 2 O2

b. CO2 + 2 H2O

c. CH4 + 2 H2O

d. None of the above

Solvent-Solute Water is the greatest solvent in the world!

Solvent means to dissolve, or a dissolving

agent. WATER is a SOLVENT!

Solute is what is to be dissolved. Sugar and salt are solutes and they dissolve in water.

pHpH: The measure of concentration of H+ in a

solution.

Acid: Substance that release hydrogen ions (H+) when dissolved in water.

Base: Substance that releases hydroxide ions (OH-) when dissolved in water.

pH ScaleThe pH scale measures how

acidic or basic a substance is.

It ranges from 0 to 14

A pH of 7 is neutral

A pH less than 7 is acidic

A pH greater than 7 is basic

Oven cleaner

Bleach

Ammonia solution

Soap

Sea water

Human blood

Pure waterMilkNormal rainfall

Acid rain

Tomato juice

Lemon juice

Stomach acid

Neutral

Incr

ea

sing

ly B

asi

cIn

cre

asi

ngly

Aci

dic

14 = Basic

0 = Acidic

7 = Neutral

pH Scale

AcidsAcids taste sour

Strong Acids are dangerous and can burn your skin

Examples are: Vinegar, stomach acid, and citrus fruits

Bases Solutions containing bases are often called alkaline.

Bases taste bitter

Bases feel slippery

Strong bases are very dangerous and can burn your skin

Examples: Lye and ammonia

pH QuestionAn ecologist is testing rainwater. She

tests rainwater on the south side of town and finds that the pH is 6.2. Then she tests the north side of town and finds that the pH is 6.8. Which is more acidic?

6.2 is correct!Click for answer

Buffers Buffers are weak acids or bases that can react

with strong acids or bases to prevent sharp, sudden changes in pH.

(Don’t need to write this)

For example, your stomach is upset, so you drink alka seltzer or eat a Rolaids. These are buffers or a mild base to offset the higher stomach acid.

Clicker Question #4

Which of the following is a solute?

a. Water

b. Sugar

c. Vinegar

d. Carbon dioxide

Clicker Question #5

Which of the following has the most basic pH?

a. 7

b. 7.1

c. 7.5

d. 8

Clicker Question #6

3.1 pH is: Acidic Basic Neutral None of the above

Clicker Question #7

Gastric protease works best in which type of pH?

a. Neutral

b. Basic

c. Acidic

d. All of the above

Clicker Question #8

Which of the following is a solvent?

a. Water

b. Sugar

c. Vinegar

d. Carbon dioxide

Organic MoleculesThere are 4 organic molecules

– Carbohydrates– Lipids– Proteins– Nucleic Acids

* These are also called macromolecules

CarbohydratesCarbohydrate: Organic compound

containing Carbon, Hydrogen, & Oxygen with a ratio of 1:2:1

Carbohydrates are basically sugars and starches.

***Most of an organisms’ energy come from carbohydrates!***

Carbohydrates Continued

Monosaccharides are simple sugar molecules.Examples: This is glucose, galactose, sucrose and fructose (sugars).

Glucose is

1 : 2 : 1

Many monosaccharides together make up polysaccharides. This is the excess sugar that we store as glycogen that can turn into fat

6126 OHC

Write these Video Questions & answer them while you watch the video clip.

1. Sugars belong to a class of chemicals called ___.

2. What is glucose made-up of?

3. What is a good example of a very long polymer of glucose called ___.

4. Starches are nothing more than very long chains of ____.

Carbohydrate Video Clip

Video

LipidsThis is FAT.

Lipids: these are used to store energy.

They are found in cell membranes.

Fats, oils, & waxes

Also water proofs

Video

Nucleic AcidsMade up of Carbon, Hydrogen, Oxygen,

Nitrogen, & Phosphorus

Nucleic acids store and transmit hereditary or genetic information.

Nucleic Acids Continued

Nucleotides consist of a 5 carbon sugar, a phosphate group and a nitrogen base.

2 types: Deoxyribonucleic Acid (DNA)

& Ribonucleic Acid (RNA)

Video Questions:

1. Nucleic acids are made up of long chains of subunits called ____.

2. Chromosomes contain huge molecules called deoxyribonucleic acid also known as ___.

Nucleic Acids Video Clip

Video

Clicker Question #9

Which of the following is NOT a macromolecule?

a. Carbohydrate

b. Lipid

c. Amino acid

d. Nucleic acid

Clicker Question #10

Which of the following foods is NOT an example of a carbohydrate?

a. Sugar

b. Potatoes

c. Bread

d. Meat

Clicker Question #11

Genetic material is made with this macromolecule:

a. Nucleic acid

b. Lipid

c. Protein

d. Carbohydrate

Clicker Question #12

Which of the following is NOT a sugar?

a. Glucose

b. Sucrose

c. Lactose

d. Pepsin

ProteinsProteins are composed of smaller units called

amino acids.

Amino Acids: Are small compounds that are made of carbon, nitrogen, oxygen, and hydrogen.

ProteinsActivation Energy: The minimum

amount of energy needed for reactants to form products in a chemical reactions.

ProteinsA catalyst, as well as an enzyme, is a

substance that lowers the activation energy needed to start a chemical reaction.

* Catalysts speeds up chemical

reactions thousands of

times faster.

ProteinsEnzymes are biological catalysts that speed up

the rate of chemical reactions.

* Enzymes are made of proteins.

Example: Amylase found in saliva.

Amylase speeds up the breakdown of amylose, a substance in starch (in foods).

* Most enzymes are specific to 1 reaction

Proteins: How enzymes work

Substrate: The reactants that bind to the enzyme.

Active Site: The specific location where a substance binds to an enzyme.

* The active site and the substrate have complementary shapes (“Lock & Key”)

Click on picture to see an animation!

Proteins: How enzymes work

• Only substrates with the same size and shape as the active site will bind to the enzyme (like puzzle pieces).

• pH and temperature mainly affect enzyme activity.

Click on picture for link

Pepsin: An Enzyme

Pepsin is an enzyme in the

stomach that begins the digestion of proteins by splitting them into smaller pieces.

Pepsin works at a pH level of around 2 which is acidic

Antacids are used to neutralize pepsin by increasing the pH level to around 6 or 7

CarbonCompounds

includes

that consist of that consist of that consist of that consist of

Macromolecule Concept Map

What does MacroMacro Mean?

Lets fill in the chart!

Carbohydrates

Sugars & Starches

Major source of energy for the body

Lipids

Fats & Oils

Stores energy & water proofs

Nucleic Acids

Nucleotides

Stores & Transmits

Genetic Info

Proteins

Amino Acids

Growth/ repair & make up

enzymes

Clicker Question #13

Enzymes are which type of macromolecule?

a. Lipids

b. Carbohydrate

c. Proteins

d. Nucleic Acids

Clicker Question #14

What do enzymes do during a reaction?

a. Nothing

b. Slows it down

c. Speeds it up

d. Burns it up

Clicker Question #15

What two conditions change how enzymes work?

a. Water & temperature

b. Temperature & pH

c. Solid & gas

d. None of the above

The End