BIO 1000 MOD 2 ASSN 2

BIOCHEMISTRY Worksheet #1 (Module 2)

These exercises help to “cement” the information in our brain so we can use that learning in our other tasks, both in life and in this course. When we exercise our thinking outside of reading and speaking, we remember better and accomplish more.

Goal of this activity • To solve problems with atoms, molecules, and chemistry that are critical to maintaining life (biology)

Steps for Success with this activity 1. Look through the entire document, making note of what you have seen or heard previously. Rely on

your prior learning! Use that learning to build more. 2. Please remember that biology makes chemistry EASY! We learn applications of the chemical laws that

seem difficult. Actually, learning bio-chemistry will help you succeed in chemistry! 3. Work through the problems in any order.

a. Open the Periodic Table document. b. Typically the problems with the Periodic Table are important to understand prior to the work with

carbon molecules but do them in the order that makes sense to you. c. Sometimes starting with the last page will help you see the reason to learn the 1st page.

4. Work hard before you consult the answer page! Healthy frustration is the foundation of real learning, so let yourself be in a bit a “quandary” before you check your answers.

5. Bring all questions and inconsistencies to the Tech Live sessions.

TOPICS and ACTIVITIES A. Compare atoms, elements, chemical bonds, and molecules (OpenStax, Concepts of Biology, section 2.1)

1. Define: a) Matter = b) Elements = c) Atoms =

Application questions:  Which of these groups have the largest number of members?  Which of these are the smallest in size?

2. Within an ATOM, differentiate Elementary Particles (e.g., protons, neutrons, and electrons

Elementary Particle Charge Size (approximate) Location

Application questions:  Which of these particles play a role in bonding?  What is the job of the 3rd particle? When do we see that have an impact on an atom?

BIO 1000 – Module 2 Worksheet #1, page 2

3. Compare atomic bonds: ionic, covalent, and hydrogen-bonding (see OpenStax, Concepts of Biology, Figure 2.5, and extra practice sheet for electron dot diagrams)

BASIC RULE for CHEMICAL BONDING:

The goal of any bond is to be more STABLE (i.e. use less ENERGY).

This is described by the OCTET RULE.

STEP 1: How many electrons are in the outer orbit? (use the Periodic Table)

STEP 2: Determine if the outer shell is full.

 Use the octet rule (except for Helium, on the top row).  If the outer shell is FULL, it will neither accept any more electrons, nor will it give up any

electrons.  COOL TRICK HERE: look at the Periodic Table.

• All of the atoms in the far-right column have FULL outer shells. (see column 18) • They are called “Noble Gases” for this reason; they do NOT react (e.g., form bonds)

under normal circumstances.

STEP 3: If the outer shell is not full, decide whether the electrons will be “stolen” or “shared”.

 This depends how near the atoms are to one another on the Periodic Table. WHY?

 We call this the difference in “electronegativity.” If the atoms are further apart on the Periodic Table, then the atom with an almost-full outer shell will be able “steal” another atom’s electron(s) from its almost-empty outer shell.

 Opposite sides of the Periodic Table often means: LARGE or SMALL difference in electronegative. WHY?

STEP 4: Draw the compound, showing the shared or stolen electrons (see OpenStax, Concepts of Biology, Figure 2.5, and extra practice sheet for electron dot diagrams)

STEP 5: Determine the strength of the bond

 If the electrons are “stolen,” the bond is IONIC, and easier to break.  If the electrons are “shared,” then the bond is COVALENT and much more difficult to break.

Application questions:  Which has a stronger bond? SODIUM CHLORIDE (NaCl) or METHANE (CH4)

Circle one; explain why this is true according to step 5.

ONE FINAL IDEA: After a molecule is formed, molecules are sometimes “pulled” toward each other.

 Hydrogen bonds are one example of this type of association between different molecules.  Water is one of the most famous examples of Hydrogen Bonding, shown in OpenStax,

Figure 2.7

BIO 1000 – Module 2 Worksheet #1, page 3

PRACTICE with drawing IONIC BONDING 1. Make an electron dot diagram of the atoms in the ionic compound. Check that your model is correct! 2. Draw the BEFORE model on this paper. Next, show IONIC BONDING by moving the valence electron(s). 3. Draw the AFTER model. Use arrows to show the electrons being transferred and indicate the charge of each atom.

PRACTICE with drawing COVALENT BONDING 1. Draw the electron dot diagrams of the atoms in each compound. RECOMMEND: use different colors for each atom

(or different “code”) 2. Then draw the line diagram to show each pair of shared electrons.

BIO 1000 – Module 2 Worksheet #1, page 4

Now that we have built the bonds, we can compare the bonds: ionic, covalent, and hydrogen-bonding.

Type of bond DEFINITION LOCATION of ELECTRONS STRENGTH IONIC

COVALENT

HYDROGEN- BONDING

B. Describe the properties of water that are critical to maintaining life

A. Water is a POLAR molecule due to its bond type. What does this mean? Draw it here (OpenStax, Fig. 2.7)

B. Because of its polarity, water has unique properties that support life on Earth. Name these properties of water:

1. _ 3. _

2. _ 4. _

C. Describe the ways in which carbon is critical to life

1. Life on Earth is also based on CARBON; often we call this “organic.”

2. A carbon atom can bond with 4 other atoms.

• Draw the simplest carbon molecule: Methane (CH4) (OpenStax, Fig. 2.13)

• Carbon can also make long-chain fatty acids; draw here. (OpenStax, Fig. 2.14)

D. Contrast the four major types of biological macromolecules and their functions

1. CARBOHYDRATES: made of , , and

• Always with a ratio of atoms at : : (such as glucose, C6H12O6)

2. LIPIDS include , , , , and

3. PROTEINS are made of individual parts called and have diverse functions.

4. NUCLEIC ACIDS include and . These are our genetic material (both genome and message).