Ch. 2 - Chemistry

HW/Study Guide

An enzyme works to ___ a chemical reaction by ___ the amount of energy needed to start the reaction.

speed up; lowering

Which of the following is a negatively charged subatomic particle?

electron

A buffer will release H+ ions if the pH ________.

increases

Which property of water is demonstrated by sweating?

water has a high heat of vaporization

If the element carbon has a total of six electrons, how many valence shell electrons does it have?

four

What is a cation?

an atom loses one or more electrons and acquires a net positive charge

The pH scale is ______.

based on the concentration of hydrogen ions in a solution

What type of chemical bond is formed between the oxygen atom of one water molecule and the hydrogen atom of another water molecule?

hydrogen bond

The lipids that we refer to as oils have ___.

unsaturated bonds in their fatty acid chains

A major function of carbohydrates in the body is ____.

to provide fuel for cellular activity

During a dehydration synthesis reaction, chemical bonds are ______, and a water molecule is _____.

made; released

The chemical structure of a molecule of oxygen gas is O=O. The = indicates that ____

there is a double covalent bond between the oxygen atoms

Which of the following is NOT an example of an inorganic molecule?

DNA

Hydrogen bonds are similar to ionic bonds because _______.

they are both due to opposite charge attractions

As the concentration of H+ ions in a solution _______, the measured pH will ______.

increases; decrease

The molecule ATP is broken down into ADP to provide energy for cellular needs. This is an example of a hydrolysis reaction.

True

Which level of protein structure is represented by the coiling of an amino acid chain into an alpha helix?

Secondary

A nucleotide in a DNA molecule could contain which of the following?

deoxyribose, phosphate, adenine

polar covalent bonds

a chemical bond in which electrons are shared unequally

ionic bond

a chemical bond in which electrons are completely lost or gained by the atoms involved

non polar covalent

a chemical bond in which electrons are shared equally

hydrogen bond

a type of chemical bond important in tying different parts of the same molecule together

Describe the structure of an atom. Your description should include the location and charge of protons, neutrons, and electrons.

protons and neutrons are inside the nucleus, electrons orbit - all atoms are electrically neutral

What part of atomic structure determines the reactivity of an element? Why?

The outer shell determines the reactivity of an element. The shells want a full shell

Oxygen (8O) and argon (18A) are both gases. Oxygen combines readily with other elements, but argon does not. What accounts for this difference?

Oxygen doesn’t have 8 valence electrons, while argon does

Describe ionic bonds. Relate your answer to anions, cations, and salts. What are some specific examples of molecules formed by ionic bonds in the body?

bonds are formed when one atom gives a valence electron to another, making the atoms charged - the donor becomes a cation, the acceptor a anion - all salts are ionic - NaCl is a salt vital to life (minerals, bones, nervous system)

Describe covalent bonds. How do they differ from ionic bonds? In what type of molecules are they found? What are some specific examples of molecules formed by covalent bonds in the body?

bonds are formed when electrons are shared between 2 atoms - found in H2O, HCl

What are polar molecules?

have unequally distributed charges

What causes the polarity of water molecules?

negatively charged electrons are “hogged” by oxygen

What are hydrogen bonds? In what type of molecules do hydrogen bonds form? How are hydrogen bonds different from ionic and covalent bonds? Give some specific examples of molecules in the body that have hydrogen bonds.

bonds that hold molecules together, partial neg/pos charges of a neighboring oxygen atom, form when hydrogen is with oxygen, nitrogen, flourine, “weak attractions”, DNA, H2O, proteins

Is water an inorganic or an organic compound?

inorganic

Name and describe the properties of water and its multiple roles in the human body.

polar solvent (can dissolve), body transport medium, high heat capacity, high heat of vaporization, reactivity (hydrolysis/dehydration synthesis), lubricant (mucus, spinal fluid)

Describe how a salt is formed and give some examples of salts in the body.

formed by ionic compounds, makes bones hard, muscle contraction, nervous system (electricity)

How does the structure of a water molecule make it an excellent solvent for salts?

they’re both polar, so the neg/pos sides of both molecules are compatible

Briefly explain what are acids and bases and how they relate to protons. Be able to name examples of biologically important acids and bases in the body.

acids release H+ (donors) HCl, bases take up H+ (acceptors) NH3

What is "pH"? Is this a measure of acidity or alkalinity? What values of pH are considered to be acidic, neutral, and alkaline (basic)? If the [H+] concentration of a solution increases by a factor of 10 (i.e. multiplied by 10), what will happen to the pH value of this solution? Why?

is a measure of how acidic or basic a substance is - 0 is acidic, 14 is basic - if a concentration increased by a factor of 10, the pH would increase, making it more basic

Describe the structure of carbohydrates, with reference to the difference between mono-, di-, and polysaccharides, and to hydrolysis and dehydration synthesis reactions.

rings of “hydrated” carbon, monosaccharides are one, di- two, poly- many — dehydration synthesis is making bonds and hydrolysis is breaking bonds

Be able to recognize specific examples of mono-, di-, and polysaccharides.

mono- is one (glucose), di- is two connected (sucrose), and poly- is many long chains (glycogen)

What is glycogen? What is starch and cellulose?

glycogen is storage carb of animals in liver, starch/cellulose are storage carbs of plants (we can’t harness cellulose energy)

Name 3 functions of carbohydrates in the human body.

energy, structure, signaling

Describe the structure and function of the three main types of lipids: triglycerides (including the difference between saturated and unsaturated), phospholipids, and steroids. Name examples of biologically relevant lipids and describe why they are important.

triglycerides (fats/oils) have 1 glycerol and 3 fatty acids, energy, insulation, protection (unsaturated are bent and not solid, 1 or more C double bond) — phospholipids have 1 glycerol, 2 fatty acids, 1 phosphate group, cell membranes, polar head non-polar tail — steroids (testosterone) 4 interlocking rings of carbon, cholesterol building block

Describe the structure of amino acids (only connected by peptide (covalent) bonds)

all have an amine group (-NH2), organic acid group (-COOH), and have different functional or R groups (to make acidic or basic)

What is a peptide, dipeptide, tripeptide, polypeptide, protein? How are peptide bonds formed and broken?

Peptide bonds are for amino acids, di- are two, tri- is 3, poly- is greater than/equal to 10, and 100-10,000 is a protein - bonds are formed by synthesis, and broken by hydrolysis

Describe the four levels of protein structure. Answer with as much detail as what was covered in lecture.

Primary - amino acids forming a polypeptide chain - peptide bonds, Secondary - chain forms spirals (helix/stabilized by hydrogen bonds) and sheets (zig-zag/hydrogen bonds), Tertiary - hydrogen/covalent bonds between R groups (3D shape), Quaternary - aggregation of two or more polypeptides (not all proteins have this level)

Describe how genetic mutations can cause changes in the structure/function of proteins.

Mistakes can disrupt all levels, proper 3-D shape is required for function, mistakes make non-functional/poorly functioning proteins

What type of chemical bond binds amino acids together? Is this an example of a ionic, covalent, or hydrogen bond?

peptide bonds, covalent

What type of chemical bond(s) create tertiary and quaternary structure?

intramolecular bonds/hydrogen bonds

Describe the causes and consequences of protein denaturation.

wrong physical/chemical conditions — hydrogen bonds break down, protein loses 3D shape, non-functional protein

What are some functions of proteins?

structure (collagen/keratin), muscle contraction (actin/myocin), transport (hemoglobin), regulation (hormones), defense (antibodies), catalysts (enzymes)

Describe how enzymes work as catalysts. Your answer must include reference to activation energy.

speed up chemical reactions by lowering activation energy required

Describe the basic structure of nucleotides.

pentose sugar (deoxyribose) + phosphate group + nitrogen base (A, G, C, T, U)

Describe the structure of the DNA double helix. What kinds of bonds hold the “rungs of the ladder” together?

double helix, rungs held together by hydrogen bonds (blueprints for proteins)

If one of the strands of the DNA double helix has the following nucleotide sequence, A-T-T-G-G-G-C-A-T-A, what would be the nucleotide sequence on the complimentary DNA strand?

T-A-A-C-C-C-G-T-A-T would be the complimentary strand

Describe the structural and functional differences between DNA and RNA. For example, how do they differ in nitrogenous bases, sugars, and location in the cell?

DNA is a double helix, RNA is a single, DNA is genetic material and blueprint for proteins, RNA carries out genetic instructions for protein synthesis

Describe the structure and function of adenosine triphosphate, or ATP.

energy currency of living systems, modified nucleotide w/ 3 phosphates

Why can’t most cells of the body directly utilize glucose or lipids as a fuel source?

they contain too much energy to be used by a cell

What happens when one high energy phosphate bond in an ATP molecule is hydrolyzed?

ATP becomes ADP after hydrolysis, since one phosphate bond becomes energy to use