Chapter 3

What is the major characteristic responsible for the complexity and variety of organic compounds?

Chemical versatility of carbon

Collectively most complex molecules based on carbon are known as ____ ______

organic compounds

Simplest form of hydrocarbon? a. Methane b. Pentane c. Propane d. Octane

a. Methane

What category of organic molecules make up enzymes?

Proteins

T/F - stereoisomers have the same chemical formula but different structural arrangement

False - (Structural Isomer)

What is the reaction called when a water molecule is removed?

Dehydration Synthesis

What is the bond called between two monosaccharides in a disaccharide a. Ester b. Glycosidic bond c. Peptide bond d. Phosphodiester bond

b. Glycosidic bond

In what reaction do you ADD a water to break two molecules apart?

Hydrolysis

What type of bonds are found in proteins, carbohydrates, and nucleic acids?

Proteins - peptide bond; Carbohydrates - glycosidic linkage; Nucleic Acid - Phosphodiester bond

The monosaccharide that is a component of RNA is

Ribose

Disaccharides are formed by linking two monosaccharide units by what bond?

glycosidic bond.

The disaccharide lactose is formed by the monosaccharide units _ and _.

galactose and glucose.

What disaccharide is formed by the fusion of glucose and fructose?

Sucrose

Bacteria can break down cellulose and chitin, but humans cannot. Perhaps humans lack an enzyme that _. A. Can break down complex carbohydrates B. Can break down polysaccharides that contain galactose C. Can break apart polysaccharides in which every other carbohydrate residue is flipped in orientation D. Can break apart polysaccharides that originate from plant material

C. Can break apart polysaccharides in which every other carbohydrate residue is flipped in orientation

Ramesh has a track meet tomorrow. He should focus on eating foods that are rich in what type of macromolecule?

Carbohydrates

The polysaccharide that is the major component of the tough cell wall is

cellulose.

The polysaccharide that is a component of the insects cytoskeleton is

chitin.

Saturated fatty acids are characterized by having ___ bonds between carbon atoms, are __ at room temperature, and found in ___ fats

no double bonds, solid, animal fats

Which of the following is NOT one of the three main types of compounds that fatty acids are found in? a. Triglycerides b. Phospholipids c. Cholesteryl esters d. Glycolipids

d. Glycolipids
its cholesteryl esters

What is the primary function of triglycerides in animals? a. Catalyzing biochemical reactions b. Storing energy c. Providing structural support d. Acting as signaling molecules

b. Storing energy

Triglycerides are formed when a glycerol molecule bonds with _ fatty acids through _ _ which creates an _ bond

3 fatty acids through dehydration synthesis which creates an ester bond

5. As chains get longer, they become less/more soluble in water and less/more oily.

less/more

Which of the following factors does NOT impact membrane permeability? a. Polarity of solutes b. Size of solutes c. Temperature of the environment d. Charge of solutes

c. Temperature of the environment

True or False: Membranes with longer, saturated hydrocarbon tails are more permeable than those with shorter, unsaturated tails

False - they are less

Which of the following functions is NOT typically performed by proteins? a. Structural support b. Energy storage c. Transport d. Hormone regulation

b. Energy storage

Polar R-groups in amino acids are typically a. Hydrophobic b. Hydrophilic c. Non Reactive d. Acidic

b. Hydrophilic

The solubility of an amino acid in water depends on the nature of its _

R-group

Which of the following is NOT a nonpolar amino acid? a. Methionine b. Leucine c. Tryptophan d. Tyrosine

d. Tyrosine
polar

Which of the following amino acids have a positive electrical charge? a. Cysteine b. Histidine c. Asparagine d. Aspartate

b. Histidine
(+)

What bond is formed between two amino acids? a. Peptide bond b. Phosphodiester bond c. Glycosidic bond d. Ester bond

a. Peptide bond

True or false: The peptide bond backbone has the ability to rotate?

False - The backbone has double bonds which can not rotate, only the single bonds on the ends can rotate

Amino acids are linked together via _ _

dehydration synthesis/peptide bonds

True or false: Secondary protein structures contain alpha helix and beta sheets?

True

What environmental conditions can help determine a protein’s structure? a. Salt Concentration b. pH c. Temperature d. All of the above

d. All of the above

What did Anfinsen’s Experiment help us discover about proteins? a. Ion concentration b. Renaturation c. Denaturation d. Chaperonins

b. Renaturation

What is an example of a glycoprotein? a. Cell membrane b. Antibodies c. Chromosomes d. Alpha helix

b. Antibodies
glycoprotein

An _ _ _ is a protein that lacks a fixed 3D structure

intrinsically disordered protein

Which is NOT a component of a nucleic acid? A. Hydrogen bonds B. Phosphate group C. 5-carbon sugar D. Nitrogenous Base

A. Hydrogen bonds

How many rings do purines have? A. 3 B. 1 C. 4 D. 2

D. 2

How many atoms are in pyrimidines? A. 5 B. 6 C. 3 D. 4

B. 6

How many phosphates are in a nucleotide? A. 2-5 B. 1-3 C. 6-9 D. 3-6

B. 1-3

Which direction is the sugar-phosphate backbone? A. 5’ \to 3’

A. 5’ \to 3’

Which of the following is NOT found in RNA? A. Cytosine B. Guanine C. Thymine D. Uracil

C. Thymine

Which of the following are the base pairs for DNA? A. Adenine (A) + Guanine; Cytosine (C)+ Guanine (G) B. Adenine (A) + Thymine(T); Cytosine (C) + Guanine (G) C. Cytosine (C) + Adenine (A); Thymine (T) + Uracil (U) D. Thymine (T) + Cytosine
; Adenine (A) + Guanine (G)

B. Adenine (A) + Thymine(T); Cytosine (C) + Guanine (G)

Which nucleotide base does Uracil replace in RNA? A. Thymine B. Cytosine C. Guanine D. Adenine

A. Thymine

The sides of a DNA helix are made up of hydrogen bonds. A. True B. False

B. False

What is a nucleoside made up of? A. Base + Sugar B. Base + Sugar + Phosphate group C. Base + Sugar + Hydrogen bonds

A. Base + Sugar

Q1: Which of the following about Hydrocarbons is false? A) Hydrogen is attached to the carbons backbone B) The simplest hydrocarbon is methane C) Triple bonds are not found in hydrocarbons D) Double bonds can be found in ring hydrocarbons

C) Triple bonds are not found in hydrocarbons

Q3: Which of the following statements of the Miller Experiment is false? A) The experiment was designed to simulate the microcosm of early earth B) Miller implemented boiling, electrical discharges, and freezing to place the molecules in a simulated environment where they could react with one another. C) Miller observed large quantities of toxic chemicals when analyzing the samples D) Miller concluded that precursors of proteins could be formed by simple chemical reactions

B) Miller implemented boiling, electrical discharges, and freezing to place the molecules in a simulated environment where they could react with one another.

Q6: There are many monosaccharides present in biological systems. Which of the following statements about theses sugars in false? A) Glyceraldehyde has three carbons, a triose. B) Ribose is a component of RNA and plays roles in carrying energy. C) Mannose has 5 carbons and functions as a fuel substance. D) Mannose makes up components of glycolipids and glycoproteins.

C) Mannose has 5 carbons and functions as a fuel substance.

Q7: Which of the following is false of saccharides? A) Rings are the most stable form of sugars in physiological conditions. B) An example of a disaccharide is sucrose (glucose + fructose) C) Disaccharides are not formed by a glycosidic bond D) Galactose and glucose form a B 1 \to 6 glycosidic linkage

C) Disaccharides are not formed by a glycosidic bond

Q8: Polysaccharides Animals store a polysaccharide called _ a polymer of glucose that is like amylopectin but more extensively branched. Vertebrates store glycogen mainly in _ and _ cells. Breakdown of glycogen in these cells releases glucose when the demand for energy increases.

glycogen, liver, muscle

Q9: Polysacc. Like starch, _ is a polymer of glucose with _ glycosidic linkages, but the linkages in these two polymers differ. The glucose monomers of cellulose are all in the \beta configuration, making every glucose monomer _ with respect to its neighbors.

cellulose, 1\to4,
Upside down

What is the difference between the structures of fats and phospholipids?

Both are made by a dehydration synthesis reaction that joins glycerol and fatty acid, releasing water. However, fats are made up of a single glycerol and 3 fatty acids joined together, while phospholipids are made from a single glycerol and 2 fatty acid molecules. Additionally, Phospholipids have a phosphate and a polar unit attached to the third OH of glycerol making them amphipathic.

What are the 2 types of structures that phospholipids assume when mixed with water? What is the difference between them?

Lipid micelles or lipid bilayers. Micelles are when phospholipids form a sphere and arrange in a single layer, where the hydrophobic tails interact with each other inwards and hydrophilic heads interact with the water outwards Lipid bilayers are when phospholipids form two layers, where hydrophobic tails of both layers interact with each other inwards while hydrophilic heads are on both sides of the lipid bilayer, interacting with water.

Cysteine and methionine formation reaction. The bonds form when sulfhydryl groups: SH of two Cysteine amino acids oxidize joining the two sulfur atoms covalently.

Disulfide linkage formation reaction

Polypeptide chain has two ends N-terminal _ and a C-terminal _

end that has an amine group, end that has a carboxyl

What are the four levels of protein structure and how are they produced?

Primary structure: based on amino acid sequence Secondary structure: based on twisting and turning of amino acid chain Tertiary structure: folding of amino acid chain into a 3D-protein Quaternary structure: More than one polypeptide chain

Describe the sickle cell disease mutation

Sickle cell disease is caused by a single amino acid substitution of valine instead of glutamic acid. Valine is slightly more basic than glutamic acid, causing the hemoglobin molecule to become abnormal and assume a sickle shape.

Q20: 1. What are the two arrangements that can form in a protein’s secondary structure and describe their conformation? 2. What type of bond holds together the structure?

1. Alpha helix (spiral) and beta pleated sheet (zigzag plane) 2. Hydrogen bonds

Q21: 1. In antiparallel beta pleated sheets, hydrogen bonded peptide chains run in [same/ opposite] directions. 2. In parallel beta pleated sheets, hydrogen bonded peptide chains run in [same/ opposite] directions. 3. What is it called when a protein has an irregularly folded arrangement?

1. opposite directions. 2. same directions. 3. Random coil

Q22: 1. What is the significance of the tertiary structure of proteins? 2. The positions of , , and _ play major roles in folding the protein into tertiary structure 3. Are tertiary structures flexible?

1. Gives a protein its overall 3D structure 2. Secondary structures, disulfide linkages, and hydrogen bonds 3. Yes, they are the most flexible which allow them to undergo conformational changes

Q23: 1. Give an example of a globular protein with a quaternary structure. 2. Unfolding a protein from its native conformation, which causes it to lose its structure and function and can be caused by chemical, changes in pH, high temperature, etc. is called? a. Degradation b. Denaturation c. Renaturation d. Deterioration

1. Hemoglobin 2. b. Denaturation

Q24: A _ _ is a protein that lacks fixed 3D structure, typically in the absence of macromolecular interaction partners, such as proteins and RNA

Intrinsically disordered protein

Q25: 1. What is the difference between DNA and RNA? 2. _ are the monomers of DNA 3. _ are the monomers of RNA

1. DNA stores hereditary information in eukaryotes and prokaryotes and in a large group of viruses
   RNA is the hereditary molecule of certain viruses and is involved in protein synthesis 2. Deoxyribonucleotides 3. Ribonucleotides

Q26: What are the components of a nucleotide?

Phosphate group, 5 carbon sugar, Nitrogenous bases

Q27: 1. What are the 2 types of nitrogenous bases? 2. Which nitrogenous bases are purines? 3. Which nitrogenous bases are pyrimidines?

1. Purine and Pyrimidine 2. Adenine and Guanine 3. Cytosine, thymine (DNA), and uracil (RNA)

Q28: 1. What type of bond links nucleotides together? 2. What forms the backbone of the nucleic acid chain? 3. What direction does the backbone go?

1. Phosphodiester bonds 2. Alternating sugar and phosphate bonds 3. 5’ to 3’

Q29: Nucleotides polymerize to form nucleic acids. 1. Nucleic acid polymerization takes place in cells catalyzed by _ 2. The nucleotide triphosphates are also referred to as _

1. enzymes 2. activated nucleotides

Why is carbon the most important element to life?

It forms stable bonds with many elements, including itself, allowing for a huge variety of large and complex molecules.

What are organic molecules?

Complex molecules based on carbon.

What are inorganic molecules?

All substances other than complex carbon-based molecules.

What are the four major types of macromolecules of life?

Carbohydrates, Lipids, Proteins, Nucleic acids.

Hydrocarbons

Organic molecules consisting of only carbon and hydrogen.

What is the simplest hydrocarbon?

Methane (\text{CH}_4).

What is the significance of the \text{CO}_2 concentration in the atmosphere?

Critical to photosynthesis and affects Earth’s temperature/climate (greenhouse gas).

Functional Groups

Small, reactive groups of atoms attached to the carbon skeleton that give molecules specific chemical properties.

What are the six functional groups that frequently enter biological reactions?

Hydroxyl (\text{-OH}), Carbonyl (\text{C=O}), Carboxyl (\text{-COOH}), Amino (\text{-NH}_2), Phosphate (\text{PO}_4), Sulfhydryl (\text{-SH}).

Chiral objects

Objects that are nonsuperimposable mirror images of each other.

Achiral objects

Objects that are mirror images of each other and can be superimposed.

Chiral carbon (Asymmetric carbon)

A carbon atom bonded to four different atoms or groups.

Isomerism

When compounds have the same molecular formula but different structural or spatial arrangement.

Structural isomers

Molecules with the same chemical formula but atoms arranged in different ways (e.g., glucose and fructose).

Stereoisomers (AKA Enantiomers)

Isomers with the same chemical formula but different three-dimensional spatial arrangement (mirror images).

Polymers

Macromolecules consisting of long chains of repeating subunit molecules called monomers.

Monomers

Molecular subunits used to build a macromolecule.

Metabolism

All of the chemical reactions underway in the cells and tissues of the body.

Disaccharide

Two monosaccharides covalently joined by a glycosidic bond.

Polysaccharide

Carbohydrate polymers with more than 10 linked monosaccharide monomers.

Glycosidic linkage/bond

The covalent bond formed between two monosaccharides during dehydration synthesis.

Monosaccharides

Simple sugars containing three to seven carbon atoms (\text{C}_3 to \text{C}_7).

Storage polysaccharides in plants

Starch.

Storage polysaccharides in animals

Glycogen.

Cellulose

A structural polysaccharide with \beta-1–4 glycosidic linkages, a major component of plant cell walls.

Chitin

A structural polysaccharide found in arthropod exoskeletons and fungal cell walls, polymer of N-acetylglucosamine.

Why do glucose molecules often form rings in aqueous solutions?

Ring forms are the most stable form of these sugars in physiological conditions.

Lipids

Water-insoluble (hydrophobic), nonpolar biological molecules composed mostly of hydrocarbons.

Three common types of lipid molecules

Neutral lipids, Phospholipids, Steroids.

Neutral lipids

Energy-storage molecules found in cells with no charged groups (nonpolar).

Waxes

Water insoluble and solid lipids used for protection and lubrication.