SBI4U - Unit One - Biochemistry: Bonding

Questions and Answers

What type of reaction occurs when two monosaccharides combine to form a disaccharide?

Dehydration reaction (correct)

Neutralization reaction

Condensation reaction (correct)

Hydrolysis reaction

What is the primary function of polysaccharides in biological systems?

Transport of oxygen

Energy regulation

Energy storage and structural support (correct)

Hormone production

Which statement correctly describes β linkages in polysaccharides?

They are characteristic of cellulose, providing structural support. (correct)

They form glycosidic bonds with α linkages.

They can be easily digested by human enzymes.

They have a uniform orientation of monosaccharides.

What do essential unsaturated fatty acids require from the diet?

They must be obtained from dietary sources. Signup and view all the answers

Which of the following is a characteristic of lipids?

They do not polymerize into larger structures. Signup and view all the answers

What is a primary function of phospholipids in biological systems?

To form cell membranes Signup and view all the answers

Which of the following is a function of fats other than energy storage?

Insulate and cushion organs Signup and view all the answers

What type of bonds are primarily involved in linking nucleotides together in nucleic acids?

Phosphodiester bonds Signup and view all the answers

Which class of biomolecules is primarily responsible for catalyzing chemical reactions?

Proteins Signup and view all the answers

Which of the following best describes the structure of omega-3 fatty acids?

One double bond at the 3rd carbon atom from the end Signup and view all the answers

What characterizes ionic bonds in water?

They result in the formation of cations and anions. Signup and view all the answers

Which of the following statements is true about covalent bonds?

They can be polar, nonpolar, or amphiphilic. Signup and view all the answers

What is the primary factor that determines the strength of a bond?

The electronegativity of the elements involved. Signup and view all the answers

Which type of intermolecular force is primarily responsible for the attraction between water molecules?

Hydrogen bonds. Signup and view all the answers

What occurs during a dehydration reaction?

Two smaller molecules bond to form water. Signup and view all the answers

Which of the following best describes a hydrolysis reaction?

It occurs when water is added to break down larger molecules. Signup and view all the answers

In a redox reaction, what happens to the electrons?

Electrons are lost from one atom and gained by another. Signup and view all the answers

Which statement is true regarding polarity in molecules?

Polar molecules have an unequal sharing of electrons. Signup and view all the answers

What role do fibrous proteins play in a cell?

They form a cytoskeleton to maintain cell shape. Signup and view all the answers

What happens to a plant cell when placed in a hypotonic solution?

The cell becomes turgid as turgor pressure increases. Signup and view all the answers

What is the primary characteristic of facilitated diffusion?

It occurs through specific protein channels. Signup and view all the answers

Which type of transport moves substances from low concentration to high concentration?

Active transport Signup and view all the answers

How do cholesterol molecules affect membrane fluidity at low temperatures?

They increase membrane fluidity and prevent it from solidifying. Signup and view all the answers

What defines a hypertonic solution in relation to a cell?

It has a higher concentration of solute than inside the cell. Signup and view all the answers

What type of molecules can move through simple diffusion?

Small nonpolar molecules like O2 and CO2. Signup and view all the answers

Which of the following statements about osmosis is correct?

Osmosis involves the diffusion of water across a membrane. Signup and view all the answers

What is the significance of water’s high heat of vaporization in the context of human physiology?

It allows sweat to cool the body by absorbing heat. Signup and view all the answers

Which characteristic of water allows it to have a lower density in its solid state, causing ice to float?

Hydrogen bonding causing expansion upon freezing. Signup and view all the answers

How do adhesion and cohesion contribute to capillary action in plants?

They facilitate water movement against gravity. Signup and view all the answers

Which of the following best explains the term 'functional groups' in organic chemistry?

They dictate the reactivity and properties of molecules. Signup and view all the answers

What fundamental property of carbon allows it to form complex molecules such as lipids and proteins?

Ability to form four bonds and exhibit various bonding patterns. Signup and view all the answers

Which of the following statements about the properties of water is false?

Water's surface tension is lower than most liquids. Signup and view all the answers

What is a characteristic feature of polysaccharides as compared to monosaccharides?

Polysaccharides consist of more than two sugar units. Signup and view all the answers

Which of the following best describes the process of spring/autumn turnover in aquatic systems?

It involves the mixing of different temperature layers of water. Signup and view all the answers

Study Notes

Bonding

Ionic Bonds

Formed by the transfer of one or more electrons between atoms with electronegativity greater than 1.7.
Results in oppositely charged ions: cations (positive) and anions (negative).
Easily dissociate in water, making them soluble.

Covalent Bonds

Involve the sharing of electrons between atoms.
Types include:
- Polar Covalent Bonds: Unequal sharing of electron pairs (EN 0.41 - 1.7), e.g., water (H₂O).
- Nonpolar Covalent Bonds: Equal sharing of electrons (EN < 0.4), e.g., diatomic molecules like H₂, O₂, and hydrocarbons.
- Amphiphilic Molecules: Contain both polar and nonpolar regions, e.g., fatty acids.
Polar substances dissolve in polar solvents, while nonpolar substances dissolve in nonpolar solvents.

Electronegativity

Measures the ability of an atom to attract electrons; fluorine is the most electronegative element.
Affects bond strength and molecule polarity.
Determines molecular shape, influencing properties and behavior.

Intermolecular Forces

Hydrogen Bonds: Attraction between partially positively charged hydrogen and partially negative atoms in other molecules, crucial in water.
Van der Waals Forces: Weak, transient attractions between molecules, including London dispersion and dipole-dipole forces.

Chemical Reactions

Dehydration Reaction

Combines smaller molecules by removing OH and H forming water (e.g., sugar refining).

Hydrolysis Reaction

Splits larger molecules by adding water, common in digestion (e.g., lactase activity).

Neutralization Reaction

Reaction between acids and bases yielding water and salt, such as enzymatic processes in digestion.

Redox Reaction

Involves electron transfer between atoms (e.g., cellular respiration). Remember LEO (Lose Electrons Oxidation) and GER (Gains Electrons Reduction).

Properties of Water

Polarity: Oxygen's higher electronegativity causes unequal electron distribution, leading to hydrogen bonding.
Cohesion and Adhesion: Water molecules attract each other and other polar molecules, essential for capillary action.
Surface Tension: Increased hydrogen bonding at the surface leads to unique properties in water.
Lower Density: Ice is less dense than liquid water, allowing it to float, which insulates aquatic life during winter.
Turnover: Natural mixing in lakes enhances oxygen distribution and gas release.
High Heat of Vaporization: Evaporation of sweat cools the body by pulling heat away.
High Heat Capacity: Large heat input required for temperature change, highlighting ocean temperature concerns.
Universal Solvent: Water dissolves ionic and polar substances efficiently.

Carbon Chemistry of Life

Carbon Chains

Backbone for complex molecules; capable of forming single, double, and triple bonds.

Functional Groups

Include amino (NH₂), carboxyl (COOH), carbonyl (CO), hydroxyl (OH), peptide (CHON), and phosphate (PO₄).

Macromolecules

Types: Carbohydrates, Lipids, Nucleic Acids, Proteins.

Carbohydrates

Composed of carbon, hydrogen, and oxygen (CHO).
Types include monosaccharides, disaccharides, and polysaccharides.

Monosaccharides

Basic unit, represented as CHO 1:2:1; soluble and vital for energy transport, e.g., glucose.

Disaccharides

Formed by the condensation of two monosaccharides; can be hydrolyzed back to monosaccharides. Example: sucrose.

Polysaccharides

Include structural forms like cellulose (fiber) and storage forms like glycogen and starch.
Digestive enzymes differentiate between α and β linkages.

Lipids

Comprised of carbon, hydrogen, and sometimes phosphorus (CHO(P)).
Nonpolar and hydrophobic, lacking true monomers.

Types of Lipids

Triglycerides: Consist of glycerol and fatty acids, serve energy storage and insulation.
Phospholipids: Form cell membranes, displaying amphiphilic properties with hydrophilic heads and hydrophobic tails.
Other Fats: Serve as hormones and protect biological tissues.

Nucleic Acids

Composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHONP).
Include DNA and RNA, built from nucleotides with covalent and phosphodiester bonds.

Proteins

Composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur (CHON(S)).
Built from amino acids (monomers), forming dipeptides and polypeptides.

Protein Functions

Enzymatic catalysts, antibodies, hormones, oxygen transport (hemoglobin), and structural roles (actin, myosin).

Passive Transport

Molecules diffuse from high to low concentration across membranes without energy.
Osmosis: Diffusion of water across membranes.
Facilitated Diffusion: Involves specific protein channels for large or polar molecules.

Solutions and Tonicity

Hypotonic: Lower solute concentration than inside cell; can cause bursting in animal cells.
Hypertonic: Higher solute concentration outside; can cause cell shrinkage.
Isotonic: Equal solute concentration; maintains cell equilibrium.

Active Transport

Moves substances against the concentration gradient using ATP, essential for removing toxins or nutrients.

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Description

Explore the fundamentals of bonding in biochemistry with this quiz focused on ionic and covalent bonds. Learn about the characteristics of each bond type, including electron transfer and sharing properties. Test your understanding of how these bonds contribute to molecular interactions in biological systems.