Biology Chapter 2 Quiz

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Questions and Answers

What characteristic of water arises from the unequal distribution of electrons?

Hydrophobicity

Polarity (correct)

Cohesion

Hydrophilicity

Which of the following is NOT a property of water?

Incompressibility (correct)

High specific heat

Solvency

Cohesion

What is the effect of a buffer in biological fluids?

It increases acidity.

It resists changes in pH. (correct)

It enhances osmosis.

It promotes diffusion.

Which statement about osmosis is correct?

It occurs when water moves from high to low concentration. Signup and view all the answers

Which of the following describes the dynamic equilibrium of reversible reactions?

Reactants and products coexist at constant concentrations. Signup and view all the answers

What is the primary element that serves as the backbone of life?

Carbon Signup and view all the answers

Which factor is NOT a contributor to molecular diversity in life forms?

Diverse pH levels Signup and view all the answers

Which is a correct statement regarding the dissociation of water?

It leads to the formation of OH- and H3O+. Signup and view all the answers

What is the primary way carbon enters the biosphere?

Via photosynthesis in plants Signup and view all the answers

How many electrons can carbon share to complete its valence shell?

4 Signup and view all the answers

What structural shape do molecules take when carbon forms four single covalent bonds?

Tetrahedral Signup and view all the answers

What effect does a double bond between two carbon atoms have on their bonding structure?

Forces all atoms to lie in the same plane Signup and view all the answers

What is the term used to describe carbon's ability to form four bonds?

Tetravalence Signup and view all the answers

Which of the following molecules exhibits a flat structure due to double bonds?

Ethene (C2H4) Signup and view all the answers

What distinguishes carbon from many other elements in terms of bonding?

Its ability to form large and complex molecules Signup and view all the answers

Which of these elements is NOT commonly known to form covalent bonds with carbon?

Sodium Signup and view all the answers

What are isomers with the same molecular formula but different structural arrangements called?

Structural isomers Signup and view all the answers

Which type of isomerism is represented by molecules that differ in spatial arrangement around a double bond?

Geometric isomerism Signup and view all the answers

Why can propane not form structural isomers?

It has a symmetrical structure with no double bonds. Signup and view all the answers

What do hydrocarbons primarily consist of?

Carbon and Hydrogen Signup and view all the answers

What is a common characteristic of both gasoline and fats?

Both are primarily composed of hydrocarbon chains. Signup and view all the answers

Which chemical groups can influence the properties of organic molecules?

Functional groups Signup and view all the answers

What differentiates enantiomers from other isomers?

They are mirror images of each other. Signup and view all the answers

How do molecular components attached to a carbon skeleton affect organic molecules?

They alter the molecule’s properties and interactions. Signup and view all the answers

What is the defining characteristic of cis isomers?

The groups are on the same side. Signup and view all the answers

Which of the following statements is true regarding trans-resveratrol?

It undergoes metabolism before absorption. Signup and view all the answers

What is meant by the term 'asymmetric carbon'?

A carbon attached to four different atoms or groups. Signup and view all the answers

Why are enantiomers significant in pharmacology?

One enantiomer can be biologically active while the other is not. Signup and view all the answers

Which configuration of lycopene is found in tissues?

Cis Signup and view all the answers

Which of the following best describes geometric isomers?

They differ in arrangement of atoms in space. Signup and view all the answers

What effect did thalidomide have when both enantiomers were administered?

One reduced morning sickness while the other caused birth defects. Signup and view all the answers

What is the role of the carbon atom's valence in organic molecules?

It permits bonding with up to four other atoms or elements. Signup and view all the answers

What distinguishes saturated hydrocarbons from unsaturated hydrocarbons?

Saturated hydrocarbons contain only single C-C bonds, while unsaturated contain at least one double bond. Signup and view all the answers

Which of the following statements about geometric isomers is correct?

Geometric isomers have the same covalent bonds but differ in spatial arrangement due to double bonds. Signup and view all the answers

What are structural isomers characterized by?

They differ in the covalent arrangements of their atoms. Signup and view all the answers

Which type of isomer can arise due to the inflexibility of double bonds?

Cis/trans isomers. Signup and view all the answers

What is true about aromatic compounds?

They have a coplanar structure with alternating single and double bonds. Signup and view all the answers

Why do structural isomers increase in variety with larger carbon skeletons?

They provide more space for branching and arrangement variations. Signup and view all the answers

Which characteristic is common to both glucose and fructose?

They have the same molecular weight. Signup and view all the answers

What role does the rigidity of double bonds play in the formation of isomers?

It results in the possibility of geometric isomers. Signup and view all the answers

What affects the shape and function of hormones in the body?

The chemical groups attached to the rings Signup and view all the answers

Which of the following functional groups is not reactive?

Methyl group Signup and view all the answers

Which functional groups are hydrophilic and increase solubility in water?

Hydroxyl, Carbonyl, Carboxyl, Amino, Sulfhydryl, and Phosphate groups Signup and view all the answers

What role does ATP play in cellular functions?

It stores potential energy to react with water Signup and view all the answers

Which of the following best describes how functional groups contribute to organic molecules?

They influence the chemical reactivity and properties Signup and view all the answers

What happens to ATP when it reacts with water?

It turns into a diphosphate molecule Signup and view all the answers

Which of the following functional groups is incorrectly paired with its characteristic?

Phosphate group – hydrophobic Signup and view all the answers

Which chemical group helps distinguish between male and female characteristics?

Functional groups of sex hormones Signup and view all the answers

Study Notes

Nutritional Biochemistry

This subject covers the principles of chemistry, specifically focusing on carbon as the foundation of life.
The course is titled DIET413/BHCS1019
The lecturer is Dr Nathaniel Clark, who holds qualifications including FHEA, RNutr, and MRSB.
Contact details for the lecturer are provided.

Water Properties

Water's uneven electron distribution creates a polar molecule.
Water's properties stem from attractions between its polar molecules.
The positive hydrogen (H) of one water molecule is drawn to the negative oxygen (O) of a neighboring water molecule.
Important water properties include cohesion, temperature moderation, and solvency.
Hydrophilic substances interact with water, while hydrophobic substances do not.
Moles are a useful unit for measuring solute concentrations in solutions.

Water in Biological Fluids

Water molecules can transfer H+ to form H₃O+ and OH-.
The concentration of H+ is measured as pH.
Buffers in biological fluids, like blood, resist pH changes.
A buffer consists of an acid-base pair that reacts reversibly with hydrogen ions.
Diffusion, moving from high to low concentration, is a crucial process.
Osmosis, a specific type of diffusion, plays a critical role in maintaining water balance within the body.
The presentation includes a pH scale with example solutions.

Last Time - Quiz

The quiz covers key concepts, including water's polarity and properties.
Sucrose's formula is C₁₂H₂₂O₁₁ and its weight for a 0.5L, 1M solution is provided..
Water dissociation creates H₃O+ and OH⁻ ions.
Some chemical reactions are reversible and form a dynamic equilibrium.
Water molecules not able to move play a role in osmosis.

Learning Outcomes

Understanding the formation of bonds involving carbon is essential.
Understanding the diversity of molecules arising from carbon's variations (hydrocarbons, isomers) is key.
Recognizing the critical chemical groups essential for biological molecule function is a central theme.

Carbon: The Backbone of Life

Water is the universal medium for life on Earth, though life's chemicals primarily utilize carbon.
Carbon enters the biosphere through plants utilizing solar energy to convert CO₂ into other molecules.
Carbon's unique ability to form large, complex, and diverse molecules makes it the foundation of all biological matter.
The examples of proteins, DNA, carbohydrates, and lipids exemplify carbon's role in distinguishing life from non-living matter.

Carbon Bonding

Carbon atoms have six electrons, with four in their outer shell.
Carbon's tendency is to share its four electrons to complete its outer shell with eight.
These shared electrons create covalent bonds.
The configuration of carbon's bonds forms a tetrahedral shape.
Carbon atoms can form single, double, or triple bonds.
Carbon's versatility in bonding is key to the complexity of molecules.

Single Carbon Bonds

When forming four single covalent bonds, carbon's electrons create bonds angled at the corners of a tetrahedron.
This forms the basis for 3D models, including ball-and-stick models.
Bond angles in methane are approximately 109.5 degrees.
Examples like ethane (C₂H₆) can be displayed as multiple overlapping tetrahedral shapes.

Double Carbon Bonds

In molecules with more carbon atoms, every grouping of carbon bonded to four others forms a tetrahedral shape.
Double bonds cause carbon atoms and their surrounding atoms to be located in a single plane.
Ethene (C₂H₄) is an example of a flat molecule where all atoms are co-planar.
Double bonds are vital in fatty acids.

Valency of Carbon

Carbon's electron configuration allows it to form covalent bonds with various elements.
Common partners include hydrogen, oxygen, and nitrogen.
These elements' valences are crucial in forming covalent bonds in organic chemistry.

Covalent Bonds Other Than H

Covalent bonds involving carbon atoms with partners like carbon dioxide (CO₂) and urea differ from hydrogen bonding.
CO₂ features a single carbon atom double bonded to two oxygen atoms. The structural formula illustrates this.

Covalent Bonds Other Than H (2)

The lines in molecular formulas represent shared electron pairs.
Double bonds are equivalent to four single covalent bonds in terms of their impact.
This bonding arrangement fills the outer electron shells of all atoms in the molecules involved.
Urea is an organic compound found in urine and includes a carbon atom involved in both single and double bonds.

Molecular Diversity Arising from C Skeleton

Carbon chains, the backbone of organic molecules, showcase different lengths, branching patterns, and ring structures.
Variation in carbon skeletons helps determine molecule complexity and diversity.
Variations in double bonds and ring structures are important characteristics to consider.

Hydrocarbons

Hydrocarbons are molecules made entirely of carbon and hydrogen atoms.
Hydrocarbons form an important component of fuels (e.g., petroleum).
Many biological molecules have regions composed only of carbon and hydrogen.
Fats feature hydrocarbon tails that are significant energy storage molecules.
Hydrocarbons are hydrophobic, meaning they do not dissolve in water.

Hydrocarbons (2)

Neither petroleum nor fats dissolve in water; both are hydrophobic compounds due to largely nonpolar carbon-to-hydrogen bonds.
The lack of polarity in these compounds has implications for their properties (e.g., electronegativity).
Hydrocarbons, like fats and gasoline, release relatively large amounts of energy during reactions when breaking down.
Hydrocarbons serve as a critical fuel source in cells.

Hydrocarbons: Aliphatic Compounds

Hydrocarbons are classified into two categories: aliphatic and aromatic.
Aliphatic compounds include saturated hydrocarbons (single bonds) and unsaturated hydrocarbons (double or triple bonds).
They can have open chains or be branched and are crucial in fragrances and foods, where examples include aldehydes.

Hydrocarbons: Aromatic Compounds

Aromatic compounds feature a specific ring structure with alternating double bonds, for example, benzene rings.
Aromatic rings exhibit unique bonding and structural characteristics.
They are critical components of amino acids.

Isomers

Isomers share the same molecular formula while having different structures and properties.
Three main isomer types—structural, geometric, and enantiomers are presented to describe these variations.
Glucose and fructose are examples of isomers as monosaccharides.

Structural isomers

Structural isomers differ in how their atoms connect to each other.
The number of possible structural isomers increases with the size of the carbon skeleton.

Geometric Isomers

Geometric isomers hold the same covalent bonds but have different spatial arrangements (e.g., cis and trans isomers).
Double bonds prevent rotation, leading to distinct geometric arrangements.
Geometric isomers can have profound effects on the reactions and function of molecules in the body. Specific examples using butene and lycopene are provided.

Geometric isomers (2)

Geometric isomers of trans-resveratrol are also reviewed.
This compound is a notable plant phenolic with low bioavailability.
This variation in isomeric configuration has a major impact on absorption rate and use in the body.
The different forms of resveratrol are discussed with a consideration of the impact of the molecules on various bodily mechanisms.

Enantiomers

Enantiomers are mirror images of each other, like left and right hands.
A chiral carbon atom helps form enantiomers by attaching four different atoms/groups.
Only one enantiomer form is commonly active in biological systems.
Differences in enantiomers are important in pharmaceuticals due to potential effects.

Enantiomers - Pharmacology

Enantiomers of drugs may behave differently in the body, impacting their effectiveness and even causing harm in certain cases.
Examples of this type of enantiomer effect are provided using thalidomide.
The presentation uses examples such as ibuprofen and ketamine to illustrate the importance of understanding the effects of differing enantiomer forms of chemical molecules on the body.

Summary 1

Carbon's valence allows for bonding with up to four other elements.
The variation in carbon skeletons leads to a rich diversity of organic molecules, which can exhibit numerous chemical properties.
Isomers can display the same molecular formula but differ in spatial arrangement and shape.
Examples of isomers are given with respect to carbohydrates.
Specific considerations regard molecules containing only carbon and hydrogen.
The different forms of molecules and their properties are important to remember.

Summary 2

Functional groups attached to carbon skeletons impact molecular properties, including chemical reactivity and solubility in water.
Key functional groups, such as the hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl groups, are discussed.
Examples of the influence of the chemical structure of molecules on their function are presented including those in the example of sex hormones (testosterone/estradiol).
Details regarding chemical features and function of the molecules are included.

Questions

The presentation lists questions about the nature of carbon bonding, isomers, different types of sugars, and functional groups.

Before Next Time

The lecturer urges further study using textbooks mentioned and a review of today's lecture materials.
Key terms (e.g., ionization, hydrophilic, hydrophobic, polar, charge, amine/carboxylic groups) are highlighted for future study.

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Description

Test your knowledge on the characteristics of water, molecular diversity, and the properties of carbon. This quiz covers key concepts in biology, including osmosis, buffers, and the unique qualities that make carbon essential for life. Dive in to see how well you understand these foundational principles!