Biology Chapter: Chemical Reactions and Compounds

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Questions and Answers

What nitrogenous base pairs with adenine in DNA?

Cytosine

Uracil

Thymine (correct)

Guanine

What is the main function of RNA?

To direct protein synthesis (correct)

To pair with nitrogenous bases in DNA

To store genetic information

To replicate DNA

What distinguishes ribose from deoxyribose in terms of structure?

Ribose has a hydroxyl group at the 2' position (correct)

Ribose is a six-carbon sugar

Ribose has no hydroxyl groups

Ribose contains an oxygen atom at the 1' position

Which of the following statements about the sequences of bases in DNA and RNA is correct?

The sequence of DNA bases determines the sequence of RNA bases Signup and view all the answers

What types of bonds hold the two strands of DNA together?

Hydrogen bonds Signup and view all the answers

What is the maximum number of covalent bonds a carbon atom can form?

Four Signup and view all the answers

Which term describes a bond formed when two atoms share a pair of electrons?

Single bond Signup and view all the answers

What characteristic of water molecules contributes to their ability to dissolve substances?

Polar nature Signup and view all the answers

How are the hydrogen atoms arranged in a water molecule?

At an angle Signup and view all the answers

What allows carbon to form an enormous variety of organic compounds?

Its capacity to bond with other carbon atoms Signup and view all the answers

What happens to water's temperature during energy absorption?

It remains constant Signup and view all the answers

What is formed when two atoms share three pairs of electrons?

Triple bond Signup and view all the answers

Which of the following is a property of water resulting from hydrogen bonding?

High boiling point Signup and view all the answers

Which monosaccharide serves as the main source of energy for cells?

Glucose Signup and view all the answers

Which of the following is true about the structural differences among glucose, fructose, and galactose?

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

What type of reaction combines two monosaccharides to form a disaccharide?

Condensation Signup and view all the answers

What is the primary storage form of glucose in animals?

Glycogen Signup and view all the answers

Which polysaccharide is primarily responsible for providing strength and rigidity in plant cells?

Cellulose Signup and view all the answers

Which of the following accurately describes the structure of starch molecules?

Has both branched and unbranched chains. Signup and view all the answers

What are the building blocks of proteins called?

Amino acids Signup and view all the answers

Which of the following statements about proteins is correct?

They can consist of sulfur and phosphate in their structure. Signup and view all the answers

What is the role of reactants in a chemical reaction?

They are shown on the left side of the equation. Signup and view all the answers

What does a two-direction arrow in a chemical reaction indicate?

The reaction can proceed in both directions. Signup and view all the answers

Which of the following best describes why carbon can form many different compounds?

Carbon can form stable single, double, and triple bonds. Signup and view all the answers

Which of the following is a characteristic of organic compounds?

They often contain carbon, hydrogen, and oxygen. Signup and view all the answers

What is represented by the term 'functional group' in organic chemistry?

A group of atoms that determines the properties of a molecule. Signup and view all the answers

How is a condensation reaction different from hydrolysis?

Condensation forms bonds, while hydrolysis breaks bonds. Signup and view all the answers

In a reversible reaction, what happens to the products?

They can reform into reactants under certain conditions. Signup and view all the answers

What is the pH scale primarily used to measure?

The acidity or basicity of a solution. Signup and view all the answers

What is the primary factor that allows water to dissolve many substances effectively?

Presence of hydrogen bonds Signup and view all the answers

Which of the following correctly describes adhesion in the context of water molecules?

Attraction between water and foreign molecules Signup and view all the answers

Capillarity in water is a result of which two properties?

Cohesion and adhesion Signup and view all the answers

What is the general formula for a monosaccharide?

(CH2O)n Signup and view all the answers

Which of the following statements about carbohydrates is true?

They can exist as monosaccharides, disaccharides, or polysaccharides. Signup and view all the answers

What is a monomer of carbohydrates called?

Monosaccharide Signup and view all the answers

How does the sequence of amino acids influence proteins?

It determines the protein's structure and thus its function. Signup and view all the answers

Which classes of organic compounds are essential for life processes?

Carbohydrates, Lipids, Proteins, Nucleic Acids Signup and view all the answers

What is true about enzymes and their functionality?

Enzymes can be reused after catalyzing a reaction. Signup and view all the answers

What describes the nature of lipids?

Lipids store energy more efficiently than carbohydrates. Signup and view all the answers

What distinguishes the carboxyl end of a fatty acid from its hydrocarbon end?

The carboxyl end is polar and interacts with water. Signup and view all the answers

Which statement about saturated and unsaturated fatty acids is accurate?

Saturated fatty acids have carbon atoms bonded to the maximum number of atoms. Signup and view all the answers

What are the components of a nucleotide?

A five-carbon sugar, a phosphate group, and a nitrogen-containing base. Signup and view all the answers

In terms of structure, how do DNA and RNA differ?

DNA is double-stranded, while RNA is single-stranded. Signup and view all the answers

What is the primary function of nucleic acids?

To store and transmit genetic information. Signup and view all the answers

How do the ratios of carbon and hydrogen atoms compare in lipids and carbohydrates?

Lipids have a higher ratio of carbon and hydrogen to oxygen than carbohydrates. Signup and view all the answers

Study Notes

Chemical Reactions and Energy

Living things undergo thousands of chemical reactions
Reactions are often complex and multi-step
Chemical reactions involve breaking and forming bonds
The number of atoms remains the same on both sides of the equation
Chemical reactions are linked to favorable conditions like temperature and pH
CO₂ + H₂O ⇌ H₂CO₃ (reversible reaction)

Carbon Compounds

All living things have organic and inorganic compounds
Organic compounds contain carbon covalently bonded to other carbons and elements (like hydrogen, oxygen, nitrogen)
Carbon readily forms four covalent bonds
Carbon forms straight, branched, or ring structures
Single bonds share one pair of electrons
Double bonds share two pairs of electrons
Triple bonds share three pairs of electrons

Water

Water is a polar molecule, meaning it has uneven electrical charge distribution
Water is a good solvent (for polar substances and ionic compounds)
Water molecules attract one another through hydrogen bonds
Cohesion is the attraction between water molecules
Adhesion is the attraction between unlike substances
Water has a high specific heat capacity, which helps maintain stable temperatures in organisms

Activation Energy and Catalysts

Chemical reactions require a certain amount of energy to begin (activation energy)
Catalysts (including enzymes) decrease activation energy needed to start a reaction
Enzymes have a specific shape that fits a substrate (the reactant)
The enzyme and substrate fit together like a lock and key
This interaction allows the enzyme to reduce activation energy and speed up the reaction
Enzymes are unchanged after a reaction and can be reused

Redox Reactions

Redox reactions involve electron transfer between atoms
Oxidation is when a reactant loses electrons
Reduction is when a reactant gains electrons
Redox reactions always occur together

pH

The pH scale measures the concentration of hydronium ions in a solution
A pH of 7 is neutral
A pH below 7 is acidic
A pH above 7 is basic
Buffers help regulate pH in living things

Energy Transfer

Exergonic reactions release energy
Endergonic reactions absorb energy
ATP(adenosine triphosphate) is a main energy currency in organisms
Energy is released when the bond between phosphate groups in ATP is broken

Lipids

Lipids are large, non-polar organic molecules.
Lipids are hydrophobic (do not dissolve in water)
Lipids store energy efficiently
Fatty acids form lipids
Fatty acids have a polar carboxyl head and a non-polar hydrocarbon tail
Saturated fatty acids have all single bonds
Unsaturated fatty acids have double bonds

Carbohydrates

Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of about 1:2:1
Monosaccharides are simple sugars (e.g., glucose, fructose, galactose)
Disaccharides are formed by combining two monosaccharides (e.g., sucrose)
Polysaccharides are formed by combining many monosaccharides (e.g., starch, glycogen)
Starch and glycogen are energy storage molecules in plants and animals
Cellulose is a structural component of plant cell walls

Proteins

Proteins are composed of amino acids linked together
Amino acids differ in the R-group
Proteins have diverse functions (e.g., enzymes, structural components, etc.)
Proteins shape influences function

Nucleic Acids

The text does not discuss nucleic acids

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Description

This quiz covers essential concepts of chemical reactions and energy as well as the importance of carbon compounds in living organisms. Test your knowledge on the properties of water and its role as a solvent in biological systems. Understanding these topics is crucial for grasping the basics of biochemistry.