114 Questions
What are waxes formed from?
Fatty acids combining with long-chain alcohols or hydrocarbon structures
What is the primary lipid of cell membranes?
Phospholipids
Phospholipids have a polar and a nonpolar end.
True
______ is an important component of animal cell membranes.
Cholesterol
Match the following lipid types with their functions:
Chlorophylls and carotenoids = Absorb light and help convert it to chemical energy in plants Glycolipids = Formed by combining lipids with carbohydrates in cell membranes Lipoproteins = Formed by combining lipids with proteins in cell membranes
What are the four major classes of organic molecules found in living organisms?
Carbohydrates, lipids, proteins, nucleic acids
Hydrocarbons are molecules consisting of carbon linked only to oxygen atoms.
False
What is the function of a chaperonin?
Chaperonins promote correct association of individual amino acid chains and inhibit incorrect formations.
Which types of R-group interactions are involved in determining the tertiary structure of proteins?
Hydrogen bonding
What is the process by which trees and plants convert water and carbon dioxide into sugars using sunlight?
Photosynthesis
Nucleotides, the monomers of nucleic acids, consist of a nitrogenous base, a five-carbon sugar, and __________ linked together by covalent bonds.
one to three phosphate groups
Carbohydrates contain carbon, hydrogen, and oxygen atoms in a ratio of about 1C:2H:1O, with the formula CH2O. Monosaccharides contain three to seven 1.
carbon atoms
Proteins with multiple functions often have individual functions located in the same domain.
False
What is the key difference between deoxyribose and ribose?
The chemical group bound to the 2' carbon (—H in deoxyribose, —OH in ribose)
Which structure contains only a nitrogenous base and a five-carbon sugar?
Nucleoside
In DNA, adenine pairs only with cytosine.
False
Complementary base pairing in DNA allows the sequence of one polynucleotide chain to determine the sequence of its __________ in the double helix.
partner
Match the following bases with their complementary partners:
Adenine = Thymine Guanine = Cytosine Uracil = Adenine
What type of lipids combine with long-chain alcohols or hydrocarbon structures to form waxes?
fatty acids
What is the primary lipid found in cell membranes?
Phospholipids
Steroids are lipids with structures based on a framework of five carbon rings.
False
Phospholipids form a ____________ in cell membranes, which is the structural basis of membranes.
bilayer
Match the lipid types with their functions:
Chlorophylls and carotenoids = Absorb light and help convert it to chemical energy in plants Glycolipids = Combine with carbohydrates Lipoproteins = Combine with proteins
What are the polymers of amino acid monomers called?
proteins
What are the four major classes of organic molecules found in living organisms?
carbohydrates, lipids, proteins, nucleic acids
Which functional groups frequently enter into biological reactions?
Hydroxyl
Polysaccharides are polymers of hundreds or thousands of glucose units.
True
Carbohydrates contain carbon, hydrogen, and oxygen atoms in a ratio of about 1C:2H:1O, often represented as ___.
CH2O
What are the two common types of neutral lipids?
Oils
What is the role of random coil in proteins?
Provide flexible sites for folding
What are the five important types of R-group interactions in proteins?
Hydrogen bonding
What is the key difference between deoxyribose and ribose sugars?
The chemical group bound to the 2′ carbon
What is a nucleotide?
A structure containing a nitrogenous base and a five-carbon sugar
What is denaturation of a protein?
Unfolding of a protein
Denaturation of proteins can sometimes be reversible.
True
Adenine only pairs with thymine in DNA base pairing.
True
What is the main function of chaperonin proteins in protein folding?
Guide protein folding towards correct tertiary structure
In RNA, __________ takes the place of thymine in DNA.
uracil
Match the following DNA and RNA components:
Deoxyribose = Found in DNA Uracil = Found in RNA Phosphodiester bonds = DNA and RNA backbone bonds Ribose = Found in RNA
Which types of interactions contribute to quaternary structure in proteins?
Nonpolar attractions
What are waxes primarily composed of?
Fatty acids combine with long-chain alcohols or hydrocarbon structures.
What is the primary function of waxy coatings in animals?
Protect skin, hair, or feathers
Phospholipids are the primary lipids of cell membranes.
True
In a phospholipid bilayer, the ________ groups face the surrounding water molecules.
polar
Match the following lipid types with their functions:
Chlorophylls and carotenoids = Absorb light and help convert it to chemical energy in plants Glycolipids = Combine with carbohydrates to form Lipoproteins = Combine with proteins to form, important roles in cell membranes
What is the difference between Deoxyribose in DNA deoxyribonucleotides and Ribose in RNA ribonucleotides?
Presence of a different chemical group attached to the 2' carbon
What is the term for an irregularly folded arrangement of a protein?
Random coil
DNA and RNA consist of single polynucleotide chains.
False
What is the primary difference in structure between DNA and RNA?
RNA contains uracil instead of thymine
Which of the following is NOT an important type of R-group interaction for tertiary structure?
Hydrogen bonding
The sides of the DNA ladder are composed of sugar-phosphate backbones, while the rungs are made up of ____________.
nitrogenous bases
Denaturation of a protein involves maintaining its structure and function.
False
The tertiary structure of most proteins is ________, allowing them to undergo limited conformational changes.
flexible
Match the following base pairs with the correct number of hydrogen bonds they form:
Adenine-Thymine (A-T) = Two hydrogen bonds Guanine-Cytosine (G-C) = Three hydrogen bonds
Match the following nitrogenous bases with their respective types:
Uracil, Thymine, Cytosine = Pyrimidines Adenine, Guanine = Purines
What process do trees and plants use to combine water and carbon dioxide into sugars and other carbon-based compounds?
photosynthesis
Which four major classes of organic molecules are found in living organisms?
Proteins
Hydrocarbons involve carbon atoms bonding covalently to each other and to other atoms in molecules.
True
Molecules consisting of carbon linked only to hydrogen atoms are called ________.
hydrocarbons
Match the following functional groups with their properties:
Hydroxyl group = Can donate a 'Hydrogen' ion in water, acts as an Acid. Carbonyl group = Can accept a 'Hydrogen' ion in water, acts as a Base. Phosphate group = Example of a group which can donate a 'Hydrogen' ion in water. Sulfhydryl group = Example of a group which can accept a 'Hydrogen' ion in water. Amino group = Functional group that frequently enters biological reactions.
What process allows trees and plants to convert water and carbon dioxide into sugars and other carbon-based compounds?
Photosynthesis
Which are the four major classes of organic molecules found in living organisms?
Carbohydrates
What is the function of tertiary structure in proteins?
Tertiary structure gives a protein its overall three-dimensional shape.
Enzymes that catalyze biochemical reactions involving amino acids recognize the L-stereoisomer.
True
Which type of interaction between R-groups involves weak electrical interactions?
van der Waals interactions
Monosaccharides contain _____ to _____ carbon atoms.
three
Denaturation of proteins can be caused by changes in pH.
True
Match the following types of proteins with their examples:
Enzyme = Lysozyme Complex protein = Hemoglobin Guide protein = Chaperonin
A nucleotide consists of a nitrogenous base, a sugar, and ___ phosphate group(s).
one
What are waxes primarily composed of?
Fatty acids combine with long-chain alcohols or hydrocarbon structures
Which group of lipids are the primary lipids of cell membranes?
Phospholipids
The nonpolar ends of phospholipid molecules in the bilayer face the surrounding water molecules.
False
Phospholipids have a glycerol backbone linked to two ________ groups and a polar phosphate group.
fatty acid chains
Match the following lipid types with their respective functions:
Chlorophylls and carotenoids = Absorb light and help convert it to chemical energy in plants Glycolipids = Combine with carbohydrates Lipoproteins = Combine with proteins to form structures in cell membranes
What are the two sugars that differ in DNA and RNA nucleotides?
Deoxyribose and Ribose
What is a nucleoside?
A structure containing only a nitrogenous base and a five-carbon sugar
DNA molecules are double-stranded and consist of two polynucleotide chains.
True
DNA is put together like a ladder, with antiparallel sugar–phosphate backbones forming ladder side rails and bases attached to sugars forming ladder ____.
rungs
Match the following base pairs:
Adenine = Thymine Guanine = Cytosine
What are the four major classes of organic molecules found in living organisms?
carbohydrates, lipids, proteins, and nucleic acids
What are the common types of lipid molecules?
All of the above
Saturated fatty acids contain only single bonds between carbon atoms.
True
Carbohydrates contain carbon, hydrogen, and oxygen atoms in a ratio of about ______C:2H:_O (CH2O).
1
What type of lipid combines fatty acids with long-chain alcohols to form harder and less greasy substances?
Waxes
What is the primary lipid of cell membranes containing a glycerol backbone linked to two fatty acid chains and a polar phosphate group?
Phospholipids
Steroids are lipids based on a framework of four carbon rings.
True
A ______ bond is formed by a dehydration synthesis reaction between the —NH2 group of one amino acid and the —COOH group of another amino acid.
peptide
What is the function of a chaperonin?
Chaperonins promote correct association of amino acid chains and inhibit incorrect formations.
What are the five important types of R-group interactions for proteins?
Ionic bonding
Denaturation is a process that permanently alters the structure and function of a protein.
False
A nucleotide consists of a nitrogenous base, a five-carbon, ring-shaped sugar, and one to three __________ groups.
phosphate
What is the difference between deoxyribose and ribose in terms of the chemical group bound to the 2' carbon?
Deoxyribose has -H bound to the 2' carbon, while ribose has -OH bound to the 2' carbon.
Which of the following examples are nucleotides? (Select all that apply)
Adenosine monophosphate (AMP)
RNA molecules exist mainly as double polynucleotide chains (double-stranded).
False
In RNA, the base ____ takes the place of thymine in DNA, forming A-U base pairs.
uracil
Match the following base pairings:
Adenine pairs with = Thymine in DNA Guanine pairs with = Cytosine
What is the primary structural difference between RNA and DNA?
RNA contains ribose sugar instead of deoxyribose and uracil instead of thymine.
Which process uses energy from sunlight to combine water and carbon dioxide into sugars and other carbon-based compounds?
photosynthesis
Which are the four major classes of organic molecules found in living organisms?
Nucleic Acids
Stereoisomers have different molecular structures but the same chemical formula.
True
What are the three common types of lipid molecules?
Neutral lipids, Phospholipids, Steroids
What are waxes primarily composed of?
Fatty acids combined with long-chain alcohols or hydrocarbon structures
Which lipid is the primary lipid of cell membranes?
Phospholipids
The nonpolar ends of phospholipid molecules collect together in a region that includes water.
False
Phosphate-containing phospholipids are the primary lipids of __________ membranes.
cell
What is the function of a tertiary structure in proteins?
It gives a protein its overall three-dimensional shape.
Which types of R-group interactions are important for tertiary structure?
Hydrogen bonding
Denaturation of a protein can be caused by changes in pH.
True
Nucleotides, the monomers of nucleic acids, consist of a nitrogenous base, a five-carbon, ring-shaped sugar, and one to three ________ groups.
phosphate
What is the primary difference between deoxyribose and ribose?
Chemical group bound to the 2′ carbon
What is the structure of a nucleoside?
Nitrogenous base and a five-carbon sugar
DNA and RNA consist of single polynucleotide chains.
False
Complementary base pairing in DNA allows the sequence of one polynucleotide chain to determine the sequence of its partner in the double helix through ___ and ___ base pairs.
A–T, G–C
Match the following terms with the correct description:
Ribozymes = RNAs that catalyze reactions and have three-dimensional structures Tertiary Structure in RNA = Directed by complementary base pairing Complementary Base Pairing in DNA = Determines partner sequence in the double helix
Study Notes
Organic Molecules
- Four major classes of organic molecules found in living organisms: carbohydrates, lipids, proteins, and nucleic acids
- Organic molecules consist of carbon atoms bonded covalently to each other and other atoms, forming molecules of varying sizes
Hydrocarbons
- Simplest hydrocarbon is CH4 (methane), consisting of a single carbon atom bonded to four hydrogen atoms
- More complex hydrocarbons involve two or more carbon atoms arranged in linear unbranched chains, linear branched chains, or ring structures
- Single and double bonds are found in linear and ring hydrocarbons, while triple bonds are only found in two-carbon hydrocarbons
Chemical Evolution
- Resulted in the first forms of life on Earth after the formation of organic molecules
- Involved reactions between inorganic molecules on primordial Earth and the conditions present at that time
- Stanley Miller and Harold Urey performed a classic set of experiments in 1953 to simulate chemical evolution and formed several complex organic molecules
Functional Groups
- Small, reactive groups of atoms that give larger molecules specific chemical properties
- Functional groups that frequently enter into biological reactions include the hydroxyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups
- Functional groups are linked by covalent bonds to other atoms in biological molecules, usually carbon atoms
Isomers
- Carbons linked to four different atoms or functional groups can take either of two fixed positions with respect to other carbons in a chain, resulting in isomers
- Isomers that are mirror images of each other are called stereoisomers
- Structural isomers are two molecules with the same chemical formula but with atoms arranged in different ways
Macromolecules
- Carbohydrates, lipids, proteins, and nucleic acids are large polymers assembled from subunit molecules (monomers) into a chain by covalent bonds
- Polymers are assembled from monomers by dehydration synthesis reactions
- Breakdown of polymers into monomers occurs by hydrolysis
- Each type of polymeric biological molecule contains one type of monomer
Carbohydrates
- Serve many functions, including energy storage and structural roles
- Contain only carbon, hydrogen, and oxygen atoms in a ratio of about 1C:2H:1O (CH2O)
- Monosaccharides contain three to seven carbon atoms
- Two monosaccharides polymerize to form a disaccharide
- Carbohydrate polymers with more than 10 linked monosaccharide monomers are called polysaccharides
Lipids
- Water-insoluble, primarily nonpolar biological molecules composed mostly of hydrocarbons
- Three common types of lipid molecules:
- Neutral lipids are stored and used as an energy source
- Phospholipids form cell membranes
- Steroids serve as hormones that regulate cellular activities
Proteins
- Perform many vital functions in living organisms, including structural support, enzymatic activity, movement, transport, recognition, and receptor functions
- Macromolecules composed of amino acid monomers, which contain both an amino and a carboxyl group
- 20 different amino acids are used to build proteins in all organisms### Peptide Bonds
- Peptide bonds are covalent bonds that link amino acids into polypeptide chains, which are the subunits of proteins.
- Peptide bonds are formed through a dehydration synthesis reaction between the -NH2 group of one amino acid and the -COOH group of another amino acid.
- The growing polypeptide chain has an N-terminal end and a C-terminal end, with new amino acids being linked only to the C-terminal end.
Protein Structure
- Primary structure of a protein refers to the precise sequence of amino acids linked together.
- Changing even a single amino acid can alter the secondary, tertiary, and quaternary structures of a protein, which can affect its biological function.
- Example: Substitution of a single amino acid in hemoglobin produces an altered form responsible for sickle-cell disease.
Secondary Structure
- The amino acid chain is folded into arrangements that form the protein's secondary structure.
- Two common types of secondary structure are:
- Alpha (α) helix: a twisted, regular right-hand spiral structure stabilized by regularly spaced hydrogen bonds.
- Beta (β) sheet: a flat, zigzagging structure formed by side-by-side alignment of β strands, stabilized by hydrogen bonds.
Tertiary Structure
- Tertiary structure refers to the overall three-dimensional shape of a protein, which is determined by the positions of secondary structures, disulfide linkages, and hydrogen bonds.
- Attractions between positively and negatively charged chemical groups, as well as polar and nonpolar associations, also contribute to tertiary structure.
- Tertiary structure determines a protein's function, including its chemical activity, solubility, and ability to undergo conformational changes.
Quaternary Structure
- Quaternary structure refers to the presence and arrangement of two or more polypeptide chains in a protein.
- Hydrogen bonds, polar and nonpolar attractions, and disulfide linkages hold the multiple polypeptide chains together.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Denaturation
- Denaturation is the process of unfolding a protein from its active conformation, causing it to lose its structure and function.
- Denaturation can be caused by chemicals, changes in pH, or high temperatures.
- Experiments by Christian Anfinsen showed that breaking the disulfide linkages holding a protein in its functional state caused it to unfold and lose enzyme activity.
Chaperonins
- Chaperonins are "guide" proteins that bind temporarily with newly synthesized proteins, directing their conformation towards the correct tertiary structure and inhibiting incorrect arrangements.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Nucleotides and Nucleic Acids
- Nucleic acids are macromolecules assembled from repeating monomers called nucleotides.
- DNA (deoxyribonucleic acid) stores hereditary information responsible for inherited traits in all eukaryotes and prokaryotes.
- RNA (ribonucleic acid) is the hereditary molecule of another large group of viruses and is involved in protein synthesis.
Nucleotides
- A nucleotide consists of three parts linked together by covalent bonds:
- A nitrogenous base (formed from rings of carbon and nitrogen atoms)
- A five-carbon, ring-shaped sugar (deoxyribose in DNA or ribose in RNA)
- One to three phosphate groups
Nitrogenous Bases
- Pyrimidines are nitrogenous bases with one carbon-nitrogen ring, including uracil (U), thymine (T), and cytosine (C).
- Purines are nitrogenous bases with two carbon-nitrogen rings, including adenine (A) and guanine (G).
DNA and RNA
- DNA and RNA consist of polynucleotide chains, with one nucleotide linked to the next by a phosphodiester bond.
- DNA is a double-stranded molecule, with two polynucleotide chains wrapped around each other in a spiral.
- RNA is typically single-stranded, but can form double-helical regions by folding back on itself.
Complementary Base Pairing
- The two polynucleotide chains of a DNA double helix are held together by hydrogen bonds between the base pairs.
- A base pair consists of one purine and one pyrimidine, with adenine (A) pairing with thymine (T) and guanine (G) pairing with cytosine (C).
- In RNA, the uracil (U) base takes the place of thymine (T), forming A-U base pairs.
Organic Molecules
- Four major classes of organic molecules found in living organisms: carbohydrates, lipids, proteins, and nucleic acids
- Organic molecules consist of carbon atoms bonded covalently to each other and other atoms, forming molecules of varying sizes
Hydrocarbons
- Simplest hydrocarbon is CH4 (methane), consisting of a single carbon atom bonded to four hydrogen atoms
- More complex hydrocarbons involve two or more carbon atoms arranged in linear unbranched chains, linear branched chains, or ring structures
- Single and double bonds are found in linear and ring hydrocarbons, while triple bonds are only found in two-carbon hydrocarbons
Chemical Evolution
- Resulted in the first forms of life on Earth after the formation of organic molecules
- Involved reactions between inorganic molecules on primordial Earth and the conditions present at that time
- Stanley Miller and Harold Urey performed a classic set of experiments in 1953 to simulate chemical evolution and formed several complex organic molecules
Functional Groups
- Small, reactive groups of atoms that give larger molecules specific chemical properties
- Functional groups that frequently enter into biological reactions include the hydroxyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups
- Functional groups are linked by covalent bonds to other atoms in biological molecules, usually carbon atoms
Isomers
- Carbons linked to four different atoms or functional groups can take either of two fixed positions with respect to other carbons in a chain, resulting in isomers
- Isomers that are mirror images of each other are called stereoisomers
- Structural isomers are two molecules with the same chemical formula but with atoms arranged in different ways
Macromolecules
- Carbohydrates, lipids, proteins, and nucleic acids are large polymers assembled from subunit molecules (monomers) into a chain by covalent bonds
- Polymers are assembled from monomers by dehydration synthesis reactions
- Breakdown of polymers into monomers occurs by hydrolysis
- Each type of polymeric biological molecule contains one type of monomer
Carbohydrates
- Serve many functions, including energy storage and structural roles
- Contain only carbon, hydrogen, and oxygen atoms in a ratio of about 1C:2H:1O (CH2O)
- Monosaccharides contain three to seven carbon atoms
- Two monosaccharides polymerize to form a disaccharide
- Carbohydrate polymers with more than 10 linked monosaccharide monomers are called polysaccharides
Lipids
- Water-insoluble, primarily nonpolar biological molecules composed mostly of hydrocarbons
- Three common types of lipid molecules:
- Neutral lipids are stored and used as an energy source
- Phospholipids form cell membranes
- Steroids serve as hormones that regulate cellular activities
Proteins
- Perform many vital functions in living organisms, including structural support, enzymatic activity, movement, transport, recognition, and receptor functions
- Macromolecules composed of amino acid monomers, which contain both an amino and a carboxyl group
- 20 different amino acids are used to build proteins in all organisms### Peptide Bonds
- Peptide bonds are covalent bonds that link amino acids into polypeptide chains, which are the subunits of proteins.
- Peptide bonds are formed through a dehydration synthesis reaction between the -NH2 group of one amino acid and the -COOH group of another amino acid.
- The growing polypeptide chain has an N-terminal end and a C-terminal end, with new amino acids being linked only to the C-terminal end.
Protein Structure
- Primary structure of a protein refers to the precise sequence of amino acids linked together.
- Changing even a single amino acid can alter the secondary, tertiary, and quaternary structures of a protein, which can affect its biological function.
- Example: Substitution of a single amino acid in hemoglobin produces an altered form responsible for sickle-cell disease.
Secondary Structure
- The amino acid chain is folded into arrangements that form the protein's secondary structure.
- Two common types of secondary structure are:
- Alpha (α) helix: a twisted, regular right-hand spiral structure stabilized by regularly spaced hydrogen bonds.
- Beta (β) sheet: a flat, zigzagging structure formed by side-by-side alignment of β strands, stabilized by hydrogen bonds.
Tertiary Structure
- Tertiary structure refers to the overall three-dimensional shape of a protein, which is determined by the positions of secondary structures, disulfide linkages, and hydrogen bonds.
- Attractions between positively and negatively charged chemical groups, as well as polar and nonpolar associations, also contribute to tertiary structure.
- Tertiary structure determines a protein's function, including its chemical activity, solubility, and ability to undergo conformational changes.
Quaternary Structure
- Quaternary structure refers to the presence and arrangement of two or more polypeptide chains in a protein.
- Hydrogen bonds, polar and nonpolar attractions, and disulfide linkages hold the multiple polypeptide chains together.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Denaturation
- Denaturation is the process of unfolding a protein from its active conformation, causing it to lose its structure and function.
- Denaturation can be caused by chemicals, changes in pH, or high temperatures.
- Experiments by Christian Anfinsen showed that breaking the disulfide linkages holding a protein in its functional state caused it to unfold and lose enzyme activity.
Chaperonins
- Chaperonins are "guide" proteins that bind temporarily with newly synthesized proteins, directing their conformation towards the correct tertiary structure and inhibiting incorrect arrangements.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Nucleotides and Nucleic Acids
- Nucleic acids are macromolecules assembled from repeating monomers called nucleotides.
- DNA (deoxyribonucleic acid) stores hereditary information responsible for inherited traits in all eukaryotes and prokaryotes.
- RNA (ribonucleic acid) is the hereditary molecule of another large group of viruses and is involved in protein synthesis.
Nucleotides
- A nucleotide consists of three parts linked together by covalent bonds:
- A nitrogenous base (formed from rings of carbon and nitrogen atoms)
- A five-carbon, ring-shaped sugar (deoxyribose in DNA or ribose in RNA)
- One to three phosphate groups
Nitrogenous Bases
- Pyrimidines are nitrogenous bases with one carbon-nitrogen ring, including uracil (U), thymine (T), and cytosine (C).
- Purines are nitrogenous bases with two carbon-nitrogen rings, including adenine (A) and guanine (G).
DNA and RNA
- DNA and RNA consist of polynucleotide chains, with one nucleotide linked to the next by a phosphodiester bond.
- DNA is a double-stranded molecule, with two polynucleotide chains wrapped around each other in a spiral.
- RNA is typically single-stranded, but can form double-helical regions by folding back on itself.
Complementary Base Pairing
- The two polynucleotide chains of a DNA double helix are held together by hydrogen bonds between the base pairs.
- A base pair consists of one purine and one pyrimidine, with adenine (A) pairing with thymine (T) and guanine (G) pairing with cytosine (C).
- In RNA, the uracil (U) base takes the place of thymine (T), forming A-U base pairs.
Organic Molecules
- Four major classes of organic molecules found in living organisms: carbohydrates, lipids, proteins, and nucleic acids
- Organic molecules consist of carbon atoms bonded covalently to each other and other atoms, forming molecules of varying sizes
Hydrocarbons
- Simplest hydrocarbon is CH4 (methane), consisting of a single carbon atom bonded to four hydrogen atoms
- More complex hydrocarbons involve two or more carbon atoms arranged in linear unbranched chains, linear branched chains, or ring structures
- Single and double bonds are found in linear and ring hydrocarbons, while triple bonds are only found in two-carbon hydrocarbons
Chemical Evolution
- Resulted in the first forms of life on Earth after the formation of organic molecules
- Involved reactions between inorganic molecules on primordial Earth and the conditions present at that time
- Stanley Miller and Harold Urey performed a classic set of experiments in 1953 to simulate chemical evolution and formed several complex organic molecules
Functional Groups
- Small, reactive groups of atoms that give larger molecules specific chemical properties
- Functional groups that frequently enter into biological reactions include the hydroxyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups
- Functional groups are linked by covalent bonds to other atoms in biological molecules, usually carbon atoms
Isomers
- Carbons linked to four different atoms or functional groups can take either of two fixed positions with respect to other carbons in a chain, resulting in isomers
- Isomers that are mirror images of each other are called stereoisomers
- Structural isomers are two molecules with the same chemical formula but with atoms arranged in different ways
Macromolecules
- Carbohydrates, lipids, proteins, and nucleic acids are large polymers assembled from subunit molecules (monomers) into a chain by covalent bonds
- Polymers are assembled from monomers by dehydration synthesis reactions
- Breakdown of polymers into monomers occurs by hydrolysis
- Each type of polymeric biological molecule contains one type of monomer
Carbohydrates
- Serve many functions, including energy storage and structural roles
- Contain only carbon, hydrogen, and oxygen atoms in a ratio of about 1C:2H:1O (CH2O)
- Monosaccharides contain three to seven carbon atoms
- Two monosaccharides polymerize to form a disaccharide
- Carbohydrate polymers with more than 10 linked monosaccharide monomers are called polysaccharides
Lipids
- Water-insoluble, primarily nonpolar biological molecules composed mostly of hydrocarbons
- Three common types of lipid molecules:
- Neutral lipids are stored and used as an energy source
- Phospholipids form cell membranes
- Steroids serve as hormones that regulate cellular activities
Proteins
- Perform many vital functions in living organisms, including structural support, enzymatic activity, movement, transport, recognition, and receptor functions
- Macromolecules composed of amino acid monomers, which contain both an amino and a carboxyl group
- 20 different amino acids are used to build proteins in all organisms### Peptide Bonds
- Peptide bonds are covalent bonds that link amino acids into polypeptide chains, which are the subunits of proteins.
- Peptide bonds are formed through a dehydration synthesis reaction between the -NH2 group of one amino acid and the -COOH group of another amino acid.
- The growing polypeptide chain has an N-terminal end and a C-terminal end, with new amino acids being linked only to the C-terminal end.
Protein Structure
- Primary structure of a protein refers to the precise sequence of amino acids linked together.
- Changing even a single amino acid can alter the secondary, tertiary, and quaternary structures of a protein, which can affect its biological function.
- Example: Substitution of a single amino acid in hemoglobin produces an altered form responsible for sickle-cell disease.
Secondary Structure
- The amino acid chain is folded into arrangements that form the protein's secondary structure.
- Two common types of secondary structure are:
- Alpha (α) helix: a twisted, regular right-hand spiral structure stabilized by regularly spaced hydrogen bonds.
- Beta (β) sheet: a flat, zigzagging structure formed by side-by-side alignment of β strands, stabilized by hydrogen bonds.
Tertiary Structure
- Tertiary structure refers to the overall three-dimensional shape of a protein, which is determined by the positions of secondary structures, disulfide linkages, and hydrogen bonds.
- Attractions between positively and negatively charged chemical groups, as well as polar and nonpolar associations, also contribute to tertiary structure.
- Tertiary structure determines a protein's function, including its chemical activity, solubility, and ability to undergo conformational changes.
Quaternary Structure
- Quaternary structure refers to the presence and arrangement of two or more polypeptide chains in a protein.
- Hydrogen bonds, polar and nonpolar attractions, and disulfide linkages hold the multiple polypeptide chains together.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Denaturation
- Denaturation is the process of unfolding a protein from its active conformation, causing it to lose its structure and function.
- Denaturation can be caused by chemicals, changes in pH, or high temperatures.
- Experiments by Christian Anfinsen showed that breaking the disulfide linkages holding a protein in its functional state caused it to unfold and lose enzyme activity.
Chaperonins
- Chaperonins are "guide" proteins that bind temporarily with newly synthesized proteins, directing their conformation towards the correct tertiary structure and inhibiting incorrect arrangements.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Nucleotides and Nucleic Acids
- Nucleic acids are macromolecules assembled from repeating monomers called nucleotides.
- DNA (deoxyribonucleic acid) stores hereditary information responsible for inherited traits in all eukaryotes and prokaryotes.
- RNA (ribonucleic acid) is the hereditary molecule of another large group of viruses and is involved in protein synthesis.
Nucleotides
- A nucleotide consists of three parts linked together by covalent bonds:
- A nitrogenous base (formed from rings of carbon and nitrogen atoms)
- A five-carbon, ring-shaped sugar (deoxyribose in DNA or ribose in RNA)
- One to three phosphate groups
Nitrogenous Bases
- Pyrimidines are nitrogenous bases with one carbon-nitrogen ring, including uracil (U), thymine (T), and cytosine (C).
- Purines are nitrogenous bases with two carbon-nitrogen rings, including adenine (A) and guanine (G).
DNA and RNA
- DNA and RNA consist of polynucleotide chains, with one nucleotide linked to the next by a phosphodiester bond.
- DNA is a double-stranded molecule, with two polynucleotide chains wrapped around each other in a spiral.
- RNA is typically single-stranded, but can form double-helical regions by folding back on itself.
Complementary Base Pairing
- The two polynucleotide chains of a DNA double helix are held together by hydrogen bonds between the base pairs.
- A base pair consists of one purine and one pyrimidine, with adenine (A) pairing with thymine (T) and guanine (G) pairing with cytosine (C).
- In RNA, the uracil (U) base takes the place of thymine (T), forming A-U base pairs.
Organic Molecules
- Four major classes of organic molecules found in living organisms: carbohydrates, lipids, proteins, and nucleic acids
- Organic molecules consist of carbon atoms bonded covalently to each other and other atoms, forming molecules of varying sizes
Hydrocarbons
- Simplest hydrocarbon is CH4 (methane), consisting of a single carbon atom bonded to four hydrogen atoms
- More complex hydrocarbons involve two or more carbon atoms arranged in linear unbranched chains, linear branched chains, or ring structures
- Single and double bonds are found in linear and ring hydrocarbons, while triple bonds are only found in two-carbon hydrocarbons
Chemical Evolution
- Resulted in the first forms of life on Earth after the formation of organic molecules
- Involved reactions between inorganic molecules on primordial Earth and the conditions present at that time
- Stanley Miller and Harold Urey performed a classic set of experiments in 1953 to simulate chemical evolution and formed several complex organic molecules
Functional Groups
- Small, reactive groups of atoms that give larger molecules specific chemical properties
- Functional groups that frequently enter into biological reactions include the hydroxyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups
- Functional groups are linked by covalent bonds to other atoms in biological molecules, usually carbon atoms
Isomers
- Carbons linked to four different atoms or functional groups can take either of two fixed positions with respect to other carbons in a chain, resulting in isomers
- Isomers that are mirror images of each other are called stereoisomers
- Structural isomers are two molecules with the same chemical formula but with atoms arranged in different ways
Macromolecules
- Carbohydrates, lipids, proteins, and nucleic acids are large polymers assembled from subunit molecules (monomers) into a chain by covalent bonds
- Polymers are assembled from monomers by dehydration synthesis reactions
- Breakdown of polymers into monomers occurs by hydrolysis
- Each type of polymeric biological molecule contains one type of monomer
Carbohydrates
- Serve many functions, including energy storage and structural roles
- Contain only carbon, hydrogen, and oxygen atoms in a ratio of about 1C:2H:1O (CH2O)
- Monosaccharides contain three to seven carbon atoms
- Two monosaccharides polymerize to form a disaccharide
- Carbohydrate polymers with more than 10 linked monosaccharide monomers are called polysaccharides
Lipids
- Water-insoluble, primarily nonpolar biological molecules composed mostly of hydrocarbons
- Three common types of lipid molecules:
- Neutral lipids are stored and used as an energy source
- Phospholipids form cell membranes
- Steroids serve as hormones that regulate cellular activities
Proteins
- Perform many vital functions in living organisms, including structural support, enzymatic activity, movement, transport, recognition, and receptor functions
- Macromolecules composed of amino acid monomers, which contain both an amino and a carboxyl group
- 20 different amino acids are used to build proteins in all organisms### Peptide Bonds
- Peptide bonds are covalent bonds that link amino acids into polypeptide chains, which are the subunits of proteins.
- Peptide bonds are formed through a dehydration synthesis reaction between the -NH2 group of one amino acid and the -COOH group of another amino acid.
- The growing polypeptide chain has an N-terminal end and a C-terminal end, with new amino acids being linked only to the C-terminal end.
Protein Structure
- Primary structure of a protein refers to the precise sequence of amino acids linked together.
- Changing even a single amino acid can alter the secondary, tertiary, and quaternary structures of a protein, which can affect its biological function.
- Example: Substitution of a single amino acid in hemoglobin produces an altered form responsible for sickle-cell disease.
Secondary Structure
- The amino acid chain is folded into arrangements that form the protein's secondary structure.
- Two common types of secondary structure are:
- Alpha (α) helix: a twisted, regular right-hand spiral structure stabilized by regularly spaced hydrogen bonds.
- Beta (β) sheet: a flat, zigzagging structure formed by side-by-side alignment of β strands, stabilized by hydrogen bonds.
Tertiary Structure
- Tertiary structure refers to the overall three-dimensional shape of a protein, which is determined by the positions of secondary structures, disulfide linkages, and hydrogen bonds.
- Attractions between positively and negatively charged chemical groups, as well as polar and nonpolar associations, also contribute to tertiary structure.
- Tertiary structure determines a protein's function, including its chemical activity, solubility, and ability to undergo conformational changes.
Quaternary Structure
- Quaternary structure refers to the presence and arrangement of two or more polypeptide chains in a protein.
- Hydrogen bonds, polar and nonpolar attractions, and disulfide linkages hold the multiple polypeptide chains together.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Denaturation
- Denaturation is the process of unfolding a protein from its active conformation, causing it to lose its structure and function.
- Denaturation can be caused by chemicals, changes in pH, or high temperatures.
- Experiments by Christian Anfinsen showed that breaking the disulfide linkages holding a protein in its functional state caused it to unfold and lose enzyme activity.
Chaperonins
- Chaperonins are "guide" proteins that bind temporarily with newly synthesized proteins, directing their conformation towards the correct tertiary structure and inhibiting incorrect arrangements.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Nucleotides and Nucleic Acids
- Nucleic acids are macromolecules assembled from repeating monomers called nucleotides.
- DNA (deoxyribonucleic acid) stores hereditary information responsible for inherited traits in all eukaryotes and prokaryotes.
- RNA (ribonucleic acid) is the hereditary molecule of another large group of viruses and is involved in protein synthesis.
Nucleotides
- A nucleotide consists of three parts linked together by covalent bonds:
- A nitrogenous base (formed from rings of carbon and nitrogen atoms)
- A five-carbon, ring-shaped sugar (deoxyribose in DNA or ribose in RNA)
- One to three phosphate groups
Nitrogenous Bases
- Pyrimidines are nitrogenous bases with one carbon-nitrogen ring, including uracil (U), thymine (T), and cytosine (C).
- Purines are nitrogenous bases with two carbon-nitrogen rings, including adenine (A) and guanine (G).
DNA and RNA
- DNA and RNA consist of polynucleotide chains, with one nucleotide linked to the next by a phosphodiester bond.
- DNA is a double-stranded molecule, with two polynucleotide chains wrapped around each other in a spiral.
- RNA is typically single-stranded, but can form double-helical regions by folding back on itself.
Complementary Base Pairing
- The two polynucleotide chains of a DNA double helix are held together by hydrogen bonds between the base pairs.
- A base pair consists of one purine and one pyrimidine, with adenine (A) pairing with thymine (T) and guanine (G) pairing with cytosine (C).
- In RNA, the uracil (U) base takes the place of thymine (T), forming A-U base pairs.
Organic Molecules
- Four major classes of organic molecules found in living organisms: carbohydrates, lipids, proteins, and nucleic acids
- Organic molecules consist of carbon atoms bonded covalently to each other and other atoms, forming molecules of varying sizes
Hydrocarbons
- Simplest hydrocarbon is CH4 (methane), consisting of a single carbon atom bonded to four hydrogen atoms
- More complex hydrocarbons involve two or more carbon atoms arranged in linear unbranched chains, linear branched chains, or ring structures
- Single and double bonds are found in linear and ring hydrocarbons, while triple bonds are only found in two-carbon hydrocarbons
Chemical Evolution
- Resulted in the first forms of life on Earth after the formation of organic molecules
- Involved reactions between inorganic molecules on primordial Earth and the conditions present at that time
- Stanley Miller and Harold Urey performed a classic set of experiments in 1953 to simulate chemical evolution and formed several complex organic molecules
Functional Groups
- Small, reactive groups of atoms that give larger molecules specific chemical properties
- Functional groups that frequently enter into biological reactions include the hydroxyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups
- Functional groups are linked by covalent bonds to other atoms in biological molecules, usually carbon atoms
Isomers
- Carbons linked to four different atoms or functional groups can take either of two fixed positions with respect to other carbons in a chain, resulting in isomers
- Isomers that are mirror images of each other are called stereoisomers
- Structural isomers are two molecules with the same chemical formula but with atoms arranged in different ways
Macromolecules
- Carbohydrates, lipids, proteins, and nucleic acids are large polymers assembled from subunit molecules (monomers) into a chain by covalent bonds
- Polymers are assembled from monomers by dehydration synthesis reactions
- Breakdown of polymers into monomers occurs by hydrolysis
- Each type of polymeric biological molecule contains one type of monomer
Carbohydrates
- Serve many functions, including energy storage and structural roles
- Contain only carbon, hydrogen, and oxygen atoms in a ratio of about 1C:2H:1O (CH2O)
- Monosaccharides contain three to seven carbon atoms
- Two monosaccharides polymerize to form a disaccharide
- Carbohydrate polymers with more than 10 linked monosaccharide monomers are called polysaccharides
Lipids
- Water-insoluble, primarily nonpolar biological molecules composed mostly of hydrocarbons
- Three common types of lipid molecules:
- Neutral lipids are stored and used as an energy source
- Phospholipids form cell membranes
- Steroids serve as hormones that regulate cellular activities
Proteins
- Perform many vital functions in living organisms, including structural support, enzymatic activity, movement, transport, recognition, and receptor functions
- Macromolecules composed of amino acid monomers, which contain both an amino and a carboxyl group
- 20 different amino acids are used to build proteins in all organisms### Peptide Bonds
- Peptide bonds are covalent bonds that link amino acids into polypeptide chains, which are the subunits of proteins.
- Peptide bonds are formed through a dehydration synthesis reaction between the -NH2 group of one amino acid and the -COOH group of another amino acid.
- The growing polypeptide chain has an N-terminal end and a C-terminal end, with new amino acids being linked only to the C-terminal end.
Protein Structure
- Primary structure of a protein refers to the precise sequence of amino acids linked together.
- Changing even a single amino acid can alter the secondary, tertiary, and quaternary structures of a protein, which can affect its biological function.
- Example: Substitution of a single amino acid in hemoglobin produces an altered form responsible for sickle-cell disease.
Secondary Structure
- The amino acid chain is folded into arrangements that form the protein's secondary structure.
- Two common types of secondary structure are:
- Alpha (α) helix: a twisted, regular right-hand spiral structure stabilized by regularly spaced hydrogen bonds.
- Beta (β) sheet: a flat, zigzagging structure formed by side-by-side alignment of β strands, stabilized by hydrogen bonds.
Tertiary Structure
- Tertiary structure refers to the overall three-dimensional shape of a protein, which is determined by the positions of secondary structures, disulfide linkages, and hydrogen bonds.
- Attractions between positively and negatively charged chemical groups, as well as polar and nonpolar associations, also contribute to tertiary structure.
- Tertiary structure determines a protein's function, including its chemical activity, solubility, and ability to undergo conformational changes.
Quaternary Structure
- Quaternary structure refers to the presence and arrangement of two or more polypeptide chains in a protein.
- Hydrogen bonds, polar and nonpolar attractions, and disulfide linkages hold the multiple polypeptide chains together.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Denaturation
- Denaturation is the process of unfolding a protein from its active conformation, causing it to lose its structure and function.
- Denaturation can be caused by chemicals, changes in pH, or high temperatures.
- Experiments by Christian Anfinsen showed that breaking the disulfide linkages holding a protein in its functional state caused it to unfold and lose enzyme activity.
Chaperonins
- Chaperonins are "guide" proteins that bind temporarily with newly synthesized proteins, directing their conformation towards the correct tertiary structure and inhibiting incorrect arrangements.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Nucleotides and Nucleic Acids
- Nucleic acids are macromolecules assembled from repeating monomers called nucleotides.
- DNA (deoxyribonucleic acid) stores hereditary information responsible for inherited traits in all eukaryotes and prokaryotes.
- RNA (ribonucleic acid) is the hereditary molecule of another large group of viruses and is involved in protein synthesis.
Nucleotides
- A nucleotide consists of three parts linked together by covalent bonds:
- A nitrogenous base (formed from rings of carbon and nitrogen atoms)
- A five-carbon, ring-shaped sugar (deoxyribose in DNA or ribose in RNA)
- One to three phosphate groups
Nitrogenous Bases
- Pyrimidines are nitrogenous bases with one carbon-nitrogen ring, including uracil (U), thymine (T), and cytosine (C).
- Purines are nitrogenous bases with two carbon-nitrogen rings, including adenine (A) and guanine (G).
DNA and RNA
- DNA and RNA consist of polynucleotide chains, with one nucleotide linked to the next by a phosphodiester bond.
- DNA is a double-stranded molecule, with two polynucleotide chains wrapped around each other in a spiral.
- RNA is typically single-stranded, but can form double-helical regions by folding back on itself.
Complementary Base Pairing
- The two polynucleotide chains of a DNA double helix are held together by hydrogen bonds between the base pairs.
- A base pair consists of one purine and one pyrimidine, with adenine (A) pairing with thymine (T) and guanine (G) pairing with cytosine (C).
- In RNA, the uracil (U) base takes the place of thymine (T), forming A-U base pairs.
Organic Molecules
- Four major classes of organic molecules found in living organisms: carbohydrates, lipids, proteins, and nucleic acids
- Organic molecules consist of carbon atoms bonded covalently to each other and other atoms, forming molecules of varying sizes
Hydrocarbons
- Simplest hydrocarbon is CH4 (methane), consisting of a single carbon atom bonded to four hydrogen atoms
- More complex hydrocarbons involve two or more carbon atoms arranged in linear unbranched chains, linear branched chains, or ring structures
- Single and double bonds are found in linear and ring hydrocarbons, while triple bonds are only found in two-carbon hydrocarbons
Chemical Evolution
- Resulted in the first forms of life on Earth after the formation of organic molecules
- Involved reactions between inorganic molecules on primordial Earth and the conditions present at that time
- Stanley Miller and Harold Urey performed a classic set of experiments in 1953 to simulate chemical evolution and formed several complex organic molecules
Functional Groups
- Small, reactive groups of atoms that give larger molecules specific chemical properties
- Functional groups that frequently enter into biological reactions include the hydroxyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups
- Functional groups are linked by covalent bonds to other atoms in biological molecules, usually carbon atoms
Isomers
- Carbons linked to four different atoms or functional groups can take either of two fixed positions with respect to other carbons in a chain, resulting in isomers
- Isomers that are mirror images of each other are called stereoisomers
- Structural isomers are two molecules with the same chemical formula but with atoms arranged in different ways
Macromolecules
- Carbohydrates, lipids, proteins, and nucleic acids are large polymers assembled from subunit molecules (monomers) into a chain by covalent bonds
- Polymers are assembled from monomers by dehydration synthesis reactions
- Breakdown of polymers into monomers occurs by hydrolysis
- Each type of polymeric biological molecule contains one type of monomer
Carbohydrates
- Serve many functions, including energy storage and structural roles
- Contain only carbon, hydrogen, and oxygen atoms in a ratio of about 1C:2H:1O (CH2O)
- Monosaccharides contain three to seven carbon atoms
- Two monosaccharides polymerize to form a disaccharide
- Carbohydrate polymers with more than 10 linked monosaccharide monomers are called polysaccharides
Lipids
- Water-insoluble, primarily nonpolar biological molecules composed mostly of hydrocarbons
- Three common types of lipid molecules:
- Neutral lipids are stored and used as an energy source
- Phospholipids form cell membranes
- Steroids serve as hormones that regulate cellular activities
Proteins
- Perform many vital functions in living organisms, including structural support, enzymatic activity, movement, transport, recognition, and receptor functions
- Macromolecules composed of amino acid monomers, which contain both an amino and a carboxyl group
- 20 different amino acids are used to build proteins in all organisms### Peptide Bonds
- Peptide bonds are covalent bonds that link amino acids into polypeptide chains, which are the subunits of proteins.
- Peptide bonds are formed through a dehydration synthesis reaction between the -NH2 group of one amino acid and the -COOH group of another amino acid.
- The growing polypeptide chain has an N-terminal end and a C-terminal end, with new amino acids being linked only to the C-terminal end.
Protein Structure
- Primary structure of a protein refers to the precise sequence of amino acids linked together.
- Changing even a single amino acid can alter the secondary, tertiary, and quaternary structures of a protein, which can affect its biological function.
- Example: Substitution of a single amino acid in hemoglobin produces an altered form responsible for sickle-cell disease.
Secondary Structure
- The amino acid chain is folded into arrangements that form the protein's secondary structure.
- Two common types of secondary structure are:
- Alpha (α) helix: a twisted, regular right-hand spiral structure stabilized by regularly spaced hydrogen bonds.
- Beta (β) sheet: a flat, zigzagging structure formed by side-by-side alignment of β strands, stabilized by hydrogen bonds.
Tertiary Structure
- Tertiary structure refers to the overall three-dimensional shape of a protein, which is determined by the positions of secondary structures, disulfide linkages, and hydrogen bonds.
- Attractions between positively and negatively charged chemical groups, as well as polar and nonpolar associations, also contribute to tertiary structure.
- Tertiary structure determines a protein's function, including its chemical activity, solubility, and ability to undergo conformational changes.
Quaternary Structure
- Quaternary structure refers to the presence and arrangement of two or more polypeptide chains in a protein.
- Hydrogen bonds, polar and nonpolar attractions, and disulfide linkages hold the multiple polypeptide chains together.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Denaturation
- Denaturation is the process of unfolding a protein from its active conformation, causing it to lose its structure and function.
- Denaturation can be caused by chemicals, changes in pH, or high temperatures.
- Experiments by Christian Anfinsen showed that breaking the disulfide linkages holding a protein in its functional state caused it to unfold and lose enzyme activity.
Chaperonins
- Chaperonins are "guide" proteins that bind temporarily with newly synthesized proteins, directing their conformation towards the correct tertiary structure and inhibiting incorrect arrangements.
- Chaperonins promote the correct association of individual amino acid chains and inhibit incorrect formations.
Nucleotides and Nucleic Acids
- Nucleic acids are macromolecules assembled from repeating monomers called nucleotides.
- DNA (deoxyribonucleic acid) stores hereditary information responsible for inherited traits in all eukaryotes and prokaryotes.
- RNA (ribonucleic acid) is the hereditary molecule of another large group of viruses and is involved in protein synthesis.
Nucleotides
- A nucleotide consists of three parts linked together by covalent bonds:
- A nitrogenous base (formed from rings of carbon and nitrogen atoms)
- A five-carbon, ring-shaped sugar (deoxyribose in DNA or ribose in RNA)
- One to three phosphate groups
Nitrogenous Bases
- Pyrimidines are nitrogenous bases with one carbon-nitrogen ring, including uracil (U), thymine (T), and cytosine (C).
- Purines are nitrogenous bases with two carbon-nitrogen rings, including adenine (A) and guanine (G).
DNA and RNA
- DNA and RNA consist of polynucleotide chains, with one nucleotide linked to the next by a phosphodiester bond.
- DNA is a double-stranded molecule, with two polynucleotide chains wrapped around each other in a spiral.
- RNA is typically single-stranded, but can form double-helical regions by folding back on itself.
Complementary Base Pairing
- The two polynucleotide chains of a DNA double helix are held together by hydrogen bonds between the base pairs.
- A base pair consists of one purine and one pyrimidine, with adenine (A) pairing with thymine (T) and guanine (G) pairing with cytosine (C).
- In RNA, the uracil (U) base takes the place of thymine (T), forming A-U base pairs.
This quiz covers the process of photosynthesis, its importance, and the role of carbon compounds in living organisms and industry.
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