Biology Chapter on Macromolecules
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Questions and Answers

Which of the following is NOT considered a macromolecule?

  • Nucleic acids
  • Proteins
  • Carbohydrates
  • Lipids (correct)

What type of bond links monosaccharides to form disaccharides?

  • Glycosidic bond (correct)
  • Peptide bond
  • Ionic bond
  • Hydrogen bond

What is the primary function of carbohydrates in living organisms?

  • Long-term energy storage
  • Genetic information storage
  • Primary source of energy and structural roles (correct)
  • Catalyzing biological reactions

Which monosaccharide is known as 'fruit sugar'?

<p>Fructose (C)</p> Signup and view all the answers

Which disaccharide is formed from two molecules of glucose?

<p>Maltose (B)</p> Signup and view all the answers

Which of the following is formed of glucose and galactose?

<p>Lactose (C)</p> Signup and view all the answers

In the body, where is fructose primarily metabolized?

<p>Liver (B)</p> Signup and view all the answers

Which of the following is a disaccharide commonly known as table sugar?

<p>Sucrose (D)</p> Signup and view all the answers

Which element is NOT a primary component of biological molecules?

<p>Calcium (B)</p> Signup and view all the answers

Excessive consumption of fructose has been linked to which of these health issues? (Select all that apply)

<p>Non-alcoholic fatty liver disease (B), Obesity (D)</p> Signup and view all the answers

Which of the following best describes the primary function of triglycerides?

<p>Providing a concentrated energy storage form (A)</p> Signup and view all the answers

What is the main role of cholesterol in cell membranes?

<p>Regulating membrane fluidity and stability (A)</p> Signup and view all the answers

What type of bonds link amino acids together to form polypeptide chains?

<p>Peptide bonds (C)</p> Signup and view all the answers

Which of the following is a primary function of proteins?

<p>Regulating metabolism through enzymatic activity (B)</p> Signup and view all the answers

What is a key function of proteins like actin and myosin?

<p>Participating in muscle contraction and movement (C)</p> Signup and view all the answers

Which term best describes the monomer of a nucleic acid?

<p>Nucleotide (D)</p> Signup and view all the answers

A nucleoside is composed of which of the following?

<p>Nitrogenous base and pentose sugar (B)</p> Signup and view all the answers

What are the two types of nucleic acids?

<p>DNA and RNA (B)</p> Signup and view all the answers

Which of these lipids are synthesized in the liver?

<p>Cholesterol (C)</p> Signup and view all the answers

Which of the following is NOT a function of proteins?

<p>Hereditary information storage (D)</p> Signup and view all the answers

What is the primary function of starch in plants?

<p>Energy storage as a glucose polymer. (A)</p> Signup and view all the answers

Which nitrogenous base is NOT found in RNA?

<p>Thymine (D)</p> Signup and view all the answers

Which storage polysaccharide is primarily found in animal liver and muscle cells?

<p>Glycogen (D)</p> Signup and view all the answers

What is the role of cellulose in plant cells?

<p>Structural support in cell walls. (D)</p> Signup and view all the answers

What type of bond connects the nitrogenous bases in opposite strands of the DNA double helix?

<p>Hydrogen bond (C)</p> Signup and view all the answers

The exoskeleton of arthropods, such as insects and spiders, is primarily composed of which polysaccharide?

<p>Chitin (B)</p> Signup and view all the answers

How many hydrogen bonds link guanine (G) and cytosine (C) in a DNA molecule?

<p>Three (D)</p> Signup and view all the answers

Which of the following is NOT a primary function of carbohydrates?

<p>Formation of the plasma membrane. (C)</p> Signup and view all the answers

What is the approximate distance between two successive base pairs in a DNA molecule?

<p>0.34 nm (D)</p> Signup and view all the answers

Which of the following correctly describes the structure of DNA?

<p>Double stranded helix, with deoxyribose sugar (B)</p> Signup and view all the answers

What is a key characteristic of lipids compared to carbohydrates?

<p>Lipids are hydrophobic hydrocarbons. (A)</p> Signup and view all the answers

What is the width of the DNA double helix structure?

<p>2 nm (B)</p> Signup and view all the answers

What distinguishes saturated fatty acids from unsaturated fatty acids?

<p>Saturated fatty acids have no double bonds and are solid at room temperature. (D)</p> Signup and view all the answers

Which of the following statements about the two strands of a DNA molecule is true?

<p>They are antiparallel, running in opposite directions. (A)</p> Signup and view all the answers

Which of the following best describes a phospholipid molecule?

<p>A molecule with a hydrophilic head and a hydrophobic tail. (C)</p> Signup and view all the answers

Which of the following is a pyrimidine?

<p>Cytosine (A)</p> Signup and view all the answers

What is the function of phospholipids in cells?

<p>Formation of plasma membranes. (A)</p> Signup and view all the answers

Which bond holds nucleotides together within a single strand of DNA?

<p>Phosphodiester bond (D)</p> Signup and view all the answers

What structural characteristic is shared by all steroids?

<p>A carbon skeleton consisting of four fused rings. (D)</p> Signup and view all the answers

How often does the DNA double helix complete a full turn?

<p>Every 3.4 nm (B)</p> Signup and view all the answers

Which of the following is a characteristic of cholesterol?

<p>It is insoluble in water. (A)</p> Signup and view all the answers

Which of the following is a correct statement about macromolecules?

<p>Carbohydrates, proteins, and nucleic acids are polymers and considered to be macromolecules. (A)</p> Signup and view all the answers

Which of the following elements is not a primary component of the main classes of biological molecules?

<p>Calcium (A)</p> Signup and view all the answers

What is a key function of triglycerides in living organisms?

<p>Serving as a highly concentrated energy storage. (A)</p> Signup and view all the answers

The majority of enzymes are classified as which type of macromolecule?

<p>Proteins (B)</p> Signup and view all the answers

Glucose and galactose are examples of:

<p>Monosaccharides with different properties although structurally similar, varying only by the orientation of one hydroxyl group. (B)</p> Signup and view all the answers

Which of these functions is carried out by both proteins and steroids?

<p>Acting as signaling molecules via hormones. (C)</p> Signup and view all the answers

Which of the following is the most accurate description of fructose metabolism?

<p>It is primarily metabolized in the liver where it is converted to glucose, energy or stored as glycogen. (A)</p> Signup and view all the answers

What is the main role of nucleic acids in living organisms?

<p>To store and transmit hereditary information. (B)</p> Signup and view all the answers

What distinguishes maltose from sucrose at a molecular level?

<p>The presence of fructose in sucrose and its absence in maltose. (D)</p> Signup and view all the answers

Why are carbohydrates considered primary sources of energy for living organisms?

<p>They contain high energy covalent bonds that can be catabolized to produce energy. (B)</p> Signup and view all the answers

A nucleoside is best defined as a nucleotide without which component?

<p>Phosphate group (B)</p> Signup and view all the answers

How do monosaccharides relate to polysaccharides?

<p>Monosaccharides are the monomeric building blocks of polysaccharides. (A)</p> Signup and view all the answers

Which of these functions is NOT primarily associated with proteins?

<p>Providing insulation and protection for cells. (B)</p> Signup and view all the answers

Which is a primary structural difference between glucose and galactose?

<p>The orientation of a hydroxyl group at a specific carbon. (B)</p> Signup and view all the answers

Which of the following is a function of proteins like collagen and keratin?

<p>Providing structural support to cells and tissues. (B)</p> Signup and view all the answers

What is the specific bond that links monosaccharides together, forming a disaccharide?

<p>Glycosidic covalent bond (D)</p> Signup and view all the answers

What is the primary function of actin and myosin?

<p>Muscle contraction and movement. (D)</p> Signup and view all the answers

Which of these biological molecules is NOT a polymer?

<p>Cholesterol (D)</p> Signup and view all the answers

How does excessive consumption of fructose, particularly in processed foods, affect the body?

<p>It increases the risk of conditions such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease. (D)</p> Signup and view all the answers

Which of the following best describes the relationship between monosaccharides and polysaccharides?

<p>Monosaccharides are the building blocks that combine to form polysaccharides. (C)</p> Signup and view all the answers

What is the primary function of glycogen in the human body?

<p>To store glucose for energy in liver and muscle cells. (C)</p> Signup and view all the answers

Which of these polysaccharides is a structural component of plant cell walls?

<p>Cellulose (D)</p> Signup and view all the answers

How do unsaturated fatty acids differ structurally from saturated fatty acids?

<p>Unsaturated fatty acids have one or more double bonds between carbon atoms. (A)</p> Signup and view all the answers

Which characteristic of phospholipids allows them to form the lipid bilayer of cell membranes?

<p>They are amphipathic with a hydrophilic head and a hydrophobic tail. (A)</p> Signup and view all the answers

How are steroid molecules structurally characterized?

<p>By a carbon skeleton consisting of four fused rings. (B)</p> Signup and view all the answers

Which of the following is NOT a function of carbohydrates in living organisms?

<p>Acting as a structural component in cellular membranes. (C)</p> Signup and view all the answers

What distinguishes a fat from a phospholipid at a molecular level?

<p>Fats have three fatty acids, while phospholipids have two, along with a phosphate group. (D)</p> Signup and view all the answers

The primary function of chitin is best described as:

<p>Providing a strong, structural material for arthropod exoskeletons. (D)</p> Signup and view all the answers

What is the significance of the double bonds in unsaturated fatty acids?

<p>They introduce kinks in the fatty acid chain, affecting its packing properties. (A)</p> Signup and view all the answers

How many rings are present in a pyrimidine?

<p>One six-membered ring (A)</p> Signup and view all the answers

Which of the following nitrogenous bases pairs with adenine in a DNA molecule?

<p>Thymine (C)</p> Signup and view all the answers

In a double helix, what is the characteristic of the two strands regarding their direction?

<p>Antiparallel, running in opposite directions (5’ to 3’ and 3’ to 5’) (C)</p> Signup and view all the answers

What is the sugar present in RNA?

<p>Ribose sugar (C)</p> Signup and view all the answers

What type of bond connects nucleotides within a single strand of DNA?

<p>Phosphodiester bond (B)</p> Signup and view all the answers

Which of the following is a purine?

<p>Guanine (A)</p> Signup and view all the answers

How many hydrogen bonds are formed between adenine and thymine in the DNA double helix?

<p>Two (C)</p> Signup and view all the answers

What is the distance between two successive base pairs in a DNA molecule?

<p>0.34 nm (D)</p> Signup and view all the answers

Which of the following describes the structure of RNA?

<p>Single strand, short chain (B)</p> Signup and view all the answers

How long is a complete turn of the DNA double helix?

<p>3.4 nm (B)</p> Signup and view all the answers

Flashcards

Biological Molecules

Large molecules that are the building blocks of life, playing essential roles in various biological processes like metabolism, energy storage, and information transfer.

Classes of Biological Molecules

The four main types of biological molecules that are essential for life and found in all living organisms.

Polymers

Large molecules made up of many identical building blocks linked together by covalent bonds.

Monomers

The smaller units that make up a polymer.

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Monosaccharides

The simplest carbohydrates consisting of a single sugar unit.

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Glucose

The most important source of energy for living cells.

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Galactose

A sugar that is structurally similar to glucose, differing only in the orientation of one hydroxyl group.

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Fructose

Known as fruit sugar due to its high concentration in fruits and honey. Metabolized primarily in the liver, where it can be converted into glucose, used for energy production, or stored as glycogen.

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Disaccharides

Carbohydrates formed of two monosaccharide sugar units linked together by a glycosidic covalent bond.

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Sucrose

The most prevalent disaccharide, formed of two monomers of glucose and fructose.

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Polysaccharides

Large molecules made up of many monosaccharide units linked together by glycosidic bonds.

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Starch

A storage form of glucose in plants, primarily found in roots and seeds.

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Glycogen

A storage form of glucose in animals and humans, mainly stored in the liver and muscle cells.

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Cellulose

The main component of plant cell walls, providing structural support.

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Chitin

A structural polysaccharide that forms the exoskeleton of arthropods, such as insects and spiders.

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Lipids

Large biological molecules that are hydrophobic (water-repelling) and non-polar.

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Fats

Fats are composed of glycerol and fatty acids, with three fatty acids attached to each glycerol molecule.

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Saturated and Unsaturated Fatty Acids

Fatty acids can be saturated (no double bonds) or unsaturated (one or more double bonds).

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Phospholipids

Essential components of cell membranes, composed of a hydrophilic head and a hydrophobic tail.

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Steroids

Lipids characterized by a fused ring structure, important for various biological processes like hormone regulation.

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Cholesterol

A type of lipid that is insoluble in water, synthesized in the liver and obtained from the diet. High levels in the blood can contribute to atherosclerosis.

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Triglycerides

Triglycerides are the main type of fat found in the body. They are composed of glycerol and three fatty acid chains.

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Proteins

Proteins are large molecules made up of long chains of amino acids, linked together by peptide bonds. They play crucial roles in almost every biological process.

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Enzymes

Enzymes are proteins that act as biological catalysts, accelerating chemical reactions without being consumed in the process.

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Structural Proteins

Structural proteins like collagen and keratin provide support and stability to cells, tissues, and organs.

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Nucleic Acids

Nucleic acids are macromolecules that store and transmit genetic information. They consist of long chains of nucleotides.

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Nucleotides

A nucleotide is the basic building block of nucleic acids. It consists of a phosphate group, a five-carbon sugar, and a nitrogenous base.

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Nucleosides

A nucleoside is a component of a nucleotide, consisting of a nitrogenous base and a five-carbon sugar.

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Nitrogenous Bases

Nitrogenous bases are organic molecules that contain nitrogen and are essential components of nucleic acids (DNA and RNA). They form the building blocks of genetic code, carrying and transmitting information.

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Pentose Sugars

Pentose sugars are five-carbon monosaccharides (simple sugars) that are crucial components of nucleic acids. They provide the structural backbone for DNA and RNA.

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Purines

Purines are a family of nitrogenous bases, containing two rings (one six-membered ring fused to a five-membered ring). They include Adenine (A) and Guanine (G).

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Pyrimidines

Pyrimidines are a family of nitrogenous bases, containing a single six-membered ring of carbon and nitrogen atoms. They include Cytosine (C), Thymine (T) and Uracil (U).

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DNA Structure

DNA is a double-stranded nucleic acid that stores genetic information. It has a helical structure with two antiparallel strands running in opposite directions (5' to 3' and 3' to 5').

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RNA Structure

RNA is a single-stranded nucleic acid that plays a crucial role in protein synthesis. It's involved in copying and translating genetic information from DNA to proteins.

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Base Pairing Rules

In DNA, Adenine (A) always pairs with Thymine (T) via two hydrogen bonds, and Guanine (G) pairs with Cytosine (C) via three hydrogen bonds. These specific base pairings are essential for maintaining DNA's structure and function.

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Hydrogen Bonds in DNA

The two strands of DNA are held together by hydrogen bonds between the nitrogenous bases. This bond is relatively weak but plays a crucial role in maintaining the stability of DNA.

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DNA Dimensions

The distance between two successive base pairs in DNA is 0.34 nm, while the width of the DNA double helix is 2 nm.

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Carbohydrates

Large biological molecules composed of carbon, hydrogen, and oxygen in a ratio of approximately 1:2:1. They are the primary source of energy for living organisms and play structural roles in cells.

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Functions of Carbohydrates

The primary source of energy for cells, involved in energy storage, structural support, and cell signaling.

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What are Nitrogenous Bases?

Nitrogenous bases are organic molecules containing nitrogen, forming the building blocks of genetic code within nucleic acids like DNA and RNA.

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What are Pentose Sugars?

Pentose sugars are five-carbon monosaccharides (simple sugars) that act as the structural backbone for DNA and RNA.

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What are Purines?

Purines are a family of nitrogenous bases with two rings, one six-membered ring fused to a five-membered ring. Examples include adenine (A) and guanine (G).

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What are Pyrimidines?

Pyrimidines are a family of nitrogenous bases with a single six-membered ring of carbon and nitrogen atoms. Examples include cytosine (C), thymine (T), and uracil (U).

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Describe the structure of DNA

DNA is a double-stranded helix (spiral) with two strands running in opposite directions (antiparallel), from 5' to 3' and 3' to 5'.

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What is RNA?

RNA is a single-stranded molecule that plays a crucial role in protein synthesis. It is involved in copying and translating genetic information from DNA to proteins.

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What are the base pairing rules in DNA?

In DNA, adenine (A) always pairs with thymine (T) via two hydrogen bonds, and guanine (G) pairs with cytosine (C) via three hydrogen bonds.

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What are the dimensions of DNA?

The distance between successive base pairs in DNA is 0.34 nm, and the width of the DNA double helix is 2 nm.

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How are the DNA strands held together?

Hydrogen bonds hold the two strands of DNA together via the interactions between the nitrogenous bases.

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How do the nitrogenous bases bond in DNA?

The 2 strands of DNA are attached to each other by hydrogen bonds between the nitrogenous bases. Adenine (A) always pairs with thymine (T) by 2 hydrogen bonds, and guanine (G) pairs with cytosine (C) by 3 hydrogen bonds.

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Study Notes

Biological Molecules

  • Biological molecules are the fundamental building blocks of life. They play critical roles in various biological processes, including metabolism, energy storage, and information transfer within cells.
  • Living organisms contain four main classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids.
  • All of these classes except lipids are macromolecules, which are huge biological molecules.

Carbohydrates

  • Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio.
  • They serve as a primary energy source for living organisms and play structural roles in cells.
  • Carbohydrates are classified into three main groups: monosaccharides, disaccharides, and polysaccharides.

Monosaccharides

  • Monosaccharides are the simplest carbohydrates, which are single sugar units (monomers).
  • Examples include glucose, fructose, and galactose.
  • Glucose is a crucial energy source for living cells.
  • Galactose is structurally similar to glucose, differing only in the orientation of one hydroxyl group.
  • Fructose is known as fruit sugar due to its abundance in fruits and honey.
  • Fructose is primarily metabolized in the liver, where it can be converted into glucose, used for energy, or stored as glycogen.
  • Excessive fructose consumption (particularly in the form of high-fructose corn syrup) is linked to health problems like obesity, type 2 diabetes, and non-alcoholic fatty liver disease.

Disaccharides

  • Disaccharides are formed by linking two monosaccharide sugar units via a glycosidic covalent bond.
  • Examples include maltose, sucrose, and lactose.
  • Maltose consists of two glucose molecules.
  • Sucrose, commonly known as table sugar, comprises glucose and fructose.
  • Lactose is composed of glucose and galactose.

Polysaccharides

  • Polysaccharides are macromolecules formed by many linked monosaccharides via glycosidic linkages.
  • Some polysaccharides function as storage materials, while others serve as structural components.
  • Starch is a plant glucose storage form found in roots and seeds.
  • Glycogen is the animal glucose storage form, primarily stored in the liver and muscle.
  • Cellulose is a major component of plant cell walls, providing structural support.
  • Chitin forms the exoskeleton of arthropods (insects and spiders) and is also used in surgical thread (that decomposes after healing).
  • Carbohydrates serve as energy sources, structural components, and play roles in cellular recognition, communication, adhesion, immune response, and cell signaling; they also provide dietary fiber.

Lipids

  • Lipids are large biological molecules that are not true polymers.
  • They are hydrophobic (poorly mix with water) and non-polar molecules.
  • Lipids include fats, phospholipids, and steroids.

Fats

  • Fats are formed from glycerol and fatty acids (3 fatty acids per glycerol molecule).
  • Fats are stored in fat cells to form adipose tissue.
  • Fatty acids vary in length (typically 16 or 18 carbon atoms).
  • Saturated fatty acids have no double bonds and are solid at room temperature (e.g., lard and butter).
  • Unsaturated fatty acids contain one or more double bonds and are liquid at room temperature (e.g., oils).
  • Fats from plants and fish are generally unsaturated.

Phospholipids

  • Phospholipids are essential for cell membranes.
  • They contain two fatty acids linked to a glycerol molecule and a phosphate group head.
  • Phospholipids have an amphipathic nature; the head is hydrophilic (attracted to water), and the tail is hydrophobic (repels water).
  • This dual nature is crucial for their function in forming cell membranes. They create a lipid bilayer, a double layer that forms the foundation of cell membranes.

Steroids

  • Steroids are lipids with a unique carbon skeleton consisting of four fused rings.
  • Cholesterol is a common steroid that is a component of animal cell membranes.
  • Cholesterol is synthesized in the liver and obtained from the diet.
  • High cholesterol levels in the blood are associated with atherosclerosis.
  • Steroids serve as precursors for various hormones, such as cortisone and testosterone.
  • Lipids serve as concentrated energy stores, contribute to cell membranes, aid in insulation and protection, and support hormone production.

Proteins

  • Proteins are the most abundant molecules in living tissues, accounting for more than 50% of the dry mass of most cells.
  • Proteins are polymer macromolecules (polypeptide chains) constructed from amino acid monomers linked by peptide bonds and arranged in linear structures.
  • Many enzymes are proteins that catalyze metabolic reactions (chemical reactions that speed up processes within the body).
  • Other protein examples include hormones, plasma proteins, antibodies, actin, and myosin.
  • Proteins play multifaceted roles, including acting as biological catalysts (enzymes), providing structural support, facilitating molecular transport across membranes, acting as signaling molecules (hormones), conducting immune responses (antibodies), and enabling muscle contraction (actin and myosin).

Nucleic Acids

  • Nucleic acids are macromolecules that exist as polymers called polynucleotides.
  • Each polynucleotide is composed of nucleotide monomers.
  • Nucleic acids store and transmit hereditary information.
  • There are two types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

Nucleotides

  • Nucleotides have three components: a nitrogenous base, a five-carbon sugar (pentose sugar), and phosphate groups.

  • Each nucleotide has only one phosphate group attached.

  • A nucleoside is the portion of a nucleotide that lacks the phosphate group.

  • Nitrogenous bases in nucleic acids come in two families: purines (adenine and guanine) and pyrimidines (cytosine, thymine, and uracil).

  • Purines have a double ring structure, while pyrimidines have a single ring structure.

DNA

  • DNA structure is a double helix.
  • The two strands of DNA run antiparallel (in opposite directions).
  • The strands of the helix are joined by hydrogen bonds between complementary base pairs: adenine (A) with thymine (T), and guanine (G) with cytosine(C).
  • The distance between successive base pairs is 0.34 nm.
  • The width of DNA's double helix is 2 nm.
  • The two strands form one full turn every 3.4 nm.

RNA

  • RNA is a single-stranded molecule.
  • RNA contains the nitrogenous bases adenine (A), guanine (G), cytosine (C), and uracil (U).
  • RNA differs from DNA, most noticeably in the sugar component (ribose rather than deoxyribose) and base uracil replaces thymine.

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Test your knowledge of macromolecules in biology with this quiz. Questions cover carbohydrates, proteins, lipids, and their functions in living organisms. Ideal for students looking to deepen their understanding of these essential biological compounds.

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