Name: biomolecules and their tests
Uploaded: 2019-01-29T11:04:45.000Z
Duration: 6 min 26 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Biology

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms- Structures and Processes

LS.Bio.1.1

Macromolecules

Knowing what macromolecules are is an important step to understanding how nutrients are absorbed and used by cells. The term macromolecules simply means large molecules and refers to four different compounds, carbohydrates, lipids, proteins, and nucleic acids. Each of these has a unique structure and function. Let&#39;s talk about carbohydrates first. 
All carbohydrates are composed of carbon, hydrogen, and oxygen. Those with simple structures are called monosaccharides or sugars. Monosaccharides can join to form more complex carbohydrate chains called polysaccharides or starch. Starch&#39;s normal form resembles a coiled spring because of the bond angles in the polymer chain. 
The next type of macromolecule we&#39;ll discuss is protein. Proteins are built from chains of amino acids, organic compounds that each have an amino group or N-terminal at one end and a carboxyl group, or C-terminal at the other. There are 20 standard amino acids and while they all have a similar base structure, each has a unique side chain known as the R-group. Different amino acids can link together to form a chain connected by peptide bonds and create a protein. 
The final class of macromolecules we will examine is lipids. The most common types of lipids are fats, also called triglycerides because they are composed of a glycerol molecule connected to three fatty acid chains. 
Now, let&#39;s talk about detecting these macromolecules in a lab setting. Benedict&#39;s Reagent is commonly used for detecting monosaccharides. Benedict&#39;s Reagent is normally blue because it contains copper ions in the form of copper sulfate. This metal salt is an example of an oxidizing agent. Monosaccharides that contain a hemiacetal group, such as glucose, are considered reducing sugars. In an aqueous solution, monosaccharides with hemiacetal groups exist in both the cyclic and open chain form which has a reactive aldehyde. From this aldehyde, an electron is transferred to the copper II ion. This reduces the copper II ion to copper I ion and oxidizes the reducing sugar. Because copper I ions are seen to be rust red, the solution will begin to change color. In the presence of small amounts of monosaccharide, the solution will change to green. Higher concentrations of the monosaccharide will lead to more copper being reduced and the solution&#39;s color will change more dramatically, eventually becoming a reddish orange.
Starches can be detected with the normally yellow-brown iodine indicator. This indicator contains various polyiodide anion species such as I-3 negative, I-5 negative, and I-7 negative. The negatively charged iodines in each anion act as charge donators while the neutral iodines act as charge acceptors. This is a charge transfer complex and electrons in these complexes are easily excited with light to a higher energy level. The light is absorbed in the process and its complementary color can be seen by the human eye. The absorptions of the different species in this solution are what give it the yellow-brown color. When a starch is added, it forms a new charge transfer complex with the polyiodide anions. With the starch acting as a charge donator and the polyiodide as an acceptor. While the specifics of the reaction are not known, it is thought that the iodine and starch combine to form infinite polyiodide homopolymer. This complex absorbs light of a different wavelength, turning the color of the solution dark blue.
Proteins can be detected using Biuret&#39;s Reagent, a blue solution that contains copper ions but bind to the nitrogen found in peptide bonds, forming chelate complexes. Chelate complexes involving three to four peptide bonds produce a violet color, which changes the color of the solution. The intensity of the color is directly related to the peptide bond concentration. The greater the concentration, the more intense the violet color will be. 
Finally, lipids can be detected in a solution using the Sudan IV test. Sudan IV is a dye that is not soluble in water, but it is soluble in lipids, so when it is added to a solution containing lipids it will stain them red. 
In this laboratory, you will determine which macromolecules are in the provided mystery solutions using four different indicator reagents.

macromolecules

<h4>Biomolecules</h4>
Organisms contain a wide variety of organic molecules with numerous functions which depend on the chemical structures and properties of these molecules. All organic molecules contain a carbon backbone and hydrogen atoms. The carbon atom is central in the formation of a vast variety of organic molecules ranging in size, shape and complexity; inorganic molecules on the other hand, generally have simpler structures. The outermost shell of a free carbon atom can accommodate eight electrons but is occupied by only four electrons, therefore it can form four covalent bonds and bond with up to four atoms. Alternatively, it can also bond with fewer atoms by forming double or triple bonds. This versatility of carbon atoms allows organic molecules to display intricate structures, such as chains, branches, and rings, among others.
Organic molecules that naturally occur in organisms are called biomolecules. Besides carbon and hydrogen, biomolecules also contain other elements such as oxygen, nitrogen, phosphorus, and sulfur. In general, smaller units of biomolecules come together, as repetitive sequences, to form larger biomolecules. These small modular units of biomolecules are called monomers. Two monomers typically join each other to form a dimer through a process known as dehydration synthesis, which is simply the removal of a hydrogen atom from one monomer and a hydroxyl (OH-) ion from the other monomer to create a water molecule to be expelled out while linking the two monomers with a covalent bond. The reverse of this process is called hydrolysis, in which the molecule splits back into its original monomers with a water molecule providing a hydrogen atom to one monomer and a hydroxyl ion to the other. Many monomers can be attached together by dehydration to form polymers. Sometimes different polymers can come together to form even larger and more complex molecules, which are known as biological macromolecules.
Biomolecules are classified based on the elements that compose them, and their structure and function inside living organisms. Almost all biomolecules can be classified into one of the four general categories: carbohydrates, lipids, proteins, and nucleic acids.
<h4>Carbohydrates</h4>
Carbohydrate simply means &#8220;carbon water&#8221; because these molecules are composed of carbon, hydrogen, and oxygen atoms roughly in the ratio of 1:2:1. Carbohydrate monomers are known as monosaccharides, which are also referred to as simple sugars. Glucose (C6H12O6) is the most common monosaccharide in living organisms and is a subunit of many polysaccharides. Numerous organisms also synthesize other six-carbon monosaccharides with the same chemical formula as glucose but slightly different structures, such as fructose and galactose. When two monosaccharides are linked together, they form disaccharides. For example, sucrose is composed of glucose and fructose, whereas lactose contains glucose and galactose. These monosaccharides and disaccharides are used for short-term energy storage in living organisms. Maltose is another disaccharide that is made up of two glucose molecules and is usually formed when polysaccharide chains such as starch and glycogen are broken down during digestion. Starch is a polysaccharide that serves as an energy storage molecule in plants and is made up of two types of glucose polymers: amylose and amylopectin. Amylose constitutes 10-20% of starch and is a helical polymer of glucose. Amylopectin makes up the bulk of the starch and is a branched polymer of glucose. Glycogen is virtually the same as starch, however it is synthesized, stored and used in animal liver and muscle tissues.
Besides serving as energy stores, carbohydrates also have other functions in organisms. The five-carbon monosaccharides, ribose and deoxyribose, are integrated into the nucleic acid structure and are present in every living cell. Moreover, the polysaccharide cellulose, which is a long polymer made up of glucose, serves as a rigid structural material in plants. Humans do not have digestive enzymes to break down cellulose in food, which is also called dietary fiber. However, dietary fiber consumption helps to maintain a healthy gut flora, which in turn contributes to the health of digestive and immune systems1. Similar to plants, some animals and fungi use another polysaccharide, chitin, as a structural molecule. Arthropods use chitin to build and maintain their exoskeletons, whereas fungi incorporate it into their cell walls to maintain rigidity.
<h4>Lipids</h4>
The second class of biological macromolecules are lipids, which include fats, oils, and waxes. Lipids are hydrophobic molecules that are almost entirely made up of carbon and hydrogen atoms. Often, lipids are grouped in three major categories; triglycerides, phospholipids, and steroids.
The most common type of lipid is triglycerides, which include fats from animals and oils from plants. Triglycerides generally serve as long-term energy storage molecules, except indigestible waxes, which are instead used as a waterproofing substance in both plants and animals. Triglycerides contain three fatty acid chains, which can be either saturated or unsaturated, connected to a glycerol molecule. Saturated fatty acid chains are linear molecules with a maximum number of hydrogen atoms, where every carbon in the chain is connected via a single bond. On the other hand, unsaturated fatty acid chains have kinks due to the presence of at least one double bond. Additionally, unsaturated fats can be &#8220;trans&#8221; fats if the hydrogens around the double bond oppose each other. While trans fats occur naturally, they are generated during industrial production of saturated vegetable oils with hydrogen. Similar to saturated fatty acids, trans fats stack very well due to their relative linearity. However, trans fats cause problems for human heart health, such as the damaging the lining of arteries and causing inflammation when digested2.
Phospholipids are similar to triglycerides, however, one of the fatty acid chains is replaced with a phosphate-containing polar group. Therefore, phospholipids have a hydrophilic head and two hydrophobic fatty acid tails. These properties of phospholipids are crucial to the cell membrane structure and function.
Steroids are lipids that are composed of fused carbon rings with varying functional groups. Cholesterol is a steroid that is also a cell membrane component. Moreover, cholesterol is used to synthesize other steroids, including sex hormones such as estrogen and testosterone. Although cholesterol is essential for cell membrane structure and hormone synthesis, high levels of plasma cholesterol are implicated in plaque accumulation inside blood vessels and causing coronary disease3.
<h4>Proteins</h4>
The third class of biological macromolecules are proteins, which are made up of chains of amino acids. There are 20 different amino acids, all with a similar base structure but each has a unique side chain called an &#8216;R-group&#8217;. A single amino acid has an N-terminal end which is an amino group (NH3+) and a C-terminal end which is a carboxyl group (-COOH). These groups link together, N-terminal to C-terminal, in a chain connected by peptide bonds. Proteins are important for maintaining body functions as enzymes, hormones, structural components and transport molecules, and play vital roles in muscle contractibility, immunity and blood clotting. However, issues can arise in protein structure and function, and these issues are often genetic. For instance, normal red blood cells are round, but in people affected by sickle cell anemia, cells have a curved shape with an exposed hydrophobic region, caused by a mutation in a protein called hemoglobin S. This shape reduces the capacity to carry oxygen and causes the cells to get stuck in blood vessels. This results in many detrimental symptoms to the person carrying the mutation, and people who inherit two copies of the sickle cell gene often suffer ill effects or even possibly die because of the reduced capacity of sickled cells to transport oxygen. In a twist, those carrying only one copy of the gene are resistant to infection from malaria, so the disease has been able to be passed on and persists in countries with elevated levels of malaria infections4.
<h4>Nucleic Acids</h4>
The fourth class of biological macromolecules are the nucleic acids, which are composed of monomers known as nucleotides. These monomers are composed of three parts: a phosphate group, a ribose sugar and a nitrogen base. Nucleotides differ from each other by their nitrogen bases and the type of ribose they contain. Single nucleotides generally act as energy carriers inside cells, as well as function as messenger molecules. However, the nucleotide polymers or nucleic acids such as deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) are hereditary molecules that contain the genetic information to construct cellular products.
<h4>Macromolecule Detection</h4>
Biological macromolecules in food or other substances can be detected by using their specific chemical properties. For example, monosaccharides have free aldehyde (-CHO) or ketone (-C=O) groups that can reduce other compounds, meaning they are substances that cause other molecules to lose electrons, thus monosaccharides are also known as reducing sugars. This property is used to detect the presence of monosaccharides with an indicator called Benedict&#8217;s reagent. This indicator contains copper ions (Cu2+) which are reduced by monosaccharides as observed with a change of the solution color from blue to a reddish orange, though the intensity of the color varies based on the original concentration of the reducing sugar. As such, observation of a green color means that there is only a small amount of reducing sugars present in the solution. Amylose in starch exists in a coiled structure because of the bond angles in the polymer chain. The iodine indicator, iodine-potassium iodide (IKI), reacts with these coiled molecules and will turn the solution a dark bluish-black to indicate the presence of amylose. However, if starch amylose isn&#8217;t present, the reaction will not take place, and the solution will remain a yellowish-brown color. A Sudan IV test is performed to test for the presence of lipids. This dye is lipophilic and solubilizes when lipids are present, thus a red color is retained in the presence of lipids. Biuret&#8217;s reagent, an indicator for the presence of proteins, contains copper ions (Cu2+) which react with the peptide bonds and turn the solution from blue to dark violet color. This reagent needs to react with a sufficient number of these peptide bonds to produce the expected violet color, so a pinkish color will result if the amino acid chains are not long enough.
<h4>References</h4>
<ol class="references">
	<li>Rasnik K. Singh, Hsin-Wen Chang, Di Yan, Kristina M. Lee, Derya Ucmak, Kirsten Wong, Michael Abrouk, Benjamin Farahnik, Mio Nakamura, Tian Hao Zhu, Tina Bhutani, Wilson Liao. Influence of diet on the gut microbiome and implications for human health. J Transl Med. 2017, Vol. 15, 73 doi: 10.1186/s12967-017-1175-y.</li>
	<li>Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am J Clin Nutr. 2010, Vol. 91, 3 (535-46).</li>
	<li>Joseph L. Goldstein, Michael S. Brown. A Century of Cholesterol and Coronaries: From Plaques to Genes to Statins. Cell. 2015, Vol. 161, 1 (161-72).</li>
	<li>Michael Aidoo, Dianne J Terlouw, Margarette S Kolczak, Peter D McElroy, Feiko O ter Kuile, Simon Kariuki, Bernard L Nahlen, Altaf A Lal, Venkatachalam Udhayakumar. Protective effects of the sickle cell gene against malaria morbidity and mortality. Lancet. 2002, Vol. 359, 9314 (1311-1312).</li>
</ol>

Biomolecules
Organisms contain a wide variety of organic molecules with numerous functions which depend on the chemical structures and properties of these ...

Education

JoVE Lab Manual

Fundamentals

biomolecules and their tests

Biomolecules are the organic molecules that living things use for structure, energy, and heredity. They all have a carbon backbone and hydrogen atoms, and carbon can form four covalent bonds. That bonding flexibility lets carbon build chains, branches, rings, and other complex shapes. Biomolecules also commonly include oxygen, nitrogen, phosphorus, and sulfur.

Small building blocks join together to make larger molecules. These units are called monomers. Two monomers can form a dimer through dehydration synthesis, which removes a hydrogen atom from one monomer and a hydroxyl group from the other. This releases water and creates a covalent bond. The reverse reaction is hydrolysis, where water helps split the molecule back into its original monomers. Many monomers can link into polymers, and different polymers can combine into biological macromolecules. Most biomolecules fall into four main groups: carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates are often called carbon water because they contain carbon, hydrogen, and oxygen in about a 1:2:1 ratio. Their monomers are monosaccharides, or simple sugars. Glucose is the most common monosaccharide in living organisms, and fructose and galactose are other six-carbon sugars with the same formula but different structures. When two monosaccharides join, they form disaccharides such as sucrose, lactose, and maltose. These sugars support short-term energy storage.

Larger carbohydrate polymers also have important jobs. Starch stores energy in plants and includes amylose and amylopectin. Amylose makes up about 10-20% of starch and forms a helical chain, while amylopectin is the main branched form. Glycogen is very similar to starch, but animals store and use it in liver and muscle tissue. Ribose and deoxyribose are five-carbon sugars found in nucleic acids. Cellulose is a rigid plant polymer made of glucose, and humans cannot digest it because they do not have the right enzymes. Even so, dietary fiber helps support healthy gut flora. Chitin is another structural polysaccharide. Arthropods use it in exoskeletons, and fungi use it in cell walls.

Lipids include fats, oils, and waxes. They are hydrophobic, which means they do not mix well with water, and they are made mostly of carbon and hydrogen. The main lipid groups are triglycerides, phospholipids, and steroids. Triglycerides contain glycerol and three fatty acid chains. They usually serve as long-term energy storage, while waxes act as waterproofing substances in plants and animals. Fatty acid chains can be saturated or unsaturated. Saturated chains are straight and have only single bonds. Unsaturated chains contain at least one double bond and have kinks. Some unsaturated fats are trans fats, which can form during industrial hydrogenation of vegetable oils. These fats stack well, but they can damage artery linings and promote inflammation. Phospholipids have a polar phosphate head and two hydrophobic tails. This structure helps form cell membranes. Steroids are fused carbon-ring lipids. Cholesterol is one steroid found in cell membranes, and it is also used to make sex hormones such as estrogen and testosterone. However, high plasma cholesterol can contribute to plaque buildup and coronary disease.

Proteins are chains of amino acids. There are 20 common amino acids, and each has the same basic structure plus a unique R-group, or side chain. Each amino acid has an N-terminal amino group and a C-terminal carboxyl group. Amino acids join from N-terminal to C-terminal through peptide bonds. Proteins work as enzymes, hormones, structural materials, and transport molecules. They also help with muscle contraction, immunity, and blood clotting. Protein changes can cause disease. In sickle cell anemia, a mutation in hemoglobin S changes red blood cell shape and exposes a hydrophobic region. This lowers oxygen transport and can make cells stick in blood vessels. People with two copies of the sickle cell gene can be severely affected. People with one copy are more resistant to malaria, which helps explain why the gene remains common in areas with malaria.

Nucleic acids store and pass on genetic information. Their monomers are nucleotides, each made of a phosphate group, a ribose sugar, and a nitrogen base. Nucleotides differ by their bases and by the type of sugar they contain. Single nucleotides can act as energy carriers and messenger molecules inside cells. Polymer forms of nucleotides include DNA and RNA, which contain the instructions used to build cellular products.

Biomolecules can be detected by using their chemical properties. Benedict’s reagent tests for reducing sugars, which are monosaccharides with free aldehyde or ketone groups that can reduce other compounds. Copper ions in the reagent change from blue to reddish orange, and a green color shows only a small amount of reducing sugar. IKI, or iodine-potassium iodide, tests for amylose in starch and turns dark bluish-black when amylose is present. If amylose is absent, the solution stays yellowish-brown. Sudan IV tests for lipids and leaves a red color when lipids are present. Biuret’s reagent tests for proteins by reacting with peptide bonds and changing from blue to dark violet. If the amino acid chain is too short, the color may appear pink instead of violet.

Biomolecules and Their Tests

scientific method

Scientific Method Steps and Controls

The scientific method gives scientists a way to solve problems and explain natural events. Its development grew alongside new ideas in science during the European Renaissance. Thinkers such as Francis Bacon, Galileo, and Isaac Newton helped formalize the process. Although the method has changed over time, much of its basic framework is still used today. The process begins with observation and a clear question. A scientist first notices a natural phenomenon and then asks why it happens. This...

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Biomolecules are the organic molecules that living things use for structure, energy, and heredity. They all have a carbon backbone and hydrogen atoms, and carbon can form four covalent bonds. That bonding flexibility lets carbon build chains, branches, rings, and other complex shapes. Biomolecules also commonly include oxygen, nitrogen, phosphorus, and sulfur. Small building blocks join together to make larger molecules. These units are called monomers. Two monomers can form a dimer through...

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fundamentals

Learn how carbohydrates, lipids, proteins, and nucleic acids are built, what they do, and how common lab tests identify them.

Biomolecules and Their Tests | JoVE K12

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Cells

Cellular processes

Virginia  Standards of Learning

HIgh School

BIO.2

BIO.2.b

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

High School

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HS-LS1-6

Next Generation Science Standards

Florida Department of Education

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SC.912.L.18.1

new-york-state-science-learning-standards

New York State Science Learning Standards

matter-and-energy-in-organisms-and-ecosystems

Matter and Energy in Organisms and Ecosystems

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Georgia Standards of Excellence

SB1.c

Prepare glucose, cornstarch, gelatin, and oil samples for a high school macromolecules lab. Learn the solution setup and beaker labeling steps.

Macromolecule Indicator Solution Prep | JoVE K12

Use Benedict's, iodine, Sudan IV, and Biuret tests to identify sugar, starch, lipid, and protein in unknown solutions through color changes.

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Compounds Essential to Human Function

The human body is composed of cells that are fundamentally made up of several different molecules. These molecules are essential to carry out all ...

Solution Preparation
ExpandCAUTION: It is important to always use care when handling reagents. For example, iodine will stain clothes and skin so wear ...

Identifying Macromolecules with Indicator Solutions
ExpandHYPOTHESES: In this activity, the experimental hypothesis might be that the addition of an ...

pH Regulation in Cells

pH plays a critical role in maintaining normal cellular activities. It helps maintain the structure and function of various proteins, dictates the charge ...

Chemistry of the Cell

Overview of Functional Groups

Functional groups are a group of atoms with characteristic properties, which when linked to the carbon skeleton of a molecule, alter the properties of ...

Introduction to Carbohydrates

Carbohydrates, proteins, and fats are the primary macronutrients in the human diet. However, carbohydrates are the most favored source of energy in the ...

Carbohydrate Metabolism

Sugars as Energy Storage Molecules

What are Lipids?

lipid-derived-compounds-in-the-human-body

Lipid-derived Compounds in the Human Body

Fats and lipids are crucial components in the human body. Some lipid-derived compounds, such as fat-soluble vitamins, eicosanoids, lipoproteins, and ...

Fats as Energy Storage Molecules

What are Proteins?

Protein Organization

Globular Proteins

In organisms, proteins are the most abundant macromolecules. They act as the building blocks of life and play various crucial roles in the body. Proteins ...

Fibrous Proteins

Fibrous proteins are either long and narrow proteins or assemble to form long and thin structures. They contain repetitive units and usually consist of ...

Protein Denaturation

The function of proteins depends on their native three-dimensional structure, which is dictated by the amino acid sequence of the specific protein. ...

Role of Proteins in the Human Body

Proteins are the building block of life. They are also&#160; the most abundant macromolecules with as many diverse roles in the body. They are part of ...

Nucleic Acids and Nucleotides

Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell&#39;s genetic blueprint and have instructions for its ...

Nucleic Acid Structure

The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group ...

ATP Energy Storage and Release

ATP and Macromolecule Synthesis

Biological macromolecules are organic compounds, predominantly composed of carbon atoms. The carbon atoms are covalently bonded with hydrogen, oxygen, ...

Construct an explanation to illustrate relationships between structure and function of major macromolecules essential for life.

Introduction to Enzymes

The use of enzymes by humans dates to 7000 BCE. Humans first used enzymes to ferment sugars and produce alcohol without knowing that this was an ...

Enzymes and Activation Energy

The activation energy (or free energy of activation), abbreviated as Ea, is the small amount of energy input necessary for all chemical reactions to ...

Introduction to Enzyme Kinetics

Enzyme kinetics studies the rates of biochemical reactions. Scientists monitor the reaction rates for a particular enzymatic reaction at various substrate ...

Turnover Number and Catalytic Efficiency

The turnover number of an enzyme is the maximum number of substrate molecules it can transform per unit time. Turnover numbers for most enzymes range from ...

Catalytically Perfect Enzymes

The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at ...

introduction-to-mechanisms-of-enzyme-catalysis

Introduction to Mechanisms of Enzyme Catalysis

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Ligand Binding and Linkage

Cooperative Allosteric Transitions

Ribozymes

Carry out investigations to illustrate how enzymes act as catalysts for biochemical reactions and how environmental factors affect enzyme activity.

LS.Bio.1.2

What are Cells?

Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium or trillions of them, ...

Cell Size

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Eukaryotic Compartmentalization

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Prokaryotic Cells

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Cytoplasm

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The Nucleus

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Endoplasmic Reticulum

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Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Golgi Apparatus

As they leave the Endoplasmic Reticulum (ER), properly folded and assembled proteins are selectively packaged into vesicles. These vesicles are ...

Lysosomes

Lysosomes are membrane-enclosed spherical sacs derived from the Golgi apparatus. The most important function of the lysosome is degrading macromolecules ...

Peroxisomes

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Introduction to the Cytoskeleton

Overview of the Cytoskeleton
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Introduction to Actin

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Cell Structure

Background
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Overview of Myosin Structure and Function

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Visualizing Onion and Cheek Cells
ExpandImmediately before the experiment, wash and peel onion bulbs for the class.
Remove the entire brown outer skin and ...

Microtubules

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Types of Intermediate Filaments

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Gap Junctions

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The Extracellular Matrix

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Tissues

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Plant Cell Wall

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Plasmodesmata

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LS.Bio.1.3

Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium, or trillions of them, ...

the-tree-of-life-bacteria-archaea-and-eukaryotes

The Tree of Life - Bacteria, Archaea, and Eukaryotes

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Construct explanations to compare prokaryotic and eukaryotic cells in terms of structures and degree of complexity.

LS.Bio.1.4

The DNA Helix

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RNA is the Missing Link Between ...

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RNA Structure

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Types of RNA

Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse ...

Transcription

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Bacterial RNA Polymerase

Eukaryotic RNA Polymerases

General Transcription Factors

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RNA Polymerase II Accessory Proteins

Transcription Elongation Factors

Alternative RNA Splicing

Nuclear Export of mRNA

Transfer RNA Synthesis

Ribosomal RNA Synthesis

The Nucleolus

Additional Subnuclear Structures

Translation

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Construct an explanation to summarize how DNA and RNA direct the synthesis of proteins.

LS.Bio.1.5

Analyze how the relationship between structure and function supports life processes within organisms.

Biomolecules and Their Tests

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