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AP®︎/College Biology
Course: AP®︎/College Biology > Unit 1
Lesson 4: Properties, structure, and function of biological macromolecules- Molecular structure of DNA
- Antiparallel structure of DNA strands
- Molecular structure of RNA
- Introduction to amino acids
- Overview of protein structure
- Introduction to carbohydrates
- Carbohydrates
- Molecular structure of triglycerides (fats)
- Saturated fats, unsaturated fats, and trans fats
- Biological macromolecules review
- Properties, structure, and function of biological macromolecules
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Biological macromolecules review
Key terms
| Term | Meaning | |
|---|---|---|
| Biological macromolecule | A large, organic molecule such as carbohydrates, lipids, proteins, and nucleic acids. | |
| Monomer | A molecule that is a building block for larger molecules (polymers). For example, an amino acid acts as the building blocks for proteins. | |
| Polymer | A large molecule made of repeating subunits (monomers). For example, a carbohydrate is a polymer that is made of repeating monosaccharides. |
Types of biological macromolecules
| Biological macromolecule | Building blocks | Functions | Examples |
|---|---|---|---|
| Carbohydrates | Monosaccharides (simple sugars) | Provide cells with quick/short-term energy, source of dietary fiber | Glucose, sucrose, starch, cellulose, chitin |
| Lipids | Fatty acids and glycerol | Provide cells with long-term energy, make up biological membranes | Fats, phospholipids, waxes, oils, grease, steroids |
| Proteins | Amino acids | Provide cell structure, send chemical signals, speed up chemical reactions, etc | Keratin (found in hair and nails), hormones, enzymes, antibodies |
| Nucleic acids | Nucleotides | Store and pass on genetic information | DNA, RNA |
Common mistakes and misconceptions
- Describing macromolecules as “large” is relative. We refer to them as “macro” because they are large compared to other, smaller molecules. However, this does not mean that they are large enough to view with the naked eye. Even a large protein, like hemoglobin, is still a million times smaller than a grain of rice!
- Not all fats and carbohydrates are “bad.” Information about different kinds of diets can be confusing and may lead someone to believe that all fats or all carbohydrates are unhealthy. This simply isn’t the case. Fats and carbohydrates are actually essential for cellular function!
Want to join the conversation?
After reading the key terms, I am a little bit confused.. to my understanding, monomers are the makeup of polymers... is that correct? If so, are the terms "polymer" and "biological macromolecules" synonymous?(43 votes)
Hello,
As I understand it, polymers are a subdivision of biological macromolecules. 'Polymer' is the branch of macromolecules that is made up of ONLY ONE monomer that repeats itself.
For example, a carbohydrate is a macromolecule that is classified as a polymer because it is made up of repeating monosaccharides, but a fat (lipid) is a macromolecule that cannot be further classified because if you look under the 'monomers' column, it is built up by more than one monomer.
Hope this helped!(104 votes)
Isn't protein an energy molecule for muscles?(13 votes)
Rather than providing energy for muscles, they are structural components, which means they build and repair muscles. Protein is only used as energy if carbohydrates and lipids aren't available for energy (side note: breaking down protein for energy is unhealthy and dangerous!).
Hope this helps, - Layla(43 votes)
how can lipids act as a chemical messenger?(12 votes)
Some lipids such as steroid hormones serve as chemical messengers between cells, tissues, and organs, and others communicate signals between biochemical systems within a single cell.(17 votes)
Are phospholipids polymers?(11 votes)- There is considerable interest in the polymers bearing phospholipids in the main chains as the structures of these polymers are similar to biological tissues. Several polymers containing a phospholipid in the polymer backbone have been synthesized and characterized(8 votes)
- chicken fingers(14 votes)
Why aren't minerals a macromolecule?(7 votes)
What are the characteristics of a macromolecule?
Can you think of a mineral that meets all those criteria?
Does that help you to answer your question?(7 votes)
- which would be the differences between DNA and RNA were not very clear to me, they seem technically the same and I cannot differentiate them very well(5 votes)
If you are asking what the difference between the two is, here you go.
There are several differences. To start, DNA stands for deoxyribonucleic acid, while RNA stands for ribonucleic acid. These names describe the sugar that makes up their backbone--DNA = deoxyribose and RNA = ribose.
Second, while each has four nucleiotide bases, there is one difference. You probably know that DNA has guanine, cytosine, adenine, and thymine, and that guanine links to cytosine and adenine links to thymine. But RNA doesn't have thymine. Instead, it has uracil, a nucleiotide base with a slightly different chemical makeup. Thymine had the chemical formula C5H6N2O2 and uracil is C4H4N2O2. Uracil links to adenine in RNA just like thymine does in DNA
Finally, DNA is double-stranded and forms a double helix structure. RNA is single-stranded and is generally straight. DNA is a complete set of instructions needed for life (unless you're a virus, but that's a whole different story/debate) and RNA is used to copy DNA and to synthesize proteins. I know this is a lot to take in, but there are several videos and articles on Khan Academy to help. Here are a few.
https://www.khanacademy.org/science/high-school-biology/hs-molecular-genetics/hs-rna-and-protein-synthesis/v/molecular-structure-of-rna
https://www.khanacademy.org/science/high-school-biology/hs-molecular-genetics/hs-rna-and-protein-synthesis/v/rna-transcription-and-translation
https://www.khanacademy.org/science/high-school-biology/hs-molecular-genetics/hs-rna-and-protein-synthesis/a/hs-rna-and-protein-synthesis-review
Anyway, this is probably a lot, but I hope it helps!(14 votes)
- whats the main difference between saturated and unsaturated fats(3 votes)
From a chemistry perspective, saturated fats have no double bonds between carbon atoms, while unsaturated fats have one or more double bonds.
From a state of matter standpoint, saturated fats are solid at room temperature, while unsaturated fats are liquid or soft.
From a nutritionist's point of view, saturated fats can increase the risk for heart disease (because it stays as a solid at room temperature and can lead to atherosclerosis) and unsaturated fats can help maintain proper bodily functioning (because they stay as a liquid at room temperature and are less likely to clog your arteries.)
I know you asked for a main difference, but I included three because there are many differences between saturated and unsaturated fats. I hope you have a better understanding of saturated and unsaturated fats.(15 votes)
- why are vitamins not digested in the body(6 votes)
Vitamins are not digested, whereas, they are absorbed.
Vitamins are organic compounds that are required for normal animal metabolism but are either not created in the body or are created in insufficient amounts and must be received through your diet. Almost all of vitamin absorption goes to the small intestine.
Vitamin absorption in the intestine is important for avoiding deficiency disorders, and it can be limited by a variety of factors, including intestinal disease, genetic abnormalities in transport molecules, excessive alcohol use, and drug interactions.(9 votes)
Are monomers and monosacchrides the same thing? Also, what is a polypeptide?(7 votes)
Monomers are the building blocks of the four basic macromolecules of life- monosaccharides are the monomers of carbohydrates, amino acids are the monomers of proteins, glycerol/fatty acids are the monomers of lipids, and nucleotides are the monomers of DNA.
Polypeptides consist of a bunch of amino acids bound together- so in a way it's a monomer of proteins!(7 votes)