Biology 101 - Biochemical Basics Part 2
This deck covers key concepts in protein structure, lipid types, nucleic acids, and metabolic processes, providing a foundational understanding of biochemical principles.
Define: the primary structure of a protein
Key Terms
Define: the secondary structure of a protein
Refers to the folding of the amino acid chain into repetitive structures due to hydrogen bonding between backbone groups.
What functional group is present in all peptide bonds?
amides In fact, they are sometimes alternatively known as amide linkages. A peptide bond forms when the amine group of one amino acid attacks the c...
Define: the quaternary structure of a protein
It is present only in proteins that are composed of multiple subunits. This level of structure refers to interactions between subunits. For example...
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| Term | Definition |
|---|---|
Define: the primary structure of a protein | It is simply its linear amino acid sequence. Primary structure is often written using either a one- or a three-letter abbreviation for each amino acid (for example, 'Gly-Pro-Ile-Cys…' or 'GPIC…'). |
Define: the secondary structure of a protein | Refers to the folding of the amino acid chain into repetitive structures due to hydrogen bonding between backbone groups. |
What functional group is present in all peptide bonds? | amides In fact, they are sometimes alternatively known as amide linkages. A peptide bond forms when the amine group of one amino acid attacks the carbonyl carbon of another. |
Define: the tertiary structure of a protein | Refers to its large-scale three-dimensional shape. Tertiary structure is determined by interactions between side chains and by hydrophobic interactions (the tendency for nonpolar groups to avoid facing the watery environment). |
Define: the quaternary structure of a protein | It is present only in proteins that are composed of multiple subunits. This level of structure refers to interactions between subunits. For example, hemoglobin (shown here) consists of four separate subunits, held together by various interactions and attractive forces. |
Define: lipids | A class of organic macromolecule characterized by their nonpolar (non-water-soluble) nature. Most notably, lipids include triglycerides (fats), oils, steroids, waxes, and phospholipids. |
What type of lipid is pictured here? | triglyceride A triglyceride is commonly known simply as a fat. It consists of three fatty acid molecules attached to a three-carbon glycerol backbone. |
The diagram below depicts a fatty acid. Is this fatty acid saturated, monounsaturated, or polyunsaturated? | polyunsaturated Saturated fatty acids have carbon chains that include only single bonds, while unsaturated fatty acids include one or more double bonds in their chains. Since this fatty acid contains three carbon-carbon double bonds, it is polyunsaturated. (To be monounsaturated, a fatty acid must include only one double bond in its carbon chain.) |
What functional groups are present in a typical fatty acid? | A carboxylic acid (COOH) group attached to a hydrocarbon chain. Fatty acids can combine with glycerol to form triglycerides, or fat. Fatty acids can also be broken down to provide cells with energy. |
What type of lipid would be expected to be most predominant in a eukaryotic cell membrane? | phospholipids The cell membrane (in both eukaryotes and prokaryotes) is composed mainly of phospholipids in the form of a 'bilayer,' or double layer. |
A typical phospholipid includes both a polar 'head' region and two nonpolar 'tails.' What term describes this property of having both polar and nonpolar regions? | amphipathic Specifically, the polar 'head' region includes phosphate, which is charged; this charge is what gives the head group its polarity. The two 'tails' consist of fatty acids, which are largely nonpolar due to their long hydrocarbon chains. |
What class of lipid is derived from the molecule below and plays a vital role in the endocrine system? | steroid hormones Steroid hormones are derived from cholesterol (shown here). These lipid molecules can be easily spotted due to their structures, which include four fused rings. |
Structures like that shown below are found in which of the four major classes of organic macromolecules? | Nucleic acids The structure pictured here is a nucleotide, as is evident from its nitrogenous base, sugar, and phosphate group. Nucleotides are the monomers ('building blocks') that form nucleic acids, including DNA and RNA. |
A student is analyzing an unknown biomolecule. He knows that the molecule includes covalent bonds and that it is not a lipid. He is also certain that the molecule contains carbon, hydrogen, and phosphorus, although it may also include other elements. This biomolecule is most likely a: | Nucleic acid All four of the main classes of organic macromolecule include covalent bonds, so that piece of information is unhelpful. However, only nucleic acids and (some) lipids can contain phosphorus. Since we are told that this molecule is not a lipid, it must be a nucleic acid. |
Define: nucleic acids | A class of organic macromolecule, which consists of long chains of nucleotide monomers and are involved in the storage and transmission of genetic material. |
Define: metabolism | It collectively refers to the biological processes that occur within cells. Specifically, these processes either generate energy through the breakdown of molecules or use energy to build molecules. Metabolism is also known as 'cellular respiration.' |
Define: catabolism | It is the biological breakdown of molecules into smaller units. Catabolic processes are accompanied by the generation of energy. The opposite of this class of metabolic reactions is anabolism. |
Define: anabolism | It is the creation of larger biomolecules from smaller units. Anabolic processes require energy input. The opposite of this class of metabolic reactions is catabolism. |
What broad distinction separates aerobic and anaerobic respiration? | Aerobic respiration requires oxygen, while anaerobic respiration does not require oxygen. As part of metabolism, both processes involve the breakdown of biological molecules and the eventual release of energy. |
Which metabolic process occurs in the cytosol regardless of the presence or absence of oxygen? | Glycolysis Glycolysis is a biochemical process that forms pyruvate from the breakdown of glucose. The pathway produces 2 NADH and a net total of 2 ATP per glucose molecule. |