Biochemistry: Carbohydrates and Lipids Flashcards
How many covalent bonds can a carbon atom form, and what types of bonds can it create?
A carbon atom can form up to four covalent bonds. It can create single, double, or triple bonds with other atoms, including other carbon atoms.
What elements are commonly bonded to carbon in organic molecules?
hydrogen, oxygen, and nitrogen in organic molecules
Why is carbon essential in the formation of organic molecules?
Forms four covalent bonds, creates complex and diverse structures like long chains, rings, and branches, which are the backbone of organic molecules.
How does a carbon atom complete its valence shell?
A carbon atom completes its valence shell by sharing its four outer electrons with other atoms, forming covalent bonds.
What is the ratio of carbon, hydrogen, and oxygen in carbohydrates?
Carbohydrates have a 1:2:1 ratio of carbon, hydrogen, and oxygen (C:H:O)
What are the three major groups of carbohydrates, and how are they classified?
The three major groups of carbohydrates are monosaccharides, disaccharides, and polysaccharides. They are classified by size and the number of building blocks they contain.
What is the function of glucose in the body, and how is excess glucose stored?
Glucose is the main energy molecule, converted into ATP for energy. Excess glucose is stored as glycogen in the liver and muscles, it may also be stored as fat.
What is the difference between dehydration synthesis and hydrolysis in carbohydrate digestion?
Dehydration synthesis joins monosaccharides to form disaccharides or polysaccharides by removing water. Hydrolysis breaks disaccharides and polysaccharides into monosaccharides by adding water.
What are some examples of polysaccharides, and what are their roles in organisms?
- Glycogen (animal glucose storage)
- starch (plant glucose storage)
- cellulose (structural component of plant cell walls)
What are functional groups, and how do they affect organic molecules like carbohydrates?
groups of atoms, influence the chemical properties, involved in chemical reactions and impact specific properties to organic molecules.
What are two distinctive properties of organic molecules dependent on?
The carbon skeleton and functional groups.
What is a monosaccharide?
Simplest carbohydrate unit, includes pentose sugars (deoxyribose & ribose), hexose sugars/isomers (fructose, galactose, mannose, glucose), isomers
The four functions of Carbohydrates
ATP, component of DNA & RNA, attached to glycoproteins or glycolipids, energy storage (glycogen)
Function of glycoproteins and glycolipids.
Membrane structure, connective tissue structure and lubrication fluids, cell-cell recognition
Describe the main molecule that supplies energy?
Glucose, converted in ATP, CO2, H2O which aids in cellular respiration.
What is a disaccharide?
2 monosaccharides joined together via covalent bond formed by dehydration synthesis.
Examples of disaccharides
Lactose, Maltose and Sucrose
Why are disaccharides be broken down during digestion, and how is this process carried out?
Disaccharides are too large to be absorbed directly into the body, so they must be broken down into their monosaccharide components. This process is carried out by hydrolysis, which is performed by digestive enzymes
What is a polysaccharide?
Many monosaccharides joined together covalently
What elements primarily compose lipids, and what is the significance of the low oxygen content in lipids?
Lipids are primarily composed of carbon (C) and hydrogen (H), with very little oxygen (O). The low oxygen content makes lipids more energy-dense compared to carbohydrates, allowing them to store more energy.
Why are lipids considered more energy-dense than carbohydrates?
Lipids are more energy-dense because they contain more carbon-hydrogen bonds and less oxygen, which allows them to store more energy than carbohydrates.
What does it mean for a molecule to be non-polar, and how does this relate to fatty acids?
A non-polar molecule has equal sharing of electrons in its bonds, and fatty acids are non-polar, meaning they do not mix well with polar substances like water.
What is the difference between hydrophilic and hydrophobic molecules?
Hydrophilic molecules can mix with water (water-loving), while hydrophobic molecules cannot mix with water (water-fearing) and tend to push away from it.
Why do water and oil (containing non-polar molecules like fatty acids) not mix?
Water and oil do not mix because water is polar, and oil contains non-polar molecules, so they repel each other due to differences in polarity.
What are triglycerides made of, and how are they synthesized?
Triglycerides are made of a glycerol molecule and three fatty acid chains. They are synthesized through a dehydration reaction, where water is removed to bond the components.
What is the structure of a phospholipid, and what role does it play in the body?
A phospholipid consists of a polar, hydrophilic head, two non-polar, hydrophobic tails, and a phosphate group. Phospholipids are major components of cell membranes, helping with membrane structure and fluidity.
How do steroids differ from other lipids, and what are some examples and their functions?
Steroids have four interlocking hydrocarbon rings and various functional groups. Examples include sex hormones (e.g., estrogen, testosterone), cholesterol (for cell membranes and bile production), and bile salts (for fat digestion).
What are the functions of fats in the body?
- Energy storage (triglycerides provide energy when glucose is unavailable).
- Cell membrane structure (phospholipids and cholesterol).
- Fat-soluble vitamin absorption (A, D, E, K).
- Hormone production (e.g., cortisol, testosterone).
- Insulation and protection of organs.
What is the main difference between saturated and unsaturated fats in terms of their chemical structure?
Saturated fats have only single bonds between carbon atoms, with all bonds filled by hydrogen, making them straight and solid at room temperature. Unsaturated fats have one or more double bonds between carbon atoms, causing the chain to bend and making them liquid at room temperature.
What are polyunsaturated fats, and why are they considered beneficial?
Polyunsaturated fats have two or more double bonds in their fatty acid chains. They are beneficial because they can help control blood cholesterol levels, making them healthier than saturated fats.
Why do unsaturated fats tend to be liquid at room temperature, while saturated fats are solid?
Unsaturated fats have double bonds in their carbon chains, causing the chain to bend and preventing tight packing, making them liquid. Saturated fats have only single bonds and straight chains, allowing them to pack closely and remain solid at room temperature.
What is the structure of a phospholipid molecule?
A phospholipid has two fatty acid chains (non-polar tails) and a phosphate group (polar head) attached to a glycerol molecule.
How do the polar head and non-polar tail of a phospholipid differ in terms of their interaction with water?
The polar head is hydrophilic (water-loving) and interacts with water, while the non-polar tail is hydrophobic (water-fearing) and avoids contact with water.
Why are phospholipids important for cell membranes?
Phospholipids form a bilayer in which the hydrophilic heads face outward toward water and the hydrophobic tails face inward, creating a semi-permeable membrane that controls the passage of substances in and out of the cell.
