Chapter 5 - Biological Macromolecules and Lipids Flashcards
What are the four main classes of the most important large molecules found in all living things?
Carbohydrates, lipids, proteins and Nucleic acids.
As carbohydrates, proteins, and nucleic acids are so large what do we call them?
Macromolecules.
What does the protein called alcohol dehydrogenase do?
Breaks down alcohol in the body
What are polymers?
A polymer is a long molecule consisting of many similar or identical building blocks linked by covalent bonds, much as a train consists of a chain of cars.
What are monomers?
The repeating units that serve as the building blocks of a polymer are smaller molecules called monomers. In addition to forming polymers, some monomers have functions of their own.
What is the difference between a polymer and a monomer?
A monomer is small repeating units which make up what you would call a polymer.
How are polymers broken down?
Polymers are disassembled to monomers by hydrolysis, a process that is essentially the reverse of the dehydration reaction.
What is a dehydration reaction?
In chemistry, a dehydration reaction is a conversion that involves the loss of water from the reacting molecule or ion.
How are bonds made between monomers?
When a bond forms between two monomers, each monomer contributes part of the water molecule that is released during the dehydration reaction: One monomer provides a hydroxyl group (OH), while the other provides a hydrogen (H). This reaction is repeated making a polymer (also called polymerization).
How are bonds made between monomers?
When a bond forms between two monomers, each monomer contributes part of the water molecule that is released during the dehydration reaction: One monomer provides a hydroxyl group (OH), while the other provides a hydrogen (H). This reaction is repeated making a polymer (also called polymerisation).
What is a hydrolysis reaction?
In its simplest definition, hydrolysis is a chemical reaction in which water is used to break down the bonds of a particular substance. Hydrolysis means water breakage (from the Greek hydro, water, and lysis, break)
What is an example of hydrolysis in our bodies?
An example of hydrolysis within our bodies is the process of digestion. The bulk of the organic material in our food is in the form of polymers that are much too large to enter our cells. Within the digestive tract, various enzymes attack the polymers, speeding up hydrolysis. Released monomers are then absorbed into the bloodstream for distribution to all body cells.
Other than the formation and breakdown of polymers what other molecule can we use dehydration and hydrolysis reactions for?
Lipids
What is the term for the simplest carbohydrates?
Monosaccharides
What are polysaccharides?
Carbohydrate macromolecules that are made up of many monosaccharide subunits linked by covalent bonds.
What is the most common Monosaccharide?
Glucose (C6H12O6)
What is the essential parts of the structure of a sugar (Carbohydrate)?
The Carbonyl group (C=O) and the multiple hydroxyl groups (-OH)
Depending on the location of the Carbonyl group what are the two types of molecule a sugar can be?
Aldose (Aldehyde sugar), or a Keytose (Keytone sugar)
What type of sugar is glucose?
An aldose (Aldehyde sugar)
What are things to remember about classifying and naming sugars?
Most names for sugars end in -ose. And another criterion for classifying sugars is the size of the carbon skeleton, which ranges from three to seven carbons long. Small differences in the structure is enough to have a complete different sugar.
What is a triose?
A three-carbon sugar (C3H6O3)
What is a pentose?
A five-carbon sugar (C5H10O5)
What is a Hexose?
A six-carbon sugar (C6H12O6)
Although it is convenient to draw glucose with a linear car- bon skeleton, this representation is not completely accurate. How would you accurately draw this 6 carbon structure?
In aqueous solutions, glucose molecules, as well as most other five- and six-carbon sugars, form rings, because they are the most stable form of these sugars under physiological conditions.
What is cellular respiration?
Cellular respiration is the process by which cells in plants and animals break down sugar and turn it into energy, which is then used to perform work at the cellular level.
Which Monosaccharide is a major nutrient for cells in terms of cellular respiration?
Glucose
Other than being a major nutrient for cells what else does glucose do for the body?
The carbon skeleton of glucose serves as raw material for the formation of other types of small organic molecules, such as amino acids and fatty acids.
What is a disaccharide?
two monosaccharides joined by a glycosidic linkage, a covalent bond formed between two monosaccharides by a dehydration reaction
What is sucrose?
A disaccharide composed of the two monosaccharides Glucose and Fructose
How do plants transport carbohydrates?
Generally via the leafs to the plants roots in the form of sucrose
What is the sugar present in milk?
Lactose
What type of carbohydrate is lactose?
A Disaccharide composed of a glucose molecule joined to a galactose molecule.
What must happen too disaccharides to be used as energy?
Disaccharides must be broken down into monosaccharides to be used for energy by organisms
What is Lactase?
Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives milk its sweetness.
What is lactose intolerance?
A common condition in humans who lack lactase, the enzyme that breaks down lactose. The sugar is instead broken down by intestinal bacteria, causing formation of gas and subsequent cramping.
What are polysaccharides?
Polysaccharides are macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages.
What do polysaccharides do?
Some polysaccharides serve as storage material, hydrolysed as needed to provide sugar for cells. Other polysaccharides serve as building material for structures that protect the cell or the whole organism.
What type of polysaccharides do plants store and how does it use this for energy?
Starch, forming starch enables the plant to stockpile surplus glucose. Because glucose is a major cellular fuel, starch represents stored energy. The sugar can later be withdrawn by the plant from this carbohydrate “bank” by hydrolysis, which breaks the bonds between the glucose monomers.
What is starch?
A polysaccharide made up of glucose units joined by glycosidic bonds. In plants starch is the main way its plant cells stores energy in the form of glucose.
What are plastids?
Plastids are the site of manufacture and storage of important chemical compounds used by the cells of autotrophic eukaryotes.
Where in a plant is starch stored?
In its Plastids.
How is starch released from a plant cells plastids?
Through Hydrolysis. AKA the chemical breakdown of a compound due to a reaction with water.
What kind of linkages join the glucose monomers together in starch?
Generally 1-4 linkages (number carbon 1 to number carbon 4)
What is the simplest form of starch as its function?
Amylose is important in plant energy storage. Although it is less readily digested than other forms of starch such as amylopectin it is preferred for starch storage in plants due to its helical structure which takes up less space in the cell.
Which polysaccharide do animals store for chemical energy?
Glycogen
Where is glycogen (Carbohydrate) stored in animals?
Mainly in the liver and muscle cells
What happens when a demand of sugar increases in the body?
Hydrolysis of the glycogen stores occurs which releases glucose into the cells.
Why is glycogen a good form of carbohydrate storage in the body?
Because it is so extensively branched it has multiple free ends available for hydrolysis therefore it breaks down into glucose easily.
Why are low carbohydrate diets not ideal?
Glycogen stores are easily depleted in the body and require regular replenishing (are not long term sources of chemical energy). Therefore without regular servings of carbohydrates the body can become weak and experience fatigue.
What are structural polysaccharides?
Any polysaccharide that serves to supply stiffness to a plant or insect.
`What is the major component of the tough walls that enclose plant cells?
Cellulose
What is the most plentiful organic compound on earth?
Cellulose
What is cellulose?
A structural polysaccharide in plants
How many linkages join the glucose monomers together in cellulose?
1-4 glycosidic linkages
Both starch and cellulose have 1-4 linkages but how do these linkages differ?
Starch can have two different placements of the hydroxyl group (-OH), either below or above carbon number 1. In starch all monomers are in the same orientation (alpha config- with the -OH group below 1st carbon), In cellulose the glucose monomers are in the b config making each glucose monomer opposite to its neighbours. Due to these differences in linkages starch molecules tend to form a helical shape and cellulose molecules tend to form a straight shape
What are microfibrils in plants?
A microfibril is a fibre like strand consisting of glycoproteins and cellulose. Cellulose microfibrils are laid down in the inner surface of the primary cell wall. They are a strong building material for plants.
Why is it important that cellulose is unbranched?
This allows the molecule to form long and straight chains as a straight chain is ideal for the formation of strong fibers.
Can the same enzymes that digest starch in the body by hydrolysing, hydrolyse cellulose and why?
NO, because 1: enzymes are reaction specific and 2: it is very rare than your body will have cellulose hydrolysing enzymes
What is Chitin?
Chitin is a structural polysaccharide in arthropods (insects, spiders, crustaceans, and related animals) to build their exoskeletons.
What is an exoskeleton?
A hard case that surrounds the soft parts of an animal. It is made out of chitin embedded in a layer of proteins, the case is leathery and flexible at first, but becomes hardened when the proteins are chemically linked to each other (as in insects) or encrusted with calcium carbonate (as in crabs)
What is the function of chitin in fungi?
Instead of using cellulose, fungi uses chitin as the building material for its cell walls.
What are lipids and their functions?
A lipid is a biomolecule that is soluble in nonpolar solvents. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. … Although the term “lipid” is sometimes used as a synonym for fats, fats are a subgroup of lipids called triglycerides..
Do lipids mix well or poorly with water?
poorly
Why are lipids hydrophobic?
The hydrophobic behavior of lipids is based on their molecular structure. Although they may have some polar bonds associated with oxygen, lipids consist mostly of hydrocarbon regions.
What are 3 important types of lipids?
- Fats 2. Phospholipids 3. Steroids
What are fats?
large molecules constructed from two kinds of smaller molecules called: glycerol and fatty-acids
What is glycerol?
Glycerol is an alcohol; each of its three carbons bears a hydroxyl group.
What are fatty acids?
A fatty acid has a long carbon skeleton, usually 16 or 18 carbon atoms in length. The carbon at one end of the skeleton is part of a carboxyl group, the functional group that gives these molecules the name fatty acid.
Why are fats hydrophobic?
The carbon chain of fatty acids is composed of carbon and hydrogen atoms making the chain non-polar and therefore unable to react with waters polar bonds (Hydrophobic).
What is the structure of a fat?
Three fatty acid molecules are each joined to glycerol by an ester linkage, a bond formed by a dehydration reaction between a hydroxyl group and a carboxyl group. The resulting fat, also called a triacylglycerol, thus consists of three fatty acids linked to one glycerol molecule.
What is a saturated fatty acid and what is it saturated with?
A saturated fat is a type of fat in which the fatty acid chains have all or predominantly single bonds. If there are no double bonds between carbon atoms composing a chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton. Such a structure is said
to be saturated with hydrogen
What is an unsaturated fat?
An unsaturated fatty acid has one or more double bonds, with one fewer hydrogen atom on each double-bonded carbon. Nearly every double bond in naturally occurring fatty acids is a cis double bond, which creates a kink in the hydrocarbon chain wherever it occurs.
What is the difference between cis and trans?
The difference between the two is that the cis isomer is a polar molecule whereas the trans isomer is non-polar.
Are animal fats typically saturated or unsaturated?
Saturated as their flexibility allows the fat molecules to pack together tightly therefore they are solid at room temperature.
Are plants typically saturated or unsaturated?
Unsaturated which means they have double or triple bonds. The kinks where the cis double bonds are located prevent the molecules from packing together closely enough to solidify at room temperature. Therefore these fats typically exist as liquids at room temperature.
What does hydrogenated vegetable oils mean on food labels?
That unsaturated fats have been synthetically converted to saturated fats by adding hydrogen, allowing them to solidify. Peanut butter, margarine, and many other products are hydrogenated to prevent lipids from separating out in liquid (oil) form.
What is cardiovascular disease known as atherosclerosis caused by?
A diet rich in saturated fats
What is the cardiovascular disease known as atherosclerosis?
In this condition, deposits called plaques develop within the walls of blood vessels, causing inward bulges that impede blood flow and reduce the resilience of the vessels
What type of double bonds in fats contribute to coronary heart disease?
Trans fats (Trans double bonds)
