AP Biology : Identify structure and purpose of carbohydrates, lipids, proteins, and nucleic acids
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Example Question #21 : Identify Structure And Purpose Of Carbohydrates, Lipids, Proteins, And Nucleic Acids
The tails of phospholipids are __________.
hydrophobic
polar
lipophilic
hydrophilic
hydrophobic
The tails of phospholipids consist of hydrocarbons only. Thus they are nonpolar, hydrophobic, lipophilic and fat-soluble.
Example Question #21 : Identify Structure And Purpose Of Carbohydrates, Lipids, Proteins, And Nucleic Acids
In a cell membrane, the tails of the phospholipids point towards __________.
The exterior of the membrane, away from water
the exterior of the membrane, towards water
either the interior or the exterior of the membrane, depending on the type of cell membrane
the interior of the membrane, away from water
the interior of the membrane, away from water
The tails of phospholipids are hydrocarbons and are thus hydrophobic so they point towards the interior of the membrane to avoid contact with the aqueous solutions of the cytoplasm and the extracellular fluid.
Example Question #55 : Macromolecules
A given molecule has a structure containing a carbon skeleton of four fused rings. Which of the following is it most likely to be?
Cholesterol
Fat
Phospholipid
Fatty acid
Cholesterol
Cholesterol is class of lipids known as steroids. All steroids have four fused carbon rings in their structures. Fats, fatty acids and phospholipid do not contain any ring structures. Fatty acids are components of both fats and phospholipids and are long chains of hydrocarbons. Phospholipids contain two fatty acids attached to a polar head and a phosphate group.
Example Question #56 : Macromolecules
In a cell membrane, the heads of the phospholipids point toward __________.
None of these; it varies randomly throughout the membrane.
the interior of the membrane, away from water
the exterior of the membrane, facing water
Cannot be determined without knowing the type of cell membrane
the exterior of the membrane, facing water
The heads of phospholipids are hydrophilic and so they will face the exterior of the cell membrane in order to interact with the aqueous environments of the extracellular fluid and the cytosol. The hydrophobic tails will face the interior of the membrane to avoid water contact.
Example Question #23 : Identify Structure And Purpose Of Carbohydrates, Lipids, Proteins, And Nucleic Acids
Lipids consist mostly of __________.
oxygen
glycogen
hydrocarbons
amino acids
hydrocarbons
Lipids are mostly made up of hydrocarbons, which makes them nonpolar and thus, hydrophobic. Glycogen is a type of carbohydrate; it is the storage form of glucose in animals. Amino acids are the monomeric units of polypeptides.
Example Question #61 : Macromolecules
An important trait that all lipids share is __________.
hydrophilicity
hydrophobicity
basicity
solubility
acidity
hydrophobicity
Because lipids are made mostly of hydrocarbons, they are nonpolar and thus hydrophobic, which means they avoid contact with water. The root "hydro" refers to water and the root "phobic" refers to fear. Hence hydrophobic means "water fearing". Hydrophilic on the other hand means "water loving" and is used to describe polar molecules.
Example Question #62 : Macromolecules
Which of the following is not an example of lipid(s)?
Phospholipids
Glycogen
Oils
Fatty acids
Glycogen
Glycogen is a carbohydrate. It is a polysaccharide that animals use to store glucose when sugars are needed by the body for fuel. All other answer choices are lipids.
Example Question #61 : Macromolecules
Which of the following is not an example of lipid(s)?
Fructose
Waxes
Triglycerides
Testosterone
Fructose
Monosaccharides such as fructose are carbohydrates not lipids. Waxes, steroid hormones such as testosterone, estrogen and progesterone, and triglycerides (fats) are composed mainly of hydrocarbons and are classified as lipids.
Example Question #26 : Identify Structure And Purpose Of Carbohydrates, Lipids, Proteins, And Nucleic Acids
Chitin is what class of molecule?
Lipid
Wax
Nucleic acid
Carbohydrate
Carbohydrate
Chitin is a carbohydrate. Specifically, it is a polysaccharide used by arthopods to build exoskeletons, and is found in the cell walls of fungi. Waxes are types of lipids, and nucleic acids are DNA and RNA.
Example Question #26 : Identify Structure And Purpose Of Carbohydrates, Lipids, Proteins, And Nucleic Acids
Starch belongs to which class of macromolecules?
Polypeptides
Lipids
Nucleic acids
Carbohydrates
Carbohydrates
Starch is a carbohydrate. Specifically, it is a polysaccharide carbohydrate used in plants. The enzyme amylase breaks down starch in the mouth and small intestine, where it can is absorbed as monosaccharides and disaccharides.
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