Concept explainers
Label the components in the following diagram of a small portion of a plasma membrane. Indicate whether regions are hydrophobic or hydrophilic.
To label: The components in the given diagram of a small portion of a plasma membrane and indicate whether the regions are hydrophobic or hydrophilic.
Introduction: All living organisms are made up of one or many cells. The organisms are classified as prokaryotes and eukaryotes. The prokaryotes are usually unicellular including the bacteria and archaea, while the eukaryotes are usually multicellular including the plants and animals. The prokaryotic cells are simpler and smaller than the eukaryotic cells.
Answer to Problem 1IQ
Pictorial representation: Fig.1 illustrates the diagram of a small portion of plasma membrane.
Fig.1: Plasma membrane
Explanation of Solution
Plasma membrane is a selectively permeable membrane with lipid bilayer and protein. The lipid bilayer structure is a barrier structure. Lipid molecule consists of the polar head region called hydrophilic head, and a non-polar fatty acid chain tail called hydrophobic tail. The hydrophilic region is attracted toward aqueous condition, and the hydrophobic end is repelled away from the aqueous condition.
Membrane proteins are a part of biological membrane that primarily interacts with it to perform various functions in the cell. There are various membrane proteins that help in the transportation of molecules in and out of the cell. Based on the extend of attachment to the membrane, the membrane proteins are classified as integral proteins, peripheral proteins, and transmembrane proteins.
- Integral membrane proteins: Integral membrane proteins are a type of membrane proteins that are firmly bound to the membrane. These types of proteins are amphipathic in nature. Here, the hydrophilic head region is extended out of the cell, and its hydrophobic tail region interacts with the fatty acids present on the membrane phospholipids.
- Transmembrane proteins: Transmembrane proteins extend completely through the membrane. These types of proteins majorly function on both sides of the layer (intracellular and extracellular) and help to transport molecules across it.
- Peripheral membrane proteins: Peripheral membrane proteins are located on the inner and outer surfaces of the plasma membrane, and are not embedded in the lipid bilayer as the other membrane proteins. They bound to the exposed regions of the integral proteins through non-covalent interactions.
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Chapter 7 Solutions
Study Guide for Campbell Biology
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- Put the following structures in order according to the pathway of a secreted protein: a. plasma membrane b. Golgi bodies c. endoplasmic reticulum d. post-Golgi vesiclesarrow_forwardWhich of the following methods of transport is being used to transfer the substance into the cell in the accompanying graph? a. diffusion down a concentration gradient b. osmosis c. facilitated diffusion d. active transport e. vesicular transport f. It is impossible to tell with the information provided.arrow_forwardCell membranes consist mainly of a _________. a. carbohydrate bilayer and proteins b. protein bilayer and phospholipids c. phospholipid bilayer and proteinsarrow_forward
- Using the answer code on the right, indicate which membrane component is responsible for the function in question: 1. channel formation____________________________________ (a) lipid bilayer 2. barrier to passage of water- __________________ (b) proteins soluble substances ____________________________________ (c) carbohydrates 3. receptor sites 4. membrane fluidity 5. recognition of self 6. membrane-bound enzymes 7. structural boundary 8. carriersarrow_forwardDraw a lipid bilayer, and focus on three lipids that are on the same side of the membrane. Color in the areas where you expect the hydrophobic interactions, and in another color, shade in the areas that are hydrophilic. Draw another lipid bilayer, and for this one, include two membrane proteins. One of them should be an integral membrane protein and the other one a peripheral membrane protein. Label the lipid bilayer, the side the faces the cytoplasm and the side that faces outside the cell. Also label the two proteins, and shade in the areas where you predict that you would find hydrophobic amino acids and hydrophilic amino acids.arrow_forwardWhich of the following statements about a typical plasma membrane is correct? The hydrophilic interior of the membrane is composed primarily of the fatty acid tails of the phospholipids. Carbohydrates on the membrane surface are important in determing the overall bilayer structure. Phospholipids are the primary component that determines which solute can cross the plasma membrane. The two sides of the plasma membrane have different lipid and protein composition. The plasma membrane is covalently linked network of phospholipids and proteins that controls the movement of solutes into and out of a cell.arrow_forward
- According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids? They frequently flip-flop from one side of the membrane to the other. They have hydrophilic tails in the interior of the membrane. They can move laterally along the plane of the membrane. They are free to depart from the membrane and dissolve in the surrounding solution.arrow_forwardBesides lipid molecules, cell membranes also contain many different types of proteins, each with specific functions. In the following table, select the common type of membrane protein in the right-hand column that each statement in the left-hand column describes. The choices on the Type of Membrane Protein are the same for theFunction of the Membrane Proteinarrow_forwardProvide a detailed, written explanation of the plasma membrane structure explaining both composition and arrangement. Refer to your drawings as necessary.arrow_forward
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