Which of the following statements best describes the role of cholesterol in the cell membrane?

A. Increases fluidity at high temperatures only

B. Decreases fluidity at both high and low temperatures

C. Increases fluidity at low temperatures and decreases it at high temperatures

D. Decreases fluidity at low temperatures only

Which function is not typically associated with integral proteins in the cell membrane?

A. Enzyme activity

B. Cell signalling

C. Energy storage

D. Transport

What is the primary reason for the amphipathic nature of phospholipids in the cell membrane?

A. To allow integral proteins to function

B. To form a semi-permeable barrier

C. To facilitate cell signalling

D. To enable endocytosis

Peripheral proteins are often involved in which of the following cellular processes?

A. Transport of molecules across the membrane

B. Cell signalling and recognition

C. Formation of the lipid bilayer

D. Active transport using ATP

Which factor primarily contributes to the fluidity of the cell membrane?

A. Presence of cholesterol

B. Number of integral proteins

C. Concentration of extracellular ions

D. Amount of peripheral proteins

a) Explain the amphipathic nature of phospholipids and how this property contributes to the formation of the lipid bilayer in cell membranes. [3]

b) Discuss the role of the lipid bilayer as a semi-permeable barrier, and how this is essential for cellular function. [2]

a) Describe the functions of integral proteins in the cell membrane, providing examples of their roles. [3]

b) Differentiate between integral and peripheral proteins in terms of their position and attachment in the cell membrane. [2]

a) Discuss the importance of membrane fluidity and how it is affected by temperature in animal cells. [3]

b) Explain how cholesterol molecules in the cell membrane contribute to both fluidity and stability. [2]

a) Elaborate on how the amphipathic nature of phospholipids contributes to the self-assembly of the lipid bilayer in cell membranes. [4]

b) Discuss the various functions of peripheral proteins in the cell membrane and provide examples. [3]

c) Explain the implications of membrane fluidity for animal cells at different temperatures, and how cells adapt to these changes. [3]

a) Describe the role of integral proteins in transport and provide examples of different types of transport they facilitate. [4]

b) Discuss how the structure of the cell membrane contributes to its semi-permeable nature. [3]

c) Explain the role of cholesterol in maintaining membrane stability, especially in varying temperature conditions. [3]

At lower temperatures, what is the role of cholesterol in the cell membrane?

A. Decreases fluidity by increasing rigidity

B. Increases fluidity by preventing close packing of phospholipids

C. Forms additional barriers to ion passage

D. Facilitates the attachment of peripheral proteins

Which of the following is not a function of integral proteins?

A. Facilitating passive transport

B. Acting as receptors for cell signalling

C. Synthesising ATP

D. Enabling active transport

How do peripheral proteins primarily interact with the lipid bilayer?

A. Through hydrophobic interactions

B. By penetrating the hydrophobic core

C. Through electrostatic and hydrogen bonding

D. By forming covalent bonds with lipids

What is the significance of the amphipathic nature of phospholipids in the formation of the cell membrane?

A. It allows the formation of a hydrophobic barrier

B. It enables the attachment of carbohydrates

C. It facilitates the integration of cholesterol

D. It promotes the asymmetrical distribution of lipids

Which of the following statements about the fluidity of the cell membrane is true?

A. Fluidity remains constant across different temperatures

B. Cholesterol decreases fluidity at both high and low temperatures

C. Fluidity is independent of fatty acid saturation levels

D. Cholesterol can both increase and decrease membrane fluidity depending on the temperature

a) Explain how the amphipathic nature of phospholipids is essential for the formation of membrane-bound organelles within the cell. [3]

b) Discuss the various functions of membrane proteins, highlighting their importance in cell signalling and intercellular joining. [4]

c) Describe how animal cells maintain membrane fluidity and stability at different temperatures. [3]

a) Discuss the role of the lipid bilayer in creating a selective barrier and how this is crucial for maintaining cellular homeostasis. [3]

b) Differentiate between the functions of integral and peripheral proteins in the cell membrane, providing examples. [4]

c) Explain how variations in temperature can affect the fluidity of the cell membrane and the adaptations cells employ to counteract these effects. [3]

a) Elucidate the amphipathic nature of phospholipids and how this characteristic is fundamental to the formation of the lipid bilayer in cellular membranes. [4]

b) Discuss the diverse functions of integral proteins within the cell membrane, providing specific examples for each function. [4]

c) Explain the role of peripheral proteins and how they differ from integral proteins in terms of structure and function. [3]

d) Describe how the fluidity of the cell membrane is influenced by temperature and the presence of cholesterol, and discuss the implications of these factors for animal cells. [4]

a) Discuss the significance of the semi-permeable nature of the lipid bilayer in maintaining the internal environment of the cell. [3]

b) Describe the various roles of membrane proteins, emphasizing their importance in transport and cell signalling. [4]

c) Differentiate between the structures of integral and peripheral proteins and how these structures relate to their functions in the cell membrane. [4]

d) Explain the adaptations that animal cells employ to maintain membrane stability and fluidity under varying temperature conditions. [4]

a) Elaborate on the amphipathic nature of phospholipids and its implication in forming the structure of cell membranes. [4]

b) Discuss the diverse functions of integral and peripheral proteins in the cell membrane, providing examples for each type of protein. [4]

c) Explain how cholesterol molecules interspersed in the lipid bilayer contribute to membrane fluidity and stability. [3]

d) Discuss the adaptations and mechanisms employed by animal cells to maintain membrane fluidity at varying temperatures. [4]