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Questions and Answers
What is the term for the movement of molecules from high to low concentration?
What is the term for the movement of molecules from high to low concentration?
Which of the following is NOT a function of the cell membrane?
Which of the following is NOT a function of the cell membrane?
Which type of protein is embedded within the phospholipid bilayer?
Which type of protein is embedded within the phospholipid bilayer?
What is the main function of cholesterol in the cell membrane?
What is the main function of cholesterol in the cell membrane?
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What is the term for the dynamic, fluid structure of the cell membrane?
What is the term for the dynamic, fluid structure of the cell membrane?
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What is the purpose of peripheral proteins in the cell membrane?
What is the purpose of peripheral proteins in the cell membrane?
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What is the term for the movement of molecules against their concentration gradient?
What is the term for the movement of molecules against their concentration gradient?
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What is the effect of increased temperature on the cell membrane?
What is the effect of increased temperature on the cell membrane?
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What is the purpose of the phospholipid bilayer in the cell membrane?
What is the purpose of the phospholipid bilayer in the cell membrane?
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In which stage of cellular respiration is pyruvate converted into acetyl-CoA?
In which stage of cellular respiration is pyruvate converted into acetyl-CoA?
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What is the primary function of the cristae in the mitochondrial inner membrane?
What is the primary function of the cristae in the mitochondrial inner membrane?
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What is the energy source used to pump protons across the mitochondrial inner membrane during ATP synthesis?
What is the energy source used to pump protons across the mitochondrial inner membrane during ATP synthesis?
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What is the role of ATP synthase in the electron transport chain?
What is the role of ATP synthase in the electron transport chain?
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What is the primary function of mitochondria in eukaryotic cells?
What is the primary function of mitochondria in eukaryotic cells?
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Why is mitochondrial DNA more susceptible to mutations?
Why is mitochondrial DNA more susceptible to mutations?
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What is the result of mitochondrial dysfunction?
What is the result of mitochondrial dysfunction?
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What is the pattern of inheritance for mitochondrial DNA?
What is the pattern of inheritance for mitochondrial DNA?
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What is the purpose of mitochondrial DNA in forensic science?
What is the purpose of mitochondrial DNA in forensic science?
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What is the region inside the mitochondrial inner membrane where the citric acid cycle and fatty acid oxidation take place?
What is the region inside the mitochondrial inner membrane where the citric acid cycle and fatty acid oxidation take place?
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Study Notes
Cell Membrane
Structure:
- Phospholipid bilayer: composed of two layers of phospholipid molecules with hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails
- Embedded proteins: integral proteins (transmembrane) and peripheral proteins (attached to surface)
- Cholesterol: helps maintain fluidity and stability
Functions:
- Selective permeability: regulates what enters and leaves the cell
- Protection: acts as a barrier against external environment
- Cell signaling: involved in cell-cell communication and signaling pathways
- Cell recognition: allows cells to recognize and interact with each other
Permeability:
- Semipermeable: allows certain molecules to pass through while keeping others out
- Passive transport: movement of molecules down concentration gradient (diffusion, osmosis)
- Active transport: movement of molecules against concentration gradient using energy
Membrane Transport:
- Simple diffusion: movement of molecules from high to low concentration
- Facilitated diffusion: assisted by transport proteins (e.g., channels, carriers)
- Active transport: uses energy to pump molecules against concentration gradient (e.g., ATP-powered pumps)
Membrane Fluidity:
- Fluid mosaic model: membrane is a dynamic, fluid structure with proteins and lipids moving laterally
- Temperature: affects membrane fluidity (increased temperature increases fluidity)
- Cholesterol: helps maintain fluidity by filling gaps between phospholipid tails
Cell Membrane Structure
- Phospholipid bilayer consists of two layers of phospholipid molecules with hydrophilic heads and hydrophobic tails
- Embedded proteins include integral proteins (transmembrane) and peripheral proteins (attached to surface)
- Cholesterol helps maintain fluidity and stability of the membrane
Cell Membrane Functions
- Selective permeability regulates what enters and leaves the cell
- Acts as a barrier against external environment for protection
- Involved in cell-cell communication and signaling pathways for cell signaling
- Allows cells to recognize and interact with each other for cell recognition
Membrane Permeability
- Semipermeable, allowing certain molecules to pass through while keeping others out
- Passive transport involves movement of molecules down concentration gradient through diffusion and osmosis
- Active transport uses energy to move molecules against concentration gradient
Membrane Transport Mechanisms
- Simple diffusion involves movement of molecules from high to low concentration
- Facilitated diffusion is assisted by transport proteins like channels and carriers
- Active transport uses energy to pump molecules against concentration gradient, e.g., ATP-powered pumps
Membrane Fluidity
- Fluid mosaic model describes the membrane as a dynamic, fluid structure with moving proteins and lipids
- Temperature affects membrane fluidity, with increased temperature increasing fluidity
- Cholesterol helps maintain fluidity by filling gaps between phospholipid tails
Mitochondrial Structure
- Mitochondria have two main parts: outer membrane and inner membrane, with the inner membrane being highly folded to form cristae, increasing the surface area for cellular respiration
- Mitochondrial matrix, the region inside the inner membrane, is where the citric acid cycle and fatty acid oxidation take place
- Mitochondrial DNA (mtDNA) is found in the mitochondrial matrix
Cellular Respiration
- Cellular respiration, the process of generating energy from glucose, occurs in mitochondria
- Glucose is converted into pyruvate in the cytosol during glycolysis
- Pyruvate is then converted into acetyl-CoA, producing ATP, NADH, and FADH in the citric acid cycle
- Electron transport chain, occurring in the mitochondrial inner membrane, uses NADH and FADH to produce ATP
ATP Synthesis
- ATP synthesis takes place in the mitochondrial inner membrane during the electron transport chain
- Energy from NADH and FADH is used to create a proton gradient across the inner membrane
- The proton gradient drives the production of ATP through chemiosmosis, catalyzed by ATP synthase
- ATP synthase generates ATP from ADP and Pi
Mitochondrial Function
- Mitochondria are the primary site of energy production in eukaryotic cells
- Mitochondria regulate cell growth, division, and apoptosis (programmed cell death)
- Mitochondrial dysfunction can lead to diseases such as neurodegenerative disorders and metabolic disorders
Mitochondrial Inheritance
- Mitochondrial DNA is inherited solely from the mother, as only egg cells contribute mitochondria to the fertilized egg
- Mitochondrial DNA is susceptible to mutations due to its lack of protection by the nuclear membrane
- Mitochondrial DNA mutations can lead to mitochondrial diseases, often inherited in a maternal pattern
- Mitochondrial DNA is used in forensic science and evolutionary biology to study genetic relationships and ancestry
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Description
Learn about the structure and functions of the cell membrane, including the phospholipid bilayer, embedded proteins, and cholesterol. Understand how the cell membrane regulates what enters and leaves the cell and protects it from the external environment.
