Active Transport Across Cell Membrane
Mechanisms involving energy expenditure to move substances against their concentration gradient, such as pumps, endocytosis, and exocytosis.
What is Active Transport Across Cell Membrane?
The movement of molecules across a cell membrane against their concentration gradient, requiring energy.
Key points
- Define active transport and its necessity.
- Differentiate between primary and secondary active transport.
- Explain the role of pumps and carriers in active transport.
- Describe the mechanisms of endocytosis and exocytosis.
Common exam trap
Confusing active transport with passive transport (diffusion, facilitated diffusion).
Definitions
- Term
Active Transport
- Meaning
The movement of molecules across a cell membrane against their concentration gradient, requiring energy.
- Term
Primary Active Transport
- Meaning
Active transport that uses ATP directly to move substances across the membrane.
- Term
Secondary Active Transport
- Meaning
Active transport that uses the energy stored in an electrochemical gradient, established by primary active transport, to move substances.
- Term
Endocytosis
- Meaning
A process by which cells absorb molecules from outside the cell by engulfing them with their cell membrane.
- Term
Exocytosis
- Meaning
A process by which cells transport molecules (e.g., waste, proteins) out of the cell (exo- 'out of').
- Term
Electrochemical Gradient
- Meaning
The combined effect of concentration gradient and electrical potential difference across a membrane.
Learning objectives
Define active transport and its necessity.
Differentiate between primary and secondary active transport.
Explain the role of pumps and carriers in active transport.
Describe the mechanisms of endocytosis and exocytosis.
Provide examples of substances transported via active transport.
Prerequisites
Cell Membrane Structure (Fluid Mosaic Model)
Concentration Gradient
Diffusion
Facilitated Diffusion
ATP and Cellular Respiration
Common mistakes
Confusing active transport with passive transport (diffusion, facilitated diffusion).
Forgetting that active transport requires energy (ATP).
Not distinguishing between primary and secondary active transport.
Overlooking endocytosis and exocytosis as forms of active transport.
Keywords
Active Transport
Cell Membrane
ATP
Concentration Gradient
Electrochemical Gradient
Sodium-Potassium Pump
Endocytosis
Exocytosis
Primary Active Transport
Secondary Active Transport
Carrier Proteins
Pumps
Practice preview
The movement of ions across a cell membrane against their electrochemical gradient by a carrier protein, utilizing ATP, is an example of:…
easy
Which of the following is a characteristic of active transport?…
easy
The sodium-potassium pump is a classic example of active transport. Which of the following statements accurately describes its function?…
medium