Transport across cells Flashcards
What is the main function of the cell membrane?
Controlling the movement of substances in and out of the cell/organelle.
What model describes the structure of the cell membrane?
Fluid mosaic model.
What are the two types of proteins found in the cell membrane?
- Intrinsic proteins
- Extrinsic proteins
What role do intrinsic proteins play in the cell membrane?
Allow substances to cross the membrane, provide mechanical support, act as receptors.
What is the function of cholesterol in the cell membrane?
Makes the membrane more rigid, reduces lateral movement of phospholipids, prevents leakage of water and dissolved ions.
What are glycolipids and their function?
Carbohydrates bound to lipids that act as cell surface receptors and allow cells to adhere to one another.
What role do glycoproteins serve in the cell membrane?
Act as cell surface receptors and neurotransmitters, enabling cells to recognize one another and form tissues.
Define diffusion in the context of cell membranes.
Passive movement of small, non-polar, lipid soluble molecules from high concentration to low concentration.
What is facilitated diffusion?
Movement of polar, charged, and water soluble molecules across the membrane via channel proteins.
What is osmosis?
Diffusion of water molecules from high water potential to low water potential through a partially permeable membrane.
What is required for active transport?
Energy in the form of ATP.
What is the process of endocytosis?
Transport of large particles into the cell enclosed in vesicles made from the cell surface membrane.
What occurs during exocytosis?
Vesicles containing large particles fuse with the cell surface membrane and release their contents from the cell.
Describe co-transport and its significance in epithelial cells.
Uses ions to move substances into and out of cells, particularly in the ileum where sodium and potassium ions facilitate glucose and amino acid transport.
Fill in the blank: The rate of gas exchange by diffusion becomes more rapid as the ______ increases.
surface area of the surface increases.
True or False: The diffusion gradient has no effect on the rate of diffusion.
False.
List the factors that increase the rate of gas exchange by diffusion.
- Surface area increases
- Diffusion distance decreases
- Diffusion gradient becomes steeper
- Temperature increases
