5 Written questions
5 Matching questions
- Cell Membrane Function: A Biological Barrier
- Types of Transport Across Membranes: Passive Transport
- Transport Across Cell Membranes: Concentration Gradient
- Transport Across Cell Membranes: Selective Transport
- Three Types of Passive Transport: 1. Diffusion
- a the movement of only certain substances across the cell membrane
- b a cell membrane prevents many materials from entering the cell.
- c movement across cell membranes without an input of energy
2 reasons molecules move.
1. Brownian Motion
2. Concentration gradients
- d the net movement of particles from an area of high concentration to an area of low concentration
- no energy is expended
- in a cell very small particles can cross the cell membrane by moving between the phospholipid molecules
- e the difference in concentration between two areas for any given molecule produces a gradient or path of movement in which molecules move toward areas where the concentration of particles is lower
- molecules move down a concentration gradient
5 Multiple choice questions
- Cell membrane molecules are in constant motion (drifting past each other) resulting in:
a) membrane flexibility
b) cell's ability to change shape
- Loss of water in a plant cell resulting in WILTING
- in a liquid or gas, particles are in constant, random motion
- diffusion of molecules across the cell membrane by way of transport proteins.
- - salts - atoms - viruses
- sugar - ions - bacteria
- proteins (7? this is what was in the notes)
most organelles are surrounded by membranes with the same structure as a cell membrane
5 True/False questions
Hypotonic solution, → has a higher concentration of solute compared to the inside of the cell
Two types of transport proteins → have 3-D shapes that make them highly selective, recognizing atoms or molecules by shape, size or charge.
Cell Membrane Function: A Selective Filter → a cell membrane prevents many materials from entering the cell.
Proteins in membranes serving the following functions → a) moving substances across the membrane
b) carrying out chemical reactions (they act as enzymes)
c) some have "marker" molecules (carbohydrate chains) on their surface allowing cells to recognize each other
d) allow messenger molecules (such as hormones) to attach
e) assist in cell-to-cell communication and control of cell functions
Membranes at Work 2. Kidney Dialysis → filters toxic wastes that accumulate in the blood while retaining necessary proteins, glucose, amino acids & ions