BIOL 1408 Ch. 5 Flashcards

Questions and Answers

What is the function of cholesterol in the plasma membrane?

Assists in cell division.

Provides energy to the cell.

Helps to stabilize the structure of the plasma membrane. (correct)

Acts as a barrier to toxins.

What are phospholipids recognized by?

The presence of a head and two tails.

What is a glycoprotein composed of?

Both a carbohydrate and a protein.

What is diffusion across a biological membrane called?

Passive transport. Signup and view all the answers

When molecules move down their concentration gradient, they move from where they are _ to where they are _.

more concentrated...less concentrated Signup and view all the answers

Facilitated diffusion is a type of what?

Passive transport. Signup and view all the answers

What name is given to the process by which water crosses a selectively permeable membrane?

Osmosis. Signup and view all the answers

What does hypertonic mean?

Having a higher concentration of solute outside the cell. Signup and view all the answers

You know that this cell is in a(n) _ solution because the cell _.

hypotonic...swelled Signup and view all the answers

You know that this cell is in a(n) _ solution because it _.

hypertonic solution...lost water Signup and view all the answers

Endocytosis moves materials _ a cell via _.

into...membranous vesicles Signup and view all the answers

You can recognize the process of pinocytosis when?

The cell is engulfing extracellular fluid. Signup and view all the answers

A white blood cell engulfing a bacterium is an example of what?

Phagocytosis. Signup and view all the answers

Which cell junction forms a barrier to the passage of materials?

Tight junctions. Signup and view all the answers

What is the primary role of desmosomes?

To bind animal cells together. Signup and view all the answers

What aid in the coordination of the activities of adjacent animal cells?

Gap (communicating) junctions. Signup and view all the answers

Why can't cells get as large as golf balls?

A cell that large would not have enough surface area to use in exchanging materials. Signup and view all the answers

Which substance will diffuse across the membrane fastest if there are no membrane proteins?

Oxygen. Signup and view all the answers

Which direction is water most likely to move if there is a membrane or concentration difference between two regions?

Water will move out of a hypotonic solution into a hypertonic solution. Signup and view all the answers

What simple property causes molecules to diffuse from high concentration toward a lower concentration?

The continuous random motion of molecules. Signup and view all the answers

What is the word for membrane proteins that have carbohydrates attached to them?

Glycoprotein. Signup and view all the answers

Which membrane proteins increase the rate of chemical reactions?

Enzymatic proteins. Signup and view all the answers

Desmosomes are similar to what structure?

The cytoskeleton. Signup and view all the answers

Which of the following is most like a gap junction?

A nuclear pore. Signup and view all the answers

Study Notes

Cholesterol and Membrane Structure

Cholesterol stabilizes the plasma membrane by maintaining its structure.

Phospholipids

Phospholipids characterized by a hydrophilic head and two hydrophobic tails play a crucial role in forming cell membranes.

Glycoproteins

Glycoproteins are molecules composed of both carbohydrates and proteins, important for cell recognition and signaling.

Transport Mechanisms

Passive Transport involves diffusion across biological membranes without energy expenditure.
Molecules move from areas of higher concentration to areas of lower concentration during diffusion.
Facilitated diffusion is a passive transport method that requires specific membrane proteins but no energy input.

Osmosis

Osmosis is the process by which water crosses selectively permeable membranes.

Solutions and Cell Behavior

Hypertonic solutions have a higher concentration of solute outside the cell, causing water to move out, leading to cell shrinkage.
Hypotonic solutions lead to water influx, causing cells to swell.

Endocytosis

Endocytosis transports materials into the cell through membranous vesicles.
Pinocytosis refers to the process where a cell engulfs extracellular fluid.
Phagocytosis occurs when a white blood cell engulfs a bacterium, demonstrating the cell's ability to consume large particles.

Cell Junctions

Tight junctions form barriers that prevent material passage between cells.
Desmosomes anchor cells together for structural support.
Gap junctions facilitate communication and coordinate activities among adjacent animal cells.

Cell Size Limitations

Cells cannot grow as large as golf balls due to insufficient surface area for material exchange.

Diffusion of Molecules

Oxygen diffuses fastest across membranes when no membrane proteins are present due to its small size.
Water typically moves from a hypotonic region (low solute) to a hypertonic region (high solute).

Molecular Behavior

Molecules diffuse from high to low concentration driven by their random motion.

Membrane Proteins

Glycoproteins have carbohydrates attached, influencing cell interactions.
Enzymatic proteins facilitate and increase the rate of chemical reactions within the cell.

Structural Support

Desmosomes function similarly to the cytoskeleton by providing structural integrity to cells.
A nuclear pore is analogously comparable to a gap junction, allowing communication between cellular compartments.

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Description

Test your knowledge of cell membrane components with these flashcards from BIOL 1408 Chapter 5. Learn about key terms like cholesterol, phospholipids, and glycoproteins. Enhance your understanding of passive transport and membrane structures.