Biology Unit 4: Cell Transportation and Parts

What things would affect the rate of passive transport in/out of a cell?

Increase in temperature or concentration will increase the rate of diffusion

How does active transport contribute to an organism's ability to stay alive/maintain homeostasis?

It allows large or charged molecules to get in/out of the cell since they cannot move through the membrane passively.

How does the structure of the cell membrane contribute to an organism's ability to stay alive/maintain homeostasis?

It is semi-permeable, allowing certain molecules in/out. There are also proteins embedded that allow other molecules in/out of the cell. These molecules are either molecules the cell needs to maintain homeostasis or waste products the cell wants to expel.

How does passive transport contribute to an organism's ability to stay alive/maintain homeostasis?

It is the movement of molecules that does not require the cell to use up its energy; some needed molecules can move into the cells and waste products can move out

What is the term that described the diffusion of water through a selectively permeable membrane?

Osmosis

Explain why osmosis is really just a special case of facilitated diffusion.

Osmosis is the movement of water through specialized channel proteins called aquaporins.

Describe Plant vs Animal Cells

Plants: -Cell Wall -Chloroplasts -Large Vacuoles Both: -Plasma Membrane -Endoplasmic Reticulum -Mitochondria -Golgi Apparatus Animal: -Centrioles & Centrosomes -Small Vacuoles -Cilia or Flagella

What are the characteristics of active transport?

Requires cell to use energy, movement from high to low conc or low to high conc, does not stop at equilibrium, involves larger molecules or molecules with a charge

How are the transport problems of a freshwater organism different from those of a saltwater organism?

Salt water organisms have to work hard to prevent water loss which freshwater organisms must prevent water gain.

Why are small cells more efficient at exchanging materials?

Small cells have a high SA:V ratio so they are able to exchange the necessary materials in less time. The rate of diffusion is constant for all cell sizes, so smaller cells are more efficient

A student draws a fence with several gates as part of a model of cellular transport. Explain what the fence and the gates represent, relating their structures to their functions. Explain how the model could represent both active transport using protein pumps and facilitated diffusion.

The fence represents the phospholipid bilayer. Some things would be small enough to wiggle through the fence, just like some small, uncharged molecules can diffuse through the phospholipid bilayer. The gates represent transport proteins. The transport proteins have different roles in transport. Channel proteins work during passive transport (diffusion, osmosis). Carrier proteins work during passive transport (facilitated diffusion) and active transport. Pumps work during active transport.

Water molecules diffuse through the cell membrane through aquaporins. How are these proteins helpful in osmosis?

These proteins allow water to cross the cell membrane. Without these proteins, water would not be able to cross the phospholipid bilayer due to the hydrophobic lipid tails.

Large molecules such as glucose move across cell membranes through special protein channels during: a. Active transport b. Facilitated diffusion c. Osmosis d. Bulk transport

a. Active transport b. Facilitated diffusion <--- Correct answer c. Osmosis d. Bulk transport

Which type of macromolecule transports material into and out of the cell? a. Carbohydrate b. Protein c. Lipid d. Nucleic acid

a. Carbohydrate b. Protein <--- Correct answer c. Lipid d. Nucleic acid

What are the different types of passive transport? Describe them.

a. Diffusion- The movement of molecules from and area of high concentration to an area of low concentration until equilibrium is reached. b. Osmosis- Diffusion of water through a semipermeable membrane c. Facilitated diffusion- diffusion across the membrane through channel proteins

What are the different types of active transport? Describe them

a. Endocytosis- Process when cells absorb molecules from the outside/external surrounding by the cell membrane wrapping around molecules -Phagocytosis- "cell eating"- cell membrane extends outward to bring solid particles into the cell -Pinocytosis- "cell drinking"- cell membrane sinks inward to bring liquids and very small particles into the cell, forms bubble-like vesicles inside the cell b. Exocytosis- "cell regurgitation"- the reverse of pinocytosis, the cell fuses vesicles to the cell membrane in order to secrete liquid and very small particles c. Transport with proteins/specific transport

The relatively stable set of internal conditions that organisms maintain is called: a. Metabolism b. A genome c. Evolution d. Homeostasis

a. Metabolism b. A genome c. Evolution d. Homeostasis <--- Correct answer

Solute particles move from an area of higher concentration to an area of lower concentration in a process called: a. Osmosis b. Transport c. Diffusion d. Equilibrium

a. Osmosis b. Transport c. Diffusion <--- Correct Answer d. Equilibrium

In an investigation, plant cells are placed in water that has been tinted blue. The investigators observe the color of the cells changing to blue. What additional observation would be evidence that the cells maintain homeostasis in response to this change? a. The cells burst apart. b. The cell membranes shrink away from the cell walls. c. The central vacuole in the cells increases in size. d. The cells pump out water by endocytosis.

a. The cells burst apart. b. The cell membranes shrink away from the cell walls. c. The central vacuole in the cells increases in size. d. The cells pump out water by endocytosis. <-- Correct

What is the relationship between cell size and SA:V?

As cells increase in size, their SA:V decreases. SA and V don't increase at equal rate (volume increases quicker)

You want to know how temperature affects the rate of diffusion. Describe an investigation that would provide evidence to support a conclusion.

Design an investigation in which you vary temperature and measure rates. Increased temperatures would increase the rate of diffusion because molecules move faster at higher temperatures.

What is the difference between diffusion and facilitated diffusion?

Diffusion- Movement of molecules from areas of high to areas of low concentration. Facilitated diffusion- Diffusion of molecules through carrier proteins. Facilitated diffusion is specific. Any small, uncharged molecule can diffuse.

What are the characteristics of passive transport?

Does not use cells ENERGY- it's a passive process, movement from high to low concentration until equilibrium is reached, involves smaller sized molecules