What is meant by passive vocabulary?

Words that a person understands but does not use regularly

Words that are only used in writing

Words that are commonly outdated

Which of the following best describes active vocabulary?

Words that a person uses regularly in speech and writing

Words that have fallen out of use

Words that are heard but not understood

Words that are not commonly used

What is an example of a word in your passive vocabulary?

A word you can understand when reading but don't use in conversation

A word you've never heard before

How can reading help to enhance your passive vocabulary?

By exposing you to new words in context

By reducing the need to learn new words

By simplifying the words you already know

What strategy can you use to convert passive vocabulary into active vocabulary?

Practice using the words in your speech and writing

Focus only on learning new words

Avoid reading materials with difficult words

What role does context play in understanding passive vocabulary?

It helps you infer the meaning of unfamiliar words

It has no impact on understanding

It only applies to active vocabulary

It makes words harder to understand

Which activity could primarily help improve your active vocabulary?

Engaging in conversations where you use new words

Watching movies without subtitles

What is typically true about a person's passive vocabulary compared to their active vocabulary?

It is larger and encompasses more words

It is smaller and less important

It is the same size as active vocabulary

It consists only of technical terms

Why is it important to expand both active and passive vocabulary?

It improves communication skills and comprehension

It allows for the use of more slang

It decreases language complexity

How can using new words in writing improve your active vocabulary?

It reinforces learning and helps the words stick in your memory

It has no impact on vocabulary retention

It makes your writing longer without purpose

Passive and active vocabulary

In many cases, cells must move materials from an area of lower concentration to an area of higher concentration, or “up” their concentration gradient. Such movement of materials is known as active transport. Unlike passive transport, active transport requires a cell to expend energy. CELL MEMBRANE PUMPS Ion channels and carrier proteins not only assist in passive trans- port but also help with some types of active transport. The car- rier proteins that serve in active transport are often called cell membrane “pumps” because they move substances from lower to higher concentrations. Carrier proteins involved in facilitated diffusion and those involved in active transport are very similar. In both, the molecule first binds to a specific kind of carrier protein on one side of the cell membrane. Once it is bound to the molecule, the protein changes shape, shielding the molecule from the hydrophobic interior of the phospholipid bilayer. The protein then transports the molecule through the membrane and releases it on the other side. However, cell membrane pumps require energy. Most often the energy needed for active transport is supplied directly or indirectly by ATP. Sodium-Potassium Pump One example of active transport in animal cells involves a carrier protein known as the sodium-potassium pump. As its name sug- gests, this protein transports Na ions and K ions up their con- centration gradients. To function normally, some animal cells must have a higher concentration of Na ions outside the cell and a higher concentration of K ions inside the cell. The sodium- potassium pump maintains these concentration differences. Follow the steps in Figure 5-6 on the next page to see how the sodium-potassium pump operates. First, three Na ions bind to the carrier protein on the cytosol side of the membrane, as shown in step . At the same time, the carrier protein removes a phosphate group from a molecule of ATP. As you can see in step , the phos- phate group from the ATP molecule binds to the carrier protein. Step shows how the removal of the phosphate group from ATP supplies the energy needed to change the shape of the carrier pro- tein. With its new shape, the protein carries the three Na ions through the membrane and then forces the Na ions outside the cell where the Na concentration must remain high. 3 2 1 SECTION 2 OBJECTIVES ● Distinguish between passive transport and active transport. ● Explain how the sodium-potassium pump operates. ● Compare endocytosis and exocytosis. VOCABULARY active transport sodium-potassium pump endocytosis vesicle pinocytosis phagocytosis phagocyte exocytosis www.scilinks.org Topic: Active Transport Keyword: HM60018 mb06se_homs02.qxd 5/18/07 11:02 AM Page 103 104 CHAPTER 5 K+ K+ K+ K+ K+ K+ INSIDE OF CELL OUTSIDE OF CELL Carrier protein Cell membrane P P P P Na+ Na+ Na+ ATP ADP Na+ Na+ Na+ Na+ Na+ Na+ 1 2 3 4 5 6 At this point, the carrier protein has the shape it needs to bind two K ions outside the cell, as step shows. When the K ions bind, the phosphate group is released, as indicated in step , and the carrier protein restores its original shape. As shown in step this time, the change in shape causes the carrier protein to release the two K ions inside the cell. At this point the carrier protein is ready to begin the process again. Thus, a complete cycle of the sodium-potassium pump transports three Na ions out of the cell and two K ions into the cell. At top speed, the sodium-potassium pump can transport about 450 Na ions and 300 K ions per second. The exchange of three Na ions for two K ions creates an electrical gradient across the cell membrane. That is, the outside of the membrane becomes positively charged relative to the inside of the membrane, which becomes relatively negative. In this way, the two sides of the cell membrane are like the positive and nega- tive terminals of a battery. This difference in charge is important for the conduction of electrical impulses along nerve cells. The sodium-potassium pump is only one example of a cell membrane pump. Other pumps work in similar ways to transport important metabolic materials across cell membranes.

Passive and Active

PASSIVE AND ACTIVE VOICE QUIZ

Passive And Active Voice

PASSIVE AND ACTIVE TRANSPORT (COMPLEX)

PASSIVE AND ACTIVE TRANSPORT (2 COMPLEX/5 BASIC)

PASSIVE AND ACTIVE TRANSPORT (WEIGHTED)

PASSIVE AND ACTIVE TRANSPORT

Related quizzes

Related quizzes