Mastering Biology Chapter 5 Flashcards
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Questions and Answers

What must be specifically fitted for an enzyme to catalyze a reaction?

substrate and the enzyme's active site

Antibiotics can be used to treat viral infections, such as the common cold.

False

Why can't antibiotics like penicillin be used to treat viral infections?

They inhibit enzymes that are essential to the survival of bacteria only.

What is the mode of action for Azidothymidine (AZT) in treating HIV?

<p>competitive inhibition</p> Signup and view all the answers

What is the function of Structure E?

<p>stabilization of the phospholipids</p> Signup and view all the answers

Identify Structure D.

<p>phospholipid bilayer of membrane</p> Signup and view all the answers

Identify Structure A.

<p>glycoprotein</p> Signup and view all the answers

Structure A in the figure is a(n) _____.

<p>transport protein</p> Signup and view all the answers

Which of these is hydrophobic like the interior of the plasma membrane?

<p>Lipid soluble molecules</p> Signup and view all the answers

How is the rejection of transplanted organs related to plasma membranes?

<p>Each person has a unique set of carbohydrate chains attached to his or her plasma membranes</p> Signup and view all the answers

What is the primary component of membranes that gives them cell-specific properties?

<p>proteins</p> Signup and view all the answers

The lipids in a cell membrane are arranged _____.

<p>so that the nonpolar parts of two lipids point toward each other</p> Signup and view all the answers

Which of the following can pass freely through the plasma membrane with no assistance?

<p>Oxygen</p> Signup and view all the answers

What would be the order of components observed from the inside out?

<p>water, hydrophilic head, hydrophobic tail, hydrophobic tail, hydrophilic head, water</p> Signup and view all the answers

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

<p>more concentrated; less concentrated</p> Signup and view all the answers

Diffusion across a biological membrane is called __________.

<p>passive transport</p> Signup and view all the answers

What is the side with a higher concentration of molecules called?

<p>A</p> Signup and view all the answers

What is the plasma membrane referred to as?

<p>B</p> Signup and view all the answers

What is the side with a lower concentration of molecules called?

<p>C</p> Signup and view all the answers

What does diffusion cause?

<p>a net movement of molecules down their concentration gradient</p> Signup and view all the answers

In active transport, how do molecules move?

<p>across the plasma membrane against their concentration gradient</p> Signup and view all the answers

A molecule moves down its concentration gradient using a transport protein in the plasma membrane. This is an example of _________.

<p>facilitated diffusion</p> Signup and view all the answers

How does water cross the plasma membrane?

<p>through facilitated diffusion or diffusion</p> Signup and view all the answers

What is the sodium-potassium pump an example of?

<p>active transport</p> Signup and view all the answers

The plasma membrane forms a pocket that pinches inward, forming a vesicle that contains material from outside the cell. This describes the process of _____.

<p>endocytosis</p> Signup and view all the answers

The movement of atoms, ions, or molecules from a region of higher concentration to regions of lower concentration is called _____.

<p>diffusion</p> Signup and view all the answers

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

<p>osmosis</p> Signup and view all the answers

This cell is in a(n) _____ solution.

<p>hypertonic</p> Signup and view all the answers

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

<p>hypotonic...swelled</p> Signup and view all the answers

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

<p>hypertonic solution...lost water</p> Signup and view all the answers

What is the real driving force for osmosis?

<p>the difference in water concentration across a selectively permeable membrane</p> Signup and view all the answers

Brine shrimp must _____.

<p>actively pump water back into their cells to counter its loss due to osmosis</p> Signup and view all the answers

In the process of osmosis, water displays a net movement from an area of __________ water concentration to an area of __________ water concentration.

<p>higher...lower</p> Signup and view all the answers

Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions?

<p>a hypertonic sucrose solution</p> Signup and view all the answers

Facilitated diffusion is a type of _____.

<p>passive transport</p> Signup and view all the answers

Structure A is a _____.

<p>solute</p> Signup and view all the answers

Structure B is a _____.

<p>Transport Protein</p> Signup and view all the answers

What descriptive statement can be made about passive transport?

<p>Passive transport can transport molecules without the assistance of proteins from an area of high concentration to an area of lower concentration.</p> Signup and view all the answers

Which of these statements describes what occurs in facilitated diffusion?

<p>Facilitated diffusion of solutes occurs through protein pores in the membrane.</p> Signup and view all the answers

What condition might result from an excess of aquaporins?

<p>fluid retention in pregnant women</p> Signup and view all the answers

Side with lower concentration of square molecules.

<p>A</p> Signup and view all the answers

What is the transport protein?

<p>B</p> Signup and view all the answers

What requires energy input from the cell?

<p>C</p> Signup and view all the answers

What is the plasma membrane?

<p>D</p> Signup and view all the answers

Side with higher concentration of square molecules.

<p>E</p> Signup and view all the answers

What is the most likely transport mechanism for a molecule moving across a plasma membrane regardless of concentration?

<p>active transport</p> Signup and view all the answers

Endocytosis moves materials _____ a cell via _____.

<p>into...membranous vesicles</p> Signup and view all the answers

You can recognize the process of pinocytosis when _____.

<p>the cell is engulfing extracellular fluid</p> Signup and view all the answers

A white blood cell engulfing a bacterium is an example of _____.

<p>phagocytosis</p> Signup and view all the answers

What does exocytosis refer to?

<p>figure 1</p> Signup and view all the answers

What does endocytosis refer to?

<p>figure 2</p> Signup and view all the answers

Which statement best describes phagocytosis?

<p>A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a vacuole.</p> Signup and view all the answers

How does a nursing infant obtain disease-fighting antibodies?

<p>via endocytosis</p> Signup and view all the answers

Which of these is exhibiting kinetic energy?

<p>a space station orbiting Earth</p> Signup and view all the answers

'Conservation of energy' refers to the fact that _____.

<p>energy cannot be created or destroyed but can be converted from one form to another</p> Signup and view all the answers

Chemical energy is a form of _____ energy.

<p>potential</p> Signup and view all the answers

What process converts the chemical energy found in glucose into the chemical energy found in ATP?

<p>cellular respiration</p> Signup and view all the answers

Which of these are by-products of cellular respiration?

<p>all of the above</p> Signup and view all the answers

Light is _____ energy, which is converted into _____ energy by plants.

<p>kinetic...chemical</p> Signup and view all the answers

Energy is conserved. This means that in any system, _____.

<p>total energy input equals total energy output</p> Signup and view all the answers

Kinetic energy is energy in motion. Potential energy is _____ energy.

<p>stored</p> Signup and view all the answers

Which of the following is highest in chemical energy?

<p>one molecule of glucose</p> Signup and view all the answers

In cellular respiration, most energy is released and transferred to ATP when _____.

<p>high-energy electrons 'fall' to lower energy levels</p> Signup and view all the answers

What does the first law of thermodynamics state?

<p>energy is neither created nor destroyed</p> Signup and view all the answers

What happens to the chemical energy extracted from molecules but not used for work?

<p>It contributes to the entropy of the system</p> Signup and view all the answers

What allows simple molecules to assemble and disassemble in cells but not outside of living cells?

<p>Cells couple energy-releasing reactions to energy-requiring reactions</p> Signup and view all the answers

Which of these is ATP?

<p>Figure C</p> Signup and view all the answers

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule?

<p>hydrolysis</p> Signup and view all the answers

In this reaction _____.

<p>the products have less potential energy than the reactants</p> Signup and view all the answers

In this reaction _____.

<p>heat has been released to the environment</p> Signup and view all the answers

The reaction A --> B + C + heat is released in a(n) _____ reaction.

<p>exergonic</p> Signup and view all the answers

A(n) _____ reaction occurs spontaneously.

<p>exergonic</p> Signup and view all the answers

Which of these reactions requires a net input of energy from its surroundings?

<p>endergonic</p> Signup and view all the answers

In cells, what is usually the immediate source of energy for an endergonic reaction?

<p>ATP</p> Signup and view all the answers

The reaction ADP + P --> ATP is a(n) _____ reaction.

<p>endergonic</p> Signup and view all the answers

The energy for an endergonic reaction comes from a(n) _____ reaction.

<p>exergonic</p> Signup and view all the answers

What is the fate of the phosphate group removed when ATP is converted to ADP?

<p>It is acquired by a reactant in an endergonic reaction</p> Signup and view all the answers

This graph illustrates a(n) _____ reaction.

<p>endergonic</p> Signup and view all the answers

Select the INCORRECT association.

<p>exergonic...uphill</p> Signup and view all the answers

What is energy coupling?

<p>the use of energy released from an exergonic reaction to drive an endergonic reaction</p> Signup and view all the answers

Why is DNA stable despite being an exergonic reaction?

<p>The activation energy required to initiate this reaction is seldom reached</p> Signup and view all the answers

Study Notes

Membrane Structure and Function

  • Cholesterol stabilizes phospholipids within the plasma membrane, ensuring structural integrity.
  • The phospholipid bilayer consists of heads facing outward and tails pointing inward, creating a barrier between aqueous environments.
  • Glycoproteins play a key role in cell recognition and signaling, comprising carbohydrate and protein components.
  • Transport proteins facilitate the entry of solute molecules into the cell, influencing permeability.
  • Lipid-soluble and hydrophobic molecules can cross membranes easily due to their compatibility with the lipid bilayer.

Membrane Permeability and Transport Mechanisms

  • Plasma membranes are selectively permeable, allowing oxygen and carbon dioxide to move freely.
  • Molecules move from areas of higher concentration to lower concentration through diffusion, which is a passive transport process.
  • Active transport requires energy to move molecules against their concentration gradient, such as the sodium-potassium pump.
  • Facilitated diffusion involves transport proteins assisting molecules to cross membranes without energy expenditure.
  • Osmostic processes dictate that water moves from areas of lower solute concentration to areas of higher concentration.

Solutions and Cell Behavior

  • A hypertonic solution causes cells to lose water, while a hypotonic solution results in swelling due to water influx.
  • Osmosis is driven by differences in water concentration, rather than solute concentration directly.
  • Brine shrimp must actively pump water to maintain internal balance in hypertonic environments.
  • Red blood cells shrink in hypertonic sucrose solutions due to water moving out of the cell.

Energy and Metabolic Processes

  • Energy cannot be created or destroyed (first law of thermodynamics) but can be converted from one form to another.
  • Chemical energy, a form of potential energy, is converted into ATP during cellular respiration.
  • Cellular respiration produces heat and water as by-products.
  • ATP hydrolysis releases energy, allowing cells to perform work, especially in endergonic reactions which require energy input.

Reaction Types and Enzyme Function

  • Exergonic reactions release energy and occur spontaneously, while endergonic reactions require energy to proceed.
  • Enzymes function by providing an active site where substrates can bind precisely, allowing reactions to occur efficiently.
  • Competitive inhibition occurs when a substance resembles a substrate and occupies the enzyme’s active site, hindering normal substrate function.
  • Antibiotics target bacterial enzymes, making them ineffective against viruses, which have different biological mechanisms.

Importance of Energy Coupling

  • Energy coupling is the process of using energy from exergonic reactions to drive endergonic ones, crucial for maintaining cellular functions.
  • The conversion of ADP to ATP is an endergonic reaction that consumes energy, sustaining cellular processes.
  • Hydrolysis of ATP releases energy, which can be harnessed for reactions requiring energy input.

These notes encapsulate the fundamental concepts of membrane structure, transport mechanisms, the role of energy in cellular activities, and enzyme functionality, providing a comprehensive overview of key topics in biological processes.

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Test your knowledge of Chapter 5 in Mastering Biology with these flashcards. Learn about the key structures in the plasma membrane and their functions. Perfect for review and memorization of essential biological concepts related to cell membranes.

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