H-Biology: Chapter 5 Test

phagocytosis

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

coenzyme

A(n) _____________, which is often a vitamin, binds to an enzyme and plays a role in catalysis

active site

An enzyme is specific because the shape of its ________________ matches only particular reactants.

result in cell death

Anything that prevents ATP formation will most likely

passive transport

Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of

into ... membranous vesicles

Endocytosis moves materials _____ a cell via _____.

cellular respiration

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

active

Substrates bind to an enzyme's ________ site.

helps to keep phospholipids from being too close to one another

The cholesterol associated with animal cell membranes

diverse proteins embedded in a phospholipid bilayer

The fluid mosaic model describes the plasma membrane as consisting of

phosphorylation

The transfer of a phosphate group to a molecule or compound is called

proteins

most of a cell's enzymes are

endergonic reactions can be fueled by coupling them with the hydrolysis of high-energy phosphate bonds in ATP

ATP can be used as the cell's energy exchange mechanism because

feedback inhibition

Bacterial production of the enzymes needed for the synthesis of the amino acid tryptophan declines with increasing levels of tryptophan and increases as tryptophan levels decline. This is an example of

transport proteins; down

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

denature

High temperatures or changes in pH can ____________ an enzyme, causing it to lose its shape and biological activity.

figure C is essentially a summary of the data in Figure A

How do the data in Figure A relate to the data in Figures B and C?

competitive inhibitors bind to the active site of the enzyme; noncompetitive inhibitors bind to a different site

How does inhibition of an enzyme-catalyzed reaction by a competitive inhibitor differ from inhibition by a noncompetitive inhibitor?

substrate

In a catalyzed reaction, a reactant is often called a(n) _____________.

lyse

In a hypotonic solution, an animal cell will

are able to drift about in the plasma membrane

Membrane phospholipids

proteins

Most of the functions of a cell membrane, including transport and enzymatic function, are performed by

the diffusion of water

Osmosis can be defined as

passive transport

Oxygen crosses a plasma membrane by

drinking

Phagocytosis is to eating as pinocytosis is to

hypertonic

There is a net diffusion of water out of an animal cell when it is placed in a(n) _______________ solution.

-Enzymes lower the overall energy input needed for a reaction to occur. -Reactants cannot convert to products without an initial input of energy to start the reaction. -By binding to reactant molecules, enzymes make it easier for the bonds in the molecules to break apart.

Use the graph and your knowledge of enzymes to identify the three true statements about enzymes. Enzymes lower the overall energy input needed for a reaction to occur. Reactants cannot convert to products without an initial input of energy to start the reaction. By binding to reactant molecules, enzymes make it easier for the bonds in the molecules to break apart. Chemical reactions cannot occur without enzymes. Only reactions that are controlled by enzymes require activation energy

exergonic reactions release energy; endergonic reactions absorb it

What is the basic difference between exergonic and endergonic reactions?

osmosis

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

hydrolysis

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

exergonic; endergonic

When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction.

it lowers the activation energy of the reaction

When an enzyme catalyzes a reaction,

more concentrated; less concentrated

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

exhibit a net movement to the side with lower free water concentration

When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will

red curve; line b

Which curve shows the course of the reaction in the presence of an enzyme-- the black curve or the red curve? Which line represents the activation energy for that reaction--a, b, or c?

protein synthesis

Which of the following processes is classified as a metabolic pathway? -cell lysis -passive diffusion -osmosis -protein synthesis

the synthesis of glucose from carbon dioxide and water

Which of the following processes is endergonic? -the breakdown of glucose -cellular respiration -the burning of wood -the synthesis of glucose from carbon dioxide and water

it releases energy when one phosphate group leaves ATP

Which of the following statements about the ATP molecule is true? -It contains five phosphate groups. -Extremely stable bonds link the second and third phosphate groups. -It contains the sugar glucose. -It releases energy when one phosphate group leaves ATP.

a zinc atom

Which of the following substances could be a cofactor? a polypeptide a zinc atom a ribosome a protein

heat and water

Which of these are by-products of cellular respiration? -ATP -water -glucose and water -ATP and water -heat and water

a space station orbiting Earth

Which of these is exhibiting kinetic energy? -a person sitting on a couch while watching TV -a space station orbiting Earth -a rock on a mountain ledge -the high-energy phosphate bonds of a molecule of ATP -an archer with a flexed bow

part D

Which part of the ATP molecule breaks free of the rest when an ATP molecule is used for energy?

mix the blood in a hypotonic solution, which will cause the RBCs to lyse

White blood cells (WBCs) are more resistant to lysis than red blood cells (RBCs). When looking at a sample of blood for WBCs, what could you do to reduce interference from RBCs?

activation energy

the energy required to initiate an exergonic reaction is called

hypertonic

This cell is in a(n) _____ solution. *the figure shows a cell membrane, the extracellular fluid, and the cytoplasm. The concentration of the solute is higher outside the cells. The figure shows 2 states of the cell: when it was just placed in this solute and over the time.*

energy cannot be created or destroyed but can be converted from one form to another

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

catalyst

1. An enzyme is considered a(n) ______________ because it speeds up a chemical reaction without being used up.

isotonic to its environment

A cell that has neither a net gain of water nor net loss of water when it is immersed in a solution must be

the relative inelasticity and strength of the plant cell wall

If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference?

hypotonic

In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the balloon is ________ relative to the solution in the beaker.

water will leave the balloon

In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur? -Sucrose will leave the balloon. -Water will enter the balloon. -Water will leave the balloon. -Sucrose will enter the balloon.

the plasma membrane allows some substances to enter or leave a cell more easily than others

Plasma membranes are selectively permeable. This means that

prevents the spontaneous breakdown of molecules in the cell

an energy barrier

structure; function

All cells are enclosed by a plasma membrane that is similar in ________ and ________.

changing the enzyme's three-dimensional shape

Heating inactivates enzymes by

proteins

The molecules responsible for membrane transport are

ATP

What is this? (be able to identify the structure of ____)

elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze various reactions

A child is brought to the hospital with a fever of 107°F. Doctors immediately order an ice bath to lower the child's temperature. Which of the following statements offers the most logical explanation for this action? -Elevated body temperature will increase reaction rates in the child's cells and overload the limited number of enzymes found in the cell. -Elevated body temperatures will increase the energy of activation needed to start various chemical reactions in the body. This will interfere with the ability of enzymes to catalyze vital chemical reactions. -Elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze various reactions. -Elevated body temperatures cause molecules to vibrate more quickly and prevent enzymes from easily attaching to reactants. This would slow vital body reactions.

becomes turgid because of an inflow of water

A plant cell in a hypotonic solution

hypertonic

A plant cell placed in a(n) ________________ solution will lose water and plasmolyze.

isotonic

A plant cell surrounded by a(n) _____________ solution will be flaccid (limp).

hypotonic

An animal cell placed in a(n) ___________ solution will gain water, swell, and possibly burst.

activation energy

An enzyme speeds up reactions by lowering the ______________.

allow water to cross the plasma membrane via facilitated diffusion

Aquaporins

receptor-mediated endocytosis

Cells acquire low-density lipoproteins (LDLs) by

exocytosis

Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion? pinocytosis exocytosis diffusion endocytosis

potential

Chemical energy is a form of _____ energy.

passive transport

Facilitated diffusion is a type of _____.

a signaling molecule binds to a protein that extends to the outside of the cell

Relaying a message from a membrane receptor to a molecule that performs a specific function within a cell occurs when

easily pass through a membrane's lipid bilayer

Small, nonpolar, hydrophobic molecules such as fatty acids

is hypotonic to the protozoan

Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment

solute

Structure A is a _____. *the figure shows a scheme of a facilitated diffusion. The lipid bilayer, extracellular fluid, and the cytoplasm are pictured there. There is a carrier in the membrane. Particles can seen inside and outside the cell, but their concentration is higher outside. These particles are labeled as A.*

transport protein

Structure B is a __________. *the figure shows a scheme of a facilitated diffusion. The lipid bilayer, extracellular fluid, and the cytoplasm are pictured there. There is a carrier in the membrane. Particles can seen inside and outside the cell, but their concentration is higher outside. Also, there is a large molecule which pierces the membrane. This molecule is labeled as B.*

induced fit

The ___________________ between an active site and its substrate often strains bonds and helps the reaction proceed.

the region of an enzyme that attaches to a substrate

The active site of an enzyme is

hypotonic

The ideal osmotic environment for a plant cell is a(n) _____________ environment.

isotonic

The ideal osmotic environment for an animal cell is a(n) __________ environment.

phagocytosis

The process of a white blood cell engulfing a bacterium is

cell A

Which figure depicts an animal cell placed in a solution hypotonic to the cell?

vitamin B6

Which of the following is a coenzyme? vitamin B6 iodine zinc iron

the solute moves against the concentration gradient

Which of the following is a typical feature of an ATP-driven active transport mechanism? -The solute moves against the concentration gradient. -The transport protein is irreversibly phosphorylated as transport takes place. -The transport protein catalyzes the conversion of ADP to ATP. -The transport protein must cross to the correct side of the membrane before the solute can bind to it.

active transport

Which of the following processes can move a solute against its concentration gradient? -facilitated diffusion -passive transport -osmosis -active transport

the concentration gradient is the driving force

Which of the following statements is true for all types of passive transport? -The concentration gradient is the driving force. -Proteins are needed to transport molecules across the membrane. -Only small polar molecules are able to cross the plasma membrane. -Ions never cross the plasma membrane by passive transport.

active transport is driven by the concentration gradient

Which of the following statements regarding active transport is false? -Active transport can move a solute against its concentration gradient. -Active transport requires the cell to expend energy. -Active transport is driven by the concentration gradient. -Active transport uses ATP as an energy source.

diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated

Which of the following statements regarding diffusion is false? -Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated. -Diffusion requires no input of energy into the system. -Diffusion occurs even after equilibrium is reached and no net change is apparent. -Diffusion is a result of the thermal energy of atoms and molecules.

enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction

Which of the following statements regarding enzyme function is false? -Enzymes emerge unchanged from the reactions they catalyze. -An enzyme's function depends on its three-dimensional shape. -Enzymes are very specific for certain substrates. -Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction.

enzymes catalyze specific reactions

Which of the following statements regarding enzymes is true? -An enzyme's function is unaffected by changes in pH. -Enzymes are inorganic. -All enzymes depend on protein cofactors to function. -Enzymes catalyze specific reactions.

the plasma membrane is the control center of the cell

Which of the following statements regarding membrane function is false? -The plasma membrane plays a role in transferring signals to the cell's interior. -The plasma membrane is the control center of the cell. -The plasma membrane has receptors for chemical messages. -The plasma membrane forms a selective barrier around the cell.

membrane proteins transfer genetic information to the cytoplasm

Which of the following statements regarding membrane protein function is false? -Membrane proteins serve as enzymes. -Membrane proteins form junctions between cells. -Membrane proteins act as receptors to molecules like hormones. -Membrane proteins transfer genetic information to the cytoplasm.

Na+

Which of the following substances would have the most trouble crossing a biological membrane by diffusing through the lipid bilayer? -CO2 -a small, nonpolar molecule such as butane (C4H10) -O2 -Na+

you dehydrate yourself

You are adrift in the Atlantic Ocean and, being thirsty, drink the surrounding seawater. As a result,

the cell is engulfing extracellular fluid

You can recognize the process of pinocytosis when _____.

hypertonic solution ... lost water

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

hypotonic ... swelled

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