Chapter 5

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? A) Diffusion is a result of the thermal energy of atoms and molecules. B) Diffusion requires no input of energy into the system. C) Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated. D) Diffusion occurs even after equilibrium is reached and no net change is apparent.

membrane proteins transfer genetic information to the cytoplasm

Which of the following statements regarding membrane protein function is false? A) Membrane proteins serve as enzymes. B) Membrane proteins act as receptors to molecules like hormones. C) Membrane proteins form junctions between cells. D) 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? A) O2 B) CO2 C) Na+ D) a small, nonpolar molecule such as butane (C4H10)

plant

a hypotonic solution is only good for what kind of cell?

concentration gradient

a region along which the density of a chemical substance increases or decreases

metabolic pathway

a series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds

tonicity

a term that describes the ability of a surrounding solution to cause a cell to gain or lose water

animal

an isotonic solution is only good for what kind of cell?

noncompetitive inhibitors

bind to the enzyme somewhere other than the active site, change the shape of the active site, and prevent the substrate from binding

competitive inhibitors

bloc substrates from entering the active site and reduce an enzyme's productivity

second law of thermodynamics

energy conversions increase the disorder of the universe

potential energy

energy that matter possesses as a result of its location or structure

biological catalysts

enzymes function as __________.

ibuprofen

example of an enzyme inhibitor

phosphorylation

hydrolysis of ATP releases energy by transferring its third phosphate from ATP to some other molecule in a process called ______________.

coenzyme

if a cofactor is an organic molecule, such as most vitamins

shriveled

in a hypertonic solution animal and plant cells are ________.

turgid (normal)

in a hypotonic solution, a plant cell is ________.

normal; flaccid

in an isotonic solution, an animal cell is ________ and a plant cell is _______.

exergonic reaction

in this chemical reaction, energy is released

endergonic reaction

in this chemical reaction, it requires an input of energy and stores energy

isotonic

in this solution, in an animal cell, the concentration of solute is the same on both sides of a membrane, and the cell volume will not change

hypertonic

in this solution, in an animal cell, the solute concentration is higher outside the cell, water molecules move out of the cell, and the cell will shrink

hypotonic

in this solution, in an animal cell, the solute concentration is lower outside the cell, water molecules move in to the cell, and the cell will expand and may burst

active

in this transport a cell must expand energy to move a solute against its concentration gradient

endocytosis

is used to take in large molecules

receptor-mediated endocytosis

kind of endocytosis that uses membrane receptors for specific solutes

cofactors

many enzymes require nonprotein helpers called _________, which bind to the active site and function in catalysis

entropy

measure of disorder or randomness

energy

the capacity to cause change or to perform work

kinetic energy

the energy of motion

transport materials

the function of the plasma membrane

facilitated diffusion

the passage of a substance through a specific transport protein across a biological membrane down its concentration gradient; does not require energy

chemical energy

the potential energy available for release in a chemical reaction and is the most important type of energy for living organisms to power the work of the cell

substrate

the specific reactant that an enzyme acts on is called the enzyme's ___________.

thermodynamics

the study of energy transformations that occur in a collection of matter

diffusion

the tendency of particles to spread out evenly in an available space

aquaporin

the very rapid diffusion of water into and out of certain cells is made possible by a protein channel called a(n) ___________.

heat

thermal energy in transfer from one object to another

metabolism

total of an organisms chemical reactions

thermal energy

type of kinetic energy associated with the random movement of atoms or molecules

transport proteins

type of protein that allows specific ions or molecules to enter or exit the cell

attachment proteins

type of protein that is connected to the extracellular matrix and cytoskeleton, helps support the membrane, and can coordinate external and internal changes

enzymes

type of protein that may be grouped to carry out sequential reactions and speed up a reaction

junction proteins

type of proteins that form intercellular junctions that attach adjacent cells

receptor proteins

type of proteins that relay the message by activating other molecules inside the cell

glycoproteins

type of proteins that serve as ID tags and may be recognized by membrane proteins of other cells

exocytosis

used to export bulky molecules such as proteins or polysaccharides

energy coupling

uses the energy released from exergonic reactions to drive endergonic reactions, typically using the energy stored in ATP molecules

adenosine and triphosphate tail of three phosphate groups

what is ATP made of?

passive does not require energy, but active does

what is the difference between passive transport and active transport

feedback inhibition

when the product in a reaction acts as an inhibitor of one of the enzymes in the pathway that produced it

isotonic to its environment

A cell that neither gains nor loses water when it is immersed in a solution must be A) isotonic to its environment. B) hypertonic to its environment. C) hypotonic to its environment. D) metabolically inactive

transport proteins; against

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient. A) energy and transport proteins . . . down B) transport proteins . . . down C) energy and transport proteins . . . against D) transport proteins . . . against

lyse

In a hypotonic solution, an animal cell will A) lyse B) experience turgor C) neither gain nor lose water D. shrivel

passive transport and facilitated diffusion

In which two diffusions do the concentrations movie high to low?

kinetic energy is the energy of a moving object, whereas chemical energy is the the potential energy of molecules

Kinetic energy differs from chemical energy in that A) kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement. B) kinetic energy can be converted into various forms of energy, whereas chemical energy can only be converted into heat. C) kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules. D) chemical energy is a particular form of kinetic energy.

are able to drift about in the plasma membrane

Membrane phospholipids a) have hydrophobic heads that face the center of the membrane and are shielded from water. b) have hydrophilic tails that face outward and are exposed to water. c) are able to drift about in the plasma membrane d) remain fluid because they are tightly packed against one another.

b) proteins

Most of the functions of a cell membrane, including transport and enzymatic function are performed by: a) glycolipids b) proteins c) phospholipids d) cholesterol

the diffusion of water

Osmosis can be defined as: a) the diffusion of water b) the diffusion of non polar molecules c) active transport d) the diffusion of a solute

passive transport

Oxygen crosses a plasma membrane by: a) osmosis b) active transport c) pinocytosis d) passive transport

diverse proteins embedded in a phospholipid bilayer

The fluid mosaic model describes the plasma membrane as consisting of: a) a phospholipid bilayer with embedded carbohydrates. b) two layers of phospholipids with cholesterol sandwiched between them. c) carbohydrates and phospholipids that can drift in the membrane. d) diverse proteins embedded in a phospholipid bilayer.

d) proteins

The molecules responsible for membrane transport are A) steroids B) phospholipids C) carbohydrates D) proteins

phagocytosis

The process of a white blood cell engulfing a bacterium is A) osmosis B) receptor-mediated endocytosis C) pinocytosis D) phagocytosis

exergonic reactions involved ionic bonds; endergonic reactions involve covalent bonds

What is the basic difference between exergonic and endergonic reactions? A) Exergonic reactions involve ionic bonds; endergonic reactions involve covalent bonds. B) Exergonic reactions involve the breaking of bonds; endergonic reactions involve the formation of bonds. C) Exergonic reactions release energy; endergonic reactions absorb it. D) In exergonic reactions, the reactants have less chemical energy than the products; in endergonic reactions, the opposite is true.

osmoregulation

What is the process an animal cell needs to survive in a hypotonic or hypertonic environment that is the control of water balance

cell-surface carbohydrates

When physicians perform an organ transplant, they choose a donor whose tissues match those of the recipient as closely as possible. Which of the following cell components are being matched? A) plasma membrane phospholipids B) plasma membrane proteins C) cell-surface carbohydrates D) plasma membrane cholesterols

protein synthesis

Which of the following examples is classified as a metallic pathway? A) protein synthesis B) osmosis C) cell lysis D) passive diffusion

allow the cells of an embryo to sort themselves into tissues and organs

A major function of glycoproteins and glycolipids in the cell membrane is to: a) glue cells together to form tissues b) allow the cells of an embryo to sort themselves into tissues and organs c) attach the cell membrane to cytoskeleton b) help the cell retain its shape

the first law of thermodynamics

According to ____________, energy cannot be created or destroyed. A) Aristotle's first principle B) the first law of thermodynamics C) the second law of thermodynamics D) the third law of thermodynamics

b. 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? A) endocytosis B) exocytosis C) diffusion D) pinocytosis