BIOL 120 Exam 2

What is the correct label for A?

Energy of activation (E_A)

In the figure, how does the molecule labeled A affect enzyme function?

? It is an inhibitor that changes the enzyme’s active site ?

Structure A is a ____

Solute

Structure B is a ____

Transport protein

This cell is in a(n) ____ solution

Hypertonic

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

Hypotonic…swelled

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

Hypertonic…lost water

Enzymes speed up chemical reactions by lowering the ____, which allows the reaction to proceed much more quickly.

Activation energy

Lactose takes years to break down on its own. But if exposed to the protein lactase, the reaction proceeds very quickly, while lactase itself remains unchanged. Lactase is an example of a(n) ____.

Enzyme

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

Catalyst

During an enzymatic reaction, a molecule of ____ binds to the enzyme and is broken down into one or more molecules of ____, which are released.

Substrate…product

A(n) ____ is a molecule that can bind to an enzyme and prevent the enzyme from working.

Inhibitor

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

Denature

The specific location within an enzyme molecule where the substrate binds is called the ____.

Active site

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

Induced fit

What major theme of biology is represented in the following: The region of an enzyme called the active site has the shape and chemistry that fits one specific substrate molecule

Relationship of structure to function

What major theme of biology is represented in the following: There is more oxygen gas in the air of our lungs than in the blood. Therefore, oxygen moves by passive transport from the air into the bloodstream

Interactions within biological systems

What major theme of biology is represented in the following: Because all cells have a plasma membrane, it is logical to infer that membranes first developed in the earliest forms of life on Earth

Evolution

What major theme of biology is represented in the following: ATP energizes other molecules in cells by transferring phosphate groups to those molecules

Pathways that transform energy and matter

What is the best definition of energy?

The capacity to cause change

What is true about energy?

It cannot be created nor destroyed

What is an example of potential energy?

A bowling ball placed on the top shelf of a closet

How are combustion and cellular respiration different?

Cellular respiration breaks down sugar and combustion breaks down octane

What is the function of ATP?

It provides energy for cellular work

A space station orbiting Earth is exhibiting what type of energy?

Kinetic

“Conservation of energy” refers to the fact that ____

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

Chemical energy is a form of ____ energy

Potential

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

Cellular respiration

What molecule do cells use to store the chemical energy released by the breakdown of food molecules during cellular respiration?

ATP

What are the components of the molecule ATP?

An organic molecule called adenosine and three phosphate groups

ATP drives work in cells by ____

Transferring its phosphate group to other cell molecules

Most enzymes are ____

Proteins

Enzymes work by ____

Reducing activation energy in a reaction

An enzyme is a(n) ____

Organic catalyst

What name is given to the reactants in an enzymatically catalyzed reaction?

Substrate

As a result of its involvement in a reaction, an enzyme ____

Remains unchanged

An enzyme is a molecule that ____

Changes the rate of a metabolic reaction without being consumed by the reaction

Activation energy can be described as ____

Energy that must be invested to start a reaction

What best explains the observation that enzymes are selective in the reactions they catalyze?

There is a precise compatibility between an enzyme’s active site and the substrate molecule

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

More concentration, less concentrated

Diffusion across a biological membrane is called ____.

Passive transport

Endocytosis moves materials ____ a cell via ____.

Into…membranous vesicles

You can recognize the process of pinocytosis when ____

The cell is engulfing extracellular fluid

A white blood cell engulfing a bacterium is an example of ____

Phagocytosis

Facilitated diffusion is a form of ____ transport

Passive

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

Osmosis

Exocytosis involves the movement of molecules from ____ the cell to ____ the cell.

Inside…outside

Endocytosis involves the movement of molecules from ____ the cell to ____ the cell.

Outside…inside

A vesicle inside the cell fuses with the plasma membrane and releases its contents outside the cell is ____

Exocytosis

____ is a form of passive transport in which molecules move across the plasma membrane using a transport protein.

Facilitated diffusion

The plasma membrane forms a pocket that pinches inward, forming a vesicle that contains material from outside the cell is ____

Endocytosis

____ is a form of passive transport in which molecules move across the plasma membrane by crossing a lipid bilayer.

(Simple) Diffusion

____ requires energy from the cell. Molecules move against their concentration gradient.

Active transport

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

Isotonic

An animal cell placed in a(n) hypotonic solution will ____.

Gain water, swell, and possibly burst

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

Hypertonic

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

Hypotonic

A plant cell placed in a(n) hypertonic solution will ____.

Lose water and plasmolyze

A plant cell surrounded by a(n) isotonic solution will be ____.

Flaccid (limp)

The passive movement of molecules from an area of higher concentration to an area of lower concentration is called ____.

Diffusion

An animal cell placed in a hypertonic solution will ____ water by ____.

Lose…osmosis and shrivel

In osmosis, water moves across a selectively permeable membrane toward the ____ solution; that is, toward the solution with the ____ solute concentration.

Hypertonic…greater

The concentration of calcium in a cell is 0.3%. The concentration of calcium in the surrounding fluid is 0.1%. How could the cell obtain more calcium? Through ____ transport.

Active

“The use of energy to move molecules across a membrane” is the definition of ____.

Active transport

What is sometimes referred to as cell eating?

Phagocytosis

What is sometimes referred to as cell drinking?

Pinocytosis

Can an object at rest have energy?

Yes; it can have potential energy because of its location or structure

What major theme of biology is illustrated by the following: You turn the crank of a well, raising a bucket of water from below ground to the surface.

Pathways that transform energy and matter

How does ATP power cellular work?

ATP is hydrolyzed into ADP + Pi. The Pi is transferred to another molecule such as an ion channel or an enzyme, activating that molecule

What is the source of energy regenerating ATP from ADP?

Chemical energy harvested from sugars and other organic fuels via cellular respiration

How does an enzyme recognize its substrate?

The substrate and the enzyme’s active site are complementary in shape and chemistry

How does an enzyme affect the activation energy of a chemical reaction?

By lowering the activation energy

Which major theme of biology is illustrated by the following: Enzymes unravel and stop functioning if the environment gets too hot.

The relationship of structure to function

Which major theme of biology is illustrated by the following: Your ability to walk depends upon the coordination of many different enzymes and other cellular structures.

Interactions within biological systems

What does it mean to say that molecules move ‘down the concentration gradient’?

Molecules move from an area of high concentration to an area of low concentration

Why is facilitated diffusion a form of passive transport?

It uses proteins to transport materials down a concentration gradient without expending energy

What two processes make up bulk transport?

Endocytosis and exocytosis

What are two examples of endocytosis?

Phagocytosis and pinocytosis

What are the four types of tissues?

Epithelial, connective, muscle, and nervous

Place these levels of biological organization in order from largest to smallest: Cell, organ, atom, organ system, molecule, organism, tissue, macromolecules

Atoms, molecules, macromolecules, organelles, cells, tissues, organs, organ systems, organism

Bird wings are hollow, which makes them lighter. How does this illustrate the structure-function principle?

The structure of the wing, with hollow bones, makes it lightweight, which correlates with the function of flight

Which major theme of biology is illustrated by the following: Your body is able to build new muscle when nutrients absorbed by the digestive system are transported by the circulatory system to tissues of the muscular system.

Interactions within biological systems

Which major theme of biology is illustrated by the following: Your body is able to build new muscle when nutrients absorbed by the digestive system are transported by the circulatory system to tissues of the muscular system.

Information flow

Which process helps maintain homeostasis?

Negative feedback

What is the difference between negative and positive feedback?

Positive - end results intensify the process; Negative - end result inhibits the process

When you flush a toilet, water begins to refill the tank. The rising water level lifts a float. When the float reaches a certain height, it stops more water from entering the tank. This is an example of what kind of homeostatic control? Why?

This is an example of negative feedback because the result of a process (water filling the tank) inhibits that same process

What are three features of the human body that helps release heat?

Sweating, dilation of blood vessels, panting

What are three features of the human body that help to retain body heat?

Shivering, constriction of blood vessels, increased metabolic rate

A patient receives fluid through an intravenous (IV) line that causes his interstitial fluid to have a very high solute concentration. What will happen to his cells?

They will shrink as water exits via osmosis

What is a nephron?

Basic functional unit of the kidney

What are the four processes of the nephron that occur as kidney tubules process blood and create urine?

Filtration, reabsorption, secretion, and excretion

Which major theme of biology is illustrated by the following: Your kidneys contain highly branched tubes that allow for a large volume of fluid to be in contact with cells, aiding filtration.

Relationship of structure to function

A correct comparison between a benign and a malignant tumor is that ____

Benign tumors do not metastasize, malignant tumors do

A cell that neither gains nor loses a net amount of water at equilibrium when it is immersed in a solution is ____

Isotonic to its environment

A diver at the top of a diving board contains ____ energy

Potential

The sum total of all the chemical reactions that occur in organisms is called ____

Metabolism

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

Transport proteins; down

An object at rest has no ____ energy, but it may have ____ energy resulting from its location or structure

Kinetic; Potential

A boulder at the top of a hill is or is not an example of potential energy?

It is

Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing ____

Chemical energy into kinetic energy