BIOL 1107K Exam 2

Which of the following are forms of carrier-mediated transport?

Both facilitated diffusion and carrier-mediated active transport

Which of the following statements concerning ATP is FALSE?

It stores energy for long periods.

Which of the following statements concerning enzymes is FALSE?

Most enzymes are RNA molecules

Nucleoli contain chromosomal regions that specialize in making:

RNA

Which of the following is NOT true of cell membranes?

They are composed of 4 carbohydrate layers. (They are actually composed of 2 layers.)

Which of the following statements concerning phospholipids is FALSE?

They contain three fatty acid chains

The cis face of the Golgi complex is most directly involved in which of the following?

accepting vesicles from the ER

Parts of the enzyme molecule that interact with a substrate are called:

active sites

An outside source of energy (ATP) is required for

active transport

A carrier molecule is required for

active transport and facilitated diffusion

An allosteric enzyme:

allows a substance other than the substrate to bind to the enzyme, thereby activating or inactivating it

An organism can exchange matter and energy with its surroundings. Thus, any change in an organism's energy content must be balanced by a corresponding change in the energy content of the surroundings. As such, an organism is referred to as:

an open system

Pathways that have an overall energy requirement are referred to as:

anabolic reactions

Which of the following lacks a cell wall?

animal cell

Integral proteins

are amphipathic

One difference between tight junctions and desmosomes is that tight junctions

are regions where plasma membrane from 2 neighboring cells are in actual contact

All of the following are cell membrane functions EXCEPT for

being freely permeable to all substances

Peripheral proteins are linked to either surface of the plasma membrane by

bonding to integral proteins through noncovalent interactions

Receptor-mediated endocytosis

brings about the selective uptake of materials by enclosing them in membranous vesicles

Because enzymes affect the speed of chemical reactions without being consumed, they are referred to as:

catalysts

In cells that are constantly involved in secretion, an equivalent amount of membrane must be returned to the interior of the cell for each vesicle that fuses with plasma membrane; if not, what happens?

cell surface will keep expanding

Plant cell walls are primarily composed of

cellulose

Cell structures that function in cell division are

centrioles

Which of the following pairs is correctly matched?

centrosome-cell division

An energy-converting organelle is a

chloroplast

Food (organic molecules such as glucose) is produced in the

chloroplast

Stroma and grana are found in the

chloroplast

Which of the following structures would not be found in cells of a plant's roots?

chloroplasts

DNA is associated with proteins, forming a complex called

chromatin

_________________ are NOT composed of microtubules.

chromosomes

A transmembrane protein differs from other membrane proteins because it

completely extends through the membrane

For diffusion to occur, a _______________ _______________ is necessary.

concentration gradient

One job of the nuclear membrane is to

control entry to and exit from the nucleus

The fluid material located outside of the nucleus is the

cytosol

A membrane is NOT necessary in

diffusion

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

diffusion

The force necessary to cause microtubules of cilia and flagella to slide alongside one another is provided through the action of ___ proteins, which derive the energy to perform their work directly from ___ molecules.

dyeing:ATP

In a reaction in which the rate of the reverse reaction is equal to the rate of the forward reaction, a state of ___ is attained

dynamic equilibrium

Every type of chemical bond contains a certain amount of energy. The total bond energy, which is essentially equivalent to the total potential energy of the system, is a quantity known as:

enthalpy

Which word is defined by this statement: A measure of this disorder, or randomness?

entropy

The golgi apparatus packages

enzymes

The reaction ATP + H2O -> ADP + Pi is classified as an:

exergonic reaction

Eukaryotic cells are found in the group known as

fungi, plants, animals (all of the above)

Which of the following is involved in the synthesis and packaging of certain molecules produced for secretion by a cell?

golgi apparatus

A eukaryotic cell:

has a variety of membranous organelles

Solutions that are isotonic:

have equal concentrations of solute and water

Which of the following does NOT represent a method by which cells regulate enzyme activity?

heat denaturation of the enzyme

In a lipid bilayer, __________ fatty acid tails face each other within the bilayer and form a region that excludes water.

hydrophobic

The phospholipids of a cellular membrane will have their ____ ends facing each other (inside) and their ____ ends facing away from each other (outside)

hydrophobic;hydrophilic

If the concentration of solutes in a cell is less than the concentration of solutes in the surrounding fluid, then the extracellular fluid is said to be:

hypertonic

Pinocytosis:

is the nonspecific uptake of fluids by pinching inward of the plasma membrane

Enzymes are important biological catalysts because they:

lower the activation energy of a biochemical reaction

The breakdown of which of the following leads to self-destruction of the cell?

lysosome

The ratio of the size of the image seen with the microscope to the actual size of the object called:

magnification

Which of the following accurately represents the relationship between the terms anabolism, catabolism, and metabolism?

metabolism = catabolism + anabolism

Which of the following is a key component of the cytoskeleton?

microtubules

Which of the following organelles plays an important role in apoptosis, or programmed cell death?

mitochondria

Prokaryotic cells lack

mitochondrion

The aerobic cellular respiration (release of energy from food) of carbohydrates occurs in the

mitochondrion

What is meant by the term "fluid mosaic model"?

movement of lipids and integral proteins within the lipid bilayer

Osmosis is the

net movement of water across a differentially permeable membrane

Select the hydrogen acceptor molecule that stores electrons in the process of photosynthesis:

nicotinamide adenine dinucleotide phospate (NADP+)

Which of the following structures is found inside the nuclear membrane?

nucleolus

A single cell in a smoker's lung has become cancerous. It doubles its DNA and divides much faster than a normal lung cell. The most likely change that would have caused this condition took place in the:

nucleus

Electron microscopes have a much higher resolution than either the human eye or any light microscope because:

of the very short (nanometer) wavelengths of electrons

What refers to the situation in which the binding of a substrate to the enzyme causes a change in the enzyme's shape, facilitating an enzyme's function?

orientation sites

Which of the following membrane activities does NOT require the expenditure of energy by the cell?

osmosis

___ is a process where energy (as electrons) is released, whereas ___ is a process where energy (as electrons) is accepted.

oxidation; reduction

XH2 + NAD+ -> NADH + H+. In the preceding equation, NAD+ is said to be:

oxidized

A human white blood cell engulfs bacterial cell by

phagocytosis

__________ is a cell engulfing large solid materials, and ___________ is a cell engulfing materials dissolved in solution.

phagocytosis;pinocytosis

The MAIN components of a cell membrane are

phospholipids and proteins

Which of the following molecules is LEAST likely to cross a cellular membrane by simple diffusion?

potassium ion

If a toxin, such as a bacterial toxin, destroys ribosomes, what cellular activity will be affected first?

protein synthesis

Ribosomes are the site of

protein synthesis

Chromatin material is

really the same as a chromosome.

Facilitated diffusion

requires a transmembrane protein

Which of the following cell organelles contains RNA?

ribosomes

Which of the following structures or activities is NOT directly part of the endomembrane system?

ribosomes

Differential centrifiguration is a process that:

separates components of the cell that have different densities

Cilia are different from flagella in that the cilia are

shorter and more numerous

A cell that is 98% water is placed in 50% salt water. This cell will

shrink

A cell encounters a change in its environment (electrical or heat) that could be fatal. However, it is able to respond in a protective manner because this information is sent INDIRECTLY through the cell membrane to the nucleus where it stimulates the appropriate response. This is more likely a process known

signal transduction

A bottle of perfume is opened on the opposite side of the room and within minutes you begin to smell the perfume. This phenomenon is a classic example of:

simple diffusion

Biological membranes are normally permeable to:

small hydrophobic molecules

simple diffusion may involve movement of _____ _________ ___________ through the plasma membrane down a concentration gradient

small nonpolar molecules

In the cotransport of glucose and sodium ions:

sodium ions are transported down their concentration gradient

An exergonic reaction is considered to be:

spontaneous

The smooth endoplasmic reticulum

synthesizes lipids

Evidence that all living cells have a common origin is provided by

the fact that all new cells come from previously existing cells

The life and death of cells are governed by:

the laws of thermodynamics

Difference between chromatin material and chromosomes is

their structure

During an infection, white blood cells travel to the infected site and phaogcytize the pathogens. After phagocytosis, primary lysosomes fuse with the phagocytic vesicle to form a larger vesicle called a secondary lysosome. The reason for this is:

to mix the pathogens with strong hydrolytic enzymes and destroy them

which of the following statements about the sodium-potassium pump is true?

transports 3 sodium ions out of cell in exchange for 2 potassium ions

A plant cell placed in a hypertonic solution will:

undergo plasmolysis

A storage container in a cell is generally called a

vacuole

Most components of energy conversion systems evolved very early; thus, the most fundamental aspects of energy metabolism tend to be:

very similar in a wide range of different organisms.

Which scientist first viewed living cells?

Anton van Leeuwenhoek