when biologist wish to study the internal ultrastructure of cells, they can acheve the finest resolution by using

A)a phase -contrast light microscope
B) a scanning electron microscope
C)a transmission electonic microscope
D) a confocal fluorescene microscope
E) a super-resolution fluorescent microsope

C) transmission electonic microscope

A primary objective of cell fractionation is to

A) view teh structure of cell membranes
B)sort cells based on theri size and weight
C)determine the size of various organelles
D)separate teh major organelles so that their paricular functions can be determined
E)separate lipid-soluble from water-soulble molecules

D) separate the major organelles so that their particular functions can be determined

which of the following is a major cause of the size limits for certain types of cells?

A)limitation on the strength and integrity of the plasma membranes as cell size increases
B)the difference is plasma membrane between prokaryotes and eukaryotes
C)evolutionary prgression in cell size; more priitive cells have smaller sizes
D) teh need for a surface area of sufficient area to support the cells metaboic needs
E)rigid cell wals that limit cell size expansion

D) the need for a surface area of sufficient area to suport the cells metabolic needs

The ultrastructure (intenral membrane) of a chloroplast is best seen by using a

A)transmission electron microscope
B)scanning electron microscope
C)phase-contrast light microscope
D) fluorescent microscope

A)transmission electron microscope

which of the following is incorrectly paired with its function?

A)peroxisome-contains enzymes that break down hydrogen peroixde (H2O2)
B)nucleolus-produces ribosomal RNA, site of assembly of ribosome subunits
C)lysosomes-contains pigments in plant cells
D)ECM (extracellular matrix)- supports and anchors cells, communicates information to the inside of the cell
E) golgi apparatus-processes, tags and ships cellular products

C) lysosomes- contains pigments in plant cells

the cytoskeleton is composed of which type of molecule?

A) protein
B)cellulose microfibrils
C) phopholipids
D)DNA

A) protein

A growing plant cell elongates primairly by

A)increasing the number of vacuoles
B) takign up water into the central vacuoles
C)synthesizing more cytoplasm
D)synthesizing more cellulose

B) taking up water into the central vacuole

contractile elements of muscle cells are composed of

A) intermediate filaments
B) microfilaments made of actin
C) microtubules made of tubulin
D)centrioles made of tubulin

B)microfilaments made of actin

plasmodesmata in plant cells have similar function to ____ in animal cells.

A) desmosomes
B) tight junctions
C) gap junctions
D) integrins

C) gap junctions

Ions (charged atoms) diffuse across membranes down their

A) electrochemical gradient
B) osmotic gradient
C) concentration gradient
D) electrogenic gradient

A) electrochemical gradient

bacteria that are in the blood stream enter the white blood cells by ___, and are digested when teh vescle fuses with a _____.

A) phagocytosis, lysosome
B) receptor-mediated endocytosis, lysosome
C)pinocytosis, contractile vacuole
D)exocytosis, food vacuole

A) phagocytosis, lysosome

the difference between teh sugar in DNA and the sugar in RNA is that the sugar in DNA

A) is a six-carbon sugar and the sugar RNA is a five carbon sugar
B) can form a double-stranded moecule
C) is an aldehyde sugar and the sugar in RNA is a keto sugar
D) is in the alpha configuration and the sugar in RNA is in teh beta configuration.
E) contains one less oxygen atom at carbon 2 of the sugar

E) contains one less oxygen atom at carbon 2 of the sugar

how are teh nucleotide monomers connected to form a polynucleotide chain?

A) hydrogen bonds between complemntary nitrogenous base pairs.
B) ionic attractions between phosphate groups
C)disulfide bridges between cysteine amino acids
D) covalent bonds between teh 3' carbon of the pentose sugar of one nucleotide and the phosphate group of the next nucleotide

D) covalent bonds between the 3' cabon of teh pentose sugar of one nucleotide and the phosphate group of the next nucelotide

Which of the following describes teh components of a stand of DNA

A) deoxyribose sugar, phosphate, adenine, guanine, cytosine, thymine
B) deoxyribose sugar, adenine, guanine, cytosine, uracil
C) ribose sugar, adenine, guanine, cytosine, uracil,
D) ribose suar, phospate, adenine, guanine, cytosine, thymine

A) deoxyribose sugar, phosphate, adenine, guanine, cytosine, thymine

What is the complementary sequence of DNA to this sequence? 3'ATGCCGTA5'

A) 5' ATGCCGTA 3'
B) 3' TACGGCAT 5'
C)5' TACGGCAT 3'
D) 3' UACGGCAU 5'
E) 5' UACGGCAU 3'
F) none of these

C) 5' TACGGCAT 3'

what is teh sequence of mRNA that can be made for the sequene 3'ATGCCGTA5'

A) 5' ATGCCGTA 3'
B) 3' TACGGCAT 5'
C)5' TACGGCAT 3'
D) 3' UACGGCAU 5'
E) 5' UACGGCAU 3'
F) none of these

E) 5'UACGGCAU3'

which of the following statements is not true of teh nitrogenous base thymine

A) thymine binds directly to the phosphate
B) thymine hydrogen bonds with adenine
C) thymine is a pyridmidine
D)thymine binds to the number 1 carbon of deoxyribse sugar

A) thymine binds directly to phosphate

what technique woudl be most apporpriate to use to observe the movements of condensed chrosmosomes with living cells during cell division?

A) light microsopy
B) scanning electron microscopy
C) transmission electron microscopy
D) confocal fluorescence microsopy
E) super-resolution fluorescence microsopy

A) light microscopy

what is the reason that a modern electron microscope (TEM) can resolve biological images to the subnanometer level, as opposed to tens of nanometers achievable for the best super-resolution light microscope?

A) the focal length of the electron microsope is significantly longer
B) contrast is enhanced by staining with atoms of heavy metal
C) electron beams have much shorter wavelengths than visible light
D) the electron microsope has a much greater ratio of images size to real size
E) the electron cicrosope cannnot image whole cells at one time

C) electron beams have much shorter wavelenghts than visible light

cells of teh salivary glands are tagged with a green fluorescent protein that binds to a-amylase. This "tagging" of newly synthesized proteins enables a researcher to track their location in this case, teh researcher is trackign alpha amaylase, an enzyme secreted by salivary gland cells. which of the following is teh most likely pathway?

A) rough ER->transport vescle->golgi->transport vesicle-> nucleus
B) golgi-> transport vescle-> rough ER-> transport vesicle-> lysosome
C) nucleous-> transport vescle-> roup ER-> transport vesicle> Golgi
D) rough ER-> transport vesicle -> golgi-> storage vesicles that fuse with plasma membrane and release their contents into the extracellular duct
E) rougph ER-> transport vesicle -> lysosome -> vesicles that fuse with the food vacuole

D) rough ER-> transport vesicle-> Golgi-> storage vesicles that fuse with plasma membrane and release their contents into the extracellular duct (tube)

the cells of an ant and an elephate are on average the same size; an elephate jsut has more cells. what is the main advantage of small cell size

A) small cells are easier to organize into tissues and organs
B) a small cell has a larger plasma membrane surface area than does a large cell facilitation the exhange of suffcient materials with its environmetns
C) a small cell has a smaller cytoplasmic volume relative to its plasma membrane
D) small cells requrie less oygen than i do larger cells
E) the cytoskeleton of a large cell would have to be so larege that cells owuld be to heavy

C) a small cell has a smaller cytoplasmic volume relative to its surface area, which helps to ensure teh exchagne of suficient materials across its plasma membrane

the membrane (charge) potential of a cell favors the

A)the movement of cations into the cell
B) the movement of anions into the cell
C)the action of an electrogenic pump
D) movement of sodium out of the cell
E) action of a proton pump

A) the movement of a cations into the cell

LDLs (low density lipoproteins) which carry cholesterol enter animal cells by

A) diffusion through the lipid bilayer
B) pinocytosis
C) receptor-mediated endocytosis
D) facilitated diffusion

C) receptor-mediated endocytosis

in which cell would you expect to find abundant mitochondria

A) muscle cells in the thigh muscle of a long-distance runner
B)pancreatic cell that manufactures digestive enzymes
C)magrophage (white blood cell) that engulfs bacteria
D)epithelial cell lining digestive tract
E)ovarian cell that produces estrogen (a steroid hormone)
F) leaf cell of the Elodea plant

A) muscle cells in the thigh muscle of a long-distance runner

In which cell would you expect to find abundant lysosomes?

A) muscle cells in the thigh muscle of a long-distance runner
B)pancreatic cell that manufactures digestive enzymes
C)magrophage (white blood cell) that engulfs bacteria
D)epithelial cell lining digestive tract
E)ovarian cell that produces estrogen (a steroid hormone)
F) leaf cell of the Elodea plant

C) macrophage (white blood cell) that engulfs bacteria

in which cell would you expect to find the most rough ER

A) muscle cells in the thigh muscle of a long-distance runner
B)pancreatic cell that manufactures digestive enzymes
C)magrophage (white blood cell) that engulfs bacteria
D)epithelial cell lining digestive tract
E)ovarian cell that produces estrogen (a steroid hormone)
F) leaf cell of the Elodea plant

B) pancreatic cell that manufactures digestive enzymes

In which cell would you expect to find the most smooth ER

A) muscle cells in the thigh muscle of a long-distance runner
B)pancreatic cell that manufactures digestive enzymes
C)magrophage (white blood cell) that engulfs bacteria
D)epithelial cell lining digestive tract
E)ovarian cell that produces estrogen (a steroid hormone)
F) leaf cell of the Elodea plant

E) Ovarian cell that produces estrogen (a steroid hormone)

in which cell would you find choroplasts?

A) muscle cells in the thigh muscle of a long-distance runner
B)pancreatic cell that manufactures digestive enzymes
C)magrophage (white blood cell) that engulfs bacteria
D)epithelial cell lining digestive tract
E)ovarian cell that produces estrogen (a steroid hormone)
F) leaf cell of the Elodea plant

F) Leaf cell of the Elodea plant

in which cell would you expect to find tight junctions?

A) muscle cells in the thigh muscle of a long-distance runner
B)pancreatic cell that manufactures digestive enzymes
C)magrophage (white blood cell) that engulfs bacteria
D)epithelial cell lining digestive tract
E)ovarian cell that produces estrogen (a steroid hormone)
F) leaf cell of the Elodea plant

D) epithelial cell lining digestive tract

which organelle is responsible for making proteins

ribosomes

in which organelle woudl you find proteins, newly synthesized by the ribosomes that are destined to be exported from teh cell? Ribosomes are associated with this organelle

Rough ER

which organelle is responsible for adding sugar groups onto the proteins before they are exported from the cell? this was named after an italian scientiest who discoved these

Golgi apparatus

which organelle makes ATP in the process of cellular respiration

mitochondria

in which organelle are old mitochondria is broken down and recycled?

lysosome

which organelle is responsible for makign RNA for the ribosomes, and assembling the ribosomes in the nucleus

nucleolus

which organelle makes membranes in all teh cells, detoxifies drugs and alcohol in the liver, and stores calcium ions in the muscle cells

smooth ER

which protein woudl you find in flagella and cilia that help cells move from one place to another

microtubules

which organelle contains the chromosomes and nucleolus?

nucleus

glycoproteins and glycolipids in teh plasma membrane are important for

A)facilitated diffusion
B)cell-cell recognition
C)active transport
D)contransport

B) cell-cell recognition

a single layer of phospholipid molecules coats the water surface in a beaker. Which part of the molecules will face teh air? (molecules of oxygen and nitrogen in the air are nonpolar.)

A) the phosphate groups
B)the hydorcarbon tails
C)both head adn tail, since the molecules are resting sideways on the beaker
D)the phospholipids would dissolve in the water and not form a membrane coat
E) the glycolipid regions

B)the hydrocabon tails

the proton pump in plant cells is the functional equivalent of an animals cell's

A)cotransport mechanism
B)sodium-potassium pump
C)contractile vacuole (osmoregulation)
D) ATP pump

B) sodium-potassium pump

a plant cell placed in a hypertonic environment, such as 5% saline, will

A)plasmolyze
B)shrivel
C)become turgid
D)become flaccid

A) plasmolyze

support for the fluid mosaic model of membrane structure comes from

A) teh freeze-fracture technique of electron microscopy
B) teh movement of proteins in human-mouse hybrid cells
C)the hydrophobic nature of the side chains of proteins embedded in the membrane
D)both a and c
E)all of the above

E) all of the above

which of the following is not true about osmosis

A)it is a passive process in cells without walls, but an active one in cells with walls
B)water moves from a hypotonic to a hypertonic solution
C)solute molecules bind to water and decrease the water available to move
D)there is no net movement of water molecules between isotonic solutions

A) it is a passive process in cells without, walls, but an active one in cells with walls

Choose the pair of terms that correctly completes this sentence: Catabolism to anabolism as____ is to ____.

A)exergonic; spontaneous
B)exergonic; endergonic
C)free energy; entropy
D)work; energy
E)photosynthesis; respiration

B) exergonic; endergonic

most cells cannot harness heat to perform work because

A)heat is not a form of energy
B)cell do not have much heat; they are relatively cool
C)temperature is ususally uniform thorughout a cell
D)heat can never be used to do work
E) heat must remain constant during work

C) temperature is usually uniform throughout a cell

negative G means that

A) the reactants have more free energy than the products
B)the reaction is spontaneous
C)the quantity G of energy is available to do work
D) teh reaction is exergonic
E) none of these statements are true for a negative G
F) all statements are true for a negative G

F) all statements are true for a negative G

the part of the chemical pathways in the cell that are focused on the breakdown of molecules so that the free energy can be released in known as____.

A) anabolism
B)catabolism
C)embolism
D)metabolism

B) catabolism

energy of motion is also known as____ energy.

A)chemical
B)kinetic
C)potential
D) electrical

B) kinetic

according to the second law of thermodynamics

A) for energy transfer results in an increase in the order of the universe
B)every energy transfer results in an increase in the order of the universe
C)the total amount of energy in the universe is conserved or constant
D) in every exchange of energy, the disorder or entropy of the universe increases

D) in every exchange of energy, the disorder or entropy of the universe increases

in an enzymatically catalyzed reaction, the binding of the substrate to active site of teh enzyme results in a chagne in the shape of the active site. This results in a stressing or bending of the substrate bonds. This phenomenon is known as____.

A) allosteric regulation
B)cooperativeity
C) energy of activation
D) induced fit

D) induced fit

how does an enzyme affect a chemical reaction in the cell

A)an enzyme increases the speed at which the rxn will occur
B)an enzyme lowers teh enregy of activation required to get a rxn going
C)an enzyme adds enrgy to a rxn
D) an enzyme makes an unfavorable rxn ( +G) favorable
E)both a and b are correct
F) both a and d are correct

E) both a and b are correct

when a cell breaks down glucose, only about 40% of the energy in the chemical bond of glucose is captured in ATP molecules. The remaining 60% of the energy is ___

A) used to increase the order necessary for life to exist
B)lost as heat because of the second law of thermodynamics
C)used to convert kinetic energy into potential energy
D)stored in starch or glycogen for later use by the cell
E)released when the ATP molecules are hydrolyzed

B) lost as heat because of the second law of thermodynamics

Zinc, an essential trace element, is bound to the active site of some enzymes what woudl be the most likely function of such zinc ions

A)zinc is coenzyme that is derived from an organic molecule, known as a vitamin
B) zinc is a substrate for the enzyme
C)zinc is a cofactor necessary for catalyziz
D)zinc is a competitive inhibitor of the enzyme

C) zinc is a cofactor necessary for catalysis

the molecule in question 65 is used to :

A)phosphorylate transporter proteins in the cellular membrane so that molecules can move against their concentration gradient
B)make motor change its shape to move along the microtubules
C)make endergonic chemical rxn happens by energy couplign rxn
D)all of the above
E) none of the above

D) all of the above

A molecule that binds to teh active site of an enzyme is usually considered___

A)an allosteric inhibitor
B) a competitive inhibitor
C)a noncompetitive inhibitor
D) a feedback inhibitor

B) a competitive inhibitor