Bio 4-7

enzymes

are specific to a reaction or closely related reactions

Which of the following are prokaryotic cells?

bacteria

allosteric regulation

bind to an enzyme in an area other than the active site

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?

induced fit

competetive inhbition

involves binding of an inhibitor to the active site

Pinocytosis

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

Light energy is a type of

kinetic energy

The higher the concentration of solute in a solution, the __________ the effective water concentration and the __________ the osmotic pressure.

lower, higher

Which of the following cell components is not directly involved in synthesis or secretion?

lysosomes

Which of the following is NOT a function of the plasma membrane?

manufactures protein

The tonoplast is

membrane enclosing the central vacuole

All the chemical reactions needed for growth, reproduction, synthesis and degradation of molecules, movement, and response to stimuli are

metabolism

Enzymes work best

optimal temperature and pH

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

proteins

Why are membrane-bounded organelles able to facilitate faster chemical reactions?

Enzymes are organized close together on the membrane surface.

Which best describes a catabolic reaction?

It involves the breakdown of large organic molecules to simple building blocks.

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

It is the movement of lipids and integral proteins within the lipid bilayer

Which of the following molecules are in the reduced form?

NADH

You conduct an experiment in which you add increasing amounts of substrate to an enzyme solution and then measure the resulting reaction rate. You plot the rate of the reaction on the Y-axis versus substrate concentration on the X-axis. What do you conclude from your graph?

The reaction rate increases with increasing substrate concentration up to a point, above which the rate remains constant.

The active site of an enzyme

Where the substance fits in and breaks down

In oxidation-reduction reactions

a reaction that involves the transfer of electrons between reactants

Why is it advantageous for cells to be small?

a small cell has a small volume relative to surface area, thereby increasing efficient transport

A bacterium containing sodium ions at a concentration of 0.1 mM lives in a pond that contains sodium ions at 0.005 mM. Evidently, sodium ions are entering the cell by:

active transport

cofactors

are required by some enzymes to be functional

ATP donates energy

by transferring its terminal phosphate to an acceptor molecule

The required energy of activation of a reaction

can be lowered by a specific enzyme

Grana, thylakoids, and stroma are all components found in

chloroplast

The passive movement of a substance along its concentration gradient is termed:

diffusion

All of the following are part of a prokaryotic cell except

endoplasmic reticulum

Which of the following structures is NOT a common destination for small vesicles that bud off the Golgi apparatus?

endoplasmic reticulum

The first law of thermodynamics states that

energy is neither created nor destroyed

Transmembrane proteins

extend completely through the membrane

Which strategy is most effective for larger cells to have an effective surface area to volume ratio?

finger-like projections

Cholesterol within membranes functions as a(n) __________ through its interactions with both hydrophobic and hydrophilic parts of phospholipids.

fluidity buffer

Junctions that allow the movement of water, ions, and small molecules between neighboring animal cells are

gap junctions

Proteins made on ribosomes may be further modified within which organelle?

golgi complex

Solutions that are isotonic:

have equal concentrations of solute and water

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

hydrophobic

A wilted flower placed in a vase of water for several hours became stiff and stood erect. When it was placed in a salt solution, it wilted. From this information we can say that the cells of the flower are:

hypertonic to fresh water but hypotonic to the salt solution.

The organelle that is involved in digestion of food, foreign particles, or worn-out organelles is the

lysosome

Cyanide binds with at least one of the molecules involved in the production of ATP. Following exposure of a cell to cyanide, most of the cyanide could be expected to be found within the

mitochondria

Cells can be described as having a cytoskeleton of internal structures that contribute to the shape, organization, and movement of the cell. All of the following are part of the cytoskeleton except

nuclear envelope

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:

nucleous

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

osmosis

What is the chemical process in which a substance loses electrons?

oxidation

A human white blood cell engulfs a bacterial cell by:

phagocytosis

Which cell component regulates movement of material into and out of the cell?

plasma membrane

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

potassium ion

Energy stored in the bonds of a chemical is a form of

potential energy

Exergonic reactions

release free energy

Facilitated diffusion:

requires a transmembrane protein

What does the nucleolus, within the nucleus, synthesize?

ribosomal RNA

Which structure is the site of the synthesis of proteins that may be exported from the cell?

rough ER

Of the following, which is probably the most common route for membrane flow in the endomembrane system?

rough ER → vesicles → Golgi → plasma membrane

A patient who has had a severe hemorrhage accidentally receives a large transfusion of distilled water directly into a major blood vessel. You would expect this mistake to:

serious life threatening, cells will hemolysis

Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids?

smooth endoplasmic reticulum

in co-transport

the movement of one solute down its concentration gradient provides energy for transport of some other solute up its concentration gradient

Which of the following statements about lipid bilayers is FALSE?

they are inflexible

proton pumps

transfer protons across a membrane against their concentration gradient

feedback inhibition

uses a product to inhibit an earlier reaction in a sequence of enzyme reactions