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Which of these is a correct representation of the hierarchy of biological organization from least to most complex?

molecule, intestinal cell organelle, intestinal cell, intestinal tissue, digestive system, organism

The lowest level of biological organization that can perform all the activities required for life is the

cell-for example, a skin cell

When blood glucose level rises, the pancreas secretes insulin, and as a result blood glucose level declines. When blood glucose level is low, the pancreas secretes glucagon, and as a result blood glucose level rises. Such regulation of blood glucose level is the result of

negative feedback

prokaryotes are classified as belonging to two different domains. What are the domains?

Bacteria and Archaea

species that are in the same_____ are more closely related than species that are only in the same______.

family; order

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates?

iodine

Which of the following best described the relationship between the atoms described below?

they are both isotopes of phosphorus

A covalent bond is likely to be polar when

one of the atoms sharing electrons is much more electronegative than the other atom.

Which of the following is not considered to be a weak molecular interaction?

a covalent bond

the molecule shown (CH4) could be described as

CH4 (methane)

an example of a hydrogen bond is the bond between

the H of one water molecule and the O of another water molecule

water is able to form hydrogen bonds because

the bonds that hold together the atoms in a water molecule are polar covalent bonds

which type of bond must be broken for water to vaporize?

hydrogen bonds

why does ice float in liquid water?

hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water

what is the PH of a solution with a hydrogen ion [H+] concentration of 10^-8 M?

PH 8

Which of the following solutions has the greatest concentration of hydroxyl ions [OH-]?

seawater at PH 8

If the PH of a solution is decreased from 9 to 8, it means that the

concentration of H+ has increased 10-fold (10x) compared to what it was at PH 9. concentration of [OH-] has decreased to one-tenth (1/10) what it was at PH 9

research indicates that acid precipitation can damage living organisms by

washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant growth

you have two beakers; one contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen.

NaCl crystals will dissolve readily in water but will not dissolve in water.

a carbon atom is most likely to form what kind of bond(s) with other atoms?

covalent

shown here are structures of glucose and fructose. these two molecules are...

structural isomers

the two molecules shown (c=c in the middle of each figure shown) are best described as

geometric isomers

thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that

are mirror images of one another

which is the best description of a carboxyl group?

a carbon atom joined to an oxygen by a double covalent bond

what is the name of the functional
//o
group shown r-c
\o-h

carboxyl

which of the following contains nitrogen in addition to carbon, oxygen and hydrogen?

an amino acid such as glycine

which two functional groups are always found in amino acids?

carboxyl and amino

amino acids are acids because they always possess which functional group?

carboxyl

a chemist wishes to make an organic molecule less acidic. which of the following functional groups should be added to the molecule in order to do so?

amino

for this pair of items, choose the option that best describes their relationship.
(A) the number of alpha glucose 1-4 linkages in cellulose. (B) the number of alpha glucose 1-4 linkages in starch

item A is less than item B

for this pair of items, choose the option that best describes their relationship.
(A) the probability of finding chitin in fungal cell walls (B) the probability of finding chitin in arthropod exoskeletons

item (A) is exactly or very approximatley equal to item (B)

for this pair of items, choose the option that best describes their relationship.
(A) the number of cis double bonds i saturated fatty acids (B) the number of cis double bonds in unsaturated fatty acids

(A) is less than item (B)

for this pair of items, choose the option that best describes their relationship.
(A) the probability that amino acids with nonpolar side chains are hydrophobic (B) the probability that amino acids with side chains containing a carboxyl group are hydrophobic

item (A) is greater than item (B)

which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

dehydration reactions assemble polymers, adn hydrolysis reactions break down polymers. macromolecular synthesis occurs through the removal of water and digestion occurs through the addition of water. (two answers are correct)

if two molecules of the general type shown (Image) were linked together, carbon 1 of one molecule 4 of the other, the single molecule that would result would be

maltose

humans can digest starch but not cellulose because

humans have enzymes that can hydrolyze the alpha (a) glycosidic linkages of starch but not the beta (a) glycosidic linkages of cellulose

which of the following statements is false for the class of biological molecules known as lipids?

they are soluble in water

why are humans sex hormones considered to be lipids?

they are steroids, which are not soluble on water

all of the following contain amino acids except

cholesterol

there are 20 different amino acids. what makes one amino acid different from another?

different side chains (R group) attached to an alpha (a) carbon

which of the following statements is true regarding the chemical reaction illustrated?

it results in a peptide bond

which bonds are created during the formation of the primary structure of a protein?

peptide bonds

at which level of protein structure are interactions between the side chains (R groups) most important?

tertiary

what would be an unexpected consequence of changing one amino acid in a protein consisting of 325 amino acids?

the primary structure of the protein would be changed. the tertiary structure of the protein might be changed. the biological activity of function of the protein might be altered. (A,B, and C are correct)

the function of each protein is a consequence of its specific shape. What is the term used for a change in a protein's three-dimensional shape or conformation due to disruption of hydrogen bonds, disulfide bridges, or ionic bonds?

denaturation

what is the term used for a protein that assists in the proper folding of other proteins?

chaperonin

which of the following methods for the transport of CO2 provides a buffering system for the blood?

co2 combines with h2o to form carbonic acid and then bicarbonate

the synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct?

water

which of the following is a branched carbohydrate made in plants?

amylopectin

what do you call the covalent bond that connects a fatty acid to the hydroxyl group on glycerol?

esther bond

the dynamics of any ecosystem include the following major processes:

the flow of energy from sunlight to producers and then to consumers, and the recycling of chemical nutrients

identical heat lamps are arranged to shine on identical containers of water and methanol, so that each liquid absorbs the same amount of energy minute by minute. the covalent bonds of methanol molecules are non-polar, so there are no hydrogen bonds among methanol molecules. which of the following shows what will happen to the temperatures of the water and the methanol?

(b) the methanol is higher than the water

research indicates that Albuterol, a drug used to relax bronchial muscles, improving airflow and thus offering relief from asthma, consists only of one enantiomer, the R-form. why is it important for this drug to consist of only one enantiomeric form, rather than a mixture of enantiomers?

different enantiomers may have different or opposite physiological effects.

the testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. in what ways do these molecules differ from each other?

testosterone and estradiol have different functional groups attached to the same carbon skeleton

a molecule with the formula C18H36O2 is probably a

fatty acid

which of the following components of the cell membrane is responsible for active transport?

protein

when a substance moves across the plasma membrane along a concentration gradient at a rate faster than would be expected by simple diffusion alone but without the expenditure of metabolic energy, the process is best described as

facilitated diffusion

which of the following is true of intercellular junctions, such as tight junctions, desmosomes, and gap junctions?

they help to integrate cells into a functioning unit

a prokaryotic cell has which of the following?

plasma membrane

simple diffusion and facilitated diffusion are related in that both

depend on a concentration gradient

if red blood cells cultured in an isotonic medium are placed in distilled water they will most likely

swell and lyse

which of the following organelles is correctly matched with its function

lysosome... lipid hydrolysis

a protein is synthesized in the cytoplasm and transported to the plasma membrane. which of the following summarizes the protein's pathway in the cell?

rough endoplasmic reticulum -> Golgi complex-> vesicle-> plasma membrane

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

the need for a surface area of sufficient area to allow the cell's function

the liver is involved in detoxification of many poisons and drugs. which of the following structures is primarily involved in the process and therefore abundant in liver cells?

smooth ER

a cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. it could be a cell from

a plant or animal

motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?

cytoskeleton

a cell lacking the ability to make and secrete glycoproteins would most likely be deficient in its

extracellular matrix (ECM) and Golgi apparatus
- both B and C

of the following molecules of the extracellular matrix (ECM), which is capable of transmitting signals between the ECM and the cytoskeleton

integrins

which of the following is present in a prokaryotic cell?

ribosome

which cell would be best for studying lysosomes?

phagocytic white blood cell

which structure-function pair is mismatched?

microtubule.... muscle contraction

the presence of cholesterol in the plasma membranes of some animals

enables the membrane to stay fluid more easily when cell temperature drops

which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?

the double bonds form kinks in the fatty acid tails, forcing adjacent lipids to be further apart

of the following functions, which is most important for the glycoproteins and glycolipids of animal cell membranes?

a cell's ability to distinguish one type of neighboring cell from another

what kinds of molecules pass through a cell membrane most easily?

small and hydrophobic

which of the following is a characteristic feature of a carrier protein in a plasma membrane?

it exhibits a specificity for a particular type of molecule

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