week 3 mastering biology

Nucleotide structure is?

5 carbon sugar, phosphate group, nitrogenous base

When nucleotides polymerize to form a nucleic acid _____. A. a hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second B. a covalent bond forms between the sugar of one nucleotide and the phosphate of a second C. covalent bonds form between the bases of two nucleotides D. hydrogen bonds form between the bases of two nucleotides

B

Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water_____. A. and the salt solution are both hypotonic to the cells of the celery stalks B. and the salt solution are both hypertonic to the cells of the celery stalks C. is hypotonic and the salt solution is hypertonic to the cells of the celery stalks D.is isotonic and the salt solution is hypertonic to the cells of the celery stalks E. is hypertonic and the salt solution is hypotonic to the cells of the celery stalks

C

A patient was involved in a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water equal to the volume of blood lostis added to the blood directly via one of his veins. What will be the most probable result of this transfusion? A. The patient's red blood cells will shrivel up because the blood has become hypotonic compared to the cells. B. It will have no unfavorable effect as long as the water is free of viruses and bacteria. C. The patient's red blood cells will burst because the blood has become hypertonic compared to the cells. D. The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells. E. The patient's red blood cells will shrivel up because the blood has become hypertonic compared to the cells.

D

Hypotonic

Having a lower concentration of solute than another solution

Nucleic acids are polymers made up of which of the following monomers? nucleotides nitrogenous bases phosphates amino acids ribose sugars

NUCLEOTIDES

Which of the following is true of osmosis? a. In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration. b. In osmosis, solutes move across a membrane from areas of lower water concentration to areas of higher water concentration. c. Osmosis only takes place in red blood cells. d. Osmosis is an energy-demanding or "active" process.

a

Polymerization

a chemical process that combines several monomers to form a polymer or polymeric compound

Consider a molecule that can diffuse across a lipid bilayer. At equilibrium ____. a. there is no change in the concentration of the molecule on either side of the membrane b. the membrane is no longer permeable to the molecules and restricts their movement c. the molecules no longer move due to a loss of thermal kinetic energy d. the molecules (solutes) spontaneously form a micelle or vesicle

a.

What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?

amphiatic nature

Which of the following are purine nitrogenous bases? A) cytosine and guanine B) guanine and adenine C) adenine and thymine D) thymine and uracil E) uracil and cytosine

b

lipids vesicles are formed containing pure water. If these vesicles are transferred to a solution that contains a rather high concentration of solutes, the solution outside the vesicle is said to be ______. a. amphipathic b. hypertonic c. isotonic d. hypotonic b. hypertonic

b.

Which of the following includes all of the pyrimidines found in RNA and DNA? cytosine, uracil, and guanine cytosine and uracil cytosine and thymine cytosine, uracil, and thymine

cytosine , uracil, thymine

Which of the following are pyrimidine nitrogenous bases? guanine and adenine ribose and deoxyribose cytosine and uracil adenine and thymine thymine and guanine

cytosine and uracil

If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell? give the reasoning

hypotonic. The salt concentration in the solution is lower than it is in the cell, so water enters the cell, causing it to burst.

If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled? proteins cellulose glucose amino acids nucleic acids

nucleic acids

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

osmosis

Which of the following particles could diffuse easily through a cell membrane? and why? Glucose Sodium ion (Na+) Hydrogen ion (H+) Oxygen (O2)

oxygen, Small nonpolar molecules such as oxygen can diffuse across cell membranes.

What is/are the variable structure(s) of a nucleotide?

the sugar and the base

True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group and why?

true, The hydrophilic, or water-loving, portion of a phospholipid is the polar head, whereas the hydrophobic portion is the nonpolar tail.

Hypertonic

when comparing two solutions, the solution with the greater concentration of solutes