BIOL1107 - Test 1 (Chapters 1-5) ** all quizzes

The temperature at which an alligator's egg is incubated will determine the sex of the offspring. The dependent and the independent variables in this experiment are ________.

sex of the baby alligator and temperature respectively

Which of the following is true of natural selection?

It requires genetic variation, results in descent with modification, and involves differential reproductive success.

How does a scientific theory differ from a scientific hypothesis?

Theories are usually an explanation for a more general phenomenon; hypotheses typically address more specific issues.

The application of scientific knowledge for some specific purpose is known as ________.

technology

Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope?

archaen

You are suffering from Streptococcus throat infection. You share the following with the bacteria that is responsible for your condition.

You both are made up of cells.

Which of these provides evidence of the common ancestry of all life?

near universality of the genetic code

Why is a scientific topic best discussed by people of varying points of view, from different subdisciplines, and representing diverse cultures?

Robust and critical discussion between diverse groups improves scientific thinking.

The process by which the information in a gene directs the synthesis of a protein is called ________.

gene expression

Which of the following are qualities of any good scientific hypothesis?

I. It is testable.

II. It is falsifiable.

III. It produces quantitative data

IV. It produces results that can be replicated

I and II

What is the maximum number of covalent bonds that an oxygen atom with atomic number 8 can make with hydrogen?

2

A covalent bond is likely to be polar when __________.

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

About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?

carbon, hydrogen, nitrogen, oxygen

What is the difference between covalent bonds and ionic bonds?

Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms.

If an atom has a charge of +1, which of the following must be true?

It has one more proton than it does electrons.

Oxygen has an atomic number of 8 and, most commonly, a mass number of 16. Thus, what is the atomic mass of an oxygen atom?

approximately 16 daltons

The atomic number of nitrogen is 7. Nitrogen-15 has a greater mass number than nitrogen-14 because the atomic nucleus of nitrogen-15 contains _________.

8 neutrons

Which of the following is broken when water evaporates?

hydrogen bonds

Which bond or interaction would be difficult to disrupt when compounds are put into water?

covalent bonds between carbon atoms

Nitrogen (N) normally forms three covalent bonds with a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). What do you predict to be the charge on ammonium?

+1

If a DNA sample were composed of 20% guanine, what would be the percentage of cytosine?

20

How many molecules of water are needed to completely hydrolyze a polysaccharide that is 10 monomers long?

9

Lactase is an enzyme composed of a single polypeptide that hydrolyzes the disaccharide lactose to produce monosaccharides. The optimal pH for lactase activity is

6

Transfer of lactase to pH 5 results in a substantial decrease in enzyme activity, likely due to the disruption of

the secondary and tertiary structures of the enzyme.

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. How do these molecules differ from each other?

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

If 4C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?

RNA

Which of the following statements is true regarding cellulose?

It is a primary structural component of plant cell walls.

Which of the following functional groups confers the properties of an acid on amino acids?

carboxyl

Collagen is a protein made of three identical polypeptides composed primarily of a (alpha) helix structure.

The a (alpha) helix is an example of a

secondary structure stabilized by hydrogen bonds.

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

contains one less oxygen atom than the sugar in RNA.

Why are hydrocarbons insoluble in water?

The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.

Which of the following organelles are enclosed by a double membrane?

nuclei and chloroplasts

A researcher disrupts cells and separates subcellular components using centrifugation. Which of the following correctly lists the order in which cellular components will pellet when disrupted cell mixtures are centrifuged at increasingly higher speeds?

nucleus, mitochondria, ribosomes

Which of the following molecules or structures may be found in eukaryotic cells but not in bacteria?

endoplasmic reticulum

A mutation that inactivates an enzyme involved in the modification of sugars associated with glycoproteins is most likely to affect the function of which of the following cellular structures?

cisternae of the Golgi apparatus

Which of the following statements concerning cells of bacteria and archaea is correct?

Chromosomes in both archaea and bacteria contain DNA.

Proteins that will be exported from the cell are synthesized by which of the following cellular components?

rough ER

Which organelle occupies much of the volume of a plant cell?

central vacuole

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

smooth ER

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

proteins

What is the primary reason that a modern transmission electron microscope (TEM) can resolve biological structures as small as 2 nm, whereas 200 nm is the limit of resolution for a light microscope?

Electron beams have much shorter wavelengths than visible light.

Based on the fluid mosaic model of cell membranes, which of the following statements about membrane phospholipids is true?

They can move laterally along the plane of the membrane.

The electrochemical gradient across a membrane would generally be increased by which of the following membrane proteins?

a hydrogen ion pump

Which of the following statements about diffusion is correct?

It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

Following activation of a receptor, which sequence below represents the correct order in which components will be involved in a signaling pathway that utilizes the second messenger cAMP?

G protein → adenyl cyclase → cAMP → protein kinase

A protein that spans the phospholipid bilayer one or more times is

a transmembrane protein.

The primary function of G proteins in signal transduction is

transmitting the signal from an activated receptor to the next protein in the pathway.

The primary function of kinases in signal transduction is to

activate protein kinases or other relay molecules in a series.

The fluid mosaic model of membrane structure suggests that membranes

are composed of protein molecules embedded in a fluid bilayer of phospholipids.

Submerging a red blood cell in distilled water will result in

lysis of the cell.

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

small hydrophobic