BLY 301 Practice Exam 1

In the lab, you choose to design a simple experiment to distinguish between hydrophilic and hydrophobic substances. You start by adding equal amounts of vinegar and oil to a container. After shaking, the vinegar and oil levels separate, based upon polarity and density. To this you add glucose and sodium citrate and shake again. Where do you expect to find the glucose and sodium citrate in greatest quantities? A. The glucose will concentrate in the vinegar, sodium citrate in the oil. B. Both will be uniform throughout both layers. C. Both will concentrate in the vinegar layer. D. Both will concentrate in the oil layer.

C. Both will concentrate in the vinegar layer.

The chemical nature of each amino acid is determined by which of the following groups? A. amino B. carboxyl C. R D. hydroxyl

C. R

How do large polar and charged molecules cross biological membranes? A. Large polar and charged molecules cross biological membranes via diffusion through the hydrophilic core of the membrane. B. Large polar and charged molecules can't cross biological membranes. C. Large polar and charged molecules must be hydrolyzed before they can cross a biological membrane. D. Large polar and charged molecules cross biological membranes via transport proteins that form hydrophilic channels through the membrane.

D. Large polar and charged molecules cross biological membranes via transport proteins that form hydrophilic channels through the membrane.

1 mm = ___________ nm A. 1,000,000 B. 0.001 C. 1000 D. 10

A. 1,000,000

Which of the following is true concerning both mitochondria and chloroplasts? A. Both mitochondria and chloroplasts contain DNA and ribosomes. B. Mitochondria likely evolved from ancient endosymbiotic prokaryotes, but chloroplasts did not. C. Both mitochondria and chloroplasts consume oxygen and produce carbon dioxide. D. Both mitochondria and chloroplasts are responsible for predominantly oxidative metabolic processes.

A. Both mitochondria and chloroplasts contain DNA and ribosomes.

In studying osteoporosis in humans, you wish to test a newly designed treatment for efficacy. Your best choice for a model organism would be... A. Mus musculus. B. Caenorhabditis elegans. C. Escherichia coli. D. Arabidopsis thaliana.

A. Mus musculus.

Which of the following statements is false? A. The R group of amino acids is similar from one amino acid to another. B. Only around 20 amino acids are used in protein synthesis. C. There are more than 60 different kinds of amino acids present in cells. D. An amino acid has an N-terminus, a C-terminus, and an R group.

A. The R group of amino acids is similar from one amino acid to another.

Which of the following biomolecules is not long polymers of repeating monomers? A. lipids B. nucleic acids C. proteins D. polysaccharides

A. lipids

The smooth endoplasmic reticulum functions in synthesis of... A. lipids. B. polysaccharides. C. proteins. D. lipids, polysaccharides, and proteins.

A. lipids.

Ribosomal subunits are manufactured by the... A. nucleolus. B. lysosome. C. rough endoplasmic reticulum. D. smooth endoplasmic reticulum.

A. nucleolus.

Which sequence reflects the locations that a secretory protein will visit on its way from its production to its secretion outside the cell? A. rough ER, ER vesicle, Golgi complex, secretory vesicle B. nucleus, Golgi complex, secretory vesicle C. ER, Golgi complex, smooth ER, ER vesicle D.. smooth ER, rough ER, Golgi complex, secretory vesicle

A. rough ER, ER vesicle, Golgi complex, secretory vesicle

The cytosol is best described as the... A. semifluid substance in which organelles are suspended. B. area of the cell not occupied by the nucleus. C. internal contents of organelles. D. fluid within the nucleus.

A. semifluid substance in which organelles are suspended.

Carbon can form ________ covalent bonds A. single, double, and triple B. single C. single and double D. double

A. single, double, and triple

The limit of resolution can best be defined as... A. the distance that two objects must be apart to be distinguished as separate objects. B. the inverse of the wavelength of light; it is greatest for black light. C. the magnification power of a microscope. D. the distance that an object must be moved to be distinguished from its background.

A. the distance that two objects must be apart to be distinguished as separate objects.

The function of triglycerides is... A. to store energy. B. regulate cholesterol levels in the cell. C. to form semipermeable membranes. D. localization the plasma membrane so as to provide identify for to cells

A. to store energy.

Which of the following is a true statement regarding lysosomes? A. None of these are correct. B. The lysosome may mature from a late endosome. C. The lysosome functions in export packaging. D. The lysosome may function in glycosylation.

B. The lysosome may mature from a late endosome.

Which of the following statements about the polymerization of macromolecules is false? A. Often the energy needed for polymerization is supplied by ATP. B. Water is added to join the monomers of the macromolecules. C. A monomer is usually activated by the coupling of the monomer to a carrier. D. The polymer chain usually has two different ends.

B. Water is added to join the monomers of the macromolecules.

The image seen here is of a ... A. an α-helix B. a parallel β-sheets C. anti-parallel β-sheets D. protein domain

B. a parallel β-sheets

Which of the following has the greatest number of glycosidic bonds? A. triacylglycerol B. amylose C. DNA D. glucose

B. amylose

Monomers are added to polymers by ________ reactions. A. redox B. condensation C. hydrolysis D. substitution

B. condensation

When the size of a cell increases, the surface area/volume ratio... A. increases. B. decreases. C. remains the same. D. decreases initially and then remains constant.

B. decreases.

A scientist is examining motile protist. He wishes to determine their direction of movement. Which of the following microscopic techniques is least likely to be used to view these cells? A. light microscopy B. electron microscopy C. phase-contrast microscopy D. fluorescence microscopy

B. electron microscopy

Scientists use various terms to describe conclusions reached through the scientific method. Which of the following terms conveys the least degree of certainty? A. law B. hypothesis C. both hypothesis and theory D. theory

B. hypothesis

Hydrogen bonding is most important in stabilizing the ________ structure of many proteins. A. primary B. secondary C. tertiary D. quaternary

B. secondary

Glyoxysomes play an important role in... A. breaking down toxins in plant cells. B. the germination of fat-storing seeds. C. is the name used for peroxisomes found plant cells. D. moving carbohydrates to the plasma membrane of plant cells.

B. the germination of fat-storing seeds.

What bond is responsible for the straight sections in glycogen and amylopectin? A. α (1—>6) glycosidic linkages B. α (1—>4) glycosidic linkages C. β (1—>6) glycosidic linkages D. β (1—>4) glycosidic linkages

B. α (1—>4) glycosidic linkages

A protein is destined to be secreted from a cell. In which organelle would you expect to find the protein just after it is produced in the rough endoplasmic reticulum? A. lysosome B. endosome C. secretory vesicle D. Golgi apparatus

D. Golgi apparatus

What is the correct order of increasing chemical bond strength? A) all of these bonds are essentially equal B) hydrogen bond : ionic bond : covalent bond C) covalent bond : ionic bond : hydrogen bond D) ionic bond : hydrogen bond : covalent bond

B) hydrogen bond : ionic bond : covalent bond

Why do you suppose that viral illnesses are more difficult to treat than bacterial illnesses? A. Because viruses can affect all types of cells. B. Because viruses have fewer components and thus fewer targets than bacteria. C. Because viral enzymes are more pathogenic to the host cells than bacterial. D. Because viruses do not have their own metabolism and are fed by the host cell.

B. Because viruses have fewer components and thus fewer targets than bacteria.

You are researching a cytoplasmic protein associated with a nerve disorder. The native form of the enzyme appears to be globular protein; however, when a sample of the purified protein is treated with a chemical that reduces disulfide bonds, the enzymatic activity decreases dramatically and multiple globular proteins can be detected in the sample. What does this tell you about the protein? A. The primary and secondary structure of the protein depends on disulfide bonds. B. The protein is most likely composed of ß sheets that are held together by disulfide bonds C. The protein is most likely composed of multiple polypeptide chains that are held together by disulfide bonds. D. The protein is most likely composed of a helices that are held together by disulfide bonds.

C. The protein is most likely composed of multiple polypeptide chains that are held together by disulfide bonds.

Protein structures have several different levels of organization. The primary structure of a protein is its amino acid sequence. The secondary and tertiary structures are more complicated. Consider the definitions below and select the one that best fits the term "protein domain." A. the tertiary structure of a substrate-binding pocket B. a complex of more than one polypeptide chain C. a protein segment that folds independently into a compact stable structure D. a small cluster of α-helices and β-sheets

C. a protein segment that folds independently into a compact stable structure

What atom forms the backbone of almost all biological molecules? A. nitrogen B. hydrogen C. carbon D. oxygen

C. carbon

The term amphipathic refers to those molecules that are... A. charged at both ends but with opposite charges. B. hydrophilic C. charged at one end and nonpolar at the other. D. hydrophobic

C. charged at one end and nonpolar at the other.

Experiments by Stanley Miller in the 1950s demonstrated that the first organic molecules on earth... A. were catalysts composed of simple amino acids and most likely formed in an extraterrestrial environment and were deposited on earth via asteroids. B. were nucleic acids such as RNA and DNA. C. could have formed abiotically in a reducing atmosphere containing hydrogen, methane, ammonia, and water vapor. D. were catalysts composed of simple amino acids.

C. could have formed abiotically in a reducing atmosphere containing hydrogen, methane, ammonia, and water vapor.

Prions are... A. primitive protein particles that are believed to be an ancient precursor of living cells. B. the site of protein synthesis in prokaryotic cells. C. infectious misfolded proteins. D. simple viruses composed of protein.

C. infectious misfolded proteins.

Fatty acids are ________; they function in the cell as ________. A. short chains of double-bonded carbon molecules; storage lipids B. short chains of double-bonded carbon molecules; vitamins, cofactors, and storage lipids C. long, unbranched hydrocarbon chains with a carboxyl group at one end; building blocks for other lipids D. long, unbranched hydrocarbon chains with a carboxyl group at one end; vitamins and cofactors

C. long, unbranched hydrocarbon chains with a carboxyl group at one end; building blocks for other lipids

The main role of the central vacuole in plant cells is to... A. help with photorespiration in association with chloroplasts and mitochondria. B. digest trapped food particles. C. maintain turgor pressure in plant tissue. D. store glycogen for plant energy.

C. maintain turgor pressure in plant tissue.

The steps of the scientific method, in the correct order, are... A. design experiments, draw conclusions, collect data, interpret results, make observations, and test the hypothesis B. collect data, interpret results, test the hypothesis, make observations, and design experiments. C. make observations, formulate the hypothesis, design experiments, collect data, interpret results, and draw conclusions. D. collect data, interpret results, test the hypothesis, design experiments, make observations, and draw conclusions.

C. make observations, formulate the hypothesis, design experiments, collect data, interpret results, and draw conclusions.

Which of the following sequences correctly lists the hierarchical nature of cellular structures, from smallest to largest? A. organic molecules, macromolecules, organelles, supramolecular structures, cells B. macromolecules, organic molecules, supramolecular structures, organelles, cells C. organic molecules, macromolecules, supramolecular structures, organelles, cells D. organic molecules, supramolecular structures, macromolecules, organelles, cells

C. organic molecules, macromolecules, supramolecular structures, organelles, cells

In which of the following properties are the archaea more like eukaryotes than the bacteria? A. mode of cell division B. microtubules and microfilaments C. translation initiation D. size

C. translation initiation

Some researchers have hypothesized that type II diabetes mellitus is caused by a mitochondrial defect. Which of the following would be the best way for them to study mitochondrial differences in fresh tissue samples from diabetic and non-diabetic mice? A. Mitochondria from both tissues could be isolated from other cellular components by using proteolytic enzymes to break down other cellular structures. B. Mitochondria are the only organelles that survive tissue homogenization, thus both tissues could be homogenized to study the mitochondria. C. Mitochondria could be identified and isolated from other cellular components using immunofluorescence microscopy in both tissues. D. Mitochondria from both tissues could be isolated from other cellular components by fractionating tissue homogenate using differential centrifugation followed by density gradient centrifugation.

D. Mitochondria from both tissues could be isolated from other cellular components by fractionating tissue homogenate using differential centrifugation followed by density gradient centrifugation.

An enzyme synthesized in the laboratory is found to have little activity when compared to the enzyme extracted from cell culture. Both enzymes were examined and have identical amino acid composition. What is the best explanation for the lack of activity of the synthesized enzyme? A. The van der Waals radius was altered during laboratory synthesis. B. Denaturation of the synthesized enzyme was not complete. C. The ATP required for self-assembly was present in the cell extract but not in the laboratory synthesis. D. The synthesized enzyme was not folded correctly because molecular chaperones were not present.

D. The synthesized enzyme was not folded correctly because molecular chaperones were not present.

While fishing, you make the following observations: • Water spiders appear to be able walk on the surface of the water. • Flat rocks may be made to skip across the water. A. Water molecules are charged. B. Water molecules are heavy. C. Water molecules are polar. D. Water molecules are cohesive.

D. Water molecules are cohesive.

You wish to obtain a purified sample of mitochondria from lysed cells. The best way to obtain this sample would be... A. both centrifugation and polyacrylamide gel electrophoresis. B. chromatography. C. polyacrylamide gel electrophoresis. D. centrifugation.

D. centrifugation.

Which of the following processes would be most likely to occur in the Golgi complex? A. detoxification of drugs B. synthesis of steroids C. degradation of proteins D. glycosylation of proteins

D. glycosylation of proteins

One reason that it might be difficult to separate lysosomes from peroxisomes by centrifugation techniques is that... A. lysosomes are smaller than peroxisomes B. lysosomes are bound to peroxisomes. C. lysosomes and peroxisomes are found in the same regions of the cytosol. D. lysosomes and peroxisomes are similar in size.

D. lysosomes and peroxisomes are similar in size.

The major structural elements of the cytoskeleton are... A. proteoglycans and cellulose microfibrils. B. the cytoplasm and cytosol. C. the extracellular matrix and the cell wall. D. microtubules, microfilaments, and intermediate filaments.

D. microtubules, microfilaments, and intermediate filaments.

Which of the following organelles is not part of the endomembrane system? A. Golgi apparatus B. endoplasmic reticulum C. lysosome D. ribosome

D. ribosome

Animal fats are solid at room temperature. How would one characterize their fatty acid chains? A. unsaturated B. saturated and kinked C. saturated D. saturated and straight

D. saturated and straight

Ionic bonds are important in biological structures. Which of the following pairs of molecules would form an ionic bond? A. two water molecules B. two phospholipids C. two different stereoisomers of the same sugar D. two amino acids with oppositely charged functional groups

D. two amino acids with oppositely charged functional groups