Unit One Bio 108 exam

The fluid mosaic model describes the structure of cellular membranes. In this model, 'fluid' describes the ___________ component, while 'mosaic' describes the ________ component.

1. Lipid 2. Protein

Cells have 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 ______.

the nuclear envelope

If an element has three electronic shells, in which shell are valence electrons found?

the orbital farthest from the nucleus.

The partial charges on a water molecule occur because of _____.

the unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule

The Seliwanoff test is a chemical test to determine if mono- or di-saccharides contain aldehyde or ketone sugars. In the test, ketone sugars turn deep red, aldehydes turn pale pink. Consider the three samples of monosaccharides below. 1. Which of these images are aldoses? 2. Based on the experimental data, identify all samples that should give a Seliwanoff result that is pale pink. (Refer to Q.25 for pics)

1. A and C 2. A and C

If a molecule moves through a membrane in an active process, it moves __________ its concentration gradient, down ____________ added energy. with

1. Against 2. with

This image shows a ______________ , the dashed circle is highlighting a ______________. (refer to Q. 35)

1. Chloroplast 2. granum

1. What is the organelle shown here? 2. What is the primary function of this organelle? (refer to Q. 25 on practice exam)

1. Golgi complex 2. processing of secretory proteins/vesicles

A red blood cell has been placed into three different solutions. One solution is isotonic to the cell, one solution is hypotonic to the cell, and one solution is hypertonic to the cell. (refer to Q. 40)

1. Hypotonic 2. isotonic 3. hypertonic

1. What type of bond results from the chemical reaction illustrated in this figure? (refer to Q. 28) 2. The —R group indicated by the dashed line is_____

1. Peptide 2. Nonpolar

Much of the diversity of macromolecules found in living organisms is due to the polymeric nature of these molecules, which are composed of a limited number of unique monomers. For each monomer listed, identify the polymer it can be a part of. 1. glucose 2. nucleotides 3. amino acids

1. Polysaccarides 2. DNA or RNA 3. Proteins

Refer to Q. 38

1. Region a and c 2. Region B

One difference in lipids is due to saturation in the acyl chains of fatty acids. Oleic acid is a fatty acid with one double bond. The lipid with a cis-arrangement around the double bond is a liquid at room temperature; whereas, the trans arrangement around the double bond is solid at room temperature. 1. At room temperature the acyl chains pack more loosely together. 2. When incorporated into phospholipids and cellular membranes, it decreases the fluidity of the membrane. 3. Are geometric isomers.

1. cis-form of oleic acid 2. trans-form of oleic acid 3. cis- and trans- form of oleic acid

Consider the molecules below and indicate whether they are hydrophilic or hydrophobic. 1. The surface of a leaf (For 2 and three refer back to Exam Q. 21)

1.Hydrophobic 2. hydrophobic 3. Hydrophilic

Studies have shown that the fusion of a human and a mouse cell is pH-dependent. The yield of fused cells is highest between a neutral pH and one pH unit more basic. Therefore, the pH needs to be between _____.

7.0-8.0

go to Q. 15 on practice exam

:)

Which cell has properties better suited for the metabolic needs of diffusing substances most rapidly from the interior to the exterior (and vice versa)?

A cell with a surface area significantly greater then its volume.

Evaluate these statements describing differences between bacteria, plant, and animal cells. Which is an accurate statement?

A nucleus is found in plant and animal cells, a nucleoid is found in bacteria cells.

Put the following molecules (that are in alphabetical order) in order from smallest to largest. a eukarytoic cell DNA from E. coli a phospholipid a prokaryotic cell

A phospholipid DNA from E. coli A prokaryote cell A eukaryote cell

For each image, indicate the cellular function for the organelle.

A. Site of cellular respiration B. Site of photosynthesis C. synthesizes membranes, produces proteins and membranes secreted from the cell D. involved in synthesis, storage, and shipping of secretory vesicles

Transport processes that require energy are ________ processes.

Active

What type of transport process would you expect if fatty acids circulating in the blood stream are transported into an adipose cell whose function is to store lipids as an energy reserve?

Active transport because the fatty acids are transported from low to high concentration into the adipose cell.

Which of the following statements about amylose and amylopectin is false? Both amylose and amylopectin are polysaccharides. Amylopectin is a polymer of α,1-4 linked and α,1-6 linked glucose monomers. Correct! Amylose is a polymer of α,1-4 linked glucose monomers found primarily in animals. Humans and other mammals can easily hydrolyze both amylose and amylopectin so are both used for energy storage. None of the above, all the statements are true.

Amylose is a polymer of α,1-4 linked glucose monomers found primarily in animals.

Which of the following increases membrane fluidity at cool temperatures?

An abundance of cholesterol and unsaturated fatty acids in membrane phospholipids.

A hydrogen atom can form a hydrogen bond when covalently bonded to which of the following atom(s)? (Select all that apply.)

Both oxygen (O-H) and nitrogen (N-H).

Which of these common elements found in biological molecules has four electrons in the valence shell?

Carbon

A carbon double-bonded to an oxygen atom, present in aldehydes and ketones.

Carbonyl

Which of the figures illustrates a prokaryotic cell? (refer to Q.36)

Cell B

When observing cells of unknown origin, if organelles are present one can conclude the cells are likely _______.

Eukaryotic

If this cell is permeable to water, glucose, and fructose, but impermeable to sucrose, which of these solutes will exhibit a net diffusion into the cell? (refer to Q. 39)

Glucose

The simple sugars of carbohydrate polymers are linked by _______ bonds

Glycosidic

Mitochondria and chloroplasts are organelles that have extensive membrane structures to increase membraneous surface area for membrane-bound proteins. Mitochondria accomplish this by______

Highly folded Cristae

A bond between a partially charged hydrogen and a partial negatively charged atom.

Hydrogen Bond

Which of the following explains most specifically the attraction of water molecules to one another?

Hydrogen bonds

The pH of a solution is defined as the negative logarithm of the concentration of [response1]. (one to two words only)

Hydrogen ions

Which of the following statements about hydrophilic molecules is false?

Hydrophilic molecules are often found in oils

Where would you find a nucleolus?

In a eukaryotic cell, in the nucleus.

Mitochondria and chloroplasts are organelles that have extensive membrane structures to increase membraneous surface area for membrane-bound proteins. In contrast, chloroplasts have ______

Internal membraneous thylakoids

A covalent bond between atoms that differ in electronegativity, imposes partial charges on each atom in bond

Ionic bond

A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water containing 0.02 molar glucose. Assuming that glucose is not actively transported into the cell, which of the following terms describes the tonicity of the external solution relative to the cytoplasm of the cell?

Isotonic

If a sampe of RNA is treated with RNase, an enzyme that degrades RNA, what monomeric units would you expect to find increasing over time? (one to four words)

Nucleotides

The pH scale shown indicates pH values of several common solutions. Which substance is ~100 times more acidic than bread at pH 6?

Orange juice

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

Proteins

A phosphorus atom bonded to four oxygen atoms.

Phosphate

If you receive cut flowers from a loved one, but they are limp and wilted, what is your best option to restore the rigidity of the stems and leaves?

Place the flowers in a hypotonic solution so the cells become turgid.

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

Rough ER to vesicles to Golgi to the plasma membrane.

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?

The phosphodiester linkages between deoxyribose sugars would be broken.

The cytoskeleton is composed of three different filament types. Put the three filament types in order from smallest to largest diameter.

Smallest: Microfilament In- between: intermediate filaments largest: mircrotubule

What term is used to describe the amount of heat that must be absorbed or lost for 1 g of a substance to change its temperature by 1o C?

Specific heat

Which of the following is an example of hydrolysis?

The breakdown of a fat, forming glycerol and fatty acids with the utlization of water

You are presented with a sample of an enzyme of unknown function. An enzyme catalyzes a chemical reaction. You test the enzyme in three solutions described below. You measure the average number of monomers present in the polymers in each sample before, and one hour after, adding the enzyme to each solution. Which of the following is a potential explanation for these observations? (refer to Q. 38 on practice exam)

The enzyme hydrolyzes phosphodiester bonds in DNA.

Which of the following events would you expect to happen if freshwater fish were placed in a saltwater aquarium?

The fish cells would be hypotonic to the saltwater, lose water, and their cells would shrivel.

The figure below shows two isomers of C4H10. Which of the statements is true? (refer to Q. 29 on practice exam)

The isomers are structural isomers.

Why do fatty acids have limited solubility in aqueous solutions?

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

Assume a membrane is polarized, so that the exterior surface has a negative charge. Which of the following descriptions of the interaction of water with the charged membrane would you expect to observe?

The water molecules within hydrogen bonding distances would orient so that the hydrogen atoms are nearest the membrane surface.

Compared to cells in the nose of a mouse in Missouri, the cells in the nose of an arctic fox in Alaska will most likely have an increased concentration of which of these molecules?

Unsaturated phospholipids

Catabolic pathways ______ complex molecules; they are dominated by _____ reactions.

break down........ hydrolytic

In the cell when molecules are broken down to release energy, heat is also released. Water is able to maintain, or to buffer, temperature in cells better then almost any other liquid. What property of water best explains the temperature buffering capabilities of water?

Water has a high specific heat capacity.

An organelle that serves a general storage function is ________.

a vacuole

Consider the molecules below and indicate whether they are hydrophilic or hydrophobic.

amino acid

The molecule shown is of the amino acid, tyrosine. Which functional group(s) is present in this molecule? (Select all that apply.) (refer to Q. 22 on practice exam)

amino group carboxyl group hydroxyl group

A transmembrane protein in which a hydrophobic region spans the hydrophobic interior of a lipid bilayer is ______________.

an integral membrane protein

A general term for membrane-enclosed structures within eukaryotic cells that have a specialized function is __________________.

an organelle

Which four elements make up approximately 96% of living matter?

carbon, hydrogen, nitrogen, oxygen

In the formation of a macromolecule polymer, what type of reaction joins two monomers together?

denaturation reaction

When a protein is unfolded, it is said to be ______________.

denatured

The pancreas is an organ found in many animals. It synthesizes and secretes a large quantity of protein hormones. You would expect a pancreas cell to have a large quantity of _______.

endoplasmic reticulum and Golgi apparatus

Consisting of proteins and polysaccharides, animal cells are embedded in an _____________.

extracellular matrix

Lactose, the primary sugar in milk, is transported by membrane proteins under conditions in which the concentration of lactose inside the cell is lower than the concentration outside the cell. What type of transport is used to move lactose into the cell?

facilitated diffusion

Which type of transport process requires transporter proteins embedded in the membrane?

facilitated diffusion and active transport

Crossing a membrane by facilitated diffusion can be distinguished from active transport because:

facilitated diffusion does not require energy, while active transport requires a source of energy.

To generate a solution that is hypertonic to a cell, you would need to make sure the solute concentration of the solution is ___________ the solute concentration in the cell

greater than

When sugars and fats are metabolized to release energy for an organism, approximately 38% of the energy is converted into usable energy, while 62% is lost as heat. What property of water acts to keep temperature levels in the cell from raising too dangerous levels?

high specific heat

An animal cell containing 0.05 M glucose is in a solution containing 0.01 M NaCl, 0.01 M glucose, 0.005 M sucrose, and 0.01 M ATP. Before any transport of solutes, the cell is _______________ to the solution.

hypertonic

Which structure is common to plant and animal cells?

mitochondrion

Monomers in DNA/RNA are linked by __________ bonds, glycosidic

phosphodiester

while monomers in proteins are linked by ________ bonds.

peptide

You are trying to characterize an unknown enzyme. When you add the enzyme to a test tube with 10 mg of nucleotides, you notice that the amount of nucleotides decreases over time, but the amount of DNA polymers increase. You conclude that the enzyme likely forms __________.

phosphodiester bonds by condensation/dehydration

Which of the following macromolecules is not a polymer?

phospholipids

Which of the following types of molecules are the major structural components of the cell membrane?

phospholipids and proteins

A cell has the following molecules and structures: DNA, plasma membrane, proteins, and Golgi apparatus. This could be a _________ cell.

plant or animal cell

Not all proteins have ____________ structure, those that do have a specific association of more then one polypeptide chain.

quaternary structure

Which sequence of flow through a cell could occur in the secretion of proteins from a pathogenic bacterium?

ribosome → secretion out of cell

The primary structure of a protein is determined by the _________ of amino acids in the protein.

sequence