BIOLOGY 108 EXAM #1

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) polysaccharides 2) DNA or RNA 3)proteins

You are presented with a sample of an enzyme of unknown function. An enzyme catalyzes a chemical reaction. You test the enzyme in the two solutions described below. Each solution is in a separate test tube. You measure the quantity of each compound before, and one hour after, adding the enzyme to each solution. Contents Quantity at start Quantity after 1 hour Solution A Amino acids Insulin (a protein) 50 mg 0 mg 1.5 mg 47 mg Solution B amino acids insulin (a protein) 0 mg 50 mg 0 mg 50 mg Analyze the data in the above table and answer the following questions. What do you believe the function of this enzyme is? (1 sentence is sufficient.) Considering the enzymatic mechanisms we discussed regarding polymer synthesis and degradation, what type of enzymatic mechanism does this data support? (1-3 words is sufficient.) Explain your conclusion in question 2. Please number your answer. 1. The function is to break down amino acids in turn increasing protein production. 2. Protein synthesis 3. In the solution where and amino acid is present the enzyme decreases the amino acid and increases the proteins

1) synthesizes proteins (or insulin) 2) condensation or dehydration 3) In solution A, the amount of protein increased over time, and the amount of AA decreased, so the enzyme is producing a protein polymer. note: need to relate conclusion to data.

The amino acid, as defined by the highlighted region in pink: (There is no pink in second diagram)

1. hydrophobic 2. 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

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.

The functional group is _________

An amino acid

Consider the structure shown here. How many carbons are in this structure? How many hydrogens are in this structure?

Carbons: 8 Hydrogens: 11

The -R group or side chain of the amino acid threonine is -CH2CH2-OH. The -R group or side chain of the amino acid leucine is -CH2CH3(CH3)2. Where would you expect to most likely find these amino acids in a globular protein in aqueous solution?

Leucine would be in the interior, and threonine would be on the exterior of the globular protein.

In a research article printed in Medicine and Biology (2006) "The Electron-microscopic findings on the liver in chronic abuse of heroin", the authors found that the most prominent changes in cellular organelles was the enlargement and increased number of smooth endoplasmic reticulum. Which of the following statements most likely explains this observation?

One of the functions of the smooth ER is detoxification

Cells of the pancreas will incorporate radioactively labeled amino acids into proteins. This "tagging" of newly synthesized proteins enables a researcher to track their location. In this case, we are tracking a protein secreted from the pancreatic cells. What is its most likely pathway of the protein through the cell?

Rough ER to vesicles to Golgi apparatus to the plasma membrane.

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

SMALLEST: phospholipid NEXT SMALLEST: DNA from E. coli ALMOST LARGEST: a prokaryotic cell LARGEST: a eukaryotic cell

Which of the following is an example of hydrolysis?

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

When a plant cell, such as one from a daisy stem, is submerged in a very hypotonic solution, what is likely to occur?

The cell will become turgid

The moon and Earth have similar distances to the sun. Two-thirds of the Earth's surface is water, while water is not observed on the surface of the moon. Which of the following statements best explains the role of water in the difference in climate between moon and Earth?

Water has a higher specific heat then the rocks on the moon, water absorbs large quantities of heat without raising temperature.

In an aqueous solution, does this functional group act as an acid, or as a base?

a base

A bond interaction between a water molecule and an ammonia molecule is ________ bond,

a hydrogen

Which of the following descriptions best fits the class of molecules known as nucleotides?

a nitrogenous base, a phosphate group, and a pentose sugar

The movement of a substance across a biological membrane against its concentration gradient with the help of energy input is _________.

active transport

The sodium-potassium pump in animal cells transports Na+ ions that are in low concentration in the cell, to the exterior side of the cell. At the same time, K+ ions at low concentrations on the outside the cell are transported into the cell. What type of transport process is this?

active transport

List one functional group that can raise the pH of a solution.

amino

while a bond interaction between Na+ and Cl- is ________ bond.

an iconic

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

an organelle

The Great Salt Lake is________

basic

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

carbonyl

Consisting of cellulose and other saccaride and protein polymers, plant cells and bacteria are surrounded by a _____________ external to the plasma membrane.

cell wall

Which of the samples, cellulose or glycogen, is obtained from a plant?

cellulose

They have hydrophilic and hydrophobic regions.

correct

They include phospholipids and integral membrane proteins.

correct

Which of the following is not a component of a nucleus?

cristae

Compare and contrast animal and bacterial cells. List 3 differences between animal and bacterial cells. List 2 similarities between animal and bacterial cells. Please number your answers. Please note, for differences, you must indicate what both cells have; for example, you can't say that animals can speak, you need to say animals speak, bacteria sing.

differences, any three Animals have organelles, bacteria do not Animal DNA is linear, bacteria DNA is circular Bacteria are always unicellular, animals can be multicellular Animal DNA in nucleus, bacteria DNA in nucleoid Animals are eukaryotic, bacteria are prokaryotic animal cells are larger than bacterial cells similarities, any two All have genetic material in DNA All have plasma membrane All use ribosomes to synthesize proteins All metabolize energy All have metabolic pathways

The charge on the functional group is a _____.

full positive charge

What are the monomers in starch?

glucose

Which solute(s) will exhibit a net diffusion into the cell? The membrane is permeable to water, sucrose, and glucose but impermeable to lactose. ***CELL*** 0.02 lactose 0.02 M sucrose ***ENVIRONMENT*** 0.01 M sucrose 0.01 M glucose 0.01 M lactose

glucose

You determine that one of the samples has a branched polymeric chain. Is this sample cellulose, or glycogen?

glycogen

Monomers in carbohydrates are linked by _______ bonds,

glycosidic

What type of bond/interaction best describes the attraction of water molecules to one another?

hydrogen bond

The Great Salt Lake in Utah has a pH of 10. The pH indicates the concentration of

hydrogen ion

Consider the molecules below and indicate whether they are hydrophilic or hydrophobic. The surface of the leaf:

hydrophobic

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

They are disordered in the membrane.

incorrect

They are strictly hydrophobic

incorrect

The protein and carbohydrate composition on the interior and exterior sides of a plasma membrane are asymmetric. One reason for this is that ____.

membrane proteins modified inside of the Golgi end up on the outside of plasma membranes

Facilitated diffusion is a form of _________.

passive transport that allows solute molecules to diffuse through by means of carrier proteins

while monomers in DNA/RNA are linked by ________ bonds.

phosphodiester

All of the following serve an important role in determining or maintaining the structure of either plant or animal cells. Which of the following is distinct in their composition from the others in this list?

plant cell walls

The hydrogen bond between two water molecules arises because water is ____.

polar

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

proteins

The major factor limiting cell size is the _____.

ratio of surface area to volume

Protein synthesis occurs on________________.

ribosomes

At room temperature, which fatty acid is most likely in a solid form?

steric acid

When incorporated into phospholipids and cellular membranes, which fatty acid tends to decrease the fluidity of the membrane.

steric acid

A sulfur atom bonded to a hydrogen atom.

sulfhydryl

Which of the following would not pass readily through a lipid bilayer?

water, glucose, and sodium ions