Final Exam

The role of a control in an experiment is to… A) prove that a hypothesis is correct B) provide a basis of comparison to an experimental group C) ensure repeatability D) counteract the negative effect of the experiment

An investigation was designed to study the impact of drug X on recovery from Covid-19. The patients were divided into two groups: one the experimental group and one was the control. The Covid-19 patients in the experiment group were each given 50mg drug X mixed in 100ml of apple juice every 4 hours and the time to recovery was measured. Which of the following describes the best example of a control for this experiment. A) The control group were not given anything B) The control were given 50mg drug X in 100 ml of apple juice every 12 hours C) The control group were given 50mg drug X without apple juice. D) The control group were each given 100ml of apple juice without drug X every 4 hours and time to recovery was measured

Carbon (C) is above Silicon (Si) in the same column of the periodic table. This means they both have… A) the same number of electron shells B) no common chemical properties C) similar bonding properties as they have same number of valence electrons D) least abundance in a cell

The element oxygen (O) has an atomic number of 8. An atom of O has _____proton(s) and ______electron(s). Its valence shell is the _______shell and contains ______ electron(s). O will typically make ________bond(s).

A pair of atoms joined by a polar covalent bond… A) has the charge spread evenly across both atoms. B) has a slight positive charge on one atom and a slight negative charge on the other. C) will both form hydrogen bonds D) mixes well with nonpolar solvents. E) is unlikely to form hydrogen bonds with water.

This biomolecule can form a hydrophobic/water repelling barrier.

This molecule is the primary information storing biomolecule

This molecule is the most abundant organic biomolecule in an organism

This substance is the solvent in which nearly all life’s chemical reactions occur

When multiple water molecules interact, the hydrogen in one water molecule and oxygen in another water molecule are held together by a ____________ bond. A) polar covalent B) hydrogen C) none of the options are correct D) Non polar covalent E) ionic

A beaker contains two solutions of salt with different concentrations (measured by molarity, M). Side A has 0.2M salt and Side B has 0.9 M salt. The two solutions are separated by a membrane that is permeable to both salt and water. What will occur in this container? A) net movement of water across the membrane but not of salt B) net movement of water from B to A and of salt from A to B C) movement of salt across the membrane but not of water D) net movement of salt from B to A but no net diffusion of water E) net movement of water from A to B and of salt from B to A

Which number represents the pH of a solution with the highest concentration of hydrogen ions? A) pH 4 B) pH 11 C) pH 9 D) pH 1 E) pH 7

A solution of pH 2, has ______ [H+] than a solution of pH 5? A) 10x less B) 100x more C) 1000X less D) 1000x more E) 10X less F) 1000X less

The molecule below is tryptophan, an amino acid. The red arrow is pointing to a C=O bond between oxygen and carbon. This is a __________bond and the oxygen has a _________charge. Electronegativity of carbon is 2.5, oxygen is 3.4, hydrogen is 2.1. Electronegativity difference scale: 0 to 0.5 Non polar covalent, 0.5-1.7 Polar covalent, >1.7 Ionic

The NASA spacecraft Perseverance recently landed on Mars. It collects Martian soil samples to look for signs of microscopic life. What characteristics would NASA have to find in the Martian samples that would support the existence of life on Mars? Select ALL correct answers. A) stores and follows instructions B) replicates C) is spherical in shape D) membrane delimited E) capable of storing and utilizing energy F) responds to the environment G) evolves

Cells are characterized by… A) the synthesis of proteins with stable shapes B) the enclosure of biological molecules by a membrane C)the formation of reactants and products an aggregation of proteins. D) complex proteins being dissolved in water

A biologist hypothesizes that keeping mice on a restricted calorie diet will increase their aggression. The biologist designs an experiment in which 50 1-year-old male mice, all 50 grams in weight, are housed in individual cages at 27 degrees Celsius and fed the same low calorie diet. After 2 weeks they then plan to place pairs of mice together in the same cage to observe their interactions. Which is the most appropriate design of a control for this experiment. A) 50 1-year-old male mice, all 50 grams in weight, are housed in individual cages at 27 degrees Celsius and fed the normal calorie diet B) 50 1-year-old male mice, all 50 grams in weight, are housed in individual cages at 27 degrees Celsius and fed a different low calorie diet C) mice not fed a low calorie diet D) 50 1-year-old male mice, all 50 grams in weight, are housed in individual cages at 27 degrees Celsius and fed nothing E) 50 1-year-old female mice, all 50 grams in weight, are housed in individual cages at 27 degrees Celsius and fed the same low calorie diet

Oxygen is an element found in nearly all biological molecules. How many electrons does it have in its valence shell? ; How many covalent bonds can it form with other atoms? A) 8;6 B) 2;6 C) 4;2 D) 6;2

An ion with a +1 charge has ________ . A) none of these answers are correct B) a basic pH C) one more electron than protons D) one more proton than electrons E) the same number of electrons and neutrons F) the same number of protons and electrons

Indicate the types of bonds that connect the compounds or molecules below. Electronegativity values are: H 2.2, C 2.5, N 3.04, O 3.4, K 0.8, Cl 3.2 nonpolar covalent <0.5, ionic >1.7, and in between 0.5 and 1.7 polar covalent NH3 CH4 KCl Guanine pairing with Cytosine via this bond CO2 A protein’s secondary structure is defined by this type of bond: _______

________bond types involve the attraction between full opposite charges, whereas __________ bonds involve the attraction between partial opposite charges A) Ionic, hydrogen B) Nonpolar covalent, polar covalent C) Hydrophobic forces, hydrophilic forces D) Polar covalent, nonpolar covalent E) Hydrogen bond, ionic

What will happen to the cell if it is placed into a HYPO-tonic (lower salt) solution? A) cell will shrivel B) no change C) cell will swell but not burst due to the cell wall.

The concentration of NaCl inside a red blood cell is 0.9%. Which of these describes the results if red blood cells are placed into a solution of pure water with no NaCl? A) They will shrivel B) Nothing will happen C) They will burst

A solution of pH 7 has __________ [H+] than a solution of pH 4. A) 3 times higher B) no way to know C) 1,000 times higher D) 10,000 times higher E) 100 times lower F) 3 times lower G) 10,000 times lower H) 100 times higher I) 1,000 times lower