Ch 2 Knowledge Check Wk1
The atomic weight of an element whose atoms contain 8 protons, 8 electrons, and 8 neutrons is
16
The first electron shell of an atom can hold a maximum of
2 electrons
Carbon-13 is a form of carbon used to determine how old fossils are. The atomic mass of carbon-13 is 13. If carbon has 6 protons, then how many neutrons does carbon-13 have? Carbon-13 would be considered an...
7 neutrons; isotope
The breakdown of table sugar (sucrose) into glucose and fructose is an example of a/n __________ reaction.
Decomposition
Consider the following list of commonly found items and their pH values: Battery acid (1.0), vinegar (2.2), grapes (3.5-4.5), tomato (4.0-4.5), beer (4.2), coffee (5.0), white bread (5.0-6.0), butter (6.1-6.4), egg whites (7.6-8.0), baking soda (8.3), milk of magnesia (10.6), bleach (12.8) Which of the following is closest to the pH of water?
Egg whites
Nucleic acids are composed of building blocks called amino acids.
False
Proteins encode nucleic acids.
False
Sodium and chloride atoms combine readily because they both lose electrons.
False
Which organelle is incorrectly described?
Golgi apparatus - lipid synthesis
You drop a mystery compound into a beaker of water. Suppose that the compound instantly dissolves and dissociates into ions. What kind of chemical bond initially held this compound together?
Ionic
Consider the following list of commonly found items and their pH values: Battery acid (1.0), vinegar (2.2), grapes (3.5-4.5), tomato (4.0-4.5), beer (4.2), coffee (5.0), white bread (5.0-6.0), butter (6.1-6.4), egg whites (7.6-8.0), baking soda (8.3), milk of magnesia (10.6), bleach (12.8) Based on your knowledge of acid and base reactions, which of the following would be most likely to react with a base to form a salt?
Battery acid
Which of the following are Ions?
Biocarbonate
If helium (He) were to gain a proton, it would become
Lithium
A base is an electrolyte that releases ions that combine with hydrogen ions.
True
A protein is formed from a sequence of amino acids.
True
Chemically inert atoms always have their outermost electron shell full.
True
Water is an example of a compound.
True
Nucleic acids are
composed of building blocks called nucleotides.
After eating a salty bag of chips, your extracellular [Na+] skyrockets. The extracellular [Na+] is now considered to be _____ compared to the intracellular [Na+]. The cells _____.
hypertonic; shrivel
Electrolytes are substances that
ionize in water
Which of the following substances is an element?
iron
Saline has the same [Na+] as the inside of the cell. The cell neither swells nor shrivels when exposed to saline. Thus saline is considered to be a _____ solution.
isotonic
When forming a bond, an atom that has 3 electrons in its second shell and a filled first shell will
lose 3 electrons from its second shell
DNA and RNA differ in that
DNA holds genetic information and RNA uses that information to synthesize protein
In a covalent bond
atoms share a pair of more of electrons
Which of the following groups of elements accounts for more than 95% of the human body by weight?
carbon, hydrogen, oxygen, nitrogen
Which of the following best describes the reaction H2CO3 → H2O + CO2?
decomposition reaction
Synthesis reactions are particularly important in the body for
growth of body parts
A water solution that contains equal numbers of hydrogen ions and hydroxide ions is
neutral
The type of organic molecule that can replicate is a
nucleic acid
Which cell membrane transport mechanism is INCORRECTLY described?
osmosis - the movement of water from areas of low to high solute concentration
The atomic number of an atom equals the number of ________, and the atomic weight equals the ________.
protons; number of protons plus neutrons
A person has alkalosis if the blood pH
rises above 7.5
DNA
stores genetic information, including instructions for enzymes that synthesize fats and carbohydrates.
Which statement regarding the cell membrane is FALSE?
the phospholipid head is hydrophobic, whereas the tail is hydrophilic
