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42 terms

Biology Midterm

Which one of the following is NOT a trace element in the human body?
The four most common elements in living organisms are
A compound
Contains two or more elements in a fixed ratio
What is the difference between covalent and ionic bonding?
In a covalent bond, the partners share a pair of electrons; in an ionic bond, one partner transfers electrons to the other.
________ are weak bonds that bridges between molecules.
Hydrogen bonds
The ability of water molecules to form hydrogen bonds with other water molecules is critical to
The movement of water from the roots of a tree to its leaves; the abliity of certain insects to walk on the surface of water; evaporative cooling of skin surfaces; (all these factors)
Water molecules stick to other water molecules because
Hydrogen bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules.
A solution with a pH of 7 is
A solution with a pH of 1 is
Strongly acidic
Characteristics of carbon that contribute to its ability to form an immense diversity of organic molecules include its
Ability to bond with up o four other atoms; tendency to form covalent bonds; ability to bond together to form extensive, branched, or unbranched "carbon skeletons"; (all choices are correct)
Organic compounds
always contain carbon and hydrogen and are syntehsized by cells
Which one of the following is an amino group?
Monosaccharides can be joined together by a process called dehydration synthesis. Which of the following statements is/are true of this process?
Covalent bonds are formed between the monomers; one monomer loses a hydrogen atom, and the other loses a hydroxyl group; H2O is formed as the monomers are joined; (all the choices are correct)
*The molecular formula of most monosaccharides represents a multiple of
A molecule with the formula C55H110O55 is probably a(n)
Sucrose is formed
From two monosaccharides by dehydration synthesis
Which one of the following lists contains only polysaccharides?
Cellulose, starch, and glycogen
Cellulose differs from starch in that
Most animals cannot break down cellulose, whereas starch is easily digested
Foods that are high in fiber are most likely derived from
The storage from carbohydrates in animals is _________ and in plants is _________
Fatty acids with double bonds between some of their carbons are said to be
Proteins differ from one another because
The sequence of amino acids in the polypeptide chain differs from protien to protein
Glucose molecules are to starch as ________ are to protiens
Amino acids
Peptide bonds
Link amino acids together
The _______ structure of a protein consists of a chain of amino acids assembeled in a specific order
The tertiary structure of a polypeptide refers to
The overall three-dimensional structure
DNA differs from RNA because DNA
Contains thymine in place of uracil
Genetic information is encoded in the
Sequence of nucleotides in DNA
The glucose produced by a plant is used to make the carbohydrate, proteins, fats, and other nucleic acids of the plant. Which statement is true about the process of converting sugars into other molecules?
Glucose contains all of the elements needed to produce the carbohydrates and fats, but other elements must come from the soil if the plant is to produce proteins and nucleic acids.
Many names for sugars end in the suffix
Can be broken down into sub units that are exactly identical to each other
Contains nitrogen; macromolecule is found to have a gloular shape
Not soluable in water
Contains nitrogen
Nucleic Acid
Esential elements and their role in plants, animals and prokaryotes
Phosphorus: atp release storage of energy also a part of DNA
Iron: needed for the production of hemoglobin and oxygen and other proteins, carries hemoglobin in blood
Sulfur: found in amino acids building blocks of protein some prokaryotes cells witout nucelir can use sulfar containing compounds to make their food.
Sodium: important in cell membrane functioning and also used in sending nerve impulses
Calcium: bone strength, helps enzymes work speed to chem. rxns to make food
Cohesive Properites
cohesion is an attraction between moelcules of that are of the same type (digest themselves), water has cohesion because of hydrogen bonds this can be shown through surface tension, water moving up a plant, and it explains waters thermal properties.
Thermal Properties
high specific heat and high heat of melting and evaporation, waters high specific heat helps stablize temperatures because water resists temperature change, and it allows cooling and heating. Waters specific heat is high because it has a resistance to change temperature.
specific heat
amount of energy needed to change the temp.
heat of vaporization
amount of energy to go from a liquid to a gas
Solvent Properties
Water dissolves polar molecules, Positive side of water attracts to negative side of polar molecule and vice versa, It also dissolves ionic compounds
Explain the relationship between the properties of water and its uses in living organisms as a coolant, medium for metabolic reactions and transport medium
Sweat-- for water a as a coolant, Heat from skin is used to evaporate the water on skin,High heat of vaporization removes a lot of heat with a small amount of water,Because it dissolves so much, water is a great transport medium AND medium for chemical reactions!
std dev
State that the term standard deviation is used to summarize the spread of values
around a mean, and that 68% of the values fall within one standard deviation of
the mean