Flashcards in Chapter 2 Deck (84):
Name the most common biological atoms?
How many covalent bonds can atoms form?
8 minus the number of electrons in the outmost shell of the atom.
What are some characteristics of double bonds?
They are more rigid and less flexible than single bonds. Single bonds allow for rotation.
What is a polar structure?
A polar structure in one in which positive charge is concentrated at one end and negative charge is concentrated at the other. Leading to a negative and a positive pole.
What are the two most electrically negative biological atoms?
Oxygen and nitrogen
What biological atoms have a relatively weak electronegative charge?
Name a common biological bond that is relatively non-polar?
Name two common biological bonds that are relatively polar?
What makes a bond polar?
When the electrons are not shared equally in a covalent bond.
How is bond strength measured?
the amount of energy required to break the bond. this is measured in kilocalories per mole (kcal/mol) or kilojoules per mole (kj/mole)
What is stronger, ionic or covalent bonds?
When water is present covalent bonds are much stronger.
What are salts?
Ions that held together only by ionic bonds
How does water dissolve?
The electronegativeity of the O is stronger the the ionic bond of the NaCl, so it dissociates it into Na+ions and Ca- ions, which are surrounded by water.
What holds water molecules together?
Weak hydrogen bonds between the positive and negative sections of two different molecules.
Why are hydrogen bonds significant?
Without them life on earth would not exist. They are responsible for water's surface tension. Water's surface tension means that it has a high specific heat (boiling point) is liquid (not gas) at room temperature.
What type of bonds are hydrogen bonds?
What dissolves readily in water?
Anything with a positive or negative charge. These molecules are hydrophilic.
Where do hydrogen bonds form?
Between anything with a polar covalent linkage what hold a hydrogen with a positive charge when it comes in contact with something with a negative charge.
What makes a molecules hydrophobic?
These molecules are uncharged, don't form hydrogen bonds and thus do not dissolve in water.
Are hydrocarbons hydrophilic or hydrophobic?
They are hydrophobic because the H-C bonds they are composed of are non-polar.
What makes up the tails of the lipids?
Hydrocarbon (H-C) tails
How are acids formed?
When a highly polar covalent bond between hydrogen and another atom dissolves in water, the hydrogen atom gives up its election almost entirely to the other atom, so that exists as a naked proton H+ and then bonds with water creating a hydronium ion (H3O+)
Why is water the universal solvent?
1.) It is polar
2.) It cohesive
3.) It has a high specific heat
What defines and acid?
Substances that release proton (H+ ions) when they are dissolved in water.
Do hydronium ions move around water.
Yes, water molecules are continually exchanging hydronium ions hydroxyl ions. These ions then reform H2O.
What are hydronium ions?
What are hydroxyl ions?
What determines the pH of a solution?
The presence of H3O hydronium ions. The more there are the more acidic the solution, the the lower the pH.
What is another way to refer to H3O molecules.
H+. Although H3O is more accurate, the long running convention is H+
What makes an acid strong?
The more easily a substance gives up its protons, the stronger the acid.
Are carboxyl groups (COOH) acidic or basic?
What are acids?
Substances that release positively charges hydrogen ions into solutions.
What are bases?
Substances that accept positively charged hydrogen ions. because they are OH- and then the positively charged hydrogen ion attaches, it become H2O
What happens when bases are put in water?
The OH- strips the H+ off of the hydronium ion to form H2O.
What do acidic solutions have?
Lots of H+ or hydronium ions
What do basic solutions have?
Lots of OH-
What is the pH of cytosol?
What is the pH in the lysosome?
4.2. Thus is it highly acidic and good for breaking things down.
What are buffers?
They limit the changes in the pH of a solution. They weak acid and bases and can act as either as the surrounding solution becomes too basic or too acidic.
Why are buffers important in biology?
They keep pH in an appropriate range so that cells can perform their function.
Functionally, what are sugars?
They are both energy sources and the subunits of polysaccharides.
What is an organic molecule?
Molecules that have carbon
What is a chemical group?
Groups of atoms such as methyl (-CH3), hydroxyl (-OH), carboxyl (-COOH), carbonyl (-C=O), phosphoryl (-PO3^2-) and amino (-NH2) groups that occur repeatedly in organic molecules. They groups have groups of characteristics.
How many vacancies are there in carbon's outer shell?
What are inorganic molecules?
Any molecules that don't have carbon
What is the formula for glucose?
What is the empirical formula for sugars?
What are isomers?
Sets of molecules with the same chemical formula but different structures.
What is the difference between cohesion and adhesion?
cohesion is when a substance sticks to itself. Adhesion is when something sticks to something else.
Do lipids have a single monomer from with they are built?
What are the names of the bonds that link monosaccharides together to form larger carbohydrates?
How do monosaccharides become di-, tri-, tetra-, or poly- saccharides.
Through condensation reactions when the -OH of two monosaccharides are bonded leaving and O as their connection. 2 Hydrogen and another O are left over so that H2O is expelled in condensation reactions.
What is a condensation reaction?
When water is the product of a reaction. Two -OH groups come together, bond the two molecules of which they are a part, leaving a larger macromolecule bonded together at and O and producing H2O as a byproduct.
Moreover, water is expelled as the bond is formed.
What is a hydrolysis reaction?
It is the reverse of a condensation reaction. It is the use of water to break a part a bond. Instead of expelling water, water is consumed. An H and -OH are added back to the O that bonded two molecules, leaving both molecules with -OH groups.
Water is consumed in this reaction.
In what type of reaction is water consumed?
In what type of reaction is water expelled?
What is starch?
How energy is stored in plant cells
What is cellulose?
The structural sugars in plants
What is glycogen?
How animal cells store a surplus of chemical energy
What are lipids?
They are responsible for the formation of cell barriers.
What lipids make up the bilayer membrane?
What are phospholipids made of?
Long hydrocarbon tails with a polar group at the head.
What does amphipathic mean?
When something contains hydrophilic and hydrophobic parts.
What is a dehydration reaction?
Dehydration and condensation reactions are the same thing that the substance expelled is water.
What are triglycerides?
They are fatty acid tails with a glycerol head.
How do you identify a fatty acids?
What is glycerol?
An alcohol with 3 carbon, 3 OH and 5 hydrogens. It is the head of triacylglycerols.
What is a saturated fat?
A fat that doesn't contain double bonds. Since they don't contain double bonds they can be packed in more tightly leading them to be solid at room temperature.
What is a unsaturated fat?
A fat that contains double bonds. It cannot be packed a tightly because of the double bonds and therefore liquid at room temperature.
How are fatty acids stored?
in the cytoplasm of cells in the form of fat droplets composed of triacylglycerol, which are three fatty acid tails joined together by a glycerol head by covalent bonds.
What are triacylglycerols?
They are the way the energy is stored in animal fat, plants oils etc. When a plant needs energy, a fatty acid chain can be released from a triacylglycerol and broken down into two-carbon units. These two carbon units are identical to those derived from the breakdown of glucose.
What is the difference between triacylglycerols and phospholipids.
Triacylglycerols have a glycerol head and three fatty acid tails. Phospholipids have two tails, a glycerol head, the third -OH group where the final tail would have gone links to a hydrophilic phosphate group which then links to a small hydrophilic compound such as choline.
Also, triacylcycerols are strong hydrophobic.
What do steroids do?
To provide rigidity to membrane structure and hormonal signaling.
What is the structure of steroids?
What is the function of proteins?
To carry out cell activities
What defines an amino acid?
There is a carbon atom with an amino group (H2N) on one side and carboxyl group (COOH) on the other. There is also a functional group link to the carbon.
What type of bonds hold proteins together?
peptide bonds, which are formed by a type of condensation reaction. The amino (NH2) and the carboxyl (COOH) bond to create a N-H-C=O bond and an H20 is expelled.
Where are peptide bonds formed?
Between hydroxyl and amino groups
What determines the function of an amino acid?
What are the different properties amino acids can have?
polar, non-polar, charged, other.
What links nucleic acids together?
What are the two functions of nucleotides?
Storing energy (ATP) and storing genetic information
What is the base of ATP and ADP?
Where do nucleotides connect?
The phosphate group of one attaches to the hydroxyl group of the next