Molecules of Life Final Exam

Chemicals make up most of the world we live in. which of these is not a chemical: water, amino acid, protein, cellulose, bicycle

bicycle

molecules are fundamental, but can be broken down into

elements

atoms are made up of protons, neutrons, and electrons, it is the __________ that is gained, lost, or shared in chemical reactions

electrons

molecules of life are made of many elements including iron, zinc, magnesium, hydrogen, __________, nitrogen and oxygen

carbon

carbon is found in almost all molecules of life. carbon forms __________ bonds with other atoms

four

to simplify the drawing of complex molecules of life we sometimes leave out the hydrogen atoms. we know that carbon atoms form four bonds with other atoms and assume that the missing bonds are to hydrogen atoms. the formula for this compound is C=C-C

C3H6

carbons atoms in molecules are not flat. the bonds of a carbon atom point to the verticles of a regular tetrahedron. because of this, carbon atoms attached to __________ different groups can exist as mirror images and are said to be __________

four and chiral

what are ester groups in compounds

a carbon with a single bond to a carbon, a double bond to an oxygen, and a single bond to an oxygen

alcohols and acids are often joined in a condensation reaction. the byproduct from these reactions is usually __________

water

water has a molecular weight of 18 grams/mole. compounds with similar molecular weights such as methane (CH4 - molecular weight 16) and neon (molecular weight 20) are gases at room temperature. water is a liquid because there is __________ __________ to other the other water molecules

hydrogen bonding

another property of water is its ability to dissolve ionic compounds like sodium chloride. why does sodium chloride dissolve in water, but not hexane? Because of its __________

polarity

several different types of molecules of life compose the group called lipids. the physical property they have in common is their __________ in water

insolubility

fatty acids are lipids. fatty acids combine with __________ to form triglycerides which can be fats or oils

glycerol

fatty acids usually contain a double bond. how do you tell if a double bond is a trans or cis

trans is all pointy zig zags

cis has the horizontal lines that make a C sideways

soap is a sodium or potassium salt of a __________

fatty acid

fatty acids can be converted to other active compounds. the fatty acid that is a precursor for eicosanoids is __________

arachidonic acid

eicosanoids trigger a number of activities. an activity they do not trigger is: fever, pain, child birth, appetite, or blood clotting?

appetite

cell membranes contain phospholipids. phospholipids contain a two fatty acids esterified to glycerol and another group which often contains a phosphate molecules. the phospholipids are useful because they contain both __________ and __________ sections

hydrophilic and hydrophobic

the sugar that our bodies use for energy is glucose. the formula of glucose is __________

C6H12O6

many sugars that we consume are disaccharides. an example of a dissacharide would be __________, __________, and __________

sucrose, lactose, or maltose

linking __________ together can make starch or cellulose.

glucose

what is the difference between starch and cellulose molecule linking

starch: the O between each one goes way down then way up and the strand goes diagonal

cellulose: the O is parallel to each part and the strand is horizontal

blood types: A, B, AB, and O exist because red blood cells have different __________ attached to them

sugar molecules

nitrogen can form three covalent bonds, but has the ability to __________. this enables DNA to hold two strands together in a double helix and allows proteins to form alpha helices and beta-pleated sheets.

hydrogen bonding

nitrogen is present in every amino acid. amino acids contain an amine group (-NH2) and carboxylic acid group (COOH) and __________ different R groups attached to the carbon between the amine and carboxylic acid.

20

the shape of a protein is key to its function. frederick sanger first determined the primary structure of insulin. in doing so he determined the __________ or the amino acids in the protein

order

linus pauling used a careful drawing and folding paper to show that proteins can have a beta structure that is a __________ held together by hydrogen bonds.

alpha helix

the order of amino acids in a protein is determined by the section of __________ which codes for the protein

DNA

the DNA for the whole organism is contained in the nucleus of each cell of the organism. when cells divide, DNA is replicated because where there is an A base on one strand, there must be a __________ base on the pairing strand

T

the A and T bases are held adjacent to each other by __________

hydrogen bonding

to use the information coded on DNA, the information is first passed to a molecule of __________

RNA

the RNA leaves the nucleus and finds a __________ where protein synthesis takes place

ribosome

because of the great number of amino acids in a protein and endless possibilities for hydrogen bonding, it is difficult to predict the __________ structure of the protein. this structure is the overall shape of the protein.

tertiary

three natural fibers that are cellulose based are: __________, __________, and __________

cotton, flax, and hemp

before wood chips can be converted to paper, __________ must be removed

lignin

protein based natural fibers include

wool silk

wool and silk have different secondary structures. wool is based on an __________ structure

alpha helix

rubber is a useful natural polymer. rubber is useful because it is flexible. strands are not held together tightly with hydrogen bonding as in protein and cellulose fibers. in fact the polymer strands of rubber are held together so loosely in nature that they have to be cross linked usins in a process discovered by Charles Goodyear

sulfur

the glucose that is polymerized to make cellulosic fibers such as cotton and linen is formed in the __________ step of photosynthesis

second

in the first step of photosynthesis, __________ absorbs energy from the sun

chlorophyll

the energy obtained by chlorophyll in the first step of photosynthesis converts water into __________ and produces __________ which powers the second step of photosynthesis

oxygen and ATP

the enzyme that grabs carbon dioxide in the second step of photosynthesis is called __________

rubisco

rubisco can also react with __________ which eventually results in photorespiration and shrinking of the plant

oxygen

__________ plants prevent oxygen from reaching the rubisco. these plants use __________ to capture CO2 and transfer it to the rubsico

C4 and pepcase

cacti open their stomata at night to let in carbon dioxide. they close their stomata in the day to prevent loss of water vapor. their rubisco reacts with carbon dioxide to make glucose, but they may also react with __________ brought into chloroplasts with the carbon dioxide

oxygen

sunlight is so important to plants that they will bend toward light. this bending is initiated by __________ which through a series of steps causes cell and the side opposite the sun to expand

auxin

the tendency of plants to bend toward the light is called __________

phototropism

plants can also take __________ from the air to use in making DNA and amino acid

nitrogen

nitrogen is "fixed" by the action of bacteria. these bacteria exchange nitrogen containing compounds for the __________ needed to supply the energy for nitrogen fixation

ATP

plants also use sunlight to tell what time of year it is. to do this they use an enzyme called __________ which opens and closes depending on the amount of sunlight

photochrome

plants are known to borrow glucose from adjacent plants. plants utilize __________ to do this transfer.

fungi

since plants make glucose from CO2, suzanne simard used __________ CO2 to show that glucose can move from one plant to another

radioactivity

when plants are attacked by insects of other animals, they can warn adjacent plants. True or false

true