AP Bio Exam 1

quaternary protein structure

(Combine) bringing together of polypeptide chains into one large protein ex. hemoglobin

secondary protein structure

(Fold) hydrogen bonding results in "a" helix- coiled "B" pleated sheet-accordian

tertiary protein structure

(Globe) gobular due to: R groups, vander shape, walls, hydrogen bonds, and disulfide bridges

primary protein structure

(Sequence) amino acids joined in a unique sequence

Carboxylic acids

-COOH

Carboxyl

-COOH (carboxylic acids)

found in amines

-NH2

amino group

-NH2 (amines)

hydroxyl group, characterizes alcohols

-OH

hydroxyl

-OH (alcohol)

phosphate

-OPO3^-2 (dissociates H+; anion)

found in thiols

-SH

Sulfhydryl group

-SH (thiols; cross links to stabilize protein structure)

What is not a property of carbon

does NOT create compounds that always dissolve in water

Left- and Right- handed versions of same molecule

enantiomers

function of carbohydrates

energy, energy storage, structure

function of lipids

energy, insulation

function of proteins

enzymes, movement

examples of lipids

fats, oils

Not water soluble

fatty acids

Differ in spatial arrangement of atoms

geometric isomers

When do covalent bonds form?

when atoms share electrons

When do hydrogen bonds occur?

when partial opposite charges on molecules come close enough to attract each other

allosteric site

where molecules other than the substrates bind in the enzyme to alter enzyme activity, aids in proper 3 dimensional shape when linked with cofactors (essential)

carbonyl groups

>CO (aldehyde of ketone; polar group)

Which of the following best describes the process that adds a monosaccharide to an existing polysaccharide? A. The monosaccharide is completely broken down by a specific enzyme and then the atoms are reorganized and made into a polysaccharide. B. Ionic bonds are formed between adjacent carbon atoms of the monosaccharide and the polysaccharide by adding water (H2O) and a specific enzyme. C. A specific enzyme removes the hydrogen (H) from the monosaccharide and the hydroxide (OH) from the polysaccharide, creating a bond between the two and creating a water (H2O) molecule. D. A specific enzyme removes two hydroxides (OH), one from the monosaccharide, and one from the polysaccharide, creating a bond between the two monosaccharides and creating a hydrogen peroxide (H2O2) molecule.

A specific enzyme removes the hydrogen (H) from the monosaccharide and the hydroxide (OH) from the polysaccharide, creating a bond between the two and creating a water (H2O) molecule

how water is pulled up through the xylem to the leaves of the plant? A. As water exits the leaf, hydrogen bonding between water molecules pulls more water up from below. B. As water exits the leaf, signals are sent to the roots to pump more water up to the leaves through the xylem by adhesion. C. Evaporation from the leaf decreases the hydrogen bonds that form between the water molecules in the xylem, which helps the water molecules to be pulled up the xylem. D. Evaporation of water from the leaf increases the hydrogen bonds that form between water molecules in the air, providing the energy for transport.

As water exits the leaf, hydrogen bonding between water molecules pulls more water up from below.

Molecule 1 represents RNA, and molecule 2 represents DNA. Which of the following best describes a structural similarity between the two molecules shown in Figure 1 that is relevant to their function? A. Both molecules are composed of the same four nucleotides, which allows each molecule to be produced from the same pool of available nucleotides. B. Both molecules are composed of the same type of five-carbon sugar, which allows each molecule to act as a building block for the production of polysaccharides. C. Both molecules contain nucleotides that form base pairs with other nucleotides, which allows each molecule to act as a template in the synthesis of other nucleic acid molecules. D. Both molecules contain nitrogenous bases and phosphate groups, which allows each molecule to be used as a monomer in the synthesis of proteins and lipids.

Both molecules contain nucleotides that form base pairs with other nucleotides, which allows each molecule to act as a template in the synthesis of other nucleic acid molecules.

Which of the following would most likely occur if cattle lost the ability to maintain a colony of microorganisms in their digestive tract? A. Cattle would no longer be able to synthesize cellulose. B. Cattle would have to convert cellulose to starch before digesting it. C. Cattle would have to start producing enzyme B without the help of the bacteria. D. Cattle would no longer be able to use cellulose as a primary source of glucose.

Cattle would no longer be able to use cellulose as a primary source of glucose.

A student wants to modify model 1 so that it represents an RNA double helix instead of a DNA double helix. Of the following possible changes, which would be most effective in making model 1 look more like RNA than DNA? A. Changing the sequence of the base pairs B. Changing the deoxyriboses to riboses by adding −OH groups C. Changing the shapes of the nitrogenous bases to match those shown in model 2 D. Changing the sugar-phosphate backbone to a ribbon, as shown in model 3

Changing the deoxyriboses to riboses by adding −OH groups

examples of nucleic acids

DNA,RNA

polar

Molecule with partial charges. Mixes with water.

nonpolar

No partial charges. Do not mix with water.

Which of the following describes a key difference among the 20 amino acids that are used to make proteins? A. Only some amino acids have an R-group. B. Only some amino acids have a carboxyl group (COOH). C. Some amino acids are hydrophobic. D. Some amino acids contain the element phosphorus.

Some amino acids are hydrophobic.

Table 1. Effect of Enzymes A and B on Cellulose and Starch Test Tube- Polysaccharide Added- Enzyme Added - Glucose Detected after 5 Minutes at 37°C 1 Cellulose A No 2 Cellulose B Yes 3 Starch A Yes 4 Starch B No Mammals do not produce digestive enzyme B. However, sheep and cattle are two types of mammals that contain microorganisms in their digestive tract that produce enzyme B. Based on Figure 1, which of the following best compares the atomic structures of starch and cellulose? A. Starch is composed of carbon, hydrogen, and oxygen, while cellulose also contains nitrogen. B. Starch and cellulose are composed of repeating glucose monomers; however, in cellulose every other glucose monomer is rotated 180 degrees. C. Starch is composed of monomers that each have a CH2OH group, while cellulose only has a CH2OH group on every other monomer. D. Starch and cellulose are composed of identical monomers and therefore have identical structures.

Starch and cellulose are composed of repeating glucose monomers; however, in cellulose every other glucose monomer is rotated 180 degrees.

peptide bond

The chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid

Mammals do not produce digestive enzyme B. However, sheep and cattle are two types of mammals that contain microorganisms in their digestive tract that produce enzyme B. Based the information provided, which of the following statements best describes why starch and cellulose provide different functions in plants? A. The differences in the assembly and organization of the monomers of these two polymers result in different chemical properties. B. Since starch and cellulose are composed of identical monomers, the cellular environment where they are located controls their function. C. The monomers of cellulose are connected by covalent bonds, making it idea for structural support. D. The monomers of starch are connected by ionic bonds, making it ideal for energy storage for plants.

The differences in the assembly and organization of the monomers of these two polymers result in different chemical properties.

organic compound composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio

carbohydrate

Which of the following is the most likely reason for the difference in leaf growth (phosphorus starved was smaller than phosphorus sufficient? A. The phosphorus-starved plant was unable to synthesize both the required proteins and lipids, limiting growth. B. The phosphorus-starved plant was unable to synthesize both the required proteins and carbohydrates, limiting growth. C. The phosphorus-starved plant was unable to synthesize both the required nucleic acids and lipids, limiting growth. D. The phosphorus-starved plant was unable to synthesize both the required carbohydrates and nucleic acids, limiting growth.

The phosphorus-starved plant was unable to synthesize both the required nucleic acids and lipids, limiting growth

part of complete enzyme; non-protein

coenzyme

Which of the following best describes how the structure of ice benefits the organisms that live in the water below? A.The water molecules in ice are closer together than those in liquid water, so the ice prevents the passage of air to the water, maintaining a constant gas mixture in the water. B. The water molecules in ice are closer together than those in liquid water, so the ice forms a barrier that protects the organisms in the water from the freezing air temperatures. C. The water molecules in ice are farther apart than those in liquid water, so the ice floats, maintaining the warmer, denser water at the lake bottom. D. The water molecules in ice are farther apart than those in liquid water, so the ice floats, preventing the escape of gases from the liquid water.

The water molecules in ice are farther apart than those in liquid water, so the ice floats, maintaining the warmer, denser water at the lake bottom.

Chitin, a modified form of cellulose, is not only cross-linked with proteins but its glucose molecules are modified with atoms of

nitrogen

allosteric inhibitor binds here; changes enzyme shape

non-catalytic binding site

hydrophobic

not water soluble

monomers of nucleic acid

nucleotides (sugar, phosphate, and nitrogen bases)

The figure presents the flat structure of a three-nucleotide D N A molecule, with pentagons representing the pentose sugar and circles representing the phosphate group. Nitrogenous bases are attached to the sugar-phosphate backbones, and hydrogen bonds between the pairs of nitrogenous bases connect the two strands. The bottom of the left strand of the molecule is labeled 3 prime, and the bottom of the right strand is labeled 5 prime. From top to bottom, adenine on the left strand is bonded to thymine on the right, guanine on the left is bonded to cytosine on the right, and thymine on the left is bonded to adenine on the right, through a bond labeled X. On the left strand, the bond between the sugar and the phosphate that connect the second and third nucleotides is labeled W. On the right strand, the bond connecting the sugar of the middle nucleotide with cytosine to the phosphate of the top nucleotide with thymine is labeled Y. Also on the right side, the bond connecting the phosphate of the middle nucleotide with cytosine to the sugar of the bottom nucleotide with adenine is labeled Z. Figure 1 represents a segment of DNA. Radiation can damage the nucleotides in a DNA molecule. To repair some types of damage, a single nucleotide can be removed from a DNA molecule and replaced with an undamaged nucleotide. Which of the four labeled bonds in Figure 1 could be broken to remove and replace the cytosine nucleotide without affecting the biological information coded in the DNA molecule? A. Bond X only B. Bond W only C. Bonds Y and Z at the same time D. Bonds W and Z at the same time

Bonds Y and Z at the same time

A short segment of a double-stranded nucleic acid molecule Which of the following statements is correct about the molecule shown in Figure 1 ? A. It is RNA because of the relative direction of the two strands. B. It is RNA because of the number of different nucleotides found in the molecule. C. It is DNA because of the nature of the hydrogen bonds between guanine and cytosine. D. It is DNA because of the nucleotides present.

It is DNA because of the nucleotides present.

Two figures are presented. Figure 1 presents the Original Amino Acid Chain, with an aspartic acid on the left, followed by a cysteine, followed by a lysine. Aspartic acid has a negative 1 charge on its R group, cysteine has an uncharged R group composed of a carbon atom bonded to two hydrogen atoms and an S H group, and lysine has a positive 1 charge on its R group. Figure 2 presents the Mutated Amino Acid Chain, with an aspartic acid on the left, followed by a valine, followed by a lysine. Aspartic acid has a negative 1 charge on its R group, valine has an uncharged R group composed of a carbon atom bonded to one hydrogen atom and two C H 3 groups, and lysine has a positive 1 charge on its R group. How might this change affect the structure and function of the protein? A. The R-group of the new amino acid, valine, has different chemical properties than the R-group of cysteine. This will cause the protein to misfold and not function properly in the cell. B. The new amino acid, valine, has replaced cysteine in the new protein. Since the number of amino acids has remained the same, there will be no change in the three-dimensional folding, or function, of the protein. C. Since this is a linear section, it does not influence protein folding. Thus, there will be no change in protein structure or function. D. Since the new amino acid is bounded on one side by an amino acid with a negatively charged R-group and by an amino acid on the other side with a positively charged R-group, the charges will balance and the protein will fold as usual.

The R-group of the new amino acid, valine, has different chemical properties than the R-group of cysteine. This will cause the protein to misfold and not function properly in the cell.

an amino acid must have which of the following properties in order to be incorporated into a polypeptide? A. The ability to remain stable in the presence of water molecules B. An R-group that is compatible with the R-group of the last amino acid incorporated C. A central carbon atom that reacts with a nitrogen atom to form the peptide bond D. The ability to form a covalent bond with both its NH2 group and its COOH group

The ability to form a covalent bond with both its NH2 group and its COOH group

monomers of lipids

glycerol and fatty acids

what are phospholipids made out of

head- glycerol tail- fatty acids

examples of proteins

hemoglobin, pepsin

function of nucleic acids

heredity, code for amino acid sequence

what makes up a phospholipid

hydrophilic head and hydrophobic tail

Model 1 presents a relatively detailed but flat model of DNA, with alternating pentagons and circles representing the DNA backbone. A nitrogenous base is attached to each pentagon. A dotted outline around one circle, one pentagon, and one nitrogenous base is labeled Nucleotide. Hydrogen bonds between nitrogenous bases on the separate strands connect the two strands of nucleotides. The bottom left and top right ends of the strands are labeled 3 prime ends, and the bottom right and top left ends are labeled 5 prime ends. Model 2 presents a more simplified and also flat model of DNA, with the DNA backbones represented as long narrow rectangles. Pairs of nucleotides attached to the backbones hold the two strands together. Model 3 presents a yet more simplified model of DNA, showing a coiled DNA helix. The DNA backbone is shown as a ribbon, and narrow rectangular poles, shaded to represent the different nitrogenous bases, represent pairs of nucleotides connecting the two strands. Which feature of model 1 best illustrates how biological information is coded in a DNA molecule? A. The 5′ and 3′ labels at the ends of each strand B. The labeling of the hydrogen bonds between base pairs C. The lines connecting sugars and phosphate groups that represent covalent bonds D. The linear sequence of the base pairs

The linear sequence of the base pairs

what are polymers made out of

monomers

dehydration reaction

monomers to polymers the two are joined by REMOVING an H2O

monomer of carbohydrates

monosaccharides

denature

a protein when it loses its shape and ability to function

raw material binds here and is converted to product

active site

three terms associated with the travel of water up the roots through the vascular system of plants are

adhesion, cohesion, transpiration

monomers of proteins

amino acids

The term oxidation is derived from the name of the element oxygen. This is appropriate because it:

attracts electrons very strongly

When does ionic bonding occur?

between a metal and a non-metal

function of phospholipids

bilayer of cell membrane

Product of dehydration synthesis

disaccharide

most protein enzymes are

globular proteins

What characterizes RNA?

phosphate, ribose, and uracil

Found in bilayer in cell membrane

phospholipid

One or occasionally more; main constituent of an enzyme

polypeptide

globular proteins

proteins that are water soluble

When an atom gains one or more electrons, it is said to be

reduced

active site

region of enzyme that binds to substrate and aids in chemical reaction

Differ in arrangement of atoms around double bonds

structural isomers

substance on which the enzyme works; raw material of the reaction

substrate

examples of carbohydrates

sugars, starch, cellulose, glycogen

Denaturation cannot be caused by

transportation from one cell to another

hydrolysis reaction

water is ADDED to split large molecules

hydrophilic

water soluble

When do polar covalent bonds form?

when atoms pull on electrons in a molecule unequally