AP Biology - Unit 1 Progress Check: MCQ

Which of the following is common feature of the illustrated reactions showing the linking of monomers to form macromolecules?

C. Monomers are joined by a covalent bond, and a water molecule is produced.

Which of the following describes a key difference among the 20 amino acids that are used to make proteins?

C. Some amino acids are hydrophobic.

The figure shows the results of an experiment to investigate the effects of an enriched CO2 environment on plant growth. Identical plants were separated into different groups and grown either in a standard CO2 environment (400 ppm CO2) or in an enriched CO2 environment (700 ppm CO2). Of the plants in each environment, half were grown under ideal conditions and half were grown under stressed conditions. Based on the figure, which statement best describes the observed relationship between atmospheric CO2 enrichment and plant growth under ideal and stressed conditions?

C. The increase in atmospheric CO2 resulted in a greater increase in plant growth under stressed conditions than under ideal conditions.

Hydroxly

(-OH) at the ends of alcohols that gives polarity and water solubility

Phospholipid

2 Fatty Acids (Tails) and a Phosphate Group with a Glycerol (Head)

A-T

2 Hydrogen Bonds

Triglycerides

3 Fatty Acids, and 1 Glycerol

C-G

3 hydrogen bonds

In vascular plants, water flows from root to leaf via specialized cells called xylem. Xylem cells are hollow cells stacked together like a straw. A student explains that evaporation of water from the leaf pulls water up from the roots through the xylem, as shown in Figure 1. Which statement describes 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.

Figure 1 shows three amino acids that are part of a polypeptide chain. Figure 2 shows the same section of the chain after a mutation has occurred. 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.

Different polysaccharides are used by plants for energy storage and structural support. The molecular structures for two common polysaccharides are shown in Figure 1. Starch is used by plants for energy storage, and cellulose provides structural support for cell walls. The monomer used to construct both molecules is glucose. A study determined the effect of two different digestive enzymes, A and B, on these two polysaccharides. Table 1 presents the data from the study. 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.

Fatty Acids are

Amphipathic

Aldehyde

An organic molecule with a carbonyl group located at the end of the carbon skeleton.

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?

C. Bonds Y and Z at the same time

As shown in the diagram, when environmental temperatures drop below freezing, a layer of ice typically forms on the surface of bodies of freshwater such as lakes and rivers. Which of the following best describes how the structure of ice benefits the organisms that live in the water below?

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.

Keto

C=O

Polysaccharides

Can be easily hydrolysized

Water molecules are polar covalent molecules. There is a partial negative charge near the oxygen atom and partial positive charges near the hydrogen atoms due to the uneven distribution of electrons between the atoms, which results in the formation of hydrogen bonds between water molecules. The polarity of water molecules contributes to many properties of water that are important for biological processes. Which of the following models best demonstrates the arrangement of hydrogen bonds between adjacent water molecules?

D

A polypeptide is polymer of amino acids held together by peptide bonds. The process of dehydration synthesis creates these peptide bonds, as shown in Figure 1. As shown in Figure 1, an amino acid must have which of the following properties in order to be incorporated into a polypeptide?

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

Different polysaccharides are used by plants for energy storage and structural support. The molecular structures for two common polysaccharides are shown in Figure 1. Starch is used by plants for energy storage, and cellulose provides structural support for cell walls. The monomer used to construct both molecules is glucose. A study determined the effect of two different digestive enzymes, A and B, on these two polysaccharides. Table 1 presents the data from the study. 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. Which of the following would most likely occur if cattle lost the ability to maintain a colony of microorganisms in their digestive tract?

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

Figure 1 shows a short segment of a double-stranded nucleic acid molecule. Figure 1. A short segment of a double-stranded nucleic acid molecule Which of the following statements is correct about the molecule shown in Figure 1 ?

D. It is DNA because of the nucleotides present.

Which feature of model 1 best illustrates how biological information is coded in a DNA molecule?

D. The linear sequence of the base pairs

Cellulose

Has the most carbon on the pkanet

Lipids

Insoluble in H20 because of the many non polar covalent bonds (van deer Waals link them together)

Energy

Kinetic and potential

Condensation

Lengthens polymers by subtracting water

Glycogen

Main energy storage in mammals

Nucleic acids bond in condensation to form

Phosphodiester bonds, where the 5 carbon of a ribose and the 3 carbon of a ribose attach

Tertiary structure

Polypeptide chain is bent and fold, 3-D shape

Secondary structure

Regular, repeated spatial patterns in different regions, resulting from H bonding

DNA's purpose is

Replication and information is copied to RNA to instruct amino acid sequence

Ionic interactions

Salt bridges

Primary structure

Sequence of a.a. (All info for the shape is here)

Carbohydrates

Source of stored energy

Spontaneous chemical reactions

Total energy consumed by breaking the bonds is less than energy released by forming the bonds

Quaternary structure

Two or more polypeptide chains bind together by hydrophobic and ionic interactions, as well as H bonds

Disacccharides

formed by glycosidic linkages

Purines (2 rings)

guanine and adenine

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?

B. Changing the deoxyriboses to riboses by adding −OH groups

Different polysaccharides are used by plants for energy storage and structural support. The molecular structures for two common polysaccharides are shown in Figure 1. Starch is used by plants for energy storage, and cellulose provides structural support for cell walls. The monomer used to construct both molecules is glucose. A study determined the effect of two different digestive enzymes, A and B, on these two polysaccharides. Table 1 presents the data from the study. 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?

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

Different polysaccharides are used by plants for energy storage and structural support. The molecular structures for two common polysaccharides are shown in Figure 1. Starch is used by plants for energy storage, and cellulose provides structural support for cell walls. The monomer used to construct both molecules is glucose. A study determined the effect of two different digestive enzymes, A and B, on these two polysaccharides. Table 1 presents the data from the study. 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. Which of the following best describes the process that adds a monosaccharide to an existing polysaccharide?

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.

Which of the following best describes a structural similarity between the two molecules shown in Figure 1 that is relevant to their function?

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.

Phosphorous (P) is an important nutrient for plant growth. Figure 1 shows Arabidopsis thaliana plants grown under phosphorus‐sufficient (left) and phosphorus‐starved (right) conditions for six weeks. Which of the following is the most likely reason for the difference in leaf growth?

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

R Groups and Tertiary Interactions

Disulfide bridged hold polypeptides, hydrogen bonds stabilize folds, hydrophobic chains aggregate the protein interior, van der Waals interactions between hydrophobic side chains

Fibrous proteins

Strong, insoluble, high sulfur % (ex: keratin in nails)

catabolic reactions

breakdown of molecules

Hydrolosis

breaks polymers into monomers by adding a water molecule

anabolic reactions

build up large chemicals and require energy

6 elements of life

carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur

Saturated fatty acids

carbons are all joined by single bonds and are saturated with hydrogen atoms

Pyramidines (1 ring)

cytosine, thymine, uracil

unsaturated fats

one or more double bonds, prevent molecules from packing together

Ions

positively and negatively charged atoms

functional groups

small groups of atoms with specific chemical properties

Electronegativity

the ability of an atom to attract electrons when the atom is in a compound