AP Biology Chapter 1
Use the ruler shown above to determine the Rf value of xanthophyll. Show your calculations.
(d)pigment/(d)pigment; calculation 3.5/7.5= 0.5
Which of the following is most directly responsible for water's unique properties?
It forms hydrogen bonds.
Cyanide in seeds is only released and tasted if the seed is crushed... Based on the chemical structure of cyanide, identify ONE type of biological macromolecule that could serve as a chemical precursor for the production of cyanide in a plant. Justify your choice.
Proteins, because Nitrogen is only found in 2 classes of macromolecules.
Which of the following best describes a structural difference between DNA and RNA?
The backbone of DNA contains deoxyribose, whereas the backbone of RNA contains ribose.
what group carries genetic code?
nucleic acids
which of the following best describes how the properties of water at an air-water interface enable an insect to walk on the water's surface?
Hydrogen bonds between molecules at the surface of the water provide surface tension, which allows the water surface to deform but not break under the insect.
A difference between prokaryotes and eukaryotes is seen in the organization of their genetic material. Discuss the organization of the genetic material in prokaryotes and eukaryotes.
In a prokaryote, there are no introns or histones, the shape is circular with supercoiled DNA, plasmids are common, and they are not located in the nucleus. Contrarily, in a eukaryote, there are introns and histones, the shape is linear with chromatin DNA, plasmids are rare, and they are located in the nucleus, unlike a prokaryote.
The graph above shows the initial rate of an enzyme-catalyzed reaction at different substrate concentrations in the presence of a constant concentration of the enzyme. Connect the primary structure of the enzyme to its overall shape.
The amino acid sequence determines the overall shape (of the polypeptide/protein/enzyme) and R- groups interact and stabilize the structure.
Which of the following statements best describes how molecules released by the fish become nutrients for the plants?
The ammonia molecules released by the fish are converted by the bacteria to nitrates, which are used by the plants to make proteins and nucleic acids.
Which of the following best describes the effect of a greater number of cysteine amino acids on the stability of the proteins?
The change leads to increased protein stability because of an increased number of S-S bonds in the tertiary structure of the proteins.
Bacteriophages are viruses that infect bacteria. In an experiment, bacteriophages were labeled with either radioactive phosphorus or radioactive sulfur. The labeled bacteriophages were incubated with bacteria for a brief amount of time and then removed. The infected bacteria cells were found to contain significant amounts of radioactive phosphorus but not radioactive sulfur. Based on the results of the experiment, which of the following types of molecules did the bacteriophages most likely inject into the bacteria cells?
DNA
Which of the following is responsible for the cohesive property of water?
Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule
The diagram shows water molecules as solid ice at 0°C and as a liquid at 25°C. (a) Describe why hydrogen bonds form between water molecules.
A slightly negatively charged O atom in one water molecule is attracted to one of the slightly positively charged H atoms in another water molecule, so that a weak hydrogen bond forms between the two water molecules.
A processed eukaryotic mRNA... (c) Fill in the boxes in the template to identify the nucleotide sequence, from 3′ to 5′, of the tRNA anticodon that will recognize codon 5 and the tRNA anticodon that will recognize codon 510 of the mRNA template and to identify the amino acids that will be added at these two positions. A codon table is provided for reference.
Codon 5, the anticodon sequence is GCC and the amino acid added is arginine (Arg ). The response also indicates that for codon 510, there will be no tRNA with a complementary anticodon because UAG in the mRNA is a translation stop sequence, and no amino acid will be added/translation terminates.
To explain the movement of DNA fragments in the comet assay, identify one property of DNA and provide reasoning to support how the property contributes to the movement during the comet assay technique.
DNA can be different sizes, and different sized DNA fragments move at different rates.
The CFTR protein is made up of 1,480 amino acids linked together in a chain. Some humans produce a version of the CFTR protein in which phenylalanine (an amino acid) has been deleted from position 508 of the amino acid chain. Which of the following best predicts how the amino acid deletion will affect the structure of the CFTR protein?
It will affect the primary, secondary, and tertiary structures of the CFTR protein.
A processed eukaryotic mRNA... (d) Referring to the figures provided, explain why the polypeptide produced when the transformed bacteria translate the introduced eukaryotic mRNA provides evidence for the common ancestry of all living organisms.
Polypeptides produced by translation of a processed eukaryotic mRNA by a eukaryotic cell or a prokaryotic cell into which it has been introduced should have the same amino acid sequence because the genetic code is almost universal and the same codon chart can be used for both prokaryotic and eukaryotic organisms.
Which of the following statements best describes how organisms such as rabbits obtain the carbon necessary for building biological molecules?
Rabbits eat plants and break down plant molecules to obtain carbon and other atoms that they rearrange into new carbon-containing molecules.
A processed eukaryotic mRNA... (b) Referring to Figure 1, explain the process illustrated between Step 1 and Step 2.
Steps 1-2 are the growing polypeptide chain attached to the tRNA aligned with codon 3 of the mRNA is transferred to the amino ( NH2) terminus of amino acid 4 ( AA4) attached to the aligned with codon 4 of the mRNA.
The carbohydrates glucose, galactose, and fructose have the same chemical formula (C6H12O6) but different structural formulas, which of the following statements about glucose, galactose, and fructose is most likely true?
The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, and oxygen atoms.
Proteins-large complex molecules-are major building blocks of all living organisms. Discuss the following in relation to proteins. The chemical composition and levels of structure of proteins
The chemical composition of proteins includes amino acids, R-groups, and a carboxylic acid group. The structure of proteins includes the primary, secondary, tertiary, and quaternary levels. The primary structure is a sequence of amino acids linked by peptide bonds bonded through dehydration synthesis. The secondary structure is a helix or pleated sheet mad eof hydrogen bonds between the carboxyl and amino groups. The tertiary structure is a single polypeptide chain that forms a globular shape bonded by hydrogen, ionic, disulfide, and van der Waals bonds or hydrophobic interactions and the interaction between R-groups. Finally, the quaternary structure is more than one polypeptide bonded by hydrogen, ionic, disulfide, and van der Waals bonds or hydrophobic interactions and the interaction between R-groups.
Which statement best helps explain the formation of the hydrogen bond represented in the figure?
The hydrogen attached to the oxygen has a partial negative charge, and the nitrogen also has a partial negative charge.
Water is important for all living organisms. The functions of water are directly related to its physical properties. Describe how the properties of water contribute to TWO of the following: transpiration, thermoregulation in endotherms, and plasma membrane structure
The polarity and cohesiveness of water contribute to transpiration by controlling water movement; also, the high heat of vaporization of water contribute to transpiration by reducing water loss. Moreover, the polarity of water contributes to the plasma membrane by determining the arrangement of phospholipids.
Structure of Carbohydrates
They occur as monomers, chains of monomers, and branched structures.
A processed eukaryotic mRNA... (a) Describe why translation of an mRNA can start before transcription of the mRNA is complete in prokaryotes but not in eukaryotes.
This is because prokaryotes do not have a nuclear envelope that separates the genome from ribosomes in the cytoplasm of the cell, whereas eukaryotes do.
The synthesis of a protein or carbohydrate polymers always produces which of the following as a byproduct?
Water
A student analyzed a viral genome and found that the genome had the following nucleotide composition. • 28% adenine • 20% thymine • 35% cytosine • 17% guanine Which of the following best describes the structure of the viral genome?
single-stranded DNA
Which of the following characteristics of Figure 1 best shows that the fragment is RNA and not DNA?
the identity of the nitrogenous base
The physical structure of a protein often reflects and affects its function. Describe THREE types of chemical bonds/interactions found in proteins. For each type, describe its role in determining protein structure.
A covalent peptide bond in proteins has linking amino acids together and shared electrons which determine the amino acid sequence (primary structure). Also, a hydrophobic bond is made of nonpolar R-groups which determines the tertiary or quaternary structure; oppositely, an ionic bond has charged R-groups which also help determine the tertiary or quaternary structure.
The diagram shows water molecules as solid ice at 0°C and as a liquid at 25°C. (b) Explain why the arrangement of water molecules is different in ice and water.
As the water cools, the water molecules slow down and, as a result, the hydrogen bonds between them become more stable. Hence, as ice forms the hydrogen bonds cause the water molecules to space out in a crystalline form. Since the liquid water molecules are at a greater temperature, the molecules are moving more rapidly and are constantly forming and breaking their hydrogen bonds.
The stems and fruits of pineapple plants contain a group of protein-digesting enzymes ... (b) Bromelain works by breaking the enzymes that cause browning into smaller molecules. Explain how the reaction that breaks up the enzymes occurs.
Bromelain breaks the bond between amino acids by using water as a reactant.
Membranes are essential components of all cells. Identify THREE macromolecules that are components of the plasma membrane in a eukaryotic cell and discuss the structure and function of each.
In eukaryotic cells, phospholipids are components of the plasma membrane, and they include: glycerol, two fatty acids, and a polar head group; they form a lipid bilayer, creates fluidity and compartments, and signals. Another component is cholesterol, and this includes: a ring structure, steroid, and is embedded in bilayer; it moderates fluidity and stabilizes the membrane. Also, proteins are components as well, and they include polypeptides and amino acids; they transport, signal transduction, and help with recognition.
which molecule is likely to be solid at room temperature?
Palmitic acid, because the absence of carbon-carbon double bonds allows the molecules to pack closely together.
The diagram shows water molecules as solid ice at 0°C and as a liquid at 25°C. (d) The arrangement of the water molecules in ice causes the ice to float. Explain how ice floating on the surface of a body of water affects the water in a way that is beneficial to the organisms in it
The floating ice will reduce heat loss from the water below the ice, resulting in warmer water that is not likely to freeze to the bottom of the body of water.
Which of the following best describes how amino acids affect the tertiary structure of a protein?
The interactions of the different R -groups with other R -groups and with their environment determine the tertiary structure of the protein.
In a different experiment, cells are treated with a chemical mutagen that causes only nucleotide substitutions in DNA. Predict the likely results of a comet assay for this treatment.
The results would end with just a head with no tail or the tail will be shorter than the double-stranded breaks in the DNA.
For the following complex structures, describe the smaller units, their assembly into the larger structures, and one major function of these larger, organized structures. An enzyme
They are made of proteins which are made of amino acids. The function of them is to lower activation energy, the R-group interactions form active sites, and they increase the reaction rate
Water is essential to all living things. Discuss THREE properties of water.
Water has many unique properties one being its high specific heat hence water can take a lot of heat without temperature change. Another one is the water's cohesive property meaning water can attract to other water molecules because of the polarity and water has an increased surface tension compared to other substances. Contrarily, the water's adhesive property is also unique because water can stick to any other molecules that are polar or have a charge.
The stems and fruits of pineapple plants contain a group of protein-digesting enzymes ... (a) Identify the type of monomer of which this enzyme is composed.
amino acids
A feature of organic compounds NOT found in inorganic compounds is the presence of
carbon atoms covalently bonded to each other
The stems and fruits of pineapple plants contain a group of protein-digesting enzymes ... (c) The pH of a solution determines the charge of certain R groups. The pH of pineapple fruit ranges from 3.5 to 5.2. Predict the effect on the activity of bromelain if it is used in a product with a pH of 11.
changes in pH will affect the interactions between amino acid in the enzyme, which will change the folding of the enzyme and thus change its shape and ultimately its function.
