Biology Midterm Samples (Gonzalez)
Maltose is a disaccharide consisting of glucose monomers. What is the balanced chemical reaction that expresses the biosynthesis of maltose?
1 glucose + 1 glucose → 1 water + 1 maltose
Which structures are hexoses?
2, 3, and 4
If a somatic cell has 32 chromosomes prior to S and undergoes mitosis followed by cytokinesis, each new daughter cell will have how many chromosomes?
32
In the human, the body cells (non-sex cells) contain two sets of chromosomes totaling
46
Which of the following correctly illustrates a dipeptide and an amino acid in the optimal position to form a tripeptide?
A
the primary level of protein structure is determined by information contained here.
A
Chargaff's rules for the pairing of nitrogenous bases is
A pairs with T and G pairs with C.
Which of the following effects is produced by the high surface tension of water?
A water strider can walk across the surface of a small pond
After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of _____.
ATP
Since membranes are relatively impermeable to ions, most of the protons re-enter the matrix by passing through special channels in the inner mitochondrial membrane. Because of the inward flow of protons these channels allow the synthesis of
ATP from ADP and Pi
Which of the following is the driving force for active transport?
ATP hydrolysis
The citric acid cycle begins with
Acetyl CoA
Which of the following is NOT a property of carbon?
All compounds made from carbon are soluble in water
Microtubules become shorter, pulling chromatids to the ends of the spindle, during
Anaphase
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
As a disaccharide
contains newly synthesized protein.
B
Which of the following elements are in the same period?
Be, C, N, O
How is water involved in the synthesis of a triglyceride compared to its involvement in the synthesis of a disaccharide?
Both produce water as a product, but more water is produced per triglyceride molecule than per disaccharide molecule.
At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acid?
C
The formula for Ribose is, C5H10O5 What is the correct formula for deoxyribose?
C5 H10 O4
Which of the following is an enzyme?
Catalase
How do competitive and noncompetitive enzyme inhibitors differ?
Competitive inhibitors bind to the active site, whereas noncompetitive inhibitors may change the shape of the active site.
Glycolysis occurs here
Cytoplasm of the cell
As the two strands of DNA are unraveled, an enzyme relieves the strain on the two strands. The enzyme is
DNA gyrase
The enzyme that catalyzes the synthesis of new DNA molecules is called
DNA polymerase
Which reaction is used to form a triglyceride?
Dehydration synthesis
Which drawing in the figure above depicts the electron configuration of an element with chemical properties most similar to Argon?
E
Why is each element unique and different from other elements in chemical properties?
Each element has a unique number of protons in its nucleus
All of the following are true regarding eukaryotic DNA EXCEPT:
Every nitrogenous base in the molecule has encoded information for protein synthesis.
The coenzyme electron carriers produced in the Krebs cycle are
FADH2 and NADH.
Which one of the following represents the interphase?
G1 + S+G2
Dehydration synthesis involves...
Gaining water to create a peptide bond
Before starch can be used for respiratory ATP production, it must be hydrolyzed to
Glucose
Which of the following is a monomer?
Glucose
Which of the following is a part of a triglyceride?
Glycerol
Which of the following is not a monosaccharide?
Glycogen
Which of the following sequences correctly describes cellular respiration?
Glycolysis, Bridge step, Krebs Cycle, oxidative phosphorylation
What type of bond holds monosaccharides together in a polysaccharide?
Glycosidic bond
Which element does not follow the octet rule?
Hydrogen
____ bonds form between complementary bases in the DNA molecule.
Hydrogen
Why does ice float in liquid water?
Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water decreasing the density.
Chromosomes have centromeres and when chromosomes are replicated they are called sister chromatids. Which statement is accurate?
In humans somatic cells there are 46 chromosomes and thus 46 centromeres. When replicated there are 92 sister chromatids and 46 centromeres.
Location of the ATP synthase molecule
Inner Membrane
Electron Transport Chain is located here
Intermembrane space
Holds table salt (NaCl) together
Ionic bonds
The bond between cations and anions
Ionic bonds
Order the following forces from strongest (1) to weakest (4).
Ionic bonds 1 Covalent bonds 2 Hydrogen bonds 3 van der waals forces 4
An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements?
It would form ions with a +2 charge.
What is used to break down the sugar lactose?
Lactase
The figures show structures of amino acids, which are small biological molecules found in living cells. Each amino acid has a unique side chain, shown in the boxed portion of each figure. Which amino acid or acids have hydrophobic side chains?
Leucine and phenylalanine
Patients with sickle cell anemia exhibit a natural resistance to which of the following mosquito-born diseases?
Malaria
Krebs Cylce occurs here
Matrix
Found between atoms of metals
Metallic bonds
In the figure, why does the reaction rate plateau at higher reactant concentrations?
Most enzyme molecules are occupied by substrate at high reactant concentrations
All of the following are the end products of glycolysis EXCEPT:
NAD+
Regardless of the fermentation pathway employed, fermentation always produces
NAD+
After completion of the citric acid cycle, most of the potential energy from the original glucose molecule is in the form of _____.
NADH
Which of the following is produced during the citric acid cycle?
NADH and FADH2
1. How do (1) temperature and (2) pH affect the activity of this enzyme? 2. A discussion of the relationship between the structure and the function of this enzyme, as well as a discussion of how the structure and function of enzymes are affected by temperature and pH
NOT DONE
Proteins are arguably the basic "stuff of life", with other molecules having simply supporting roles. The array of different proteins found in the array of creatures on Earth is staggering. What properties of proteins account for this tremendous diversity in form and function? What similarities do all proteins share? Explain.
NOT DONE
why is an embedded protein is necessary to move glucose across a membrane?
NOT DONE
Which element requires two additional electrons to fill the outermost electron shell?
Oxygen
If my body were unable to create peptide bonds, I'd be in trouble because...
Peptide bonds are necessary for creating proteins
Which of the following is not found in an amino acid?
Phosphate group
The sugar-phosphate backbone of a DNA double helix is joined together by ________ bonds.
Phosphodiester
Ribosomes are made up of
RNA and proteins
When placed in a hypertonic solution, animal cells
Shrink
What is meant by the description "antiparallel" regarding the strands that make up DNA?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
If free, radioactively labeled adenine nucleotides are applied to a cell prior to S in the cell cycle, what might be a logical prediction of the outcome?
The DNA replication would proceed and the labeled adenine would be detected in both the sister chromatids.
You are doing a summer internship in a cell biology lab. Your supervisor asks you to change the medium on some cells she is growing. You do so and then examine the cells under a microscope. To your dismay, you can't find any cells and see only what looks like cell debris. What most likely happened to your cells and why?
The cells burst because the new medium was hypotonic to the cells.
The ATP synthase in a human cell obtains energy for making ATP directly from which of the following processes?
The flow of H+ across a membrane through the ATP synthase enzyme
The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil?
The hydrogenated vegetable oil stays solid at room temperature
If all the lysosomes within a cell suddenly ruptured, what would be the most likely result?
The macromolecules in the cytosol would break down
If a drop of red ink is placed in one end of a shallow pan filled with water, and a drop of green ink is placed in the other end, which of the following will be true at equilibrium?
The red and green inks will be uniformly distributed throughout the pan.
In humans the diploid number of chromosomes is 46. The haploid number is 23. Prior to mitosis in the cell cycle, the cell is in the G2 phase. Choose the correct statement regarding this cell in the G2 phase:
The sister chromatids have all been copied through DNA replication and are now sister chromatids.
Which of the following statements concerning saturated fats is not true?
They have multiple double bonds in the carbon chains of their fatty acids
Could two atoms of oxygen engage in ionic bonding? Why or why not?
Two atoms of oxygen can not engage in ionic bonding because they have the same electronegativity meaning that neither of the atoms have an electrons to give or receive because their valance shells are full.
The double helix model was proposed by
Watson and Crick
Examine the diagram below. R and F represent the same polypeptides under different conditions.
Y could represent no change in environment
Most cells are small because
a larger surface area-to-volume ratio increases the efficiency of processes within the cell.
Amino acids differ from each other in their "R" groups, but every amino acid contains all of the following features EXCEPT
a phosphate group
Three fatty acids bonded together with a glycerol are found in
a triglyceride
During the energy-investing portion of glycolysis, the phosphates from ATP molecules are
added to the first and sixth carbons of glucose
The peroxisome gets its name from its interaction with hydrogen peroxide. If a liver cell is detoxifying alcohol and some other poisons, it does so by removal of hydrogen from the molecules. What, then, do the enzymes of the peroxisome do?
aid in the transfer the hydrogens to oxygen molecules
Relatively small organic molecules with a central carbon atom which is bonded to a carboxyl group, an amino group, a carbon-containing group, and a hydrogen atom are called
amino acids.
Glucose is to starch as:
an amino acid is to a protein
When an atom donates an electron to another atom, it becomes
an ion
Microfilaments
are composed of actin monomers.
Lipids differ from polysaccharides in that they
are insoluble in water
During aerobic respiration, molecular oxygen (O2 ) is used for which of the following purposes?
at the end of the electron transport chain to accept electrons and form H2O
A noncompetitive inhibitor may inhibit binding of a substrate to an enzyme by
binding to an allosteric site
Competitive inhibitors of enzymes work by
binding to the active site
The three elements in a monosaccharide are
carbon, hydrogen, and oxygen
The function of NAD+ is to
carry hydrogen atoms and free energy from compounds being oxidized, and to give hydrogen atoms and free energy to compounds being reduced
Which of the following is NOT one of the functions typically associated with a type of lipid?
catalysis of metabolic reactions
The positions indicated by the letters X Y and Z represent
checkpoints where signals to continue or halt cell division are recognized.
Which of the following elements are not found in proteins?
chlorine
In order for a reaction to occur, many enzymes require ATP and ADP, which temporarily bind to and then release from the substrate. ATP and ADP are therefore considered to be
coenzymes
The best conclusion concerning delta is that the cells
contain no DNA
Found between atoms of nonmetals
covalent bonds
You watch an amoeba in culture moving along the bottom of the dish, constantly changing its shape. This change in shape is due primarily to changes in the _______ of the amoeba.
cytoskeleton
AB --> A + B is a general notation for a(n) ________ reaction.
decomposition
If acid was added to a solution of pH 4, the pH would increase or decrease?
decrease
There are 20 different amino acids. What makes one amino acid different from another?
different side chains (R groups) attached to an central carbon
Ions diffuse across membranes through specific ion channels
down their electrochemical gradients
Which components of an atom do not add significantly to its mass?
electron
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step _____.
enables the cell to recycle NAD+
Proteins serve all of the following functions EXCEPT:
encode genetic information
________ reactions release energy.
exothermic
Sickle cell anemia is an autosomal recessive disease, meaning that if you received the gene from only one of your parents you will exhibit all signs and symptoms of the disease.
false
Which part of a phospholipid does not mix with water?
fatty acid tail
In the absence of oxygen, hydrogen atoms bound to NAD+ during glycolysis are donated to organic molecules, creating free NAD+ again. This process occurs during
fermentation
Of the following, the best conclusion concerning the difference between the S phases for beta and gamma is that
gamma contains more DNA than beta
Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?
gaps left at the 3' end of the lagging strand because of the need for a primer
In all cells, glucose metabolism begins with
glycolysis
Information obtained by Franklin from X-ray crystallography of DNA suggested that it is a
helix
Which of the following combinations of atoms is most likely to form a chemical bond?
hydrogen and hydrogen
DNA consists of two antiparallel strands of nucleotide chains held together by
hydrogen bonds
Which type of bond must be broken for ice to turn to liquid water?
hydrogen bonds
Which reaction breaks down polymers?
hydrolysis
If base were added to a solution of pH 9, the pH would increase or decrease?
increase
Your hair and fingernails are made up of flattened layers of dead cells. These dead cells are tough and resistant to physical damage because they are filled with
intermediate filaments made up primarily of keratin proteins.
A bond formed by the attraction between oppositely charged ions is called a(n) _____.
ionic bonding
Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumor?
lack of appropriate cell death (apoptosis)
If an individual has abnormal microtubules, due to a hereditary condition, in which organs or tissues would you expect dysfunction?
limbs, hearts, areas with a good deal of contraction
Hydrolytic enzymes must be segregated and packaged to prevent the general destruction of cellular components. Which of the following organelles contains these hydrolytic enzymes in animal cells?
lysosome
Telomerase is associated with
maintaining intact ends of linear chromosomes
Polymerization (the formation of polymers) is a process that
may involve all answer choices
A primary function of polysaccharides attached to glycoproteins and glycolipids of animal cell membranes is to
mediate cell-to-cell recognition, communication.
Imagine looking through a microscope at a squashed onion root tip. The chromosomes of many of the cells are plainly visible. In some cells, replicated chromosomes are aligned along the center (equator) of the cell. These particular cells are in which stage of mitosis?
metaphase
Compared with fermentation, the aerobic pathways of glucose metabolism produce
more ATP
A large organelle found in eukaryotic cells that genetically controls the cell's activities is the
nucleus
A covalent bond is likely to be polar when
one of the atoms sharing electrons is much more electronegative than the other atom.
In a Lewis structure, what does the line represent?
one pair of electrons
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?
oxidation of pyruvate to acetyl CoA (bridge step) and the citric acid cycle.
Watson and Crick determined ________ bonds were used to join the phosphates and sugars that formed the "sides" of the double helix, while ______ bonds were used to join the nitrogen bases which formed the "rungs" of the double helix.
phosphodiester covalent; hydrogen
A chain of amino acids linked together end-to-end can only be found in a
polypeptide
A cell with a predominance of free ribosomes is most likely
producing primarily cytoplasmic proteins
By the end of this phase of mitosis, the centromere joining each pair of sister chromatids is attached by microtubules to opposite poles of the spindle apparatus. This phase is called
prophase
Chromosomes first become visible during which phase of mitosis?
prophase
Most enzyme molecules are occupied by substrate at high reactant concentrations
proteins
The statement "enzymes are highly specific" means that certain
reactions involving certain substrates are catalyzed by specific enzymes.
When NADH donates two electrons to ubiquinone during respiration, ubiquinone is
reduced
The function of the nuclear pores is to
regulate movement of materials across the nuclear membrane.
The nucleolus functions in the production of
ribosomes
Which of the following structures are only composed of β-pleated sheets and α-helices?
secondary structures
When DNA is replicated during S of the cell cycle, the sequence is maintained but the double strand is not. Each strand of the original double strand accompanies its new complement strand. This process is known as
semiconservative DNA replication
The shortest segment of the cell cycle shown above primarily functions to
separate the cytoplasm into daughter cells.
What kinds of molecules pass through a cell membrane most easily?
small and hydrophobic
Lipid synthesis occurs in which eukaryotic organelle?
smooth ER
The specificity of an enzyme is due to its active site. The active site is shaped so that only a certain
substrate molecule can fit into it
Which element has the same number of outer-shell (valence) electrons as oxygen?
sulfer
The 5' and 3' ends of the DNA strand reflect differences in
the exposed functional groups attached to the deoxyribose sugar.
The existence of a concentration gradient of glucose across a membrane means that
the glucose are more concentrated on one side of the membrane than on the other.
The leading and the lagging strands differ in that
the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction
The partial charges in a water molecules are a result of
the unequal sharing of electrons between the oxygen and hydrogen
Enzymatic reactions can become saturated as substrate concentration increases because
there are a limited number of the enzyme molecules present.
Overall, four molecules of ATP are produced by glycolysis. However, the products of glycolysis are two ATP molecules, two pyruvate molecules, and two NADH molecules. The ATP values do not match because
two ATP are invested in the process of glycolysis
Most ATP produced in our bodies is made
using ATP synthase
The number of chromosomes characteristic of eukaryotes, in general,
vary considerably from species to species.
What is needed to start a hydrolysis reaction?
water