Biology 201 Final Review
- 1.
All of the flollowing are tenets of the cell theory EXCEPT:
- A.
The cell is the basic unit of structure for all organisms
- B.
All cells arise from preexisting cells
- C.
All cells have a membrane bound nucleus
- D.
All organisms consist of one or more cells
- E.
None of the above
Correct Answer
C. All cells have a membrane bound nucleusExplanation
The correct answer is "All cells have a membrane-bound nucleus." This is because not all cells have a membrane-bound nucleus. Prokaryotic cells, such as bacteria, do not have a nucleus. They have a nucleoid region where their genetic material is located, but it is not surrounded by a membrane. The other statements are all tenets of the cell theory, which state that the cell is the basic unit of structure for all organisms, all cells arise from preexisting cells, and all organisms consist of one or more cells.Rate this question:
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- 2.
Which of the following biological polymers is mismatched with its monomer?
- A.
Protein - Amino Acid
- B.
DNA - Nucleotide
- C.
ATP - Nucleotide
- D.
Starch - Monosaccharide
- E.
Cellulose - Amino Acid
Correct Answer
E. Cellulose - Amino AcidExplanation
Cellulose is a complex carbohydrate and a major component of plant cell walls. It is made up of repeating units of glucose monomers, which are monosaccharides. Therefore, the mismatched pair in the given options is Cellulose - Amino Acid.Rate this question:
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- 3.
Disulfide bonds are often found to stabilize which levels of protein structure?
- A.
Primary
- B.
Secondary
- C.
Tertiary
- D.
All of the above
- E.
None of the above
Correct Answer
C. TertiaryExplanation
Disulfide bonds are covalent bonds formed between two cysteine residues in a protein. These bonds play a crucial role in stabilizing the tertiary structure of proteins. The tertiary structure refers to the three-dimensional arrangement of the protein's secondary structure elements, such as alpha helices and beta sheets. Disulfide bonds can form between different regions of the protein chain, bringing them closer together and providing additional stability. Therefore, the correct answer is "Tertiary."Rate this question:
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- 4.
The primary structure of a protein is
- A.
Important for determining the secondary and tertiary structure of the protein
- B.
The linear sequence of amino acids that are linked together by peptide bonds
- C.
Simply the order of amino acids from one end of the protein to another
- D.
Not altered during denaturation
- E.
All of the above
Correct Answer
E. All of the aboveExplanation
The primary structure of a protein refers to the linear sequence of amino acids that are linked together by peptide bonds. This sequence is important because it determines the secondary and tertiary structure of the protein. Additionally, the primary structure remains unchanged during denaturation, which is the process of unfolding or altering the protein's shape. Therefore, the correct answer is "all of the above" because all of these statements are true regarding the primary structure of a protein.Rate this question:
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- 5.
The alpha helix and beta sheet are found in many proteins because they are formed by
- A.
Hydrogen bonding between the amino acid side chains most commonly found in proteins
- B.
Noncovalent interactions between amino acid side chains and the polypeptide backbone
- C.
Hydrogen bonding between atoms of the polypeptide backbone
- D.
Ionic interactions between charged amino acid side chains
- E.
Hydrophobic interactions between the many nonpolar amino acids
Correct Answer
C. Hydrogen bonding between atoms of the polypeptide backboneExplanation
The alpha helix and beta sheet structures in proteins are formed by hydrogen bonding between atoms of the polypeptide backbone. This backbone consists of repeating units of amino acids, and the hydrogen bonds form between the carbonyl oxygen of one amino acid and the amino hydrogen of another amino acid. These hydrogen bonds stabilize the secondary structures of proteins and play a crucial role in their folding and stability.Rate this question:
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- 6.
The backbone of nucleic acids consists of
- A.
A phosphodiester bond between the 2' and 5' functional groups of neighboring sugars
- B.
A phosphodiester bond between the 3' and 5' functional groups of neighboring sugars
- C.
A glycosidic bond between a pyrimidine and a sugar
- D.
A glycosidic bond between a purine and a sugar
- E.
None of the above
Correct Answer
B. A pHospHodiester bond between the 3' and 5' functional groups of neighboring sugarsExplanation
The backbone of nucleic acids consists of a phosphodiester bond between the 3' and 5' functional groups of neighboring sugars. This is because nucleic acids, such as DNA and RNA, are composed of repeating units called nucleotides. Each nucleotide is made up of a sugar molecule (deoxyribose or ribose), a phosphate group, and a nitrogenous base (adenine, guanine, cytosine, or thymine/uracil). The phosphodiester bond forms between the 3' carbon of one sugar and the 5' carbon of the next sugar, creating a sugar-phosphate backbone that provides stability to the nucleic acid structure.Rate this question:
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- 7.
While synthesizing a new blue pigment, a chemist notices that the compound congregates between an aqueous environment and a hydrophobic environment. When added to a mixture of oil and water, the pigment creates a blue ring around the oil droplets. Which of the following statements best describes the new pigment?
- A.
The pigment is hydrophilic and will not form hydrophobic bonds with the oil
- B.
The pigment is hydrophobic and is attempting to bond with the oil
- C.
The pigment is a polar molecule and is forming hydrogen bonds with both the water and the oil
- D.
The pigment is neither polar nor nonpolar and therefore orients between the two phases
- E.
The pigment is amphipathic
Correct Answer
E. The pigment is ampHipathicExplanation
The given information states that the pigment congregates between an aqueous environment and a hydrophobic environment and creates a blue ring around the oil droplets when added to a mixture of oil and water. This suggests that the pigment has both hydrophilic and hydrophobic properties, allowing it to interact with both water and oil. Therefore, the pigment is considered to be amphipathic, meaning it has both polar and nonpolar regions.Rate this question:
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- 8.
Glucose
- A.
Is a carbohydrate so its molecular formula follows the (CH2O)n pattern
- B.
Is a ketose so it has an aldehyde group at the end of the molecule
- C.
Forms glycosidic bonds with other monosaccharides through condensation reactions
- D.
Polymers can either be linear or branched
Correct Answer(s)
A. Is a carbohydrate so its molecular formula follows the (CH2O)n pattern
C. Forms glycosidic bonds with other monosaccharides through condensation reactions
D. Polymers can either be linear or branchedExplanation
Glucose is a carbohydrate, which means its molecular formula follows the (CH2O)n pattern. This pattern indicates that glucose is composed of carbon, hydrogen, and oxygen atoms in a specific ratio. Additionally, glucose can form glycosidic bonds with other monosaccharides through condensation reactions. This allows glucose to combine with other sugars to form larger carbohydrate molecules. Lastly, glucose polymers can exist in either linear or branched forms, meaning that the glucose molecules can be arranged in a straight chain or have side branches.Rate this question:
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- 9.
A chemical reaction where = +7.67 cal/mol
- A.
Has an equilibrium constant that is less than 1 under standard conditions
- B.
Goes spontaneously to the right under standard conditions
- C.
Requires energy for the reaction to proceed under standard conditions
- D.
Cannot occur in a cell
Correct Answer(s)
A. Has an equilibrium constant that is less than 1 under standard conditions
C. Requires energy for the reaction to proceed under standard conditionsExplanation
The given chemical reaction has an equilibrium constant that is less than 1 under standard conditions, which indicates that the reaction favors the formation of reactants rather than products at equilibrium. This means that the reaction is not spontaneous in the forward direction and requires energy for the reaction to proceed under standard conditions. Since the reaction requires energy, it cannot occur spontaneously in a cell.Rate this question:
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- 10.
A spontaneous reaction
- A.
Will always have a negative value of Delta-G
- B.
Will always be exothermic
- C.
Will always increase the entropy within the reaction system
- D.
Could occur but might take a very long time
Correct Answer(s)
A. Will always have a negative value of Delta-G
D. Could occur but might take a very long timeExplanation
A spontaneous reaction will always have a negative value of Delta-G because Delta-G represents the change in Gibbs free energy, which is a measure of the available energy to do work in a system. A negative value of Delta-G indicates that the reaction releases energy and is thermodynamically favorable. However, a spontaneous reaction could still take a very long time to occur, depending on factors such as the activation energy and the presence of catalysts.Rate this question:
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- 11.
The nucleoside Adenosine
- A.
Is a purine
- B.
Consists of a sugar group, phosphate and nitrogenous base
- C.
Lacks a hydroxyl group on the 3' carbon
- D.
Base pairs with Uradine in RNA
Correct Answer(s)
A. Is a purine
B. Consists of a sugar group, pHospHate and nitrogenous base
D. Base pairs with Uradine in RNAExplanation
Adenosine is a nucleoside that is classified as a purine. It is composed of a sugar group, a phosphate group, and a nitrogenous base. Adenosine lacks a hydroxyl group on the 3' carbon. In RNA, Adenosine base pairs with Uradine.Rate this question:
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- 12.
An unsaturated triacyglyceride
- A.
Contains no double bonds in the fatty acid tail
- B.
Has three fatty acid tails linked to a glycerol molecule through ester linkages
- C.
Is nonpolar and therefore hydrophobic
- D.
Is a phospholipid if a phosphate group replaces one of the fatty acid tails
Correct Answer(s)
B. Has three fatty acid tails linked to a glycerol molecule through ester linkages
C. Is nonpolar and therefore hydropHobic
D. Is a pHospHolipid if a pHospHate group replaces one of the fatty acid tailsExplanation
An unsaturated triacylglyceride is a molecule that contains three fatty acid tails linked to a glycerol molecule through ester linkages. It is nonpolar and therefore hydrophobic, meaning it does not mix well with water. However, if a phosphate group replaces one of the fatty acid tails, it becomes a phospholipid, which is an important component of cell membranes.Rate this question:
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- 13.
One meter is equal to
- A.
10 cm
- B.
10^6 micrometers
- C.
10000 mm
- D.
1*10^9 nm
Correct Answer(s)
B. 10^6 micrometers
D. 1*10^9 nmExplanation
The answer choices provide different units of measurement that are equivalent to one meter. The correct answer is "10^6 micrometers" because one meter is equal to 10^6 micrometers. Similarly, "1*10^9 nm" is also correct as it represents one meter in nanometers. The other answer choices, 10 cm and 10000 mm, are not equivalent to one meter but are commonly used as smaller units of measurement.Rate this question:
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- 14.
This enzye catalyzes the interconversion of relaxed and supercoilded DNA by making transient breaks in the DNA strand
- A.
Helicase
- B.
Topoisomerase
- C.
Ligase
- D.
Polymerase
- E.
Hydrolase
Correct Answer
B. TopoisomeraseExplanation
Topoisomerase is the correct answer because it is an enzyme that is responsible for catalyzing the interconversion of relaxed and supercoiled DNA. It achieves this by making transient breaks in the DNA strand, allowing it to relieve the tension and supercoiling that can occur during DNA replication and transcription. Helicase, ligase, polymerase, and hydrolase are all enzymes involved in DNA replication and repair, but they do not specifically catalyze the interconversion of relaxed and supercoiled DNA like topoisomerase does.Rate this question:
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- 15.
Part of the sequence of the CODING strand of DNA is 5'-CGCATTA-3'. What is the corresponding sequence of the mRNA produced?
- A.
3'-GCGUAAU-5'
- B.
5'-GCGUAAU-3'
- C.
5'-CGCAUUA-3'
- D.
3'-CGCAUUA-5'
- E.
None of these are correct
Correct Answer
C. 5'-CGCAUUA-3'Explanation
The sequence of the mRNA is complementary to the coding strand of DNA. In this case, the coding strand of DNA is 5'-CGCATTA-3', so the corresponding sequence of the mRNA would be 5'-CGCAUUA-3'.Rate this question:
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- 16.
If the mRNA sequence at the "A" site of the ribosomee is GCA, what is the sequence of the corresponding tRNA anticodon that will recognize and bind to the mRNA
- A.
CGU
- B.
CGT
- C.
TGC
- D.
UGC
- E.
None of these are correct
Correct Answer
A. CGUExplanation
The mRNA sequence GCA corresponds to the tRNA anticodon CGU. In the process of translation, the tRNA anticodon pairs with the mRNA codon, allowing the correct amino acid to be added to the growing polypeptide chain. In this case, the tRNA with the anticodon CGU will recognize and bind to the mRNA with the codon GCA, ensuring the correct amino acid is added.Rate this question:
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- 17.
What provides the energy that drives the attachment of amino acids to the appropriate tRNA?
- A.
ATP hydrolysis
- B.
GTP hydrolysis
- C.
Hydrolysis of a high energy peptide bond
- D.
Hydrolysis of a ghigh energy ester bond
- E.
Hydrolysis of a high energy phosphodiester bond
Correct Answer
A. ATP hydrolysisExplanation
ATP hydrolysis provides the energy that drives the attachment of amino acids to the appropriate tRNA. ATP is a high-energy molecule that releases energy when it is broken down into ADP and inorganic phosphate through hydrolysis. This released energy is used to power various cellular processes, including the attachment of amino acids to tRNA molecules during protein synthesis. The energy from ATP hydrolysis allows the aminoacyl-tRNA synthetase enzymes to catalyze the formation of an ester bond between the amino acid and the tRNA molecule, ensuring accurate pairing and attachment of the correct amino acid to the appropriate tRNA.Rate this question:
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- 18.
Imagine a peptide-coding DNA sequence that is 30 nucleotides long. How many amino acids are in the peptide? Asssume the sequence contains the start and stop codons as well
- A.
9
- B.
10
- C.
30
- D.
90
- E.
3^30
Correct Answer
A. 9Explanation
The given DNA sequence is 30 nucleotides long. Each codon consists of 3 nucleotides, so there will be a total of 10 codons in the sequence (30 nucleotides / 3 nucleotides per codon). However, one codon is the start codon and another codon is the stop codon, which do not code for amino acids. Therefore, there will be 10 - 2 = 8 codons that code for amino acids. Since each codon codes for one amino acid, there will be a total of 8 amino acids in the peptide.Rate this question:
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- 19.
For a peptide-coding DNA sequence that is 36 nucleotides long, how many different amino acid sequences could be coded? Assume the sequence contains start and stop codons as well
- A.
3^20
- B.
10^20
- C.
12^20
- D.
20^10
- E.
36^4
Correct Answer
B. 10^20Explanation
The number of different amino acid sequences that could be coded for a peptide-coding DNA sequence that is 36 nucleotides long can be calculated by taking the number of possible nucleotides (4) and raising it to the power of the number of codons (3) in the sequence. This is because each codon consists of three nucleotides and can code for one amino acid. Therefore, the correct answer is 4^3, which is equal to 10^20.Rate this question:
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- 20.
Which are characteristics of the process of transcription
- A.
Bidirectional
- B.
Conservative
- C.
Occurs during the S phase of the cell cycle
- D.
Requires RNA polymerase
Correct Answer(s)
B. Conservative
D. Requires RNA polymeraseExplanation
The process of transcription involves the synthesis of RNA from a DNA template. It is not bidirectional, as it only occurs in one direction from the 3' to 5' end of the DNA strand. It is also not conservative, as it results in the production of a new RNA molecule rather than conserving the original DNA molecule. Transcription does occur during the S phase of the cell cycle, as this is when DNA replication takes place and the DNA template is available for transcription. Additionally, transcription requires RNA polymerase, an enzyme that catalyzes the formation of RNA molecules.Rate this question:
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- 21.
Which are characteristics of tRna?
- A.
Peptidyl transferase catalyzes the attachment of each amino acid to the appropriate tRNA
- B.
Initiator tRNAs in Prokaryotes carry a modified form of methionine containing a fomyl group
- C.
There are no tRNAs that recognize the mRNA sequence, UAA
- D.
Folding of the tRNA requires localized regions of hydrogen bonding
Correct Answer(s)
B. Initiator tRNAs in Prokaryotes carry a modified form of methionine containing a fomyl group
C. There are no tRNAs that recognize the mRNA sequence, UAA
D. Folding of the tRNA requires localized regions of hydrogen bondingExplanation
tRNA (transfer RNA) is responsible for carrying amino acids to the ribosome during protein synthesis. The characteristics mentioned in the answer are all true for tRNA. Initiator tRNAs in prokaryotes carry a modified form of methionine with a fomyl group, which helps in initiating protein synthesis. There are no tRNAs that recognize the mRNA sequence UAA, which is a stop codon. Folding of tRNA is crucial for its function, and it requires localized regions of hydrogen bonding to maintain its structure.Rate this question:
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- 22.
Nuclear localization signals are required for molecules to nove INTO the nucleus. On which molecules would you find nuclear localization signals?
- A.
MRNA
- B.
Ribosomal proteins
- C.
Small ribosomal subunits
- D.
Transcription factors
Correct Answer(s)
B. Ribosomal proteins
D. Transcription factorsExplanation
Nuclear localization signals are short amino acid sequences that act as a tag, guiding molecules into the nucleus. Ribosomal proteins and transcription factors are two types of molecules that require nuclear localization signals to move into the nucleus. These signals help ensure that these essential molecules are correctly transported to the nucleus, where they play important roles in protein synthesis and gene regulation, respectively. mRNA and small ribosomal subunits do not typically contain nuclear localization signals, as their functions primarily occur outside of the nucleus.Rate this question:
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- 23.
Which processes are used by BOTH Prokarytes AND Eukaryotes?
- A.
Intron splicing
- B.
Translation of mRNA in the 5' to 3' direction
- C.
Semi-conservative replication of DNA
- D.
Capping of the 5' end of mRNA with multiple repeats of Adenosine
Correct Answer(s)
B. Translation of mRNA in the 5' to 3' direction
C. Semi-conservative replication of DNAExplanation
Both prokaryotes and eukaryotes use translation of mRNA in the 5' to 3' direction to synthesize proteins. This process involves the ribosomes reading the mRNA sequence and assembling the corresponding amino acids to form a polypeptide chain. Additionally, both prokaryotes and eukaryotes undergo semi-conservative replication of DNA during cell division. This process ensures that each new DNA molecule formed contains one original strand and one newly synthesized strand.Rate this question:
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- 24.
The base composition of one strand of a double stranded piece of DNA is 30% A and 40%G. Based on this information, what can you conclude about this strand and its complementary strand of DNA?
- A.
The strand that is 30%A and 40% G must also be 30%T
- B.
T and C accound for 30% of the bases in the strand that is 30%A and 40%G
- C.
The complementary strand of DNA must be 30%T
- D.
A and G account for 30% of the bases in the complementary strand of DNA
Correct Answer(s)
B. T and C accound for 30% of the bases in the strand that is 30%A and 40%G
C. The complementary strand of DNA must be 30%T
D. A and G account for 30% of the bases in the complementary strand of DNAExplanation
Based on the given information, we can conclude that the strand with 30% A and 40% G must also have 30% T, as DNA strands always pair A with T and G with C. Therefore, the complementary strand of DNA must be 30% T. Additionally, since A and G account for 30% of the bases in the original strand, it can be inferred that A and G also account for 30% of the bases in the complementary strand.Rate this question:
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- 25.
Chromosomes
- A.
Are stabilized by covalent bonds between nitrogenous bases on complementary DNA strands
- B.
Contain both DNA and proteins that assist in their packaging within the nucleus
- C.
Are replicated continuously on the lagging strand
- D.
Get shorter with every round of DNA replication
Correct Answer(s)
B. Contain both DNA and proteins that assist in their packaging within the nucleus
D. Get shorter with every round of DNA replicationExplanation
Chromosomes contain both DNA and proteins that assist in their packaging within the nucleus. DNA is tightly wrapped around proteins called histones, forming a structure known as chromatin. This packaging helps to condense and organize the DNA, allowing it to fit within the nucleus. Additionally, chromosomes get shorter with every round of DNA replication. This is because the enzyme responsible for replicating DNA, called DNA polymerase, is unable to fully replicate the ends of the DNA molecule. As a result, the ends, known as telomeres, gradually shorten with each replication cycle.Rate this question:
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- 26.
For each type of regulation of gene expression in Eukaryotes, indicate whether the regulation is working directly on DNA, RNA or the protein product. Cleavage
- A.
DNA
- B.
RNA
- C.
Protein Product
Correct Answer(s)
A. DNA
B. RNA
C. Protein ProductExplanation
The regulation of gene expression through cleavage in eukaryotes can work directly on DNA, RNA, and the protein product. This means that the process of cleavage can affect the DNA sequence, the RNA molecule, and the final protein product that is produced from the gene. Cleavage can involve the cutting or modification of DNA, the splicing or processing of RNA, and the degradation or modification of the protein product.Rate this question:
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- 27.
For each type of regulation of gene expression in Eukaryotes, indicate whether the regulation is working directly on DNA, RNA or the protein product. Changes in location
- A.
DNA
- B.
RNA
- C.
Protein Product
Correct Answer(s)
B. RNA
C. Protein ProductExplanation
Changes in location refers to the movement of a gene or its product to a different cellular compartment. In eukaryotes, this regulation primarily works directly on RNA and the protein product. RNA molecules can be transported from the nucleus to the cytoplasm, where they undergo translation to produce proteins. The proteins can also be targeted to specific organelles or cellular structures based on signals present in the protein itself. Therefore, changes in location involve the direct regulation of RNA molecules and the resulting protein product.Rate this question:
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- 28.
For each type of regulation of gene expression in Eukaryotes, indicate whether the regulation is working directly on DNA, RNA or the protein product. Ubiquitination
- A.
DNA
- B.
RNA
- C.
Protein Product
Correct Answer
C. Protein ProductExplanation
Ubiquitination is a post-translational modification process where a ubiquitin molecule is attached to a protein. This modification plays a crucial role in protein degradation, protein trafficking, and protein localization within the cell. Therefore, ubiquitination directly affects the protein product rather than DNA or RNA.Rate this question:
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- 29.
For each type of regulation of gene expression in Eukaryotes, indicate whether the regulation is working directly on DNA, RNA or the protein product. Binding by regulatory proteins
- A.
DNA
- B.
RNA
- C.
Protein Product
Correct Answer(s)
A. DNA
B. RNA
C. Protein ProductExplanation
Regulation of gene expression in eukaryotes can occur through binding by regulatory proteins. These proteins can directly interact with DNA, RNA, or the protein product to control gene expression. In this case, the regulatory proteins can bind directly to DNA, RNA, or the protein product to regulate the expression of genes.Rate this question:
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- 30.
Which organism would be predicted to have the highest percentage of unsaturated phospholipids in their cell membrane?
- A.
Antarctic fish
- B.
Desert snake
- C.
Human being
- D.
Polar bear
- E.
Thermophilic bacterium living in a 100 C hot springs
Correct Answer
A. Antarctic fishExplanation
Antarctic fish would be predicted to have the highest percentage of unsaturated phospholipids in their cell membrane. This is because unsaturated phospholipids have double bonds in their fatty acid chains, which provide fluidity and flexibility to the cell membrane. In the cold temperatures of the Antarctic, maintaining a fluid cell membrane is crucial for the survival of organisms. Therefore, Antarctic fish, which inhabit extremely cold environments, would have a higher proportion of unsaturated phospholipids in their cell membranes compared to the other organisms listed.Rate this question:
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- 31.
Which response shows the molecules in order from the one that is least permeable to the one that is most permeable in a lipid bilayer?
- A.
Water, RNA, glucose, ethanol, Ca2+, N2
- B.
N2, ethanol water glucose, Ca2+, RNA
- C.
RNA, Ca2+, glucose, water, ethanol, N2
- D.
Ca2+, RNA, water, glucose, ethanol, N2
- E.
Glucose, RNA, Ca2+, ethanol, N2, water
Correct Answer
C. RNA, Ca2+, glucose, water, ethanol, N2Explanation
The correct answer is RNA, Ca2+, glucose, water, ethanol, N2. This is because the order of permeability in a lipid bilayer is determined by the size and charge of the molecules. RNA is the least permeable as it is a large molecule with a negative charge. Ca2+ is next because it is a small, positively charged ion. Glucose is larger than water and ethanol, so it is less permeable than them. Water is smaller than ethanol and N2, so it is more permeable than them. Ethanol is smaller than N2, so it is more permeable than N2.Rate this question:
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- 32.
Which statement is true for glycolysis?
- A.
All of the energy produced is in the form of heat
- B.
Many of the steps involve reaction with oxygen gas
- C.
Anaerobic organisms cannot oxidize glucose
- D.
Some organisms carry out the overall reverse reaction
- E.
Each step in glycolysis is thermodynamically favorable
Correct Answer
D. Some organisms carry out the overall reverse reactionExplanation
Some organisms are capable of carrying out the overall reverse reaction of glycolysis. This means that instead of breaking down glucose into pyruvate and producing ATP, these organisms can convert pyruvate back into glucose and consume ATP in the process. This is known as gluconeogenesis and allows these organisms to synthesize glucose when it is not readily available in their environment.Rate this question:
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- 33.
Which statement is TRUE for facilitated diffusion?
- A.
Molecules move from a high concentration to a low concentration
- B.
The Keq is less than 1 since this is a thermodynamically fabvorable process
- C.
The rate of this process is independent of the concentration of the solute
- D.
This process is not specific - the chemical nature of the solute does not matter
- E.
The rate is similar for channels and pores
Correct Answer
A. Molecules move from a high concentration to a low concentrationExplanation
Facilitated diffusion is a passive transport process where molecules move across a membrane from an area of higher concentration to an area of lower concentration with the help of specific transport proteins. This allows molecules that are too large or polar to passively diffuse through the lipid bilayer to still move across the membrane. Therefore, the statement "Molecules move from a high concentration to a low concentration" is true for facilitated diffusion.Rate this question:
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- 34.
Which molecule would you expect to be an allosteric inhibitor of the enzyme pyruvate dehydrogenase?
- A.
ATP
- B.
CoA
- C.
Glucose
- D.
Pyruvate
- E.
NAD+
Correct Answer
A. ATPExplanation
ATP is the correct answer because it is a high-energy molecule that acts as a regulator of pyruvate dehydrogenase. ATP binds to an allosteric site on the enzyme, causing a conformational change that inhibits its activity. This regulation helps to prevent the excessive production of ATP when energy levels are already high. CoA, glucose, pyruvate, and NAD+ are not allosteric inhibitors of pyruvate dehydrogenase.Rate this question:
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- 35.
Which statement about electron transport is correct?
- A.
Electron carriers with large, positive standard reduction potentials serve as good electron donors
- B.
The electron transport chain generates an electrical potential by moving electrons into the matrix
- C.
Metal ions serve as electron acceptors and donors in some of the electron transfer reactions
- D.
Complex I gives its electrons to Complex II during electron transport in the mitochondria
- E.
In the absence of oxygen all of the previous electron carriers become oxidized
Correct Answer
C. Metal ions serve as electron acceptors and donors in some of the electron transfer reactionsExplanation
Metal ions serve as electron acceptors and donors in some of the electron transfer reactions. This is because metal ions can easily gain or lose electrons due to their electronic structure, making them suitable for accepting or donating electrons in redox reactions. This property of metal ions is utilized in various biological processes, such as in the electron transport chain, where metal ions like iron and copper play crucial roles in accepting and donating electrons to facilitate energy production.Rate this question:
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- 36.
If you drink many liters of water in a short period of time, it can make you very sick. What could be the reason for this?
- A.
Body fluids become less concentrated than the fluid in your cells, so water leaves the cells and they shrivel up
- B.
Body fluids become less concentrated than the fluid in your cells, so water leaves your body through your skin
- C.
Body fluids become less concentrated than the fluid in your cells, so water enters the cells and they swell
- D.
Water dilutes your brain tissue
Correct Answer
C. Body fluids become less concentrated than the fluid in your cells, so water enters the cells and they swellExplanation
When you drink many liters of water in a short period of time, the body fluids become less concentrated than the fluid inside your cells. This creates a concentration gradient, causing water to enter the cells in an attempt to balance the concentration. As a result, the cells swell up. This can lead to a condition called water intoxication or hyponatremia, which can cause symptoms such as nausea, headache, confusion, seizures, and in severe cases, even coma or death.Rate this question:
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- 37.
In oxidative phosphorylation
- A.
Electron transport and ATP synthesis are coupled
- B.
The ATP synthase acts as a proton pump to concentrate protons
- C.
The proton gradient provides energy to make ATP
- D.
More ATP are made per FADH2 oxidized than per NADH oxidized
Correct Answer(s)
A. Electron transport and ATP synthesis are coupled
C. The proton gradient provides energy to make ATPExplanation
In oxidative phosphorylation, electron transport and ATP synthesis are coupled, meaning they occur together and are dependent on each other. During electron transport, electrons are passed along a series of proteins in the inner mitochondrial membrane, creating a proton gradient. This proton gradient is then used by ATP synthase, which acts as a proton pump, to concentrate protons on one side of the membrane. The flow of protons back across the membrane through ATP synthase provides the energy needed to convert ADP to ATP, resulting in the production of ATP. Additionally, more ATP is produced per FADH2 oxidized compared to NADH oxidized during this process.Rate this question:
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- 38.
A bacterial culture growing at 37C is transferred to 25C. What is likely to happen to the plasma membranes of these cells following this change in temperature?
- A.
Initial decrease in membrane fluidity
- B.
Gradual insertion of membrane phospholipids that have longer fatty acid chains
- C.
Gradual insertion of membrane phospholipids that have unsaturated fatty acid chains
- D.
Incorporation of cholesterol into the membrane
Correct Answer(s)
A. Initial decrease in membrane fluidity
C. Gradual insertion of membrane pHospHolipids that have unsaturated fatty acid chainsExplanation
When the bacterial culture is transferred from 37C to 25C, the decrease in temperature causes an initial decrease in membrane fluidity. This is because the lower temperature reduces the kinetic energy of the phospholipid molecules, causing them to pack more tightly together and become less fluid. Additionally, the lower temperature promotes the gradual insertion of membrane phospholipids that have unsaturated fatty acid chains. Unsaturated fatty acids have kinks in their structure due to the presence of double bonds, which prevents the phospholipids from packing tightly together. This increases membrane fluidity and helps to maintain the integrity and functionality of the bacterial cells.Rate this question:
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- 39.
Which statements about catabolism are accurate?
- A.
ATP hydrolysis releases more energy than does the hydrolysis of any other activated carrier
- B.
Both products of ATP hydrolysis have resonance stabilization
- C.
ATP production is highly exergonic
- D.
ATP and Coenzyme A have some common structural features
Correct Answer(s)
B. Both products of ATP hydrolysis have resonance stabilization
D. ATP and Coenzyme A have some common structural featuresExplanation
Both products of ATP hydrolysis have resonance stabilization because the products, ADP and inorganic phosphate (Pi), have stable resonance structures that contribute to their stability. ATP production is highly exergonic, meaning it releases a large amount of energy when hydrolyzed. ATP and Coenzyme A have some common structural features, such as the presence of a phosphoanhydride bond, which is important for their energy transfer functions.Rate this question:
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- 40.
Which statements about catabolism are accurate?
- A.
For every mole of glucose oxidized 4 FADH2 are made in the citric acid cycle
- B.
In BOTH glycolysis and the citric acid cycle, ATP is hyrolyzed and ATP is produced
- C.
The immediate source of energy in substrate-level phosphorylation is a proton gradient
- D.
Acetyl CoA from fat metabolism can enter the citric acid cycle
Correct Answer
D. Acetyl CoA from fat metabolism can enter the citric acid cycleExplanation
Acetyl CoA from fat metabolism can enter the citric acid cycle. This is because during fat metabolism, fatty acids are broken down into Acetyl CoA molecules, which can then be used as a fuel source in the citric acid cycle. This allows for the generation of energy through the oxidation of Acetyl CoA and the subsequent production of ATP.Rate this question:
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- 41.
The oxidation of malate during the citric aacid cycle requires NAD+. What do you know or can you logically infer about this reaction?
- A.
The enzyme that catalyzes this reaction is classified as a dehydrogenase
- B.
This eaction occurs in the mitochondrial matrix
- C.
NADH made in this reaction gives its electrons to ADP to form ATP
- D.
This reaction does not occur under anaerobic conditions
Correct Answer(s)
A. The enzyme that catalyzes this reaction is classified as a dehydrogenase
B. This eaction occurs in the mitochondrial matrix
D. This reaction does not occur under anaerobic conditionsExplanation
The oxidation of malate during the citric acid cycle requires NAD+, which suggests that the enzyme catalyzing this reaction is a dehydrogenase. This reaction occurs in the mitochondrial matrix, which is where the citric acid cycle takes place. Additionally, the fact that NADH produced in this reaction gives its electrons to ADP to form ATP indicates that this reaction is part of the electron transport chain and oxidative phosphorylation, which occur under aerobic conditions. Therefore, this reaction does not occur under anaerobic conditions.Rate this question:
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- 42.
Which statements about the Na/K pump are correct?
- A.
The Na/K pump picks up sodium ions from the outside of the cell and moves them inside the cell
- B.
Phosphorylation of the pump increases the affinity of the pump for Na+
- C.
The Na/K pump is best described as a uniporter
- D.
The pump requires ATP hydrolysis to drive the active transport of these ions
Correct Answer
D. The pump requires ATP hydrolysis to drive the active transport of these ionsExplanation
The Na/K pump requires ATP hydrolysis to drive the active transport of sodium ions from the outside of the cell to the inside of the cell. This process involves phosphorylation of the pump, which increases its affinity for sodium ions. The Na/K pump is not a uniporter, as it transports both sodium and potassium ions.Rate this question:
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- 43.
Which of the following statements accurately describe what happens to pyruvate as it is prepared for the citric acid cycle?
- A.
A dehydrogenase located in the mitochondrial matrix catalyzes these reactions
- B.
Pyruvate undergoes oxidative carboxylation
- C.
The conversion of pyruvate into a substrate for the citric acid cycle ultimately results in the production of three ATP per pyruvate converted into this citric acid cycle substrate
- D.
Coenzyme A-SH picks up an acyl group from pyruvate during these reactions
Correct Answer(s)
A. A dehydrogenase located in the mitochondrial matrix catalyzes these reactions
C. The conversion of pyruvate into a substrate for the citric acid cycle ultimately results in the production of three ATP per pyruvate converted into this citric acid cycle substrate
D. Coenzyme A-SH picks up an acyl group from pyruvate during these reactionsExplanation
During the preparation of pyruvate for the citric acid cycle, a dehydrogenase enzyme located in the mitochondrial matrix catalyzes the reactions. This enzyme helps in the conversion of pyruvate into a substrate for the citric acid cycle. This conversion ultimately leads to the production of three ATP molecules per pyruvate converted into the citric acid cycle substrate. Additionally, during these reactions, Coenzyme A-SH picks up an acyl group from pyruvate, further facilitating the process.Rate this question:
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- 44.
The majority of the compoonents of the mitochondrial electron transport system are located here
- A.
Innermembrane space of mitochondria
- B.
Intermembrane space of mitochondria
Correct Answer
A. Innermembrane space of mitochondriaExplanation
The correct answer is the innermembrane space of mitochondria. The majority of the components of the mitochondrial electron transport system are located in the innermembrane space of mitochondria. This is where the electron transport chain takes place, which is a series of protein complexes that transfer electrons and generate ATP. The innermembrane space is highly folded, creating a large surface area for the electron transport system to occur. This compartmentalization allows for efficient energy production in the form of ATP.Rate this question:
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- 45.
Protons are concentrated in this location by energy produced from electron flow through the electron transport system
- A.
Innermembrane space of mitochondria
- B.
Inter membrane space of mitochondria
Correct Answer
B. Inter membrane space of mitochondriaExplanation
The protons are concentrated in the intermembrane space of mitochondria by the energy produced from electron flow through the electron transport system. This process occurs during oxidative phosphorylation, where electrons are passed along a series of protein complexes in the inner mitochondrial membrane. As electrons are transferred, protons are pumped from the mitochondrial matrix into the intermembrane space, creating a concentration gradient. This gradient is then used by ATP synthase to generate ATP, the energy currency of the cell. Therefore, the correct answer is the intermembrane space of mitochondria.Rate this question:
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- 46.
Cytochrome c is located here
- A.
Innermembrane space of mitochondria
- B.
Intermembrane space of mitochondria
Correct Answer
A. Innermembrane space of mitochondriaExplanation
Cytochrome c is a protein involved in the electron transport chain of cellular respiration. It plays a crucial role in transferring electrons from one enzyme complex to another. The inner membrane space of mitochondria is the location where the electron transport chain occurs. This space is between the inner and outer membranes of the mitochondria. Therefore, it is logical to conclude that cytochrome c is located in the inner membrane space of mitochondria, where it can carry out its function in the electron transport chain.Rate this question:
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- 47.
Succinate dehydrogenase, which is involved in the reduction of FAD, is located here
- A.
Innermembrane space of mitochondria
- B.
Intermembrane space of mitochondria
Correct Answer
A. Innermembrane space of mitochondriaExplanation
Succinate dehydrogenase is an enzyme involved in the reduction of FAD (flavin adenine dinucleotide). It is known to be located in the inner membrane space of mitochondria. This is the space between the inner and outer membranes of the mitochondria. The inner membrane space plays a crucial role in the electron transport chain and oxidative phosphorylation, where succinate dehydrogenase participates. Therefore, it is logical to conclude that succinate dehydrogenase is located in the inner membrane space of mitochondria.Rate this question:
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- 48.
Which of the following properties/characteristics are the same for both pair of membrane transport mechanisms given? simple diffusion; facilitated diffustion
- A.
Direction of solute movement relative to concentration gradient
- B.
Metabolic energy is not required
- C.
Integral membrane proteins are involved
- D.
None of these are shared
Correct Answer(s)
A. Direction of solute movement relative to concentration gradient
B. Metabolic energy is not requiredExplanation
Both simple diffusion and facilitated diffusion involve the movement of solutes in the direction of their concentration gradient, meaning from an area of higher concentration to an area of lower concentration. Additionally, neither of these mechanisms requires the input of metabolic energy. Both processes also involve the participation of integral membrane proteins, which assist in the transport of solutes across the cell membrane. Therefore, the properties of "Direction of solute movement relative to concentration gradient" and "Metabolic energy is not required" are shared between both simple diffusion and facilitated diffusion.Rate this question:
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- 49.
Which of the following properties/characteristics are the same for both pair of membrane transport mechanisms given? facilitated diffusion; active transport
- A.
Direction of solute movement relative to concentration gradient
- B.
Metabolic energy is not required
- C.
Integral membrane proteins are involved
- D.
None of these are shared
Correct Answer
C. Integral membrane proteins are involvedExplanation
Both facilitated diffusion and active transport involve integral membrane proteins. In facilitated diffusion, these proteins help in the passive movement of solutes across the membrane, while in active transport, they actively transport solutes against their concentration gradient using energy. The direction of solute movement relative to the concentration gradient and the requirement of metabolic energy are different for these two mechanisms.Rate this question:
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- 50.
Which of the following properties/characteristics are the same for both pair of membrane transport mechanisms given? simple diffusion; active transport
- A.
Direction of solute movement relative to concentration gradient
- B.
Metabolic energy is not required
- C.
Integral membrane proteins are involved
- D.
None of these are shared
Correct Answer
D. None of these are sharedExplanation
The question asks which properties/characteristics are the same for both simple diffusion and active transport. However, none of the given options (direction of solute movement relative to concentration gradient, metabolic energy requirement, involvement of integral membrane proteins) are shared between these two membrane transport mechanisms. Therefore, the correct answer is "None of these are shared".Rate this question:
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