Final Exam -- Old tests Flashcards
T/F: The movement of a solute against a concentration gradient is called active transport.
True
T/F: An organelle that is semi-autonomous can grow and divide independently.
False
T/F: Phospholipids can flip-flop across the membrane spontaneously; the process does not require the input o energy or enzyme activity.
False
T/F: Signal transduction is the process by which cells transmit signals from inside the cell to the outside.
False
T/F: Facilitated diffusion si the movement down a gradient with the aid of a transport protein.
True
T/F: A reaction with a delta G > 0 is endergonic and requires a net input of energy to proceed.
True
T/F: Micelles are spherical structures that are formed spontaneously from amphipathic phospholipids in an aqueous environment.
True
T/F: A molecule that has been reduced has gained electrons and a hydrogen atom
True
T/F: Polar amino acids tend to be found on the surface of soluble proteins
True
T/F: Functional groups such as sulfhydryl and phosphate groups are nonpolar and will not interact with water.
False
T/F: Both covalent and noncovalent interactions are needed to stabilize proteins.
True
T/F: Denaturation causes proteins to unfold and results in enhanced function
False
Which of the following is NOT soluble in water?
- Lipids
- sugars
- amino acids
- disaccharides
- nucleic acid
Lipids
What kinds of bonds stabilize the formation of an alpha helix within a polypeptide?
- hydrogen bonds
- covalent bonds
- ionic bonds
- peptide bonds
- disulfide bonds
hydrogen bonds
Triglycerides are _____.
- carbohydrates
- nucleotides
- proteins
- lipids
- amino acids
lipids
The Anfinsen experiment showed that three-dimensional structure of a polypeptide is:
- unaffected by harsh conditions
- important for neutralizing pH
- encoded in the amino acid sequence
- determined by covalent interactions
- None of these are true
encoded in the amino acid sequence
Delta G for the following reaction is +686 kcal/mol:
C6H12O6 + 6O2 –> 6CO2 + 6H2O
This means that:
- The reaction is exergonic
- Energy is taken up from the surroundings
- There is no net charge in the energy content of the molecules
- Energy is needed to start the reaction
- The reaction is endergonic
- Energy is needed to start the reaction
- The reaction is endergonic
They type of reaction in which organic polymers are formed from their subunits is called:
- hydrolysis
- condensation
- oxidation
- saturation
- deconstructionism
Condensation
The compartmentalization of areas within eukaryotic cells:
- Allows for a smaller overall cell size relative to prokaryotic cells
- Allows them to perform several biochemical functions simultaneously
- Decreases their overall biochemical efficiency compared to prokaryotic cells
- Makes them more susceptible to sudden environmental changes
- Is more complex in animal cells than in plant cells
- Allows them to perform several biochemical functions simultaneously
Which membrane component is most important for allowing large, charged molecules to pass through the membrane?
- Peripheral proteins
- Cholesterol
- Glycosylated lipids
- Transmembrane proteins
- Carbohydrate channels
- transmembrane proteins
The concentration of solutes outside a cell is lower than the concentration of solutes inside the cell. Compared to its surroundings, the cell is:
- hypertonic
- hypotonic
- isotonic
Hypertonic
The process that involves the selective uptake of a specific cargo molecule into the cell through receptor binding is:
- pinocytosis
- receptor-mediated endocytosis
- autophagocytosis
- phagocytosis
- receptor-mediated exocytosis
Receptor-mediated endocytosis
If a lysosome bursts inside a cell, the immediate result is likely to be:
- the cell will be unable to build proteins
- the cell will be digested from within
- it will be repaired with no loss of function
- the cell will divide into daughter cells
- DNA will be transposed to the nucleus
The cell will be digested from within
Catabolism is:
- the ATP-dependent synthesis of biomolecules
- the process by which metabolic reaction are catalyzed
- the method that cells use to communicate
- the process of breaking down food molecules to synthesize ATP
- what happens if you have too many cells
- the process of breaking down food molecules to synthesize ATP
Enzymes fall into which category of biological macromolecules?
- nucleic acids
- carbs
- protein
- lipid
- none of these
protein
Which statement is NOT true with regard to plant cells?
- Plant cells possess cell walls
- Many plants lack centrioles
- Plant cells possess plasma membranes
- Plant cell slack mitochondria
- Plant cells possess lysosomes
- plant cells lack mitochondria
Competitive inhibitors are molecules that can bind an enzyme’s _____ site, blocking the substrate from binding.
- tertiary
- active
- allosteric
- cofactor
- none of these
active site
A patient exhibits a diverse range of symptoms. Lab tests reveal that multiple metabolic processes are occurring at sub-normal levels due to the lack of nutrients and molecular building blocks. Tests reveal that cells are not secreting materials normally and have an improper ion balances. What cell organelle is not functioning properly?
- mitochondria
- peroxisomes
- lysosomes
- plasma membrane
- centrosomes
PLASMA MEMBRANE
The major structural elements of the cytoskeleton are:
- the extracellular matrix and the cell wall
- microtubules, microfilaments, and intermediate filaments
- the cytoplasm and cytosol
- cleavage furrows and g-actin
- proteoglycans and cellulose microfibrils
- microtubules, microfilaments, and intermediate filaments
What is the rough ER?
Site of protein sorting and secretion
What is the cytoskeleton?
Provides cell shape, organization, and movement
What is the nucleus?
Where most genetic material is organized/expressed
What is the cytosol?
Located outside of the membrane bound organelles, inside the plasma membrane
What is the golgi apparatus?
Site of modification, sorting and secretion of lipids and proteins
What are peroxisomes?
Site of hydrogen peroxide breakdown
What are ribosomes?
Site of polypeptide synthesis
What is the smooth ER?
Site of detoxification and lipid synthesis
What is the chloroplast?
Site of photosynthesis
What is the mitochondria?
Site of ATP synthesis
T/F: Bacterial chromosomes are circular and eukaryotic chromosomes are linear
True
T/F: Rosalind Franklin’s X-Ray diffraction data was used by Watson and Crick to show that DNA is double stranded, helical molecule
True
T/F: Cancer cells have extremely high levels of telomerase enzyme activity.
True
T/F: In the genetic code, each amino acid is specified by only one codon.
False
T/F: DNA replication is semi-conservative
True
T/F: Prokaryotic cells have multiple origins of replication.
False
T/F: In both eukaryotes and prokaryotes, the replication fork for DNA replication proceeds in two directions, enabling replication fo both strands of DNA.
True
T/F: Beadle and Tatum provided evidence that a single gene controlled the synthesis of a single enzyme when they published the “one gene, one polypeptide” hypothesis.
True
T/F: Genes that are expressed at all times and at relatively constant levels are known as inducible genes.
False
T/F: The core promoter of a eukaryotic structural gene contains a short sequence of DNA called a TATA box, which is positioned about 25 base pairs upstream from the transcriptional start site.
True
T/F: Eukaryotic genes are clustered in groups called operons.
False
T/F: The anticodon is a triplet of nucleotides present on tRNA.
True
T/F: The “wobble hypothesis” states that the genetic code is degenerate.
True
T/F: Addition of nucleotides to a growing DNA strand requires the presence of a 3’ OH group.
True
T/F: DNA replication in eukaryotes results in loss of nucleotides at the end of the chromosome
True
T/F: Translation of proteins in prokaryotes occurs in the cytoplasm
True
T/F: Eukaryotic DNA contains segments of DNA, called introns, that do not code for proteins.
True
If the GC content of a DNA molecule is 60%, what are the percentages of the four bases (G, C, T, A)?
G = 30%, C = 30%, A = 20%, T = 20%
Which of the following represents the lowest level (least compact) of eukaryotic chromosome condensation?
- Radial loop domain
- 30 nm fibers
- Heterochromatin
- DNA wrapping to form nucleosomes
- DNA wrapping to form nucleosomes
On the ribosome, during the process of translation:
- The uncharged tRNA is found in the A site
- The growing polypeptide chain is found in the E site
- The anticodon of the mRNA molecule binds first to the large subunit.
- The charged tRNA enters in the A site
- The mRNA enters through the P site
The charged tRNA enters the A site
Okazaki fragments do which of the following?
- Assist in forming the replication fork
- Bind to the origin of replication
- Are formed during the synthesis of the lagging strand
- Reform the double-helix following replication
Are formed during the synthesis of the lagging strand
Which fo the following is NOT correct concerning telomeres?
- Telomeres are areas of the chromosome which contain many protein-coding genes
- Repeating region sin telomeres are important for the binding of the enzyme telomerase
- Telomeres must be lengthened after each round of replication
- Telomeres help preserves chromosomal integrity
Telomeres are areas of the chromosome which contain many protein-coding genes
Ribosomes consist of two protein subunits and ____.
- tRNA
- rRNA
- short DNA
- telomeres
rRNA
A mutation in which of the following region sis least likely to affect gene function?
- Promotor
- Coding region
- Splice junction
- Intergenic region
- Regulatory site
Intergenic region
All of the following are part of a nucleotide EXCEPT:
- pentose sugar
- nitrogenous base
- phosphate group
- fatty acid group
fatty acid group
What is the correct order that describes the central dogma of molecular biology?
DNA, RNA, protein
Griffith’s work with smooth and rough strains of S. pneumonia bacteria showed that:
- RNA transcription is essential for mouse survival
- Nonvirulent bacteria can be transformed if exposed to heat-killed virulent bacteria
- One gene provides the code for one enzyme
Nonvirulent bacteria can be transformed if exposed to heat-killed virulent bacteria
A cell’s ability to control their level of gene expression is called:
gene regulation
What type of regulatory transcription factor binds DNA and increases the transcription of a gene?
- a regulator exerting positive control
- an activator exerting positive control
an activator exerting positive control
Genes organized into an operon are beneficial to certain bacteria because the operon allows for _____.
- Differential regulation of individual genes that encode proteins with a common function
- Coordinated regulation of a group of genes that encode proteins with a common function
- Separate regulation of individual genes that encode proteins with different functions
- Coordinated regulation of a group of genes that encode proteins with different functions
- Coordinated regulation of a group of proteins involved in numerous cellular activities
Coordinated regulation of a group of genes that encode proteins with a common function
Liver cells, mammary cells, and skin cells all contain the same genome; however, their respective proteomes vary drastically. This observation is best explained by what phenomenon?
- gene regulation
- cell division
- cell cycle control
- crossing over
- evolution
gene regulation
An example of gene regulation in eukaryotes is the differential expression of human globin genes such that:
all the above
T/F: Bacteria regulate gene expression in response to changes in their environment.
TRUE
A ____ operon is one whose transcription is kept at low levels by effector molecules.
- repressible
- inducible
- coinducible
- compressible
inducible
T/F: An organelle that is semi-autonomous can grow and divide independently
False
T/F: H+ electrochemical gradients are important in the production of ATP through aerobic respiration
True
T/F: NADPH is the electron carrier used in both photosynthesis and mitochondrial electron transport chain
False
T/F: During signal transduction, the original signal is converted to a new signal inside the cell.
True
T/F: Glycolysis is the primary energy-yielding pathway for anaerobic organisms, but is not widely used by aerobic organisms.
False
T/F: Proteoglycans consist of a protein core with covalently attached carbohydrates that form a hydrated gel-like network within extracellular matrix of tissues
True
T/F: Cyanide poisoning causes cell death due to a shut down of glycolysis.
False
T/F: G-protein coupled receptors are large proteins with seven membrane-spanning domains
True
T/F: Tight junctions are present between epithelial cells within an animal’s digestive tract
True
T/F: Apoptosis is programmed cell death
True
T/F: Photosynthesis can only occur when oxygen is present
False
When placing red blood cells in fresh water,
- the red blood cell is hypotonic to fresh water
- the red blood cell is hypertonic to fresh water
- The red blood cell is isotonic to fresh water
- water moves from the red blood cell into fresh water
- the red blood cell is HYPERTONIC to the fresh water
The type of reaction in which organic polymers are formed from their subunits is called:
- hydrolysis
- condensation
- oxidation
- saturation
condensation
When a cell secretes a signaling molecule that binds to receptors on neighboring cells as well as the same cell, this is called ____.
- direct intercellular
- contact-dependent
- autocrine
- paracrine
- endocrine
Paracrine
Small molecules, such as cAMP, that relay signals within the cell are called:
- First messengers
- ligands
- g proteins
- second messengers
second messengers
Which of the following structures allow for the exchange of metabolites between the cytoplasms of two adjacent cells?
- adhesive junctions
- tight junctions
- gap junctions
- plasmodesmata
- last two
gap junctions and plasmodesmata (last two)
Which of the following characteristics best describes collagen?
- triple helix
- part of the extracellular matrix
- coated with carbohydrates
- most abundant protein in the ECM
- all the above
- triple helix
- part of the extracellular matrix
- most abundant protein in the ECM
Which of the following statements best describes the role of NAD+/NADH in glycolysis?
- NADH produces energy by directly creating the phosphoanhydride bonds in ATP
- NAD+ is used to carry electrons
- NADH is capable of pumping ions during glycoysis
- NADH is used primarily in substrate-level phosphorylation
- NAD+ is used to carry electrons
T/F: The victims of Tylenol cyanide poisoning could have been saved if medical personnel had administered oxygen therapy.
FALSE
During strenuous exercise, you may notice that your muscles burn. Why?
- Proteins are being digested to provide energy
- Carbon dioxide is building up in muscle and changing the pH
- Without oxygen, pyruvate is being converted to lactic acid
- ADP is accumulating, which produces a burning sensation
- Without oxygen, pyruvate is being converted to lactic acid
The most abundant polysaccharides in vertebrae extracellular matrix are called:
- glycosaminoglycans (GAGs)
- Hemidesmosomes (HDSs)
- Cellulogycans (CEGs)
- Plasmodesmata (PDSs)
Glycosaminoglycans (GAGs)
The light harvesting reactions of photosynthesis take place in the _____ membranes of chloroplasts.
- thyamine
- thiloplast
- thoroplast
- thylakoid
thylakoid
Which of the following substances is required in the citric acid cycle reactions as an electron acceptor?
- oxygen
- ADP
- coenzyme A
- NAD+
- CO2
NAD+
In eukaryotic cells, respiration occurs in the:
- Chloroplasts
- golgi bodies
- mitochondria
- ribosomes
- lysosomes
mitochondria
As a polypeptide is made, a ____ bond is formed between the carboxyl group in the last amino acid of polypeptide chain and the amino group in the amino group in the amino acid being added.
- covalent
- hydrogen
- electrostatic
- ionic
- phosphodiester
Covalent
Electrons are passed to the electron transport chain from which of the following substances?
- pyruvic acid
- NADH and FADH2
- oxygen and carbon dioxide
- ATP
- oxaloacetic acid
NADH and FADH2