Carmen Quizzes Flashcards
Which of the following is NOT true of all living things?
They need oxygen for respiration.
however: They can transfer and transform energy. They are made up of carbon-based organic molecules. They can grow and reproduce. They respond to their environment.
Which one of the following molecules is responsible for both the unity and diversity of life?
DNA
Biology’s core theme of evolution explains traits shared by present day organisms are a result of ________ and traits that differ as evidence of ________.
decent from a common ancester… natural selection
Many of the properties of water are a result of water molecules being able to form hydrogen bonds with _____
compounds that have polar covalent bonds
Stanley Miller’s 1953 experiments support the hypothesis that _____.
organic molecules can be synthesized abiotically under conditions that may have existed on early Earth
Why is carbon so important for biological molecules and their functions?
It can form a variety of carbon skeletons and host a variety of functional groups.
Which functional group(s) shown above is (are) found in all amino acids, the building blocks of protein?
COOH and NH2
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart.
Saturated fatty acid ______.
are the principal molecules found in lard and butter
Nucleic acids are molecular polymers made up of which of the following monomers?
nucleotides
What makes carbohydrates and lipids excellent molecules to store energy?
numerous, stable C-C and C-H bonds
Which of the following statements is FALSE? Unsaturated fats _____.
contain more hydrogens than saturated fats with the same number of carbon atoms
however:
are usually liquid at room temperature
are commonly found in plants
have double bonds in their fatty acid chains
If you disrupt all the hydrogen bonds of a protein, which level of protein structure will still be preserved?
primary
If a DNA sample were composed of 20% guanine, what would be the percentage of thymine?
30
Watson and Crick’s model of DNA was different from other scientists’ previous models because in their model
the bases were paired and placed on the interior of the helix and the strands ran in opposite direction.
Which of the following are nucleic acid polymers needed for translation?
mRNA, tRNA, and ribosomal RNA
A plant cell’s DNA can be found in all the following, except:
nucleoid
it can be found in:
a membrane enclosed nucleus
mitochondria
chloroplasts
What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?
ER → Golgi → vesicles that fuse with plasma membrane
A young child is suffering from a metabolic disease and is often tired and fatigued. Which of the following organelles is most likely malfunctioning and causing this disease?
mitochondria
The cytoskeleton is directly needed for all the following cell functions or structures, except
glycosylation
it is needed for: cell junctions trafficking of organelles and vesicles cell mobility phagocytosis
Cells need many items to be viable, but across the diversity of cells there are many components that are not essential. Which of the following items is least essential to a cell and so can be absent from the cells of some species?
mitochondria
Which structure-function pair is mismatched?
smooth ER; translation of membrane-bound proteins
correctly matched: centrosome; assembly of microtubules ribosome; translation nucleolus; transcription of ribosomal RNA Golgi; glycosylation
Which type of cell would be best for studying the lysosome?
phagocytic macrophage cells of the immune system
Researchers trying explain how vesicular transport occurs in cells attempted to assemble the transport components. They set up microtubular tracks along which vesicles could be transported, and they added vesicles and ATP (because they knew the transport process requires energy). Yet, when they put everything together, there was no movement or transport of vesicles. What were they missing?
motor proteins
Amoebae move by crawling over a surface (cell crawling), which involves _____.
growth of actin filaments to form bulges in the plasma membrane
Where would you expect to find plasmodesmata?
between plant cells
Which of the following processes involves a solute moving across the membrane AGAINST its concentration gradient?
co-transport
What will happen to a red blood cell (RBC), which has an internal ion concentration of about 1.2 percent, if it is placed into a beaker of pure water?
The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
catabolism
Which of the following is a statement of the first law of thermodynamics?
energy isn’t created or destroyed
What kinds of molecules pass through cell membranes most easily (unassisted)?
small and hydrophobic
Relative to bacteria that live in the arctic, the membranes of bacteria found near the oceans’ thermal vents _________.
contain a higher percentage of saturated phospholipids
Which of these are NOT embedded in the hydrophobic portion of the lipid bilayer?
peripheral proteins
these are embedded:
ion channels
integral proteins
transmembrane proteins
Transport across which of the following would NOT change a cell’s membrane potential?
aquaporins
Which of the following reactions types will decrease the entropy in the cell?
anabolic
When ATP releases energy, it also releases inorganic phosphate. What happens to this inorganic phosphate in the cell?
It may be used to form a phosphorylated intermediate.
The metabolic pathway for making the amino acid alanine involves the enzyme pyruvate kinase. Alanine itself is able to bind pyruvate kinase at a site separate from the enzyme’s active site and inhibit its activity. This is an example of all the following, EXCEPT
competitive inhibition
During aerobic respiration, electrons travel energetically downhill in the following sequence:
glucose → NADH → electron transport chain → oxygen
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?
100%
During fermentation, pyruvate (or a pyruvate derivative) is _________ as it _________ NADH to generate NAD+ for glycolysis.
reduced… gains electrons from
If the thylakoid membrane is damaged such that the interior of the thylakoid becomes permeable to the stroma, which of the following will most directly be affected?
ATP synthesis via photophosphorylation
Which of the following is NOT part of the light reactions of photosynthesis?
oxidation of NADPH and reduction of a 3-carbon intermediate
In photosynthesis, the cyclic flow of electrons involves
synthesis of ATP
How many glucose molecules can be formed from 16 simultaneous turns of the Calvin cycle?
2
Specialized organs release hormones into the bloodstream as chemical signals that can affect target cells. For the target cell to produce a response to a specific hormone, it must _____.
have receptors that recognize and bind the hormone molecule
If a cell was no longer able to produce GTP, what might happen to its signaling system?
It would not be able to activate and inactivate G proteins on the cytoplasmic side of the plasma membrane.
The “threshold” potential of a nerve cell membrane is the _____.
minimum depolarization needed to operate the voltage-gated sodium channels
The first gap in the cell cycle (G1) corresponds to _____.
normal growth and cell function
Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells?
32
Homologous chromosomes _____.
may carry different versions of the same genes
Upon isolating cells in different phases of the cell cycle you identify a sample of cells that have 1.5 times more DNA per cell than cells found in G1 phase. The cells in this sample are currently in _____.
the S phase of the cell cycle
Which of the following discribes how the process of cytokinesis differs between plant cells and animal cells?
Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate and animal cells form a cleavage furrow made of microfilaments.
Separation of sister chromatids during anaphase would be most affected by a drug that prevents _____.
shortening or disassembly of microtubules
If a species has a chromosome number of 2n = 28, then _______.
each diploid cell has 14 homologous pairs of chromosomes
A particular multicellular organism is diploid during the majority of its life cycle and following meiosis haploid cells are produced. How are diploid cells again generated in this species?
fertilization
Which of the following involves the separation of sister chromatids?
mitosis and meiosis II
In Chapter 14 you are informed that in Mendel’s analyses of inheritance of pea plants he made self-pollinations and cross-pollinations (crosses, or matings) using two different true-breeding plants. For example, in the P-generation (Parental generation) he crossed a true-breeding white flower plant with a true-breeding purple flower plant.
A true-breeding plant, such as a true breeding white flower plant, is one that when self-pollinated produces seeds that give rise to only plants that have white flowers.
Mendel’s crosses between a true breeding purple flower plant and a true breeding white flower plant yielded seeds (peas) that directly gave rise to:
a population of plants in which 100 % of them show purple flowers
Mendel’s crosses between a true breeding purple flower plant and a true breeding white flower plant yielded seeds (peas) that directly gave rise to a population of plants referred to as the:
F1 generation
What term or terms can we appropriately use when referring to the different forms of the gene that specify white or purple flower color in Mendel’s crosses?
Alleles
What best describes a significant difference between a monohybrid cross and a dihybrid cross?
A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid cross involves only one.
In reference to Mendel’s pea plant crosses where he analyzed the inheritance of just one trait: Why did the F1 offspring look like just one of the two P-generation true-breeding parental varieties?
One phenotype was completely dominant over another.
What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?
Traits are inherited in discrete units, and are not the results of “blending.”
At the very end of the first meiotic division which of the following is an appropriate description of the cell’s contents?
It has half the amount of DNA as the cell that began meiosis.
Which of the following best describes the genome at the conclusion of meiosis I?
Homologous chromosomes are separated.
The statement that “chromatids are separated from each other”:
is true for mitosis and meiosis II.
The statement that “Independent assortment of chromosomes occurs”:
The statement is true for meiosis I only.
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCC?
4
Which one of the following statements most correctly differentiates between independent assortment and segregation?
The law of independent assortment requires describing behavior of two or more genes on different chromosomes relative to one another.
An animal has two unlinked genes, one for head shape (H) and one for tail length (T). These are not on sex chromosomes. Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?
HT
In a cross between two parents, AaBbCc and AAbbCc where all the indicated genes are located on different autosomal chromosomes it is observed in the offspring that the phenotype due to the A allele differs between individuals carrying the C allele and individuals carrying the c allele. This is most likely due to:
epistasis
An individual with genotype AaBbCc is crossed with an individual with genotype AAbbCc. What proportion of all the offspring are expected to be of genotype AAbbCc?
1/8
Considering the two parents, (AaBbCc) and (AAbbCc) how many genotypically different gametes can be produced by each parent?
8 from (AaBbCc ): 2 from (AAbbCc)
Considering meiosis in each of two parents, (AaBbCcDD) and (AAbbCcDd) how many genotypically different gametes can be produced?
8 from (AaBbCcDD ): 4 from (AAbbCcDd )
Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?
pleiotropy
Which of the following is an example of polygenic inheritance?
skin pigmentation in humans
Males are more often affected by sex-linked traits than females because
males have one X chromosome compared to two in females.
Which of the following statements is true of linkage?
The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
Recombination between linked genes comes about for what reason?
Crossovers between these genes result in chromosomal exchange.
A particular triplet of bases in the template strand of DNA is 5’ AGT 3’. The corresponding codon for the mRNA transcribed is
3’ UCA 5’.
The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?
A gene from an organism can theoretically be expressed by any other organism.
Which of the following nucleotide triplets best represents a codon?
a triplet in the same reading frame as an upstream AUG
Which of the following provides some evidence that RNA probably evolved before DNA?
DNA polymerase uses primer, usually made of RNA.
Which of the following statements best describes the termination of transcription in prokaryotes?
RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.
Which of the following does not occur in prokaryotic eukaryotic gene expression, but does in eukaryotic gene expression?
A poly-A tail is added to the 3’ end of an mRNA and a cap is added to the 5’ end.
Transcription in eukaryotes requires which of the following in addition to RNA polymerase?
several transcription factors (TFs)
A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that
many noncoding stretches of nucleotides are present in mRNA.
During splicing, which molecular component of the spliceosome catalyzes the excision reaction?
RNA
In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after he has removed its 5’ cap and poly-A tail. Which of the following would you expect him to find?
The molecule is digested by exonucleases since it is no longer protected at the 5’ end.
What is a ribozyme?
an RNA with enzymatic activity
A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that
A) many noncoding stretches of nucleotides are present in primary RNA transcript.
Alternative RNA splicing
B) can allow the production of different proteins of different sizes from a single mRNA.
4) In the structural organization of many eukaryotic genes, an individual exon may relate to which of the following?
C) an individual domain of the polypeptide product
In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after he has removed its 5’ cap and poly-A tail. Which of the following would you expect him to find?
D) The molecule is digested by exonucleases since it is no longer protected at the 5’ end.
Which of the following is the first event to take place in translation in eukaryotes?
E) the small subunit of the ribosome recognizes and attaches to the 5’ cap of mRNA
What is the effect of a nonsense mutation in a gene?
C) It causes premature termination of the polypeptide synthesis during translation
The tryptophan operon is a repressible operon that is
E) turned off whenever tryptophan is added to the growth medium.
Which of the following is a protein produced by a regulatory gene?
repressor
The lactose operon is likely to be transcribed when
D) the cyclic AMP and lactose levels are both high within the cell.
When the function of the newly made polypeptide is to be secreted from the cell, what must occur?
B) Its signal sequence must target it to the ER, from which it goes to the Golgi.
Which of the following is a function of a signal peptide?
D) to translocate polypeptides across the ER membrane
Which of the following is the first event to take place in translation in eukaryotes?
E) the small subunit of the ribosome recognizes and attaches to the 5’ cap of mRNA
A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of correctly attaching phenylalanine to those tRNAs. The consequence of this for the cell will be that
B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.
The role of a metabolite that controls a repressible operon is to
E) bind to the repressor protein and activate its DNA-binding.
Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation to weaken its binding to DNA?
inducer
In positive control of several sugar-metabolism-related operons, the catabolite activator protein (CAP, or CRP) binds to DNA to stimulate transcription. What enhances this CAP activity?
B) decrease in glucose and increase in cAMP
If you were to observe the activity of methylated DNA, you would expect it to
C) have turned off or slowed down the process of transcription.
Two potential devices that eukaryotic cells use to regulate transcription are
D) DNA methylation and histone modification.
Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?
C) Eukaryotic exons may be spliced in alternative patterns.
Transcription of the structural genes in an inducible operon
B) starts when the pathway’s substrate is present.
A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in
A) continuous transcription of the structural gene controlled by that regulator.
Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation?
inducer
Which of the following statements describes the lysogenic cycle of lambda (λ) phage?
C) The phage genome replicates along with the host genome.
Which of the following best describes siRNA?
A) a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA
You are given an experimental problem involving control of a gene’s expression in the embryo of a particular species. One of your first questions is whether the gene’s expression is controlled at the level of transcription or translation. Which of the following might best give you an answer?
B) You measure the quantity of the appropriate pre-mRNA in various cell types and find they are all the same.
What is considered to be the earliest evidence of differentiation in the cells of an embryo?
B) the occurrence of mRNAs for the production of tissue-specific proteins
The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur?
D) Anterior structures would form in both sides of the embryo.
Which of the following statements describes proto-oncogenes?
D) They can code for proteins associated with cell growth.
Which of the following is characteristic of the lytic cycle?
D) Shortly after infection a large number of phages are released upon cell lysis
