Which of the following is most generally false relating to energy?
Kinetic energy relates to movement
Potential energy arises from the location or structure of matter
Energy cannot be converted between forms
Light is the main way energy enters our ecosystem
The disorder of the universe is increasing
Which of the following is most generally true relating to energy?
Catabolic pathways are associated with an increase in entropy
Free energy is the non-entropic energy change for a process
Spontaneous processes take in free energy from their surroundings
Metabolic pathways in a cell have evolved to reach equilibrium
An endergonic process gives out energy
Which of the following best describes why ATP is important in cells?
It can bind to DNA
It removes phosphate groups from proteins
Its ribose sugar is an energy source
It gives out energy when the bond to the terminal phosphate is broken
It accepts electrons from respiration
Which of following is false with respect to enzymes?
They speed up certain reactions
They lower the activation energy barrier for certain reactions
They can change shape when a substrate binds
They can only be regulated by molecules binding to their active site
They can be subject to feedback inhibition
Which respect to energy metabolism, which of the following statements is false?
Cells need energy from external sources
Energy obtained from nutrients is primarily stored as ATP
Energy metabolism depends on reduction of organic compounds, such as sugars
Carbohydrates, fats and proteins are all sources of fuel for respiration
Electrons from redox reactions are often transferred to NAD+ making NADH
Which of the following statements best describes the process of aerobic respiration?
It converts glucose to methane
It primarily generates NADH
It is the oxidation of pyruvate
It makes ATP, mostly through substrate-level phorphorylation
It links redox reactions to create high energy molecules
A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is most likely it's classification?
Animalia
Eukarya
Archaea
Fungi
Protista
What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?
Nucleus > ER > Golgi
ER > Golgi > vesicles that fuse with plasma membrane
ER > Lysosomes > vesicles that fuse with plasma membrane
Golgi > ER > lysosomes
ER > Golgi > nucleus
In the cells of some organisms, mitosis occurs without cytokinesis. This will result in:
cells with more than one nucleus
cell cycles lacking an S phase
destruction of chromosomes
cells that are unusually small
cells lacking nuclei
In an analysis of the nucleotide composition of DNA, which of the following will be found?
A + C = G + T
G + C = T + A
A = G and C = T
A = C
Which of the following sets of materials are required by both eukaryotes and prokaryotes for replication?
G-C rich regions, polymerases, chromosome nicks
nucleosome loosening, four dNTPS, four rNTPS
ligase, primers, nucleases
topoisomerases, telomerases, polymerases
double-stranded DNA, four kinds of dNTPs, primers, origins
A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is
3' UGA 5'
3' UCA 5'
5' TCA 3'
3' ACU 5'
either UCA or TCA
Which of the following is true of fermentation?
It produces glucose
It has a net production of NADH
There is a net consumption of ATP to produce pyruvate
During the process, lactate is converted into ethanol
It produces less ATP per glucose than aerobic respiration does
Which of the following statements is generally false?
Fermentation takes place in mitochondria
Glycolysis takes place in the cytosol
In lactate fermentation, production of lactate from pyruvate consumes NADH
ATP is produced during fermentation
Oxygen is not consumed by fermentation
Which of the following is generally true?
The citric acid cycle in eukaryotes produces acetyl CoA
The citric acid cycle in eukaryotes consumes NADH
During oxidative phosphorylation NAD+ and FAD are consumed
During oxidative phosphorylation CO2 is produced
During oxidative phosphorylation energy is dissipated as electrons progress through the transport chain
Which one of the following statements is false?
Hydrophobic molecules associate together to minimise their contact with water
If there is 20% guanine in a molecule of DNA, there must be 30% cytosine in that molecule
Steroids are hydrophobic
mRNA is exported from the nucleus to allow ribosomal protein synthesis to occur
A change in 1 unit of pH comes from a 10-fold change in proton concentration
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursoer, tubulin. Surprisingly, this stops mitosis. Specifically, Taxol must affect
chromatid assembly
the formation of the mitotic spindle
the S phase of the cell cycle
anaphase
formation of the centrioles
You have the technology necessary to measure each of the following in a sample of animal cells: chlorophylls, organelle density, picograms of DNA, cell wall components, and enzymatic activity. Which would you expect to increase significantly from M to G1?
cell wall components and DNA
chlorophyll and cell walls
organelle density and enzymatic activity
organelle density and cell walls
chlorophyll and DNA
Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
One of the daughter cells, but not the other would have radioactive DNA
Radioactive thymine would pair with nonradioactive guanine
All four bases of the DNA would be radioactive
DNA in both daughter cells would be radioactive
Neither of the two daughter cells would be radioactive
Which of the following provides some evidence that RNA probably evolved before DNA?
RNA polymerase does not require localised unwinding of the DNA
DNA polymerase has proofreading function
RNA polymerase makes a single stranded molecule
RNA polymerase uses DNA as a template
DNA polymerase uses primers, usually made of RNA
A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which of the following might this illustrate?
The sequence evolves very rapidly
The sequence does not mutate
The sequence is found in many but not all promoters
The sequence is transcribed at the start of every gene
Any mutation in the sequence is generally selected against
There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the facts that
The rules for base pairing between the third base of a codon and tRNA are flexible.
Some tRNAs have anticodons that recognise four or more different codons
Many codons are never used, so the tRNAs that recognise them are dispensible
The DNA codes for all 61 tRNAs but some are then destroyed
Competitive exclusion forces some tRNAs to be destroyed by nucleases
Which of the following is the first event to take place in translation in eukaryotes?
Base pairing of activated methionine-tRNA to AUG of the messenger RNA
Elongation of the polypeptide
The small subunit of the ribosome recognises and attaches to the 5' cap of mRNA
Covalent bonding between the first two amino acids
Binding of the larger ribosomal subunit to smaller ribosomal subunits
When translating secretory or membrane proteins, ribosomes are directed to the ER membrane by
a specific characteristic of the ribosome itself, which distinguishes free ribosomes from bound ribosomes
moving through a specialised channel of the nucleus
a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane
a signal sequence of RNA that precedes the start codon of the message
a chemical signal given off by the ER
Why might a point mutation in DNA make a difference in the level of a protein's activity?
It might exchange one serine codon for a different serine codon
It might substitute an amino acid in the active site
It might substitute the N-terminus of the polypeptide for the C-terminus
It might result in a chromosomal translocation
It might exchange one stop codon for another stop codon
In order for a eukaryotic gene to be engineered into a bacterial colony to be expressed, what must be included in addition to the coding exons of the gene?
eukaryotic tRNAs
eukaryotic polymerases
a bacterial promotor sequence
eukaryotic ribosomal subunits
the introns
The tryptophan operon is a repressible operon that is
turned off only when glucose is present in the growth medium
turned on only when tryptophan is added to the growth medium
permanently turned on
turned off whenever tryptophan is added to the growth medium
turned on only when glucose is present in the growth medium
A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in
inactivation of RNA polymerase by alteration of its active site
continuous transcription of the structural gene controlled by that regulator
complete inhibition of the transcription of the structural gene controlled by that regulator
irreversible binding of the repressor to the operator
continuous translation of the mRNA because of alteration of its structure
The lactose operon is likely to be transcribed when
the cyclic AMP and lactose levels are both high within the cell
the cyclic AMP levels are low
there is more glucose in the cell than lactose
there is glucose but no lactose in the cell
the cAMP level is high and the lactose level is low
All of the following are part of a prokaryotic cell except
a cell wall
an endoplasmic reticulum
ribosomes
a plasma membrane
DNA
What is the structural feature that allows DNA to replicate?
Complementary pairing of the nitrogenous bases
Twisting of the molecule to form an alpha-helix
Sugar-phosphate backbone
Three-component structure of nucleotides
Disulfide bonding (bridging) of the two helixes
White blood cells engulf bacteria through what process?
osmosis
phagocytosis
pinocytosis
receptor-mediated exocytosis
exocytosis
Which of the following types of molecules are the major structural components of the cell membrane?
phospholipids and cellulose
nucleic acids and proteins
phospholipids and proteins
proteins and cellulose
glycoproteins and cholesterol
How do the daughter cells at the end of mitosis and cytokineses compare with their parent cell when it was in G1 of the cell cycle?
the daughter cells have half the number of chromosome and half the amount of DNA
the daughter cells have the same number of chromosomes and twice the amount of DNA
the daughter cells have the same number of chromosomes and the same amount of DNA
the daughter cells have half the amount of cytoplasm and half the amount of DNA
the daughter cells have the same number of chromosomes and half the amount of DNA
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
8%
16%
31%
42%
It cannot be determined from the information provided.
DNA has two functions: It can self-replicate, and it acts as a template for the transcription of RNA. DNA is capable of these functions because:
Its two strands are held together by easily broken covalent bonds
its nucleotides can base pair with both ribose and deoxyribose nucleotides
its replication is semi-conservative
replication and transcription are thermodynamically spontaneous and require no enzymes
What is meant by the description "anti-parallel" regarding the strands that make up DNA?
the twisting nature of DNA creates non-parallel strands
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
Base pairings create unequal spacing between the two DNA strands
One strand is postively charged and the other is negatively charged
One strand contains only purines and the other contains only pyrimidines
In E. coli, there is a mutation in a gene called dnaB that stops the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?
No proofreading will occur
No replication fork will be formed
The DNA will supercoil
Replication will occur via RNA polymerase alone
Replication will require a DNA template from another source
To repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act?
exonuclease, DNA polymerase III, RNA ligase
helicase, DNA polymerase I, DNA ligase
DNA ligase, nuclease, helicase
DNA polymerase I, DNA polymerase III, DNA ligase
endonuclease, DNA polymerase I, DNA ligase
What is the function of topoisomerase?
relieving strain in the DNA ahead of the replication fork
elongating new DNA at a replication fork by adding nucleotides to the existing chain
adding methyl groups to bases of DNA
unwinding the double helix
stabilising single-stranded DNA at the replication fork
In eukaryotes, general transcription factors
bind to sequences just after the start site of transcription
are required for the expression of specific protein-encoding genes
inhibit RNA polymerase binding to the promoter and begin transcribing
bind to other proteins or to a sequence element within the promoter called the TATA box
usually lead to high level of transcription even without additional specific transcription factors
Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to
cut the plasmid with res enzyme X and then insert the gene into the plasmid
cut the plasmid twice with res enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with res enzyme X
cut the plasmid with restriction enzyme X and insert the fragments cut with res enzyme Y into the plasmid
cut the DNA again with res enzyme Y and insert these fragments into the plasmid cut with the same enzyme
insert the fragments cut with res enzyme X directly into the plasmid without cutting the plasmid
A principal problem with inserting an unmodified mammalian gene into a BAC, and then getting that gene expressed in bacteria, is that
bacterial RNA polymerase cannot make RNA complementary to mammalian DNA
prokaryotes use a different genetic code from that of eukaryotes
bacteria translate polycistronic messages only
bacteria cannot remove eukaryotic introns
bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible with mammalian DNA
The reason for using Taq polymerase for PCR is that
only minute amounts are needed for each cycle of PCR
it binds more readily than other polymerases to primer
it has regions that are complementary to primers
it is heat stable and can withstand the temperature changes of the cycler
all of these are correct
What do we mean when we use the terms monohybrid cross and dihybrid cross?
a monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents
a monohybrid produces a single progeny, whereas a dihybrid produces two progeny
a monohybrid results in a 9:3:3:1 ratio whereas a dihybrid gives 3:1
a dihybrid cross involves organisms that are heterozygous for two characteristics and a monohybrid cross involves only one
a monohybrid is performed for one generation, dihybrid for two
Why did the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?
the traits blended together during fertilisation
no genes interacted to produce the parental phenotype
different genes interacted to produce the parental phenotype
one phenotype was completely dominant over another
each allele affected phenotypic expression
Two plants are crossed, resulting in offspring with 3:1 ratio for a particular trait. What does this suggest?
That the parents were true breeding for contrasting traits
that each offspring has the same alleles for each of two traits
that a blending of traits has occured
that the parents were both heterozygous for a single trait
that the trait shows incomplete dominance
Which of the following would you expect of a eukaryote lacking telomerase?
a high probability of somatic cells becoming cancerous
production of Okazaki fragments
inability to repair thymine dimers
a reduction in chromosome length in gametes
high sensitivity to sunlight
If cells were unable to produce histone proteins, which of the following would be a likely effect?
there would be an increase in the amount of "satellite" DNA produced during centrifugation
the cell's DNA couldn't be packed into its nucleus
spindle fibers would not form during prophase
amplification of other genes would compensate for the lack of histones
pseudogenes would be transcribed to compensate for the decreased protein in the cell
Why do histones bind tightly to DNA?
Histones are positively charged, and DNA is negatively charged.
Histones are negatively charged, and DNA is positively charged.
Both histones and DNA are strongly hydrophobic
Histones are covalently linked to the DNA
Histones are highly hydrophobic, and DNA is hydrophillic
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
All organisms have experienced convergent evolution
DNA was the first genetic material
The same codons in different organisms translate into the different amino acids
Different organisms have different numbers of different types of amino acids
The nitrogenous base adenine is found in all members of which group?
proteins, triglycerides, and testosterone
proteins, ATP, and DNA
ATP, RNA, and DNA
a glucose, ATP, and DNA
proteins, carbohydrates, and ATP
Which of the following statements best describes the termination of transcription in prokaryotes?
RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase
RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript
RNA polymerase transcribes through an intron, and the snRNPs cause the polymerase to let go of the transcript
Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome
RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA
Which of the following does not occur in prokaryotic eukaryotic gene expression, but does in eukaryotic gene expression?
mRNA, tRNA, and rRNA are transcribed
RNA polymerase binds to the promoter
A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end
Transcription can begin as soon as translation has begun even a little
RNA polymerase requires a primer to elongate the molecule
Which of the following is a function of a poly-A signal sequence?
It adds the poly-A tail to the 3' end of the mRNA
It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~ 10-35 nucleotides away
It allows the 3' end of the mRNA to attach to the ribosome
It is a sequence that codes for the hydrolysis of the RNA polymerase
It adds a 7-methylguanosine cap to the 3' end of the mRNA
In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein?
ligase
RNA polymerase I
RNA polymerase II
RNA polymerase III
primase
When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?
0%
100%
25%
50%
75%
Cystic fibrosis affects the lungs, 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?
epistasis
multiple alleles
incomplete dominance
codominance
pleiotropy
Which of the following DNA mutations is most likely to be damaging to the protein it specifies?
a codon substitution
a base-pair deletion
a substitution in the last base of a codon
a codon deletion
a point mutation
Lipid soluble hormones
have a receptor on the surface of the cell
include the catecholamines
can diffuse through the lipid bilayer
exclude the sex hormones
have receptors coupled to 2 messenger systems to mediate their effect
The human mitochondrial genome has approx
5000 base pairs
6000 base pairs
9000 base pairs
16,000 base pairs
50,000 base pairs
Which of the following is most generally true of mitochondrial disorders?
they are always transmitted via maternal inheritance
they are always transmitted via paternal inheritance
a male does not transmit a mutation to his offspring
they often occur following a mutation that occurs de novo
can be cured by genetic techniques
Common clinical features of myopathy do not include
ptosis
myopathy
optic atrophy
diabetes mellitus
thyroid disease
What is the likely inheritance of a disorder that has 2 apparently normal parents, an affected daughter and son, and two healthy sons?
autosomal dominant condition
autosomal recessive condition
sex linked condition
new mutation in offspring
none of the above
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
there is redundancy and ambiguity in the genetic code
many nucleotides are needed to code for each amino acid
nucleotides break off and are lost during the transcription process
there are termination exons near the beginning of mRNA
Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on the specificity in the
binding of ribosomes to mRNA
shape of the A and P sites of ribosomes
bonding of the anticodon to the codon
attachment of amino acids to tRNAs
bonding of the anticodon to the codon and the attachment of amino acids to tRNAs
There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that
some tRNAs have anticodons that recognise four or more different codons
the rules for base pairing between the third base of a codon and tRNA are flexible
many codons are never used, so the tRNAs that recognise them are dispensible
the DNA codes for all 61 tRNAs but some are then destroyed
competitive exclusion forces some tRNAs to be destroyed by nucleases
Which of the following is a function of a signal peptide?
To direct an mRNA molecule into the cisternal space of the ER
to bind RNA polymerase to DNA and initiate transcription
to terminate translation of the messenger RNA
to translocate polypeptides across the ER membrane
to signal the initiation of transcription
The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in
a base-pair substitution
a nucleotide mismatch
a frameshift mutation
a polypeptide missing an amino acid
a nonsense mutation
Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?
a deletion of a codon
a deletion of two nucleotides
a substitution of the third nucleotide of an ACC codon
a substitution of the first nucleotide of a GGG codon
an insertion of a codon
Graves disease
is a disorder of cortisol expression
is associated with weight gain
is a result of excess TSH hormone production
has a characteristic eye appearance
is most common in childhood
Tetraploidy is how many sets of chromosomes?
one
two
three
four
five
Downs syndrome is a consequence of
trisomoy 5
trisomoy 8
trisomoy 13
trisomoy 15
trisomoy 21
Osteoporosis is most common in
young women
older men
elderly Maori females
elderly Caucasian females
elderly with no racial preference
Which of these statements is NOT true of genetic disorders?
for a recessive X linked trait to be expressed, a female needs 2 copies
for a recessive X linked trait to be expressed, a male needs 1 copy
X linked recessive conditions are more commonly expressed in females
X linked recessive conditions are more commonly expressed in males
X linked genes follow specific patterns of inheritance
Which of these is not an X-linked condition?
colour blindness
Duchenne muscular dystrophy
Haemophilia A
Haemophilia B
Mitochondrial myopathy
Which of these statements best describes our knowledge of the accurate inheritance of extranuclear genes?
There are always inherited maternally
They are always inherited paternally
They can come from either parent
They are more commonly from the mother
They are more commonly from the father
A lack of which molecule would result in the cell's inability to "turn off" genes?
operon
inducer
promotor
ubiquitin
co-repressor
Which of the following mechanisms is used to coordinate the expression of multiple, related genes in eukaryotic cells?
Genes are organised into clusters, with local chromatin structures influencing the expression of all the genes at once
The genes all have the same enhancer sequences regardless of genomic location, and allow activators to turn on their transcription simultaneously
The genes are organised into large operons, allowing them to be transcribed as a single unit
A single repressor is able to turn off several related genes
Environmental signals enter the cell and bind directly to promoters
If you were to observe the activity of methylated DNA, you would expect it to
be replicating nearly continuously
be unwinding in preparation for protein synthesis
have turned off or slowed down the process of transcription
be very actively transcribed and translated
induce protein synthesis by not allowing repressors to bind to it
When DNA is compacted by histones into chromatin fibres, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which process mediates this dynamic activity?
DNA supercoiling at or around H1
methylation and acetylation of histone tails
hydrolysis of DNA molecules where they are wrapped around the nucleosome core
accessibility of heterochromatin to phosphorylating enzymes
nucleotide excision and reconstruction
The number of protein-coding sequences is much smaller than expected. Which of the following accounts for the most of the DNA that does not code for proteins?
"junk" DNA that serves no purpose
rRNA and tRNA coding sequences
DNA that is translated directed without being transcribed
non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function
non-protein-coding DNA that is transcribed into several kinds of small RNAs without biological function
The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called
RNA interference
RNA obstruction
RNA blocking
RNA targeting
RNA disposal
What is the most likely diagnosis for this condition: A 6 year old boy presents to the paediatrician with muscle weakness that is making it difficult for him to walk. He has an older brother with the same condition. His medical notes refer to "Gowers sign" being positive
Cushings syndrome
Polymyositis (inflammation of muscle
Which of the following is NOT an example of a virus promoting cancer?
Human papilloma virus
Ebstein Barr virus
Hepatitis B virus
Influenza virus
Human T cell lymphotropic virus
Which of the following best describes siRNA?
a short double-stranded RNA, one of whose strands can complement and inactivate a sequence mRNA
a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns
a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor
a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits
a molecule, known as a DICER, that can degrade other mRNA sequences
BRCA1 and BRCA2 are considered to be tumor-suppressor genes because
they prevent infection by retroviruses that cause cancer
their normal products protect the cell by participating in repair of DNA damage
the mutant forms of either one of these promote breast cancer
the normal genes make estrogen receptors
they block penetration of breast cells by chemical carcinogens
Which of the following statements describes proto-oncogenes?
their normal function is to suppress tumor growth
they can code for proteins associated with cell growth
They are introduced to a cell initially by retroviruses
They are underexpressed in cancer cells
They are produced by somatic mutations induced by carcinogens
The cancer-causing forms of the Ras proteins are involved in which of the following processes?
cell-cell adhesion
cell division
relaying a signal from a growth factor receptor
DNA replication
DNA repair
The host range of a virus is determined by
the proteins in the host's cytoplasm
the enzymes produced by the virus before it infects the cell
the enzymes carried by the virus
whether its nucleic acid is DNA or RNA
the proteins on its surface and that of the host
Which of the following statements about the DNA in one of your brain cells is true?
Each gene lies immediately adjacent to an enhancer
The majority of genes are likely to be transcribed
It is the same as the DNA in one of your heart cells
Many genes are groups into operon-like clusters
Most of the DNA codes for proteins
Red green colour blindness is caused by a sex-linked recessive gene. What is the probability that the first son born to a colour blind man and a woman with normal vision whose father was colour blind will also be colour blind?
1/4
1/2
c1
nil
1/3
Which of the following is most generally false?
A water molecule is polar
Sodium chloride forms an ionic solid
Water hydrogen bonds to chloride ions
Water forms van der Waals interaction with sodium ions
Water does not form van der Waals interactions with chloride ions
Which of the following is most generally true?
Bases have a positive charge
Acids have a low pH
The proton concentration in neutral water is 10-7 M
When a solution is buffered there is an equal balance of protons and hydroxide ions
Carbon dioxide dissolves in water to give a basic solution
Which of the following is NOT a property of carbon that is important in the context of living systems?
It forms strong bonds to other carbon atoms
It can form molecules with a variety of different shapes
Compounds consisting of only hydrogen and carbon are hydrophilic
The tetrahedral shape of carbon in some molecules allows it to form enantiomers
Carbon can form strong bonds with oxygen, hydrogen, nitrogen and sulphur
Which of the following molecules is a polymer built from structurally related building blocks?
Leucine
Adenoside triphosphate
A fatty acid
Cellulose
Cholesterol
Most human-infecting viruses are maintained in the human population only. However, a zoonosis is a disease that is transmitted from other vertebrates to humans, at least sporadically, without requiring viral mutation. Which of the following is the best example of a zoonosis?
Rabies
Herpesvirus
Smallpox
HIV
Hepatitis virus
Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life?
reinfection by a closely related herpesvirus of a different strain
reinfection by the same herpesvirus strain
coinfection with an unrelated virus that causes the same symptoms
copies of the herpesvirus genome maintained in a latently infected host cell
expression of miRNA by host cell suppressing viral replication
In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following would you expect of the genes of the bacteriophage?
regulation via acetylation of histones
positive control mechanisms rather than negative
control of more than one gene in an operon
reliance on transcription activators
utilization of eukaryotic polymerases
Why do RNA viruses appear to have higher rates of mutation?
Replication of their genomes does not involve the proofreading steps of DNA replication
RNA viruses replicate faster
RNA viruses are more sensitive to mutagens
RNA nucleotides are more unstable than DNA nucleotides
RNA viruses can incorporate a variety of nonstandard bases
Antiviral drugs that have become useful are usually associated with which of the following properties?
ability to remove all viruses from the infected host
interference with the viral reproduction
prevention of the host from becoming infected
removal of viral proteins
removal of viral mRNAs
What mediates the assembly of new viruses?
host cells chaperones
assembly proteins coded for by the host nucleus
assembly proteins coded for by the viral genes
viral RNA intermediates
nothing; they self-assemble
How does a bacterial cell protect its own DNA from restriction enzymes?
adding methyl groups to adenines and cytosines
using DNA ligase to seal the bacterial DNA into a closed circle
adding histones to protect the double-stranded DNA
forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching
reinforcing the bacterial DNA structure with covalent phosphodiester bonds
Which of the following statements about fats is most generally false?
Saturated fats form solis at room temperature
Fats do not hydrogen bond to water
There are 3 fatty acids in a phospholipid
a cis double bond in a fatty acid helps reduce membrane rigidity
The polar head group of a phospholipid helps it interact with water
Entropy can be described as
An energy term that increases the universe over time
A measure of the energy available within bonds
An energy term always decreases outside a living system
A force that decreases in spontaneous events
An energy term that always increases within a living system
There is no change in Gibbs free energy
Within a system that is doing work
During glycolysis
Within a living organism
In a reaction at dynamic equilibrium
During the citric acid cycle
Which of the following statements is false?
Anabolic metabolism builds complex molecules from more simple ones
Catabolism generates energy
An enzyme increases the amount of a product formed at equilibrium
Some of the energy stored in food is lost as heat
Catabolic processes increase entropy within the cell
ATP is useful as an energy shuttle because
It breaks down to provdie energy without needing a catalyst
It can donate a phosphate group to a molecule, creating a phosphorylated intermediate
Hydrolysis of ATP to ADP provides more energy than is required to produce ATP from ADP
The Gibbs free energy change for ATP hydrolysis is positive
It localises within membranes
Which of the following does not represent a common mechanism for regulation of enzyme activity in response to an instantaneous change in a metabolic demand
Inhibitors binding to the active site
Cooperatively between protein subunits
Inhibitors binding to an allosteric site
Feedback inhibition
Activators binding to the active site
The main provider of energy to drive ecosystems on earth is
Oxygen
ATP
Light
Pyruvatc
Glucose
Fermentation does not
Couple with glycolysis
Produce ATP
Consume pyruvate
Use the electron transport chain
Use NADH/NAD+
A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using
RNA polymerase to transcribe the gene
a restriction enzyme to cut the gene into shorter pieces
reverse transcriptase to reconstruct the gene from its mRNA
DNA polymerase to reconstruct the gene from its polypeptide product
DNA ligase to put together fragments of the DNA that codes for a particular polypeptide
Which of the following is used to make complementary DNA (cDNA) from RNA?
restriction enzymes
gene cloning
DNA ligase
gel electrophoresis
reverse transcriptase
Which of the following best describes the complete sequence of steps occurring during every cycle of PCR? 1. The primers hybridize to the target DNA 2. The mixture is heated to a high temperature to denature the double-stranded target DNA 3. Fresh DNA polymerase is added 4. DNA polymerase extends the primers to make a copy of the target DNA
2, 1, 4
1, 3, 2, 4
3, 4, 1, 2
3, 4, 2
2, 3, 4
DNA microarrays have made a huge impact on genomic studies because they
can be used to eliminate the function of any gene in the genome
can be used to introduce entire genomes into bacterial cells
allow the expression of many or even all of the genes in the genome
all physical maps of the genome to be assembled in very short time
dramatically enhance the efficiency of the restriction enzymes
For a particular microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. The researchers will be looking for:
a particular gene that is amplified in all or most of the patient samples
a pattern of fluorescence that indicates which cells are overproliferating
a pattern shared among some or all of the samples that indicates gene expression differing from control samples
a group of cDNAs that act differently from those on the rest of the grid
a group of cDNAs that match those in non-breast cancer control samples from the same population
Glycolysis in eukaryotes
Occurs only when oxygen is present
Takes place in mitochondria
Generates energy at every step
Generates NADH
Produces lactate
The citric acid cycle in eukaryotes
Uses citrate from glycolysis
Produces acetyl CoA
Is a cytosolic process
Forms CO2
Consumes NADH
During oxidative phosphorylation
NAD+ and FAD are consumed
ATP is generated from the electron transport chain
Energy is dissipated as electrons progress through the transport chain
Carbon dioxide is produced
Protons are pumped into the mitochondrial matrix
Use an electron transport chain
Produce CO2
Consume O2
Occur in the cytosol
