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Biology 112 Practice Midterm Questions
1. Identify which statement is true or false
I. Bacterial cell walls prevent osmotic lysis
II. All bacterial cell walls contain an LPS layer
III. In a Gram stain, Gram positive cells are purple
IV. Teichoic acid acts to cross link phospholipids
V. Peptidoglycan is a carbohydrate
a)
b)
c)
d)
e)
Statements I, III and V are true
All statements are true
All statements are false
Statements I, III and IV are true
Statement III is true
2. The properties of phospholipids that allow for membrane formation are:
a) amphipathic
b) charged
c) hydrophobic
d) chemotrophic
e) planar
3. Bacteria and Archaea are most similar, when compared to Eukaryotes, in:
a) RNA sequences
b) Metabolism
c) DNA sequences
d) Genome organization
e) Structure
esemble either prokaryotes
4. Similarities between eukaryotes and prokaryotes are:
a) Both contain linear chromosomes
b) Both contain mitochondria
c) Both contain ribosomes
d) Both are unicellular
e) Both exhibit logarithmic growth
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5. A bacterial colony is added to 100ml of LB growth medium. After a 24hr
incubation at 37oC the density of the cell population was measured to be
5x109 cells/mL. Assuming that you inoculated the culture at the beginning of
the log phase of population growth, approximately how many cells did the
bacterial colony contain if the growth rate of the population was 0.5 hour-1?
a)
1.2x106
b)
600
c)
1.2x108
d)
1.6x107
6. If viable count declines but total cell count remains constant, what phase of
growth is a culture in?
a) lag phase
b) exponential phase
c) stationary phase
d) exponential decline
e) all of the above
f) none of the above
Use the following passage to answer questions 7-9. The Gram negative and
Gram positive cell walls differ by a number of characteristics. Identify which
characteristic is associated with which type of cell wall.
A. Gram negative.
B. Gram positive.
7. Has an outer membrane. _______.
8. Has a very thick peptidoglycan layer. _______
9. Contains LPS or lipopolysaccharide. _______
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10) You are comparing the similarity between 4 organisms of unknown ancestry
by rRNA sequencing in order to determine possible phylogenetic
relationships.
i) organism 1 is most different from organism 3
ii) organism 1 is more similar to organism 4 than organism 2
iii) organism 2 is most similar to organism 3
iv) organism 3 is most ancient
Which of the following is a possible order of evolution?
a) 2, 4, 1, 3
b) 3, 4, 2, 1
c) 3, 2, 1, 4
d) 3, 1, 4, 2
e) more than one is correct
11) _________ pathways build complex molecules while ________ pathways
break down complex molecules".
a)
b)
c)
d)
e)
metabolic, catabolic
metabolic, anabolic
metabolic, anabolic
anabolic, catabolic
anabolic, metabolic
12) Which of the following is true?
a)
b)
c)
d)
e)
Mutations always change the phenotype but not the genotype
Mutations always change the genotype and the phenotype
Mutations change the genotype but not the phenotype
Mutations always change the genotype but not the phenotype
Mutations always change the genotype and may or may not change the
phenotype
13) True or false:
Mutations in the non-coding regions of genes will have no effect on the proteins
produced because, by definition, the non-coding regions of genes do not make
up part of the protein itself.
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14) Why do bacteriophages, transposable elements and plasmids often confer
advantageous traits to bacteria?
15) Which statement about viruses is NOT correct?
a) Viruses require host cell proteins for replication.
b) Viral genomes contain overlapping transcriptional units.
c) Some viral genomes are made of DNA-RNA hybrids.
d) Some viral genomes are made of single-stranded RNA.
16) Conjugation is a process by which
a)
b)
c)
d)
e)
vesicles join the plasma membrane
chromosomes are held together during mitosis
bacteria transfer plasmids from male to a female cell
ribosomes move along the mRNA
the original endosymbiont was engulfed by a primitive eukaryote
17) Which of the following statements is false
i) lysozyme is an antibiotic made by animals
ii) Peptidoglycan is an antibiotic made by some bacteria
iii) lysozyme is an antimicrobial enzyme made by animals
iv) penicillin is an antibiotic made by some bacteria
a) 1 statement is false
b) 2 statements are false
c) 3 statements are false
d) all statements are false
e) no statements are false
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18) Which of the following statements concerning the organization of prokaryotic
genes are NOT correct?
1. Most prokaryotic genes contain spacer DNA that must be removed by
splicing.
2. All the nucleotides 5' of the +1 position are called upstream nucleotides and
are not transcribed.
3. Cis-acting elements code for proteins that regulate the transcription of genes
on the same chromosomes.
4. The number of Shine-Dalgarno sequences on a polycistronic mRNA usually
are correlated with the number of ORFs.
5. The ORFs of polycistronic mRNAs are all translated by the same ribosome.
a)
b)
c)
d)
e)
1,2, 3
1, 3, 4
1, 3, 5
2, 3, 4
3, 4, 5
19) Transcribe and translate the following sequence. Promoter is to the right of
the sequence and use the codon table provided (page 143) (Note: you do not
need to outline the steps of transcription or translation).
3’ ATG GTA CCC ATG CGA CAT GTA 5’
5’ TAC CAT GGG TAC GCT GTA CAT 3’
20) How does a cell control the level of gene expression?
a) Degradation of the mRNA transcript using DNAses
b) Promoter strength dictated by binding of ribosomes
c) Affinity of transcription factors for specific sequences
d) Stability of mRNA
e) A and C
f) C and D
21) All of the following statements about membrane structure and function are
true except:
a) diffusion, osmosis, and facilitated diffusion do not require any energy input
from the cell
b) voltage across the membrane depends on an unequal distribution of ions
across the plasma membrane
c) special membrane proteins can cotransport two solutes by coupling
diffusion with active transport
d) diffusion of gases is faster in air than across membranes
e) both sides of a membrane are identical in structure and function
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