Biology Final #1

1

Which of the following statements about electronegativity is true?

Oxygen is one of the least electronegative elements
Water is a polar molecule with a partial positive charge on oxygen due to its electronegativity
Because of its electronegativity, oxygen repels electrons
Water is a polar molecule with a partial negative charge on oxygen due to its electronegativity

2

What important feature(s) of non-covalent bonds makes them so important to life?

They are bonds in which electrons are shared unequally between molecules
They are relatively weak bonds that can be made, broken, and reformed easily in cells
They are bonds in which electrons are shared equally between molecules
They are relatively strong bonds that hold atoms together tightly in cells

3

Assume that RNA polymerase transcribes a gene containing the section of DNA shown below. If the top strand were the template strand, the RNA corresponding to this section would be?

5'-ACGAUUCGCAUC-3'
5'-CUACGCUUAGCA-3'
5'-GATGCGAATCGT-3'
5'GAUGCGAAUCGU-3'

4

Which of the following is true of DNA?

The percentage of A always equals the percentage of G in a double stranded DNA helix
All of the above are true
A phosphate group in one nucleotide is attached to the 3' OH in ribose
The nucleotides in a single strand are connected by the hydrogen bonds
A purine always forms a complementary base pair with a pyrimidine

5

The three-dimensional shape of a protein is determined by the primary, secondary, tertiary, and in many cases, the quaternary structure of the protein. The following are sentences taken from scientific articles on protein structure. For each of the statements, choose the level of protein structure that applies best.

"Hydrogen bonds between peptide backbone components form a distinct helical structure"

Tertiary
Secondary
Quaternary
Primary

6

The three-dimensional shape of a protein is determined by the primary, secondary, tertiary, and in many cases, the quaternary structure of the protein. The following are sentences taken from scientific articles on protein structure. For each of the statements, choose the level of protein structure that applies best.

"There are extensive ionic interactions between positively charged R-groups and negatively charged R-groups on the polypeptide."

Tertiary
Primary
Quaternary
Secondary

7

A particular triplet of bases in the template strand of DNA is 5'-TGA-3'. Which of the following is the anticodon component of the tRNA that binds the mRNA codon transcribed from this DNA? (note that the 3' end of each anticodon is written on the left, and the 5' on the right)

UGA
AGU
AGT
ACU

8

Which of the following molecules would be most likely to diffuse across a plasma membrane?

Small polar molecules
Small charged molecules
Small non-polar molecules
Large polar molecules

9

The interior region of a phospholipid bilayer can be characterized as being:

Hydrophilic and polar
Hydrophilic
Hydrophobic
Polar

10

How do phospholipids interact with water molecules?

The polar heads avoid water; the nonpolar tails interact with water
The polar head groups interact with water; the nonpolar tails do not
Phospholipids don't interact with water because water is polar and lipids are hydrophobic
Phospholipids dissolve in water

11

The process of facilitated diffusion requires:

A concentration gradient
All of the answers
Transport protein
A concentration gradient and transport proteins
ATP as a form of energy

12

How do membrane proteins get to the correct final destination following translation?

They are synthesized by ribosomes on the ER and then directed to their final destination
They are synthesized by ribosomes in the cytoplasm and then directed to their final destination
They are synthesized and modified at their final location (ie. proteins that's function in the nucleus are synthesized and modified on the nuclear membrane)
They are synthesized by ribosome on the ER, modified in the Golgi and then directed to their final destination.

13

In E. coli, lactose binds with:

The lactose operon operator, preventing it from binding to the repressor. This allows the lacZ and lacY genes to be transcribed
The lactose operon repressor, preventing it from binding to the operator. This allows the lacZ and lacY genes to be transcribed
The lactose operon operator, preventing RNA polymerase from being recruited. This prevents the lacZ and lacY genes from being transcribed.
The lactose operon repressor, helping it bind to the operator. This prevents the lacZ and lacY genes from being transcribed
The lactose operon operator, recruiting RNA polymerase. This allows the lacZ and lacY genes to be transcribed

14

Which of the following processes produce different proteins in different cells from the same primary transcript? select all correct choices

Chromatin remodeling
Epigenetic regulation
Histone modification
Alternative splicing
All answers are right

15

Which of the following describes an event that takes place during gene regulation at the level of the chromosome in order for transcription to occur?

Chromatin is remodeled and nucleosomes are repositioned so that specific regions of the DNA can be opened and made available for transcription
Chromatin is remodeled and nucleosomes are repositioned so that the entire chromosome can be opened and made available for the transcription
Chromatin coils more so that it can be more accessible to the proteins that carry out transcription of all genes
RNA polymerase and associated proteins bind to histone proteins of nucleosomes

16

You identify a mutation affecting the lac operon and find the following:
Proteins involved in lactose metabolism are expressed with or without lactose
The repressor is expressed normally
What could be wrong in this mutant?

Glucose levels are high
The CRP-cAMP complex is present at constantly high levels
Glucose levels are low
The operator is mutated so that is cannot bind the repressor
The promoter is non functional

17

Which of the following statements about forming phosphodiester binds during the process of DNA polymerization is incorrect?

None of these choices are correct
The reaction has a positive delta G
The reaction leads to an increase in entropy
The reaction is anabolic
The reaction is endergonic

18

Which of the following statements is true when comparing an uncatalyzed reaction to the same reaction with a catalyst?

Bonds in ATP contain more energy than bonds in other molecules
The negative charges on the phosphate groups repel each other; therefore the molecules contains more energy than can be found in most other chemical bonds
The negative charges on the phosphate groups repel each other; breakin this bind between phosphate group is exergonic, with an intermediate delta G value
The negative charges on the phosphate groups repel each other, making this the most exergonic of all biological reactions

19

HIV is the virus that causes AIDS. In the mid 1990's, researchers discovered an enzyme in HIV, called protease. Once the enzyme's structure was known, researchers began looking for drugs that would fit into the active site and block its function. If this strategy for stopping HIV infections was successful, it would be an example of what phenomenon?

Non-competitive inhibition
Competitive inhibition
Negative feedback
Allosteric regulation

20

Which of the following statements about electronegativity is true?

Oxygen is one of the most electronegative elements
All of the above
Water molecules are able to participate in hydrogen bonds with each other due to a difference in electronegativity between hydrogen and oxygen
A non-polar covalent bond is formed between two molecules with equal electronegativity
A polar covalent bond is formed between two molecules with unequal electronegativity

21

Suppose you discovered a new amino acid. It's R-group contains a hydroxyl (OH) group. Predict the behavior of this amino acid

It will form hydrogen bonds with water
It will form ionic bonds with water
It will form covalent bonds with water
It is hydrophobic

22

Which of the following are covalent bonds?

All answers are correct
Phosphodiester bonds and peptide bonds
Ionic bonds
Phosphodiester bonds
Peptide bonds

23

Which of the following is a monomer of DNA?

All of the above
Nucleotides
Sugar-phosphate backbone
Deoxyribose
Nucleic acids

24

Consider the structure and function of DNA. Which of the following statements is true

Because DNA contains carbohydrates, it provides structural support to the cells
Since DNA is made of phosphate groups that are charged, it could easily pass through a cell membrane
The phophodiester bonds that stabilize the association between two strands of DNA are easily broken and reformed
If the sequence of one DNA strand is known, then the sequence of the other strand can be deteremined

25

Nucleic acids have a definite polarity, or directionality. Stated another way, one end of the molecule is different from the other end. How are these ends described?

One end has a free 3' OH and the other has a free 5' phosphate
One end has a free 3' phosphate and the other has a free 5' OH
One end has a free 3' carbon and the other has a free 5' carbon
One end has one OH and the other has two phosphates

26

Assume that RNA polymerase transcribes a gene containing the section of the DNA shown below. If the bottom strand were the template strand, the RNA corresponding to this section would be?

5'-CUACGCUUAGCA-3'
5'-GATGCGAATCGT-3'
5'-GUAGCGAAUCGU-3'
5'-ACGAUUCGCAYC-3'

27

Adding heat-killed virulent bacteria to a strain of live non-virulent bacteria can transform it into a virulent strain of bacteria that can kill a mouse. This transformation can be prevented by first treating the heat-killed virulent bacteria with:

All of the above
DNase
RNase
Protease
No enzyme

28

Complete the following sentence. An intron is...

A series of amino acids at the end of new polypeptide that directs transcription to the ER
Part of an intact, mature mRNA that leaves the nucleus
RNA that is removed during the processing of an RNA molecules and remains inside the nucleus
A protein that is clipped out post-translationally
A transfer RNA that binds to the codon

29

Secondary structure is characterized by which one of the following types of interactions?

A covalent bond between two cysteines
Hydrogen bonding within the peptide backbone
Ionic bonding between an acidic side chain and a basic side chain
The covalent bond between an amino nitrogen and a carboxyl carbon

30

Which of the following components of an amino acid differs from one amino acid to another?

The carboxyl group
The side chain (R-group)
The a-carbon
The amino group
The hydrogen opposite the R-group

31

If a tRNA is destined to deliver an arginine (Arg, R) to a ribosome for incorporation into a growing polypeptide chain, which of the following 3' to 5' sequences could be its anticodon sequence?

GCU
GCT
CGG
TCG
ACG

32

Which one of the following statements about translation in eukaryotes is incorrect?

All of these statements about translation in eukaryotes are correct
Translation continues until a stop codon is reached
A single processed mature mRNA can only code for one protein
The large ribosome subunit is responsible for catalyzing the peptide bonds
The start codon for each transcript is different

33

Which of the following statements about both cadherins and integrins are true?

They help connect cells and provide structure to tissues
They are transmembrane proteins that attach to cytoskeletal elements inside cells
They are found on virtually all cells
There are many types and they are specific for given cell types
All of these choices are correct

34

Which of the following cellular junctions is involved in creating a barrier between cells to prevent molecules from moving between the cells?

Tight junctions
Gap junctions
Junctions connecting cadherins
Junctions connecting integrins

35

Which of the following statements describes microtubules:

All of the above
The cytoskeletal element that is dynamically instable
Hollow tube-like structures made of polymerized tubulin dimers
The cytoskeletal element with the largest diameter
The cytoskeletal element that has directionality

36

Cytoskeletal proteins combined with motor proteins:

Enable changes in cell shape
All these choices are correct
Enable movement of cells
Use ATP to power shape change and movement
Enable movement of substances within cells

37

Sister chromatids of replicated chromosomes are separated during..?

Meiosis 2
Meiosis 2 and mitosis
Meiosis 1 and mitosis
Meiosis 1
Mitosis

38

Which of the following statements concerning cyclin-dependent kinases (CDKs) is FALSE

CDKs are active, or "turned on", when complexed with cyclins
CDKs are enzymes that attach phosphate groups to other proteins
CDKs are active throughout the cell cycle
CDKs are present throughout the cell cycle
None of these choices are correct

39

Normal genes that have important functions in cells for promoting cell division, sometimes acquire mutations that cause the products of these genes to have negative effects including the development of cancer. These normal, non-mutated, genes are called:

Proto-oncogenes
Oncogenes
Tumor supressor genes
All of the above

40

Homologous pairs of chromosomes are separated during?

Meiosis 1
Meiosis 2
Meiosis 2 and mitosis
Meiosis 1 and mitosis
Mitosis

41

Meiosis results in an increase in genetic diversity because:

Homologous chromosomes recombine via crossing over
Homologous chromosomes line up in a random orientation so that the resulting sex cells inherit a random set of chromosomes from the mother and father
Homologous chromosomes recombine via crossing over and homologous chromosomes line up in a random orientation so that the resulting sex cells inherit a random set of chromosomes from the mother and father
Sister chromatids recombine via crossing over and homologous chromosomes line up in a random orientation so that the resulting sex cells inherit a random set of chromosomes from the mother and father
Sister chromatids recombine via crossing over

42

A homologous chromosome pair is best described as two chromosomes that have?

The same genes possible arranged in a different order with potentially different alleles of some of the genes
Identical sequences of nucleotides
The same alleles of the same genes in the same order
The same genes in the same order but possibly with different alleles of the genes
Different alleles of the same genes arranged in a different order

43

When carbohydrates are oxidized, the C-H and C-C bonds of the carbohydrate become C-O bonds of carbon dioxide. Why is this considered carbon oxidation?

C-O bonds in CO_2 are completely broken down from C-H and C-C bonds in glucose
Electrons in the C-O bonds are higher energy than the electrons in the C-H bonds.
The shared electrons in C-H and C-C bonds are more distant from the C nucleus than shared electrons in C-O bonds
The shared electrons in C-O bonds are more distant from the C nucleus than shared electrons in the C-H and C-C bonds

44

The regulation of phosphofructokinase by ATP is an example of:

Activation energy
Allosteric regulation
Competitive inhibition
Substrate binding

45

Which of the following statements accurately describes steps involved in the production of ATP during oxidative phosphorylation and photophosphorylation?

Electrons are transferred to ATP synthase ad power the production of ATP
Protons are transferred to ATP synthase and power the production of ATP
Potential energy stored in the proton gradienr powers the production of ATP as protons move from high to low concentration through ATP synthase
All of the above
Protons are pumped, via active transport, through ATP synthase to make ATP

46

During photosynthesis,.......is reduced to......

Water; carbon dioxide
Carbon dioxide; glucose
Oxygen; water
Carbon dioxide; oxygen
Glucose; oxygen

47

Water is..... to oxygen by...... during.......

Oxidized; the electron transport chain; cellular respiration
Oxidized; photosystem 2; photosynthesis
Reduced; the electron transport chain; cellular respiration
Reduced; photosystem 2; photosynthesis

48

How are receptors for lipid soluble and insoluble signals similar?

When activated, the signals of both types are transduced across the plasma membrane
When bound to their ligand, both types enter the nucleus to activate transcription
Both typer cause GDP to be exchanged for GTP in a G protein
Both types undergo a conformational change when they bind to their ligand

49

The fight or flight response can be terminated by:

The G-protein hydrolyzing GTP to GDP
Removing epinephrine from the system
Breaking down cAMP
All of these choices
Inactivating adenylyl cyclase

50

Which of the following steps are involved in the fight or flight response?

The signal is amplified; a large response can result from a small signal
An extracellular signal is converted into an intracellular response
All of these choices are correct
Adenylyl cyclase leads to the production of the second messenger, cAMP
Protein kinase A activation leads to the breakdown of glycogen into glucose

51

Which of the following scenarios would still result in signal transduction via the phosphorylation cascade in the absence of ligand binding to its receptor kinase?

A Ras molecules (G protein) that cannot exchange GDP for GTP
A Ras molecule (G protein) that cannot breakdown GTP to GDP
A G-protein coupled receptor that is always active
A consistently active adenylyl cyclase that always produces cAMP

52

Insertions and deletions that occur in multiples of three nucleotides will:

Cause nonsense mutations
Cause frameshift mutations
Add or delete amino acids to/ from the normal polypeptide
Shorten chromosomes
Cause cancer

53

Sequences of genomic DNA and its corresponding mature messenger RNA(mRNA) are often compared to obtain valuable information for genome annotation. Why is this comparison useful?

The genomic DNA is longer because the exons are splices together in the genomic DNA
The exclusion of introns in mature mRNA reveals the intron-exon structure of many protein coding genes
The open reading frame of the mature mRNA includes the introns of the genomic DNA
The genomic DNA is shorter because the exons are spliced together in the mature mRNA
The sequences of genomic DNA and mRNA are identical, which serves as validation of the sequence and structure

54

Which of the following statements contributes to the contradiction that the size of an organism's genome is not directly related to the complexity of the organism?

All of the above
An organism may have more than 2 copies of each chromosome
Some organisms have highly repetitive DNA sequences
Some organisms have transposable elements
Some organisms have high quantities of non-coding DNA

55

The phenotype of an individual results from an interaction between:

Allele frequency and mutation rate
Allele frequency and the environment
Genotype and the environment
Allele frequency and genotype
Genotype and mutation rate

56

There are three alleles for the beta-globin gene. Which of the following statements best describes the effect of having the S allele, which codes for sickle-cell anemia?

The effect depends on whether the allele occurs in its heterozygous or homozygous form
The effect depends on whether the allele occurs in its heterozygous or homozygous form and whether malaria is present
Having the allele is always beneficial
Having the allele is always harmful
The effect depends on whether malaria is present

57

Nondisjunction of X chromosomes may occur during meiosis 1 to form two types of eggs. If normal sperm fertilize these two types of egg, which of the following are possible genotypes of the sex chromosome for the offspring? (0 indicates absence of sex chromosome)

XX and YY
XYY and YO
XXX and XYY
XXY and XO
XYY and XO

58

If you crossed two heterozygous yellow seed pea plants (genotypes Aa):

The relative frequency of green seed plants (aa) would be 1/4
All answers are true
The relative frequency of the A allele in each parent's gametes would be 1/2
The relative frequency of homozygous yellow seed plants(AA) would be 1/4
The relative frequency of the a allele in each parent's gametes would be 1/2

59

The frequency of recombination during meiosis is a function of:

Whether or not the genes are sex-linked; X chromosomes recombine much more frequently than do autosomes
The distance between genes; the closer the genes are to each other, the more frequent the recombination between them
Which alleles are present; recombination happens less frequently among recessive alleles
The distance between genes; the farther apart the genes are from each other, the more frequent the recombination between them
Whether or not the genes are sex-linked; Y chromosomes recombine much more frequently than do the autosomes

60

If genetic contribution to variation (heredity) in a trait is negligible:

Identical twins will be more similar to one another than fraternal twins are to one another
Identical twins will be no more similar to one another than each is to any other sibling
Fraternal twins will be more similar to one another than identical twins are to one another
Identical twins will be no more similar to one another than are fraternal twins
None of these

61

Complex traits are often called.... because they....

Environmental; are influenced by the environment as well as by genes
Quantitative; are described by measurements
Epistatic; are influenced by many genes
External; are influenced by the environment as well as by genes
Qualitative; come in one if several discrete forms

62

When we say that DNA replication is semiconservative, we mean that:

When DNA is replicated, each new double helix contains one parental strand and one newly synthesized daughter strand
Parental DNA stays in the parent cell and daughter DNA ends up in the daughter cell
When DNA is replicated, one double helix contains both parental strands and one contains two newly synthesized daughter strands
Only half of an organism's DNA is replicated during each cell division

63

The leading strand is the daughter strand that has its... end point toward the replication fork and is therefore synthesized...

5'; continuously
3'; discontinuously
5'; discontinuously
3'; continuously

64

The technique of Sanger sequencing uses labeled dideoxynucleotides(ddNTPs) in addition to regular deoxynucleotides (dNTPs) because the ddNTPs will:

Stop polymerization since they do not have a 5' P group to which the DNA polymerase can attach the next nucleotide
Stop polymerization since they do not have a 3' OH group to which the DNA polymerase can attach the next nucleotide
Help define the sequence since they have a color coded 5' P group
Help define the sequence since they have a color coded 3' OH group

65

....mutations affect only the individual in which they occur; .....mutations are passed from parent to offspring

Germ-line; somatic
Somatic; point
Point; germ-line
Somatic; germ-line
Germ-line; heritable

66

Point mutations will have no effect on an organism and its offspring if:

None of these are correct
The mutation occurs only in somatic cells
The new codon codes for the same amino acid as the original codon
The mutation occurs only in germ cells
The new codon codes for an amino acid similar in size and shape as the original codon

67

Define Monophyletic

Consists of an ancestral species and all its descendants
Consists of warm-blooded animals but the most recent ancestor is cold-blooded
Consists of all the descendants of the last common ancestor of the group's members minus a small number

68

What makes up the secondary structure of a proteins

Alpha helices and beta sheets
Alpha helices
Amino acids
Polypeptide chains
Beta sheets

69

Genetic variation is what....

Allows new alleles to enter your population
Throws alleles out that don't belong
Allows new alleles to enter your environment
Categorizes alleles

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