LS23L FINAL EXAM Qs

Which of the following is FALSE about any possible ingredients that can be used in the Sanger Sequencing method?

The four types of dideoxynucleotides are using as the building blocks of the new sequences which extend the newly synthesized strands,

What event is Most responsible for causing the conformational change in the lac depressor of E. Coil?

Lactose allosterically binds to the lac repression, causing a conformational change

Which of the following represent the same orientation in humans?

Posterior and Dorsal

If one wants to measure B-galactosidase activity under different conditions, it is important to take cell density into account primarily because:

if cell density were not measured, one would not know whether more enzyme is being produced because of upregulation, or because of there just being

In the DNA extraction procedure, chelex was added to the sample of your cheek cells. What was the reason for its addition and what mechanism was used to disrupt the cell walls of your cheek cells?

Chelex binds to Magnesium, a cofactor needed for DNase, an enzyme that degrades DNA. The sample was heated to disrupt the cell membrane

Which of the following statements is considered incorrect?
a. The enzyme beta-galactosidase catalyzes the hydrolysis of lactose into galactose and glucose
b. If all the enzymes that a cell will possibly need are produced all the time, then a cell will waste a lot of energy
c. Lactose is the only energy source that bacteria can utilize
d. When lactose is present, it binds to the repressor region of the lac operon, thereby causing a conformational change of the repressor and making it fall off from the operator region
e. The transcription of beta-galactosidase is regulated by the presence or absence of lactose in the environment

c. Lactose is the only energy source that bacteria can utilize

In the Sanger method of DNA sequencing, DNA synthesis stops when a _____________ is encountered.

Dideoxyribose base

Which of the following is TRUE regarding DNA sequencing and amplification:
a. Taq polymerase is resistant to denaturation caused by heat
b. Mitochondrial DNA is amplified using the Chelex technique
c. Chelex prevents DNA degradation by binding Ca2+
d. PCR is an in vivo DNA synthesis reaction repeated many times
e. Mitochondrial DNA can trace paternal lineage

a. Taq polymerase is resistant to denaturation caused by heat

The mass of a protein as determined by gel filtration is 270kDa. SDS-PAGE analysis of this protein could produce:

two bands -- 100kDa and 35kDa

An electron microscope is different from a compound microscope in all of the ways listed below except:
a. an electron microscope cannot be used to look at living cells
b. an electron microscope has a higher magnification
c. an electron microscope uses beams of electrons to visualize an image
d. an electron microscope is more appropriate for analyzing living prokaryotic cells
e. The two types of microscopes are exactly the same, just one is less expensive

d. an electron microscope is more appropriate for analyzing living prokaryotic cells

The ______________ is the structure that releases bile, which is released into the ______________ where the majority of that fat is emulsified.

gallbladder; small intestine

During the dissection of the rat in lab, which part of the brain was observed?

Pons

Which directional term is incorrect?
a. Ventral is toward the floor
b. Lateral is toward the side
c. Dorsal is toward the back
d. Anterior is toward the front of the body
e. Distal is located away from a point of reference

a. Ventral is toward the floor

What is the major difference between a slide containing lung tissue and a slide containing adipose tissue?

The lungs are denser than adipose tissue in order to withstand respiration

Why were fish used in the Metabolism experiment?

Fish have a variable body temperature and metabolic rate that are influenced by the surroundings

The correct sequence of digestive organs from the anterior end to the posterior end of a rat is:

duodenum, large intestine, rectum

The purpose of performing the Student's t-test and finding the p-value is to:

Determine that the difference in means between two samples is statistically significant

The Spectrophotometer produces a plot of:

The absorption spectrum

While pipetting for an experiment, your P20 shows the values 1, 2, 8 from top to bottom respectively. How much did you pipette?

12.8 microliters

Which of the following is incorrect regarding Electrophoresis?
a. Electrophoresis confirms the presence of purified DNA visually and confirms the DNA purity
b. Gel electrophoresis can determine whether the amplified DNA is the correct size or composed primarily of primer-dimer
c. The polyacrylamide gel is used in the DNA analysis lab
d. When the unknown DNA is compared with markers of known molecular weights and quantity, the relative intensity of unknown DNA to the marker DNA can be estimated
e. In an agarose gel, EtBr intercalates between DNA base pairs and fluoresces under UV light

a. Electrophoresis confirms the presence of purified DNA visually and confirms the DNA purity

For the biochemical assay of B-galactosidase activity, why is the absorption at 600nm greater at 70 minutes compared to 20 minutes?

There are more cells

What elements within a haplogroup are found to be similar?

haplotypes

Why would a scientist choose to use polyacrylamide instead of agarose for gel electrophoresis?

He wants to separate DNA with very small size differences.

What is a molecular clock?

The rate of change of mutation of a particular gene.

Which of the following is INCORRECT?
a. Difference in pore size allows one to resolve smaller fragments on agarose gels than on acrylamide gels.
b. Polypeptides were visualized via fluorescence of the FITC tag, while DNA fragments were visualized using ethidium bromide
c. DNA has a uniform charge to mass ratio while polypeptides must be treated with SDS to confer a uniform ratio
d. DNA fragments can be resolved in both agarose gels and polyacrylamide gels
e. In our labs, polypeptides were resolved in a polyacrylamide gel while DNA fragments were resolved in an agarose gel

a. Difference in pore size allows one to resolve smaller fragments on agarose gels than on acrylamide gels.

Which of the following mutations would most likely remain in the genome of a species for generations after it occurs without being selected against?

A 3 base pair change in the control region of mitochondrial DNA d-loop

What pipette would you use to measure 0.5mL?

P1000

Which of these descriptions of PCR is not correct?
a. PCR is simply an in vitro DNA synthesis reaction repeated many times
b. In the first step of PCR, DNA parental strands are denatured at 94 degrees C
c. PCR requires the sequencing primer to amplify the DNA
d. Taq polymerase is used because it is heat resistant to denaturation.
e. PCR is used to amplify the region of DNA for sequencing

e. PCR is used to amplify the region of DNA for sequencing

When using SDS-PAGE, proteins are separated on the basis of their ________________.

Molecular weight

The enzyme beta-galactosidase breaks down ____________ into simpler sugars ____________ and ____________.

Lactose; glucose; galactose

Which human evolutionary theory is supported by analysis of maternal inheritance through analyzing mitochondrial DNA?

Recent African origin theory

In the goldfish lab, you divided the rate of oxygen consumption by the weight of the fish:

To ensure that the different size of the goldfish does not affect results

Which of the following tissue will appear the most vascularized (have the highest density of blood vessels)?

Lung tissue

The human heart is __________ to the stomach.

Superior

A p-value is _____________________, and when the p-value is ______________, the null hypothesis is rejected.

The probability of making a mistake in accepting the experimental hypothesis; low

When the goldfish are inside the oxygen chamber, the oxygen level is expected to ____________ over time because the chamber is a ___________ system.

Decreased; closed

The number of fish used in the metabolism experiment:

Does not matter as long as the number remains consistent throughout the experiment and that they have enough oxygen available in the chamber for the entire time of the experiment

A scientist got a p-value of 0.039 when testing his data. Assuming there was a small difference between the means in the two groups of his hypothesis, will these results give a significant difference?

Yes, because the p-value is less than 0.05.

Which of these is false regarding measuring metabolism in goldfish?
a. Weight and size of the goldfish have an effect on a goldfish's metabolic rate because they are aquatic organisms
b. The amount of oxygen consumed can be an indicator of a goldfish's metabolic rate
c. Goldfish are preferable compared to rats for manipulating metabolic rates because they are poikilothermic organisms
d. Goldfish are ideal for manipulating metabolic rates because their body temperature remains relatively constant despite environmental changes

d. Goldfish are ideal for manipulating metabolic rates because their body temperature remains relatively constant despite environmental changes

What is the special property of Taq polymerase that allows it to work in a PCR reaction?

It is heat resistant

Which of the following is NOT TRUE regarding the lac operon?
a. Gene I encodes for the lac repressor
b. Gene O is the lac repressor binding site
c. Active beta-galactosidase breaks down lactose into glucose and glycine
d. Lactose binds to the repressor protein, causing an allosteric change
e. As glucose concentrations increase, lactose concentrations decrease

c. Active beta-galactosidase breaks down lactose into glucose and glycine

What would be a reason you would use an agarose gel as opposed to a polyacrylamide gel when running electrophoresis?

It is easy to make since it is nontoxic prior to polymerization and does not need to be made in airtight conditions

Which of the following is not true regarding the BLAST searches?
a. The "E-value" indicates the probability of a random match between the two sequences in comparison
b. BLAST searches its database to compare its library of sequences to the sequence the researcher has entered
c. BLAST can search both protein and DNA sequence databases
d. The higher E-value, the more likely your sequence and the sequence in the database are a true match
e. The "score" indicates the degree of homology between your sequence and the sequence in the database

d. The higher the E-value, the more likely your sequence and the sequence in the database are a true match

Which of the following is not true regarding Bioinformatics and Migration Analysis:

Numt refers to nuclear DNA on the mitochondrial genome

Which of the following statements regarding primers is true (as learned in the context of this class)?

Primer specificity is increased by making the 3' (C terminus) end in a G or C, since G and C bind more tightly than A or T

Why do we use SDS in separating proteins in gel electrophoresis?

Gives a overall negative charge and breaks H bonds

Which of the following is NOT true about the lac operon?
a. Glucose binds to the repressor, causing a conformational change
b. The operator region is located between the promoter and the lac operon genes
c. The Lac repressor protein has a separate promoter
d. B-galactosidase can cleave ONPG, as well as its natural substrate
e. The repressor protein is constantly being made

a. Glucose binds to the repressor, causing a conformational change

Which of the following is NOT an important guideline to consider when designing primers?
a. Repeating bases in a row
b. Melting temperature
c. Length
d. Presence fo G or C at the 5' end
e. G-C content

d. Presence fo G or C at the 5' end

Polymorphic sites are defined as regions in a DNA segment that are not conserved between individuals. Which of the following primers would be the best for successfully beginning polymerization at a unique site?

A long strand along a region with no polymorphisms

Which Gene encodes for the Lac Repressor that binds on the Lac Operon Operator?

I gene

All of the following are true descriptions of agents involved in gel electrophoresis except:
a. FITC is a fluorescent tag that can be attached by its isothiocyanate group to the amino terminal and primary amines in proteins so that protein bands become visible under a UV light
b. SDS is an anionic detergent that disrupts non-covalent interactions and confers an overall negative charge to the protein in proportion to its length
c. Polyacrylamide is the gel matrix in which the denatured proteins migrate that is mounted between two buffer chambers containing separate electrodes creating an electrical connection through the gel
d. B-mercaptoethanol is a reducing agent that breaks disulfide linkages between and within polypeptide chains
e. Agar is a stain which binds to proteins so that they may be visualized

e. Agar is a stain which binds to proteins so that they may be visualized

Using gel filtration, the total size of a protein is determined to be 100kD. When the SDS-PAGE technique is applied to the protein, one band of size 40kD and one band of size 30kD appear in the gel. Based on these results, how many total subunits could this protein possess?

3

Which of the following is not true of metabolism?
a. Metabolism is the sum of catabolic and anabolic processes
b. In general, the metabolic rates of ectotherms is lower than that of mammals and birds
c. Fish are poikilotherms, their metabolic rate is highly dependent on their surroundings due to the inability to regulate their body temperature
d. Metabolic rate can be determined by the amount of oxygen consumed in a certain period of time
e. Smaller animals generally have slower relative metabolic rates than larger animals

e. Smaller animals generally have slower relative metabolic rates than larger animals

Which of the following descriptions regarding temperature and the type of organisms is incorrect?
a. Poikilotherms have varying body temperature that matches their ambient temperature
b. Metabolic rate of a frog decreases as its surrounding temperature decreases from room temperature
c. Metabolic rate of a human increases from room temperature
d. Metabolic rate of a fish increases as its surrounding temperature increases
e. Hemeotherms keep constant body temperature

b. Metabolic rate of a frog decreases as its surrounding temperature decreases from room temperature

Which of these regarding the t-test is true?

When you have a p-value of less than 0.05, you can conclude the null hypothesis can be rejected.

Metabolic rate can not be measured by:

Measuring percent NO

During the rat dissection lab, to properly examine inflation of the lungs, the air syringe had to be inserted in the:

trachea

In the metabolism lab, the oxygen level in the chamber should ____________ with time.

Decrease

If you dissected a Rat which died prematurely and had suffered from chronic use of alcohol, which organ would you be most likely to investigate first to determine the most likely cause of the rat's death?

The Liver, because alcohol causes cirrhosis of the liver when consumed in excess, and as the major organ used for detoxification of ingested substances, would lose its detoxifying properties as a result of liver failure

All are true of a compound light microscope except which of the following:
a. It contains two lenses
b. It requires a thin specimen
c. It produces a mirror image
d. It focuses on light that reflects off the surface of the specimen
e. It has discrete increments of magnification

d. It focuses on light that reflects off the surface of the specimen

Suppose I used SDS-PAGE to analyze a protein with two different sized subunits that were connected by a disulfide bond and tagged with a fluorescent marker. In my first trial, I mixed SDS with the protein, but I forgot to add a reducing agent. In the second trial, I mixed both SDS and a reducing agent with the protein. Would I see a difference on the gel between the two trial?

Yes, the first trial will result in one band and the second trial will result in two bands

What do the numbers 1, 4, 6 in succession going down the volume indicator convert to if using the P20?

14.6 microliters

In one step of PCR the temperature is lowered to about 50-60 C, what is the point of this?

Allows the annealing of the primers

A class is studying b-galactosidase activity in a bacterial culture. After a student adds ONPG to their sample, the student adds two drops of chloroform, mixes the samples, and allows the samples to sit transferring the supernatant to a cuvette for a lower than the rest of the class's. What is the best explanation for this?

The student added ONPG to the bacterial cells before lysing the cells. This does not allow the b-galactosidase to come into contact with ONPG, which may have also been damaged by its direct exposure to chloroform

You use ONPG to assay b-galactosidase activity in two E. coli cultures. OD420 values indicate similar concentrations of b-galactosidase in both cultures. You do not measure OD600. You can conclude that:

ONPG was cleaved at approximately the same rate in both cultures

A sample of E. coli would exhibit maximum B-galactosidase activity in the presence of which combination of nutrients?

luria broth and lactose

Which statement of the following is true of SDS-PAGE Electrophoresis?

Smaller proteins subunits migrate further because they have a smaller mass

The following description is for PCR. Choose one that is not correct.
a. For the first step of PCR, DNA parental strands are denatured at 94 C
b. PCR is used to make more copies of DNA for sequencing
c. The Taq polymerase is used because it is resistant to denaturation
d. PCR is Polymerase Chain Reaction
e. PCR is an in vivo DNA synthesis reaction

e. PCR is an in vivo DNA synthesis reaction

For SDS-PAGE, the ladder had multiple subunits because:

It is used to identify the size of different subunits

The reducing agent, b-mercaptoethanol, in SDS-PAGE:

reduces disulfide bonds which denatures the protein

A protein composed of four subunits with all different sized is added to a buffered with NO reducing agent and then analyzed with SDS-PAGE. "How many bands should appear if two of these subunits are connected by disulfide bonds?"

3

A high 260nm/280nm spectrophotometer absorption ration indicates which of the following?

Good nucleic acid purity

You are analyzing a tissue from a mammalian species. Some of the characteristics you notice are multinucleate cells, striations, and fairly compacted cells. Which of the following tissues best fits this analysis?

Skeletal muscle

Which organ is the most dorsal in a rat?

Kidney

Which anatomical term describes the position of the ear pinnae relative to the nose in both rats and humans?

Lateral

Which of the following statements concerning compound microscopes is FALSE?
a. there are various levels of discreet magnification in a compound microscope
b. the specimen must be dead in order to be observed
c. light passes through the specimen into the viewer's eye
d. the image produced is a mirror to what is actually observed
e. the compound microscope is composed of two lenses

b. the specimen must be dead in order to be observed

All are true of a compound light microscope except which of the following:
a. It focuses on light that reflects off the surface of the specimen
b. It produces a mirror image
c. It requires a thin specimen
d. It has discrete increments of magnification
e. It contains two lenses

a. It focuses on light that reflects off the surface of the specimen

When selecting the proper microscope to view a sample, you should choose a/an ________________ microscope to look at a fresh lung tissue (whole organ), a/an _____________ microscope to observe the patterns of cells on a slide, and a/an _____________ microscope to study individual organelles within cells in great detail.

Dissecting; compound; electron

The cecum in your rat is homologous to what in the human body?

Appendix

Goldfish are used in the metabolism lab because:

They are poikilothermic organisms whose body temperature varies with the temperature of their surroundings, making their metabolic rate easier to manipulate

Which directional term is incorrect?
a. Distal is located away from a point of reference
b. Dorsal is toward the back
c. Lateral is toward the side
d. Ventral is toward the floor
e. Anterior is toward the front of the body

d. Ventral is toward the floor

There are several ways to measure the metabolic rate of an organism. All of these are reasons to use oxygen as a way to measure metabolic rate EXCEPT:
a. The change in environment is reflected in the amount of oxygen consumed by the fish
b. A sensor probe can easily detect the amount of oxygen in the water
c. Oxygen is a component of in the respiration pathway and is therefore related to the metabolic rate
d. The closed system of the oxygen chamber allows the change in oxygen consumption to be measured
e. Oxygen consumption decreases the blood flow in the fish that has an effect on the metabolic rate

e. Oxygen consumption decreases the blood flow in the fish that has an effect on the metabolic rate

In the presence of glucose, Beta-galactosidase:

does not have to be produced because there is no need for it

In SDS-PAGE, the movement of polypeptides through the gel will be affected by polypeptide:

Size

Which of the following is NOT TRUE regarding BLAST?
a. stands for Basic Local Alignment Search Tool
b. is a set of homology search programs designed to explore all of the available sequence databases for proteins and DNA
c. The "E-value" indicates the probability of a random match between the two sequence in comparison
d. The best match has the highest "Score" and the highest "E-value"

d. The best match has the highest "Score" and the highest "E-value"

How were the proteins in the SDS-PAGE lab visualized?

The polypeptides were covalently bound to a fluorescent tag that made them visible under UV light

What region of the DNA was used to help construct the phylogenetic trees?

RNA polymerase II (RPB1) gene

Which one of the following statements should not be in the set of rules for primer design?
a. Primers should contain long runs (four or more of the same base in a row)
b. Melting temperatures should be between 55-80 C
c. Guanine and cytosine should make up 50-60% of the total base pairs
d. Primers should between 20-30 base pairs long
e. Primers should end (3') in a G or C, or CG, or GC

a. Primers should contain long runs (four or more of the same base in a row)

Why is Mitochondrial DNA only used to trace maternal lineage?

Because sperm did not contribute its mitochondria upon fertilization

Which of the following statements regarding SDS (sodium dodecyl sulfate) is false?
a. SDS is attached to the protein in the ratio of one SDS every two amino acids to give an uniform negative charge
b. SDS disrupts non-covalent linkages within and between subunits of a protein
c. Even though SDS confers more negative charge to larger proteins than smaller ones, smaller proteins will still go faster toward the positive electrode in gel electrophoresis
d. SDS is sodium laurel sulfate
e. SDS breaks disulfide linkages between subunits of a protein

e. SDS breaks disulfide linkages between subunits of a protein

Which of the following statements is true about ONPG used in the biochemical assay lab?
a. two of these
b. ONPG has a similar structure to lactose
c. all of these
d. ONPG is a compound that is naturally present in all bacterial cells
e. B-galactosidase cleaves ONPG to produce o-nitrophenol, which is a yellow compound that can be sued as an indicator of b-galactosidase activity

a. two of these

In the beta-galactosidase assay, units of enzyme activity:

Described the amount of beta-galactosidase produced per E. coli cell per minute

Which of the following organs is not located in thoracic cavity?
a. Lung
b. Diaphragm
c. Right common carotid artery
d. Salivary Glands
e. Rectum

e. Rectum

The four-lobed organ found in the thoracic cavity is most likely the:

Right lung

T-test helps the scientific studies to rely on comparison between two or more:

Population groups

Which of the following is not red/pink in the rat?
a. cecum
b. jejunum
c. duodenum
d. lungs
e. hearts

a. cecum

The heart on the rat is located ___________ to the stomach.

Anterior

Using skills obtained from the Histology lab, please identify the mammalian tissue sample with the following characteristics: branching of thin, pink strands, clear globular spaces, and at high magnification, there are red dots dispersed within the branches.

Lung

What does the spleen do?

It removes worn-out blood cells and bacteria form the blood and plays a role in immunity

Which structure and function relationship does not make sense?
a. The open spaces in the lungs allows for efficient gas exchange
b. The beating cilia on the inside layer of the trachea functions to prevent unwanted material from entering the lungs
c. The holes observed on bone samples function to hold capillaries for nutrient transport
d. The adipose tissue to spacious to allow efficient movement of fat tissue
e. The web-like structure of neurons are dendrites and axons that function to transport electrical charge across the length of the neuron

d. The adipose tissue is spacious to allow efficient movement of fat tissue