Bio Lab Final Exam Review

A chain of 4 bacteria has a length of 3 micrometers and a width of .75 micrometers. Assuming that for all bacteria the depth is the same as the width calculate the volume of 1 individual bacterium in mL

3/4 micrometers x .75 micrometers x .75= .423 micrometers x 1 mL/10^12 micrometers

The overall thickness of the lipid bilayer of the cell membrane is 4x10^-3 micrometers. How many nanometers is this?

4 x10^-3 micrometers= 4 nanometers

volume formula

4/3(pi)(r^2)

What was the wavelength that absorption was measured in the enzyme experiment?

405 nm

which 2 of the following wavelengths would account for the highest rates of photosynthesis? 425, 550, 600 or 700

425 and 600

The temple triathlon consists of a 5 km road run, a 2 km swim and a 10 km bicycle race. This year's winner covered a total of how many centimeters?

5 km= 5x10^3 m= 5 x10^5 cm 2 km= 2x10^5 cm 10 km= 10 x10^5 cm = 17 x 10^5 cm = 1.7 x 10^6 cm

32.01 meters + 5.325 meters +13 meters=

50.335= 50 meters (sig figs)

Balance the equation for photosynthesis CO2+ H2O= C6H12O6 + O2

6CO2+ 6H2O= C6H12O6 + 6O2

How is a buffer made?

A buffer is made by combining a weak acid with its salt so that this solution can act as an acid (gives up H3O+) and act as a base (accept H3O+)

What is 10% SDS and what was its purpose?

A detergent that pokes holes in membranes , emulsifies oils making them more soluble with water and denatures proteins

What is the purpose of lysozyme?

They break down the cell wall of bacterial cells making them susceptible to osmotic shock

What is the point of the tube with the tRNA

To see if our DNase was contaminated with RNase

What is the Micahelis Menten equation written in 2 ways?

Vp/Vmax= S/(S+Km) Vp= Vmax/ (1+ Km/S)

In the DNA lab where did the DNA come from

Wild type E coli

During the cell electrophoresis stage of the DNA lab we set up 5 tubes, what was special about them?

Xp+1 = control tube with DNA, buffer, water, DNase and stop solution C1= DNA, substrate, water no DNase C2= DNA, buffer, water heat killed DNase C3= Stop solution + DNA, buffer, water, DNase, not heated C4= tRNA, buffer, water, DNase

What is the definition of a buffer

a solution that resists changes in pH when small amounts of acid or base are added.

What is the Henderson Hasselbach equation?

pH= pKa +log ([A-]/[HA]) A- = conc of conjugate base HA= conc of acid

What else is crucial to a nucleic acid

phosphate group

S phase...

replication of chromosomes

What is the E coli suspended in

saline- EDTA

The biological source of the enzyme was...

serum

G2 is when...

synthesis of structures for cell division specifically

What is the name for the sugar part of a nucleic acid

the deoxyribose

what is e in OD

the molar extinction coefficient which is the OD of a 1 M substance in a 1 cm light path

In the photosynthesis experiment what was the source of carbon dioxide

the sodium bicarbonate

Structure of Leucine

nonpolar

Valine

nonpolar

You have a .5 M stock solution of Coomassie Blue. How many mL of this solution would you need to prepare 100 mL of a 20 mM solution

(.5 M)(x)=(100)(.02 M) = 4 mL

What is OD equal to

(e)(C)(l) e= molar extinction coefficient C= concentration of solute l= distance or length of tube

While constructing the standard curve in last weeks enzyme lab you used a dilution of the standard whose concentration was .025 mM. Given that the final volume was 4 mL calculate the total number of micromoles in this tube

0.025 mM/1 x .004 L x 10^3 mM= .1 mM

At 40 x magnification, 100 ocular grid divisions are equal to 250 micrometers of the stage micrometer. What is the true diameter of an adipocyte whose diameter measures 12 ocular grid divisions?

1 OG= 2.5 micrometers so 12 OG= 30

In the reaction time experiment done in lab 1 what are 2 sources of variability between different investigators

1 source of variation could have been from the amount of time or count down before dropping the ruler. Another could be the placement of fingers or which fingers used to grab the ruler

What was the pH of the reaction buffer in the enzyme experiment?

10

10 x magnification =

1000/100= 10 micrometers

4x magnification =

1000/40 = 2 micrometers

Molecule X has a molecular weight of 400. A solution of this molecule with a concentration of 4 mg/mL has an absorbance of 1000 when measured at a certain wavelength in a cute with a light path of 1 cm. What is the molar extinction coefficient of Molecule X?

1000= (x)[(4/400)/ 1 L](1 cm) = 10^5 M^-1/cm^-1

A cube has dimensions of 1x1x1 cm^3 what is its volume in terms of cubic micrometers in scientific notation

10^4 micrometers= 1 cm so... V= (10^4)^3 = 10^12

A certain protein has within its structure an alpha helical segment between amino acids 131 and 144. Therefore amino acid positioned at 133 is hydrogen bonded to amino acid at position...

137

given that a particular sample of DNA has 22% adenine how much of the other bases does it have?

22% thymine 28% guanine 28% cytosine

40 x magnification=

250/100 =2.5 micrometers

Which one of the following would provide the best buffering if the solution has to be kept between a pH of 5-7 a. Uric acid (pka=3.9) b Carbonic acid (pka= 6.3) c Hydrocyanic acid (pka= 9.2) d Formic acid (pka= 3.7) e Acetic acid (pka= 4.7)

Carbonic acid

Why did we avoid hard shaking during the DNA extraction process

DNA is a long thin molecule that can be easily separated (2 complementary strands) by shearing forces

What was diffused into the gel during gel electrophoresis to help us see the nucleic acids which can't normally be seen by the naked eye?

ETBR

Lysine

Electrically charged

What is EDTA known to do?

It is a chelating agent, it binds to divalent metal cations like Mg++ that are necessary for nucleases activity

Why did we chose 60 degrees celsius later on?

It is high enough to inactivate most DNases but low enough so DNA is not denatured

What was the purpose of the Ice cold ethanol?

It precipitates DNA from the aqueous layer for separation purposes

The michaelis menten kinetics allow us to figure out Vmax and Km. How can we do this

Km = the substrate concentration at 1/2 Vmax

Polarity amongst the chromatography tlc plates trend in what way

Least polar substances move towards solvent front and most polar substances remain towards origin

You have prepared a solution with 10 g of NaCl in a final volume of 100 mL. Calculate the concentration of this solution in terms of molarity, g/L, mg/mL, micrograms/ L

Molarity: moles/ L = 10/58.5 = .171 moles/ .1 L g/L= grams of NaCl/ Liters of water mg/mL= 10,000 mg/ 100 mL of water= 100 mg/mL micrograms/liter= 10^8 micrograms/L

What are the 3 groups of amino acids?

Non-polar : insoluble in water Electrically charged: R groups ionized at the intracellular pH levels and are water soluble Polar amino acids: polar R group and soluble in water

What is present in bacterial cells the is an enzyme capable of destroying DNA?

Nucleases

what was the name of the product?

PNP

In the enzyme lab what was the name of the substrate?

PNPP

The ratio of the distance the molecule travels to the distance the solvent travels is the

Rf value

What was the name of the enzyme

SAD

In the enzyme lab what was the buffer solution?

Sodium carbonate bicarbonate. 0.1 M with a pH of 10

What temperature was the enzyme lab experiment run?

Standard temperature conditions

The way chromatography helps distinguish between different amino acids is because

The R groups had different solubilities and thus are absorbed differently by the silica gel

G1 of cell cycle is when...

cell growth increase in enzymes and organelles prep for replication

The order of how plant pigments would migrate on a chromatography plate is:

chlorophyll b would be 1st from origin Chlorophyll a xanthophyll carotenoids

what was the color of the substrate?

clear

Arginine

electrically charged

A filter of which color placed in front of the manometer after 45 minutes would account for the slowdown and reduction of oxygen production

green

Which base pairs of nucleic acids have 3 hydrogen bonds

guanine and cytosine

In 1 mole of NaCl after being dissolved in water, there are how many atoms of NaCl? How many molecules of NaCl are there?

in 1 mole of NaCl= 6.022x10^23 atoms 2 atoms per 1 molecule so 2x 6.023x10^23= how many molecules

G1 S and G2 are all part of

interphase

In an aqueous solution of pH 7 amino acids exist in their...

ionized form

Why did we incubate the tube during the DNA lab at 37 degrees celsius

it mocks body temperature

Two enzymes E1 and E2 are both able to catalyze the same chemical reaction. If Km for E1 is larger than Km for E2 what enzyme has the higher affinity for the substrate?

km is proportional to 1/affinity for substrate therefore if E1's km is larger that means the affinity is bigger than that of E2 so E2 has the better affinity

If a protein has a certain amount (n) of peptide bonds, how many amino acids does it have

n+1

does OD have units

no

How do 2 alanine molecules bond together

via a peptide bond peptide bond links by the dehydration of 2 alanine (loss of a water molecule) So the OH group from the COOH and an H from the amine group of the other alanine molecule are removed and thats where the peptide bond forms O-C--N

What are the axes of the standard curve graph?

x= concentration y= absorbance or O.D.

In the michaelis menten equation what are the variables for the equation that give us y=mx+b for the line weaver burk plot

y= 1/Vo m=km/vmax x=1/[S] b= 1/vmax

in the enzyme lab, suppose the standard curve for PNP had this trend line: y=0.0178x+0.003 What would be the concentration of the product if the absorbance reading is 0.235.

y=absorption x= conc solve for x .235= .0178x+.003

What was the color of the product?

yellow