Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Bio Lab Test 1 > LAB TEST > Flashcards

LAB TEST Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

LAB 1

What is a standard curve?

A

A standard curve is a curve that describes the relationship between signal intensity and amount of concentration of the analyte.

  • Values known are used to compare with values that are unknown
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

LAB 1

What are standard curves used for?

A

used to quantify the amount of concentration of an analyte in a sample.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

LAB 1

what was on each axis of the graph and what were their units?

A

concentration (x-axis) and absorbance of BSA (y-axis)

concentration (mg/mL)
absorbance of BSA (AU)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

LAB 1

What protein standard did you use to design your standard curve in this lab?

A

Bovine Serum Albumin (BSA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

LAB 1

What’s the reaction in the assay that was used?

A

protein + Cu2+ -> protein-Cu1+ complex + Folin reagent

Blue color ( Absorbance = 750 nm )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

LAB 1

Why were the protein standards and unknown fish species protein samples blue in this lab?

A

Two steps that lead to color development:
1) reaction between the protein and the copper at alkaline pH
2) the subsequent reduction of Folin reagent by the copper-treated protein.

Color development was due to the amino acids tyrosine and tryptophan (with a smaller extent of cystine, cysteine, histidine) present in the protein. The amino acids reduce the Folin reagent, yielding several possible reduced species that have characteristics blue color.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

LAB 1

Why were the unknown muscle protein samples diluted?

A

They were diluted because the solutions of protein samples were too concentrated and not within the range standard of the standard curve.

dilution factor = the total number of unit volumes in which your material will be dissolved.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

mg to microgram?

A

x100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

LAB 1

the purpose of centrifuging?

A

separating the solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

LAB 1

the purpose of vortexing?

A

to mix the solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

LAB 1

what is the purpose of blanking the spectrophotometer?

A

ensures the absorbance measured in the samples is attributed only to the sample material and not the components of the solution the sample is suspended in or the cuvette.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

LAB 1

Purpose of Laemmeli buffer?

A

this is used as a blank to compare your values between samples, more importantly its a control agent that allows your dependent variables are due to an independent variable that you are testing rather than a variable non-specific.

control agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

LAB 2

What is the general purpose of SDS-PAGE electrophoresis?

A

SDS breaks down and denatures the quarternary and tertiary structures of the protein as well as it gives the protein an overall negative charge with the strength relative to the length allowing for protein separation being based on size.

It examines proteins from closely and distantly related fish species, and identifies similarities and differences in this organisms protein profiles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

LAB 2

How did SDS-PAGE electrophoresis help distinguish protein profiles of your different fish
species?

A

It separates the anodes(negative charge) and cathods(positive charge). The negative charged proteins migrate through the gel towards the cathode and away from the anode. They race towards the positive electrode. This separation allows for the protein samples to be compared to the known proteins.
The smaller proteins move faster through the gel compared to the larger ones thus the proteins over time get separated by size.
This basically ends up separating the proteins according to their size.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

LAB 2

Why were actin and myosin protein used as standards in the gel?

A

actin and myosin were used to determine the size of the unknown proteins because the molecular weight of the protein standards are known.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

LAB 2

Why was a protein ladder standard included in the gel?

A

This is used to estimate the molecular weight of the sampled proteins and monitors the progress of the electrophoretic separation.

as the SDS-page separates the protein by size, a protein ladder standard can be used to estimate the molecular weight of the proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

LAB 2

what is the purpose of Tris-HCI?

A

This is a buffering substance that plays the role of preserving the peptide bonds of the protein and preventing the bonds from breaking apart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

LAB 2

what is the purpose of Glycerol?

A

This compound has the primary role of ensuring that the sample of protein moves down into the well smoothly.

19
Q

LAB 2

what is the purpose of Bromophenol Blue?

A

This is used to indicate the sample in the gell for a human eye.

20
Q

LAB 2

What is the purpose of Diothiothreitol (DDT)?

A

This compound is used to break the disulfide bonds.

21
Q

LAB 2

Why is knowing the direction of electrical current flow in a gel so important? From which
electrode to which electrode should current flow?

A

The direction of electrical current flow is important because it separates the proteins based on size and thus allows one to identify the unknown samples.
The current should flow towards the cathod side (positive side) as the SDS page adds a negative charge to the proteins. The negative electrodes to the postive electrodes. Anodes to cathods.

22
Q

LAB 2

Before loading a protein sample into a gel well, which two main steps must be done to the
proteins?

A

adding a tracking dye (Bromophenol blue)
reheating the frozen samples to redissolve any precipitated detergent.

IDKKK

23
Q

LAB 2

What is the unit of measurement for protein mass?

A

kDa ( kilo dalton )

24
Q

LAB 2

what is a caldogram?

A

a branching diagram that represents the common characteristics of certain species. (common ancestors they share)

based on protein bands that fish have in common and their common ancestors

25
Q

LAB 2

 Do you know these technical and analytical skills:
o Reading the separation of proteins and determining their molecular weight to a known
protein standard ladder in a gel
o Designing a cladogram based on a comparison of protein bands on a gel

A

GOT TO LAB REPORT

26
Q

LAB 3

Know the structure and function of enzymes. How are they affected by changes in pH and
temperature?

A
  • Enzymes are proteins that help catalyze reactions (speed them up).
  • amino acids linked together forming a polypeptide bond - a three dimensional structure.
  • contains an active site where the substrate attaches to for the reaction to begin.
  • temperature raised= speeds it up
  • temperature decreased = slows it down
  • change in pH = slows the reaction down

you keep all other variables that can affect the rate constant, so that you can specifically look at the effect of your variable.

27
Q

LAB 3

What is the function of catalase enzyme and where is it found?

A

The function of catalase is to help remove hydrogen peroxide by breaking it down into harmless products.
Found in the peroxisomes of mammalian cells.

catalase= uses hydrogen peroxide as its substrate

28
Q

LAB 3

What reaction does catalase catalyze? What is the substrate? The products?

A

it speads up the decomposition of hydrogen peroxide into water and molecular oxygen

substrate = hydrogen peroxide
products = water + oxygen

29
Q

LAB 3

what is the purpose of doing control runs?

no substrate(control 1) OR boiled enzyme(control 2)

A

control runs are used to determine if our signal is dependent on the enzyme and the substrate added to the reactions in order to measure the background in the assay.

negative controls used in this lab

30
Q

LAB 3

What is meant by the initial reaction rate (V0)? Why did most of the initial reaction rates decline over time?

A

The initial rates helps us calculate a rate for the reaction condition (whether that being the reactants completely converted to products or the reaction reaches chemical equilibrium. Calculating the initial rate allows one to know what type of condition it is.
The rates decrease over time because the reactant is turning into the product therefore you are getting smaller concentrations of substrate.

**the rate describes how much of the substrate is used over time **

31
Q

LAB 3

what is the relationship between the reaction rate and subtrate concentration and why does it plateau at a certain subtrate concentration?

A

The relationship between the reaction rate and the substrate concentration is hyperbolic. If you increase the subtrate concentration, you are also increasing the rate of reaction. However eventually all the active sites will be occupied and the reaction rate will stay constant regardless or the addition of substrate creating a plateau on a graph.

32
Q

LAB 3

What does Vmax and Km from an enzyme saturation curve mean about the relationship between
enzyme, substrate and product of a reaction?

A

Vmax= the max reaction rate that can be achieved from the addition of substrate to an enzyme
Km= measure of the inverse of the enzymes affinity ( an enzyme with a small Km requires only a small amount of subtrate to become saturated ). - mainly its a measure of the substrate concentration required for effective catalysis to occur.
Dividing Vmax by the number of enzyme molecules gives you the number of substrate molecules each active site converts to product per unit time when functioning at its maximum capacity.

affinity= the tendency for the enzyme to bind to subtrate

33
Q

LAB 3

What is the difference between competitive inhibitor and non-competitive inhibitor?

A

competitive= attaches to the active site of the enzyme, decreasing the chances of the subtrate binding with the enzyme. - slows down the rate of reaction. - Vmax stays the same and Km increases
non-competitive= attached to the enzyme in an area other than the active site ( allosteric site ), however causes a conformational shape change to the enzyme. - Vmax decreases and Km stays the same

34
Q

LAB 3

How does a change in Vmax or Km help identify which type of inhibitor it is?

A

competitive = Vmax stays the same and Km increases
noncompetitve = Vmax decreases and Km stays the same

35
Q

LAB 3

is the intial rate taken at the beginning of the reaction or near the end?

A

beginning of the reaction as you want the most concentration of the reactants. If you take the rate at the end, you are mainly getting the data of the new formed products.

36
Q

LAB 3

what is the expected shape of a curve of a reaction rate and substrate concentration?

A

should curve to a plateau. The rate increases as there is an increase of subtrate concentration. Then when there is the proper amount of substrate bonded to the active site of the enzyme, the reaction remains constant even with the addition of substrate (hence a plateau).

its a hyperbolic relationship between the rate of reaction (initial V) and the substrate concentration.

37
Q

LAB 3

How do you calculate Vmax and Km?

A

Km= 1/2Vmax
Vmax= where the curve plateaus

38
Q

Lab 1

how do you calculate the dilution factor?

A

diluted volume / undiluted volume
=dilution factor

39
Q

lab 1

what is the detection limit in a standard curve?

A

the value of lowest concentration, calculated by the slope

40
Q

lab 1

how do you choose the correct micropipette?

A

choose the one with the smallest volume that is closest to you value.

ex: you want to measure 100 uL so choose the 100uL micropipette.

41
Q

lab 1

ml to ul

A

x1000

42
Q

lab 1

why were the proteins heated to almost 100 degrees?

A

to completely dissolve the preciptate.

so when you put the sample into the spectrophotometer there is only liquid that the light passes through.

43
Q

LAB 1

What would be in the blank control cuvette for the spectrophotometer?

A

Leammli Buffer

place this buffer first as the blank control to which you are testing so that your dependent variable is due to this independent variable and not some other unspecific variable.

44
Q

LAB 3

what happens to the products over time?

A

the reactants are being depleted and the products are accumulating over time.

Bio Lab Test 1 (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions