Lab Exam Notes

The proper procedure to use a micropipettor includes __________ it before use.

Unlocking

The maximum volume the P200 micropipettor can take is __________.

200 µL

The P10 micropipettor is designed for volumes between __________.

0.5-10 µL

In a P20 micropipettor, the bottom digit of the three-digit window represents __________.

A decimal place

The purpose of using disposable tips with a micropipettor is to prevent __________ between samples.

Contamination

The first stop on a micropipettor allows you to __________ the correct volume of liquid.

Draw

The second stop on a micropipettor allows you to __________ the entire volume.

Dispense

The primary difference between compound and dissecting microscopes is their __________.

Magnification

A compound microscope can magnify specimens typically between __________ and __________.

40x; 1000x or more

In a dissecting microscope, light is directed onto the specimen's surface, also known as __________ light.

Reflected

The eyepiece of a microscope typically provides __________ magnification.

10x

The __________ is the platform where the specimen slide is placed on a microscope.

Stage

The __________ controls the amount of light reaching the specimen on a microscope.

Diaphragm

To prepare a wet mount slide, you should first place a small drop of __________ on a clean microscope slide.

Liquid

During __________, glucose is converted into pyruvate in yeast fermentation.

Glycolysis

The gas produced during fermented yeast reactions is __________.

Carbon Dioxide (CO2)

delete this

slide

The reaction where starch is broken down into sugars by amylase is essential for __________ to occur in yeast.

Fermentation

Staining enhances the contrast of specimens and highlights specific __________ or components within cells.

Cell structures

The relationship between light levels and the rate of __________ is directly linked.

Photosynthesis

Probiotics are live microorganisms that provide __________ when consumed in adequate amounts.

Health benefits

Selective plating uses specific nutrients to encourage the growth of certain __________ while inhibiting others.

Microorganisms

Gel electrophoresis separates DNA fragments based on their __________.

Size

To determine the size of DNA fragments on a gel, a __________ ladder is used.

DNA

What is the first step in the PCR process? __________.

Denaturation

The purpose of primers in PCR is to ensure amplification of the __________ sequence.

Target

Gel electrophoresis requires an __________ current to separate the DNA fragments.

Electrical

How many base pairs are we looking for in the discussed DNA fragments? __________.

129

PCR amplifies specific DNA sequences through cycles of denaturation, annealing, and __________.

Replication (extention)

When starch is given to yeast but no amylase is present, fermentation will __________ occur.

Not easily

In a paired t-test, you compare the means of the same group under __________ conditions.

Two different

If the t-value is less than the critical value from the t-table, you would accept the __________ hypothesis.

Null

The solvent used in one of the PCR reactions serves as the negative control, which means it contains __________.

No DNA

The visual cue used to see samples on the gel during gel electrophoresis is a __________.

Dye

To enhance visual detection of DNA on a gel, a __________ is used that fluoresces under UV light.

Stain

The chloroplasts are identified in __________ cells as organelles for photosynthesis.

Plant

Methylene blue is commonly used to stain the __________ in cells.

Nucleus

Janus Green B is a stain used to visualize __________ in cells.

Mitochondria

The basic function of amylase is to __________ starch into simpler sugars.

Break down

The experiment with starch shows that starch is produced during __________ and later might be transported out of the leaf.

Photosynthesis

During fermentation in yeast, alcohol is produced alongside __________ as a byproduct.

CO₂

Before you can set up the PCR reaction, you need to know the locus that you intend to __________.

Amplify

The Caulerpa alga was used as a sample to observe the __________ of eukaryotic cells under the microscope.

Structure

Iodine is used to stain starch, showing areas of photosynthesis in a __________ processed plant leaf.

Chemically

The primary role of amylase in the fermentation lab is to ensure starch is converted into __________ sugars for yeast.

Fermentable

In gel electrophoresis, smaller DNA fragments will move __________ through the gel while larger fragments move more slowly.

Faster

The significance of the PCR process in genetics is that it allows for amplification of __________ DNA samples.

Specific

When preparing a wet mount, care should be taken to avoid trapping __________ when applying the coverslip.

Air bubbles

When analyzing results, data on gel electrophoresis can reveal the presence of __________ bands that indicate amplification of multiple DNA segments.

Additional

The total magnification provided by a compound microscope can be calculated by multiplying the __________ by the objective lens magnification.

Eyepiece magnification

What is the The difference between the first and the second stops on a micropipettor 

• First Stop: allows you to draw the correct volume of liquid

• Second Stop: allows you to dispense the entire volume

• Why disposable tips must be used 

• Prevents contamination between samples

Compound vs Disecting Microscope

• Compound Microscope- Used for viewing very small specimens can view things at higher magnification Dissecting Microscope- Designed for low magnification

• Be able to describe how wet mount slides are prepared

• Step 1: Place the Specimen: Place a small drop of liquid (e.g., water or staining solution) on a clean microscope slide.

• Step 2: Add the Sample: Place the specimen (e.g., a leaf, small organism, or a sample from a pond water) into the drop of liquid.

• Step 3: Apply a Coverslip: Carefully place a cover slip at an angle over the drop, avoiding air bubbles. Lower it gently to avoid trapping air bubbles.

• Step 4: Examine: Place the slide on the microscope stage, adjust the light and focus, and examine the sample.

What is the Purpose of Stains:

Staining is used to enhance the contrast of transparent specimens and highlight specific cell structures or components (like the nucleus or mitochondria).

• Iodine is used as a

• Stains starch in plant cells, making it useful for identifying starch storage in cells (e.g., in amyloplasts).

• Why the yeast in your tubes resort to fermentation instead of aerobic respiration

• Lack of oxygen

• What amylase does to starch 

• It is an enzyme that breaks down starch, helps speed up the fermentation process

• The hypotheses for the 3 treatments and the logic behind them 

• 5 % Glucose and yeast will have the second highest rate of fermentation

  • Logic: glucose is already a simple sugar which can be fermented.

• 1 percent Starch and yeast , in the absence of amylase, will have the lowest rate of reaction

  • Starch is a polysaccharide meaning it cannot be fermented unless it is broken down into simple sugars. Yeast can only ferment simple sugars.

•  1 percent Starch, yeast and amylase, will have the highest rate of reaction

  • Amylase is an enzyme so it will speed up reaction rates.

What is the logic process behind the starches

• If plant in dark not going to do photosynthesis, when you remove the plant to the light areas of leaf that is exposed to the light will undergo photosynthesis. Those areas will eventually produce starch. Iodine can be used to stain starch. That iodine stain will stain in the pattern of a picture (only areas that are stained are the ones which starch that has undergone photosynthesis). First boiled it in water then boiled it in ethanol that stripped all of the chlorophyll green color. 

Probiotics

Aid in healthy gut bacteria growth.

Selective plating

• The plates we used were MRS plates kinda orange. It selectively grew only lactobacilli bacteria and not ecoli bacteria. Ecoli can not grow on that plate that is called selective planting. If we had a normal plate like agar ecoli would have been able to grow.

•  What a bp (base pair) is 

• 1 base pair is 1 nucleotide connected through hydrogen bonds

• Also used as a measurement for the length of a DNA fragment

• How PCR works 

• amplifies specific DNA sequences

• First we have to extract our dna then can use for pcr

  • Steps:

• Denaturation: heat up samples so that the dna strands separate

• Annealing: (the attaching step) The reaction is cooled, allowing primers (short DNA sequences) to bind to the complementary regions of the target DNA.

• Replication: The DNA polymerase replicates DNA. 

• Why a reference gene such as FtsZ would be included in your PCR reactions 

• Can help you figure out what is in your sample, didn't do this though because primers of dna did not work

• Why water is used in one of the PCR reactions 

• Water is the negative control because there is no dna in water, 

  • so no pcr content, so there should be no band in the water sample 

• What we need to do (in general terms) to extract DNA 

• Break apart the cell

• Spin the samples 

  • Because we don't want any of the organelles 

• What gel electrophoresis is and how it works 

• Gel Electrophoresis is a method used to separate DNA fragments based on their size.

  • Gel Preparation: A gel matrix (usually agarose) is prepared and loaded into an electrophoresis chamber.

  • DNA Loading: DNA samples (typically mixed with a dye) are loaded into wells at one end of the gel.

  • Electrical Current: An electrical current is applied across the gel. DNA molecules, which are negatively charged due to their phosphate backbone, will move towards the positive electrode.

  • Separation: Smaller DNA fragments move faster through the gel, while larger fragments move more slowly, resulting in separation by size.

• Why we sometimes see additional bands on the gel 

• Amplify more than one part of the dna 

• Primers are not very specific so it binds to multiple parts of dna and produces multiple products (dont want the additional banding)

• How PCR and gel electrophoresis are used in forensic identification of genes or species

• Can amplify human vs animal vs plant dna

• What is The role of the electrical current 

• Positive electrodes that attracts dna and helps it separate out by size

• If we didn't have electrocurrent all pieces of dna would be together won't be separated out so we won't see what's in it