Genetics Lab Exam 1

What stage of mitosis is this?

Anaphase

What stage of mitosis is this?

Metaphase

Define homologous chromosomes

Homologous chromosomes are chromosomes that have both their centromere and gene loci in the same location but do not have identical genes aka they may have different alleles but have loci in the same places.

define sister chromatids

a pair of identical chromatids visible during mitosis and meiosis that are formed following replication of DNA of one member of a homologous chromosome pair. They are the product of DNA replication during S phase.

List the 3 parts of interphase

G1 phase, S phase, and G2 phase.

At which stage of meiosis does recombination take place?

Prophase 1

When do the sister chromatids split in mitosis?

during anaphase

When do sister chromatids split in meiosis?

during anaphase 2

What splits during anaphase 1 in meiosis?

The tetrad separates so the pairs of sister chromatids separate but the individual sister chromatids remain attached until anaphase.

What are the 4 possible combinations you can get from genes A, a D, d?

AD, Ad, aD, and ad

At what point during meiosis does the actual segregation occur?

Anaphase 1

What are the steps in the DNA extraction process?

1.obtain a sample of cells. 2. break the cells open. 3. separate the DNA from the rest of the cell material.

All DNA extraction procedures utilize alcohol because DNA cannot dissolve in it. When DNA is mixed with alcohol it solidifies in a process known as _____

Precipitation.

I incubated a fly in a mixture of proteinase K and ATL buffer for several hours at 55 degrees C. The proteinase K broke down the proteins so they would release from the DNA. The ATL buffer contains a detergent. What step in the DNA extraction process did the ATL buffer accomplish for us?

The ATL buffer was used to break open the cells.

If a sample of DNA was not pure, what type of molecule would probably be the source of contamination?

Proteins.

Of the three types of fingerprint patterns (arches, whorls, and loops) which one never has a triradius?

Arches

Where is the closest fire alarm?

Down the hall to the left by the lockers and stair case.

If you catch on fire during the lab what is the first thing that you should do?

Stop drop and roll.

If an accident were to occur in lab what phone number would you call to request assistance (I am not asking who to call but for the actual phone number).

206-7777

If something happened and we had to evacuate the Health Science Building on a clear sunny day, where should we meet so we can verify that everyone is safe?

The quad near PAC.

If you were to drop a beaker and it shattered into pieces what is the first thing you should do?

Tell the instructor.

How does the detergent present in ATL buffer accomplish the step of breaking open the cells?

The detergent breaks open the cells by breaking down the lipids that make up the cell membrane.

There are many different DNA extraction procedures but they all include salt. What is the reason for this?

Salt is added to DNA extractions to neutralize the high negative charge on the DNA molecules and to allow the individual molecules to clump together making it easier for the alcohol to precipitate out the proteins.

What type of charge do DNA molecules have, and what part of the molecule provides the charge? What type of charge does the column filter have?

The DNA molecules have a strong negative charge this comes from the phosphate groups attached to the DNA. The filter has a positive charge.

What type of fingerprint is this?

Whorl

What type of fingerprint is this:

A loop.

What type of fingerprint is this:

An arch.

What phase of mitosis is this?

Telophase.

What do these pop beads represent?

A chromosome.

What do these pop beads represent?

Sister chromatids.

What do these pop beads represent?

Homologous chromosomes

What stage of mitosis or interphase is this?

This is the G1 phase of interphase.

What phase of mitosis, meiosis, or interphase is this?

S phase of interphase.

If there is an emergency and we have to evacuate the Health Science Building on a day where the wether is inclement (bad), where should we meet so we can verify that everyone is safe?

The PAC lobby area near the coffee bar.

Why is it important to not press the plunger past the stop when collecting liquid with a micropipettor?

It is important not to press the plunger past the stop when collecting liquid because if you do press it past stop you could get more liquid then you meant to for instance if you press past stop when trying to get 20 microliters you could end up with 25 microliters.

Why is it important to hold the plunger of a pipette down until the tip has been completely lifted out of the water?

For transferring liquid from the tip, you want to hold the plunger down until you lift the tip out of the liquid because if you release the plunger too soon (i.e. when it’s still in the liquid) then liquid will get sucked back up into the pipette.

What stage of mitosis is this?

Metaphase

What stage of mitosis is this?

Anaphase

What stage of mitosis is this?

Metaphase

What does it mean if your A260/A280 ratio is 1.8?

your sample is 100% DNA

What does it mean if your A260/A280 ratio is 1.4?

Your sample is 75% DNA and 25% protein.

What does it mean if your A260/A280 ratio is 1.1?

Your sample is 50% DNA and 50% protein.

What does it mean if your A260/A280 ratio is 0.8?

Your sample is 25% DNA and 75% protein.

What does it mean if your A260/A280 ratio is 0.7?

Your sample is 100% protein

In a Chi square (X^2) test what does it mean if the null hypothesis is rejected?

The genes are linked.

In a Chi square (X^2) test what does it mean if the null hypothesis is not rejected?

The genes are not linked they are assorting independently.