Biology 288-Lecture 3

Cell biology

What are two types of cell division?

1) mitosis

2) meiosis

How does the cytoskeleton aid in cell division?

The cytoskeleton realigns and equally divides the chromosomes (mitosis) or half the chromosomes (meiosis)

Other than cell division, what is the purpose of rearranging the cytoskeleton?

It allows for phagocytosis to occur

How does meiosis create genetic variability?

The cells experience a crossing over event during cell division

What is the function of the cell’s filopodia that’s sent out by the cytoskeleton?

The filopodia searches for nearby molecular cues

How does chemotherapy effect the cytoskeleton?

It disrupts cell division by halting the cytoskeleton from aiding cell division at chromosome realignment

How do we prevent chemotherapy from effecting our healthy body cells?

\-We can’t!

\-The best we can do is administer enough chemotherapy that it kills the cancer cell without killing the human

What is the purpose of model organisms?

They allow us to test different components without testing them directly on humans

Why is E.coli a good model organism?

Its easy to grow and its structure is easy to manipulate

Why are rats and mice good model organisms?

\-They have a genome that’s relatively close to the human genome

Although rats and mice have a genome similar to humans, what is the downside of relying on them as model organisms?

Any research done on their genome would be hard to translate to humans for application

Why is it easy to manipulate the genome of rats and mice?

Their genome is easy to manipulate-knockout or knockin genes

What is the purpose of using fluorescence during transplant experiments?

This allows us to track where the tissue goes

Where are PC12 cells derived from?

They are derived from the adrenal gland

Describe the relationship between PC12 cells and cortisol

When cortisol is present, the PC12 cells do nothing, they just divide, but when cortisol is removed, these cells differentiate

Where were Hella cells derived from?

They were derived form the brain tumor of an African American woman

What realization came from the Hella cells?

It allowed us to realize that cells can be grown outside the body

Define immortalization

A cell is modified to divide forever, but not live forever

Why is immortalization necessary?

As cells mature, they become defined making them less likely to divide and in order to study cells for a long period of time they should be able to divide so the experiment can be conducted a number of times

What are non-defined cells?

non-immortalized cells that will divide regularly until they become defined

What are primary cells?

Cells that are taken directly from the organism

What is the Hayflick limit?

cells which are arrested and no longer divide

What do labs use in order to reprogram cells and make them immortalized?

Labs use viruses

Because an immortalized cell essentially divides forever it becomes a _______ cell

Cancerous

Why is an immortalized cell still different than the way it was in the human body although its the same cell?

An immortalized cell is genetically modified and now in a different environment than the human body

Is an organism with more genomes more complicated?

no

What does an increased number of genomes represent if not the organism’s complexity?

It represents the organism’s requirements

What does a larger genome size represent?

It shows an increased number of protein coding genes

Why is the production of protein (DNA-RNA-Protein) not a 1:1 ratio?

Post-transcriptional editing modifies the RNA allowing it to make 2 or more different proteins instead of just 1