BIO 111 Exam 4

What are the two domains in a transcription factor that respond to a small effector molecule?

1) Site where protein binds to DNA. 2) Site for small effector molecule binding.

Which type of chromosomal mutation will have the MOST detrimental effect on organismal function?

A deletion.

What is a nucleosome composed of?

A little less that 2 turns of DNA wrapped around a histone.

After a tautomeric shift in adenine...

Adenine binds with cytosine.

What are basal transcription factors?

Also known as general transcription factors, they bind to the TATA box in the promoter. They include activators and repressors.

When is a centrosome duplicated?

At the beginning of M Phase.

Homologous chromosomes pair together to form a...

Bivalent.

The visible evidence that exchange of genetic material has occurred is known as...

Chiasma.

What does lacl do?

Codes for lac repressors (highly regulatory, own promoter).

A physical exchange of material between two homologous chromosomes is called...

Crossing over.

What is polycistronic?

DIFFERENT genes, ONE promoter.

What characteristic of DNA makes nucleotide excision repair (NER) mechanisms possible?

DNA is a double helix so once the damaged region is recognized, it can be removed and synthesized based on the opposite strand.

Each centrosome...

Defines a pole.

A single, unreplicated chromosome consists of a single...

Double-stranded DNA molecule.

What does lacZ do?

Enzyme for catabolizing lactose (structural gene).

Methylation of which genes is MOST likely to lead to cancerous cell formation?

Genes that prevent cell division.

The function of sexual reproduction is to increase variation within populations. Meiosis is the molecular mechanism that leads to sexual reproduction. As such, some of the features that make it unique lead to genetic diversity. Which of these unique features are responsible for increasing genetic diversity?

Homologous recombination and reduction division.

When do hydrogen atoms move to form a nucleotide base with altered bonding properties?

In a tautomeric shift.

How does cytokinesis differ between plants and animals?

In animals, two separate daughter cells are formed. In plants, two daughter cells are formed but they share a plasma membrane.

What controls the translation of mRNA that codes for ferritin?

Iron regulatory protein.

What does the mediator do?

It mediates interactions between activators or repressors.

Where is the mediator located?

It partially wraps around GTFs and RNA Polymerase.

Docetaxel is a drug that is used in the treatment of cancer. It interferes with cell division by inhibiting microtubule depolymerization. Specifically, what effect will this have on mitosis?

It prevents sister chromatids from separating during anaphase.

Homologous chromosomes separate from one another during...

Meiosis.

Replicate DNA once, divide the cell twice?

Meiosis.

A cell division follows...

Mitosis and meiosis.

What is an operon?

Multiple genes are regulated together because they have the same promoter.

Where does DNA Methylation normally occur?

On CpG islands.

What does lacO do?

Operator that provides binding site for repressor proteins (regulatory site).

What do astral microtubules do?

Position the spindle in a cell.

RNA Polymerase binds to the...

Promoter.

What does a polar microtubule do?

Separates the two poles.

What are often end products or key metabolites of a metabolic pathway?

Small effector molecules.

Why do chromosomes condense during prophase?

So they will not be damaged when they are moved around the cell.

When a tautomeric shift occurs, the resulting nulceotide is a(n) __________ of the nucleotide prior to the shift.

Structural isomer.

Which of the following features are unique to meiosis?

Synapsis, homologous recombination, and reduction division.

The process of pairing homologous chromosomes is called...

Synapsis.

What allows crossing over?

Synapsis.

What can a promoter mutation affect?

The LEVEL of transcription.

What can a response element mutation affect?

The REGULATION of transcription.

The nucleic acid sequence in mRNA is determined by...

The nucleotide sequence in DNA.

How does the cell regulate the initiation of transcription in eukaryotes?

Through basal transcription factors.

The most efficient control of eukaryotic gene expression is achieved at the level of...

Transcription initiation.

What happens when both lactose and glucose are present?

Transcription is turned off.

What level of regulation do eukaryotes possess that prokaryotes do not?

Transport of RNA out of the nucleus.

Which molecule is produced in the highest quantity during the G2 phase?

Tubulin, the microtubule protein.

Where is a response element located?

Usually 50-100 base pairs upstream (to the right).

Why might a chromosomal duplication be a positive evolutionary force?

With two genes, one is free to mutate and take on a different function that may make it more fit.