BISC300 Lecture Notes - Lecture 17: Mutagen, Polymer, Histidine

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goldsnake224

13 Nov 2017

School

University of Delaware

Department

Biological Sciences

Course

BISC300

Professor

Thomas Hanson

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Document Summary

Induced mean you treated the cell with some agent (virus, chemical: mutations happen all the time, cells can counteract mutations and restore original genome sequence if possible, spontaneous mutations, arise without exposure to external agents. Imino or enol form mispairs: double bond allows c to pair with a instead of g, same thing with t; hydroxyl group instead of double bonded 2, In that first gen progeny, you have this g t base pair. Replication of new generation gives you the same thing until g is corrected. In second generation, 1/4 of progeny cells carries an at base pair in place of a gc base pair. All because of a small chemical alteration in dna: this is relatively rare, at is at a disadvantage and will never dominate population. In genomes, there are coding regions that have homopolymer runs (runs of an a or g, etc).

Related Questions

What is DNA?

1. DNA is often referred to as a ladder. What pieces of the DNA molecule make up the rungs of the ladder (the steps)?

2. What pieces of the DNA molecule make up the sides of the ladder?

3. What types of bond occurs between the bases in the DNA molecule?

4. What makes up chromosomes? What is Gene?

5. How long does it take 1 cell to copy its genetic information? 6. How does the DNA copy itself so fast? What tricks does it use?

7. Describe how the bonds between base pairs work to hold the DNA strand together

DNA Replication

1. How many genes are in the human genome?

2. What are the differences between mRNA and DNA?

3. Where in the cell does transcription and translation occur? (give both places)

4. Which RNA piece reads the mRNA and how does it do this?

5. What is the start sequence? What amino acid does this code for?

6. What 3 codes tell ribosomal RNA to stop reading and release the protein?

DNA Extraction

1. List three differences between the virtual DNA extraction lab and the banana extraction lab you did last week.

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QUESTION 1

How is a bone marrow transplant able to treat someone with leukemia?

		The donor blood contains antibodies that destroy cancer cells
		Donor blood contains stem cells that regenerate cells in the immune system
		Bone marrow contains induced pluripotent stem cells that turn into red blood cells
		Bone marrow contains tumor supressor genes that slow down leukemia growth
		Bone marrow contains pluripotent human embryonic stem cells

1.2 points

QUESTION 2

What would happen if siRNAs designed to target mRNA from an oncogene were introduced into cancer cells?

		Increased genomic instability would result from adding foreign nucleic acids
		New mutations would arise in the oncogene
		The oncogene would be converted back into a proto-oncogene
		The siRNAs would compete with the oncogene's active site
		Production of the oncogene protein would decrease

1.2 points

QUESTION 3

What is the purpose of chromatin-remodeling enzymes in human cells?

		The enzymes control the rate of translation of an mRNA transcript
		The enzymes add phosphate or methyl groups to histone tails
		The enzymes slide nucleosomes farther apart or closer to each other
		The enzymes send damaged proteins to the proteasome for degradation
		The enzymes cause DNA looping to occur

1.2 points

QUESTION 4

If you wanted to resurrect the mammoth, how would you do it?

		Use somatic cell nuclear transfer to insert the mammoth genome into the egg of an elephant
		Use transcription factors to re-program adult cells from elephants into mammoth cells
		Change the gene expression patterns of elephants to increase production of mammoth genes
		Use siRNAs to decrease expression of elephant-specific genes in an elephant embryo

1.2 points

QUESTION 5

How is eukaryotic transcription initiated?

		RNA polymerase is recruited to the start codon by transcription factors
		RNA polymerase begins transcription at the enhancer sequence
		RNA polymerase is activated by binding to GTP
		An initiator tRNA binds to the ribosome
		A complex of proteins forms at the promoter of a gene

I. Signaling cascades (4 pts)

1. Which of the following is an example of a signaling cascade?

A. Binding of lactose to the lac repressor

B. Binding of the lac repressor to the lac operon

C. The series of proteolytic digests that occur during clotting

D. The Collins Toggle Switch

2. Why is it important that signaling cascades have negative feedback loops?

II. Metabolism (4 pts)

1. What is a benefit of a negative feedback allosteric regulator?

A. It prevents starting materials from being unnecessarily consumed.

B. It regulated metabolism without requiring new protein synthesis.

C. It can be rapidly reversed as conditions change.

D. All of the above.

2. How is a metabolic cycle, like the citric cycle, distinct from a metabolic pathway, like glycolysis?

III. Transcription (4 pts)

1. Transcription factors, repressors, and activators are examples of proteins that _________.

A. randomly activate RNA polymerases.

B. bind specific DNA sequences.

C. bind specific rRNA sequences.

D. are found in the lysosome.

2. The trp operon is attenuated by a stem-loop structure that can form near RNA polymerase. The RNA sequencing encoding the stem loop is:

5â-AUACCCAGCCCGCCUAAUGAGCGGGCUU-3â

The stem loop is composed of 7 nucleotides which perfectly base pair. Indicate the two halves of the stem loop on the sequence above.

IV. DNA replication/repair/genome editing (4 pts)

1. What is a consequence of the need for RNA primers during DNA replication?

A. Linear chromosomes gradually shorten each cell division.

B. Transcription factors often trigger DNA replication.

C. RNA primers are not actually needed for DNA replication.

D. Lagging strands can be avoided.

2. CRISPR-mediated genome editing has gene-specific components: an sgRNA, and a double-stranded repair template. Describe the role of the sgRNA in directing genome editing.

V. Genetic circuits (4 pts)

1. Which statement best describes the mechanism of the toggle switch?

A. Inducers must be continuously applied to maintain one of two states.

B. Competing repressors keep the cell in one of two transcriptional states.

C. An activator and a repressor keep the cell in one of two states.

D. A pair of repressors cause the cell to oscillate between two states without input.

2. How is bistability achieved by the Collins toggle switch?

BISC300 Lecture Notes - Lecture 17: Mutagen, Polymer, Histidine

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