Lecture 1- Structure Of DNA and Chromsomes Flashcards

1
Q

What are the requirements for genetic information?

A

Stable for storage, available for cellular processes, faithfully replicated, able to control expression of traits, change in a controlled way

Genetic information must be stable for storage, available for cellular processes, faithfully replicated through semi-conservative replication, able to control expression of traits, and able to change in a controlled way, such as through point mutations.

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2
Q

Who isolated nuclein and when?

A

Friedrich Miescher in 1868

Miescher focused on proteins and found nuclein in human pus from bandages, discovering a non-protein substance due to its high molecular weight and acidity.

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3
Q

What did Avery, Macleod, and McCarty discover in 1944?

A

Transforming principle

Their work contributed to the understanding of DNA as the carrier of genetic information.

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4
Q

What was the key finding of Hershey and Chase in 1953?

A

Only DNA was present in bacterial cells

They used bacteriophages labeled with radioactive isotopes to demonstrate that only phosphorus (from DNA) entered the bacterial cells.

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5
Q

What technique did Rosalind Franklin use to study DNA?

A

X-ray crystallography

Franklin’s work suggested that DNA was likely helical with phosphate groups on the outside.

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6
Q

What did Watson and Crick report in 1953?

A

Base pairings and two helical chains

They described the structure of DNA as two coiled helical chains.

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7
Q

What was a controversial aspect of Watson’s career?

A

Pseudoscientific racism

Watson was suspended from his position at Cold Spring Harbor Laboratory in 2007 due to his views.

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8
Q

What was Dr. Dunston’s research focus?

A

Type 2 diabetes differences in populations

He acquired samples from African populations for the Human Genome Project.

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9
Q

What is the structure of DNA described as?

A

Right-handed helix

DNA structure includes pyrimidines (CTU) and purines (AG).

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10
Q

How are nucleosides and nucleotides formed

A

Nucleoside: sugar + base; Nucleotide: sugar + base + phosphate

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11
Q

What is the significance of 3’ and 5’ ends in DNA?

A

Directionality of DNA strands

DNA strands run antiparallel, with each strand having a 3’ and a 5’ end.

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12
Q

How many hydrogen bonds do AT and GC pairs have?

A

AT: 2 H bonds; GC: 3 H bonds

The number of hydrogen bonds affects the stability of the DNA structure.

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13
Q

What are major and minor grooves in DNA?

A

Result from angles between sugar-phosphate backbone

These grooves are important for protein binding and DNA interaction.

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14
Q

What is a genome?

A

All the DNA in the nucleus of a cell or organelle

This includes the mitochondrial or chloroplast DNA.

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15
Q

What is a karyotype?

A

Discrete units of chromosomes

A karyotype is an image showing the number and appearance of chromosomes in a cell.

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16
Q

How is DNA stored in the cell?

A

As chromatin strands

DNA wraps around histone proteins to form nucleosomes.

17
Q

What is euchromatin?

A

Less compact DNA containing frequently expressed genes

Specific acetylation and methylation marks are associated with euchromatin.

18
Q

What is heterochromatin?

A

More compact DNA with less frequently expressed genes

Heterochromatin is typically associated with gene silencing.

19
Q

What is a nucleosome?

A

DNA wrapping twice around 2 histones

20
Q

What is Artemisinin?

A

An anti malarial compound discovered by Tu Youyou made from sweet wormwood