DNA Chromosomes & Genomes I Flashcards

1
Q

What happens to the chemical structure of a gene when it is passed from a cell to daughter cell?

A

It is mostly uchanged.

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2
Q

In the 19th century, it was found that chromsomes contain DNA and protein in ___ amounts.

A

Equal

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3
Q

In a study, S strain cells were fractionated into classes of purified molecules. All of the molecules produced S strain cells except for DNA. What can be concluded from this?

A

The molecule that carries the heritable information is DNA.

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4
Q

What is found at the 5’ end of DNA?

A

Phosphoryl end

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5
Q

What is found at the 3’ end of DNA?

A

Hydroxyl end

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6
Q

How are sugars and bases linked?

A

Covalently via glycosidic bonds.

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7
Q

Are DNA strands arranged parallel or anitparallel?

A

Antiparallel.

Each strand’s sequence is complementary to the parter.

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8
Q

What are the purines?

A

Adenine and guanine

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9
Q

What are the pyrimidines?

A

Cytosine and thymine

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10
Q

How many hydrogen bonds are found between adenine and thymine?

A

2

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11
Q

How many hydrogen bonds are found between guanine and cytosine?

A

3

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12
Q

What is a genome?

A

A complete set of information in an organism’s DNA.

The entire genome must be duplicated and passed to the daughter cell.

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13
Q

Each human cell contains ___ copies of each chromosome

A

2

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14
Q

In humans, there are __ paies of autosomes and __ sex chromosomes

A

22 pairs of autosomes

2 sex chromosomes

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15
Q

When do translocations commonly occur?

A

During an abnormal recombination event.

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16
Q

Translocations commonly occur during abnormal events, such as cancer. Translocation can also be useful for what purpose?

A

Maintaining the correct amount of genetic material

17
Q

What are genes?

A

The information-containing elements that determine the characteristics of a species.

18
Q

Does condensation of chromosomes occur during interphase or mitosis?

A

Mitosis

19
Q

What are three chromosome requirements?

A

DNA replication origin

Centromere

Telomeres

20
Q

What DNA binding proteins are involved in forming chromosomes?

A

Histones and non-histone chromosomal proteins.

21
Q

What makes up chromatin?

A

Proteins and nuclear DNA.

22
Q

What is the most basic unit of chromosome packing?

A

The nucleosome

23
Q

How is DNA digested?

A

It is digested by nucleases. It cuts between nucleosomes and degrades exposed DNA between nucleosome core particles.

24
Q

How many proteins are found in each individual nucleosome?

A

8

25
Q

What are histones?

A

Small proteins with a hisone fold. They are what DNA wraps around.

They also have an N terminal amino acid tail that extends out from the core and are subject to covalent modifications important for chromatin regulation.

26
Q

What type of bond hods DNA and histones together?

A

Hydrogen bonds

27
Q

What is the purpose of chromatin remodeling complexes?

A

They allow loosening of DNA/histone contact.

28
Q

The structure of the nucleosome is temporarily changed in chromatin remodeling. What is the consequence of this?

A

DNA is less tightly bound to the histone.

29
Q

What is the zig-zag model?

A

A model in which histones are condensed into a pattern via a zig-zag fashion.

30
Q

What is a primary function of histone tails?

A

They help to condense chromatin. They are largely unstructured, suggesting they are highly flexible.

The tails can also form interactions with adjacent nucleosomes.

31
Q

What is histone H1?

A

A linker histone that contacts both DNA and protein. It changes the path of the DNA as it exits the nucleosome.