DNA Structure and History Quiz

<p>They are double-stranded DNA (B)</p> Signup and view all the answers

<p>It has a higher G+C content. (C)</p> Signup and view all the answers

<p>They are stronger than those between successive G≡C pairs. (C)</p> Signup and view all the answers

<p>B-form DNA (B)</p> Signup and view all the answers

<p>They are identical when read backward. (C)</p> Signup and view all the answers

<p>Hairpin structures (B)</p> Signup and view all the answers

<p>They cannot form cruciform structures. (A)</p> Signup and view all the answers

<p>G and C (A)</p> Signup and view all the answers

<p>It typically forms under dehydrated conditions. (C)</p> Signup and view all the answers

<p>Hydrogen bonds (B)</p> Signup and view all the answers

<p>Friedrich Miescher (C)</p> Signup and view all the answers

<p>Avery, MacLeod, and McCarty experiments (D)</p> Signup and view all the answers

<p>A = T and G = C (A), A + G = T + C (C)</p> Signup and view all the answers

<p>DNA has a right-handed double helix structure (D)</p> Signup and view all the answers

<p>Different among different organisms (B)</p> Signup and view all the answers

<p>Strands run in opposite directions (D)</p> Signup and view all the answers

<p>DNA was confirmed to be the genetic material after 1952 (C)</p> Signup and view all the answers

<p>Streptococcus pneumoniae (B)</p> Signup and view all the answers

In a double-stranded DNA molecule, adenine (A) always pairs with thymine (T) and guanine (G) always pairs with cytosine (C).

The percentage of adenine (A) in a DNA molecule is equal to the percentage of thymine (T), and the percentage of guanine (G) is equal to the percentage of cytosine (C).

The temperature at which a double-stranded DNA molecule separates into single strands.

A DNA molecule with a higher proportion of guanine (G) and cytosine (C) base pairs will have a higher melting temperature.

Organisms that thrive in high temperatures (like hot springs).

Adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C) in a DNA molecule. These pairs are held together by hydrogen bonds.

The double helix structure of DNA is stabilized by hydrogen bonds between complementary base pairs (A-T and G-C) and interactions between stacked bases.

DNA duplexes with a higher G≡C content are more stable than those with a higher A═T content. This is due to the stronger base-stacking interactions between G≡C pairs.

The B-form is the most common and physiologically relevant form of DNA. It's a right-handed helix with a smooth, uniform appearance.

A-DNA is another form of DNA, often found in dehydrated conditions or when DNA is bound to proteins. It's a wider and more compact helix.

Z-DNA is a left-handed helix with a zig-zag appearance. It's found in certain sequences, often with alternating purines and pyrimidines.

A palindrome is a sequence of nucleotides that reads the same forward and backward on both strands. These sequences can form hairpin or cruciform structures.

A mirror repeat is a sequence of nucleotides that has an inverted, self-complementary sequence within the same strand, but not in the opposite orientation. It cannot form hairpin or cruciform structures.

The substance that carries genetic information in living organisms. It is a long molecule made up of two strands of nucleotides twisted around each other to form a double helix.

Friedrich Miescher was a Swiss physician who first isolated and characterized DNA in 1869. He initially called it "nuclein" due to its phosphorus-containing nature.

Oswald Avery, Colin MacLeod, and Maclyn McCarty conducted groundbreaking experiments in the 1940s to prove that DNA, not protein, was the genetic material. They demonstrated that DNA from a virulent strain of bacteria could transform a nonvirulent strain into a virulent one.

Alfred Hershey and Martha Chase conducted experiments in 1952 that definitively confirmed DNA as the carrier of genetic information. They used radioactive isotopes to label DNA and protein in viruses, showing that only DNA was transferred to the host cells during infection.

Erwin Chargaff's rules state that in DNA, the amount of adenine (A) always equals the amount of thymine (T), and the amount of guanine (G) always equals the amount of cytosine (C). This led to the understanding that the two strands of DNA are complementary.

James Watson and Francis Crick proposed the double helix model of DNA in 1953. This model describes DNA as two strands of nucleotides wound around each other, forming a twisted ladder-like structure.

In the double helix structure of DNA, the two strands run in opposite directions, termed antiparallel. This means that one strand runs from 5' to 3', while the other runs from 3' to 5'.

The two strands of DNA are held together by hydrogen bonds between the bases. Adenine pairs with thymine (A-T) through two hydrogen bonds, while guanine pairs with cytosine (G-C) through three hydrogen bonds.