Chp 8 - Nucleic Acids Flashcards

1
Q

What are the two general types of nucleic acids, and their primary roles?

A
  1. DNA: Stores and transfers genetic information; passed during cell division.
  2. RNA: Involved in protein synthesis and enzymatic activities.
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2
Q

What are the components of a nucleotide?

A
  1. A sugar (pentose monosaccharide).
  2. One (or more) phosphate groups.
  3. A nitrogenous base.
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3
Q

List three main differences between DNA and RNA.

A
  1. DNA contains deoxyribose; RNA contains ribose.
  2. DNA uses thymine (T), RNA uses uracil (U).
  3. DNA is double-stranded, RNA is single-stranded.
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4
Q

What are the five nitrogen-containing bases, and which are exclusive to DNA or RNA?

A

Pyrimidines: Cytosine (C), Thymine (T, only in DNA), Uracil (U, only in RNA).
Purines: Adenine (A), Guanine (G).

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5
Q

How is a nucleoside formed?

A

A pentose sugar reacts with a nitrogenous base at the anomeric carbon through condensation.

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6
Q

What are the key functions of nucleotides?

A
  1. Building blocks of genetic material.
  2. Carriers of activated intermediates.
  3. Second messengers.
  4. Energy sources (ATP).
  5. Regulate metabolism.
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7
Q

What is the most precise modern definition of a gene?

A

A segment of genetic material that codes for one polypeptide or RNA product.

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8
Q

What is the sugar component in DNA and RNA called?

A

DNA: Deoxyribose
RNA: Ribose

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9
Q

What are the two types of nitrogenous bases?

A

Purines and Pyrimidines.

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10
Q

What are the structural differences between purines and pyrimidines?

A

Purines (A, G) have two rings; Pyrimidines (C, T, U) have one ring.

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11
Q

What type of bond joins nucleotides together in DNA and RNA?

A

Phosphodiester bond.

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12
Q

What is the function of a phosphodiester bond?

A

It links the 3’ carbon atom of one sugar molecule to the 5’ carbon atom of another.

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13
Q

What is the role of ATP as a nucleotide?

A

ATP acts as an energy source in metabolic processes.

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14
Q

Describe the structure of a DNA double helix.

A

Two strands of DNA form a double helix, with a sugar-phosphate backbone and nitrogenous bases paired inside.

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15
Q

What are the complementary base pairing rules in DNA?

A

A pairs with T (2 hydrogen bonds), and G pairs with C (3 hydrogen bonds).

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16
Q

How do base pairing rules differ in RNA?

A

A pairs with U (instead of T), and G pairs with C.

17
Q

What are the differences between a nucleotide and a nucleoside?

A

A nucleotide includes a sugar, a phosphate group, and a nitrogenous base; a nucleoside lacks the phosphate group.

18
Q

What is the role of mRNA in protein synthesis?

A

mRNA carries the genetic code from DNA to the ribosome for translation.

19
Q

What is the role of tRNA in translation?

A

tRNA brings the correct amino acid to the ribosome during translation.

20
Q

What is the function of rRNA?

A

rRNA forms the core of ribosomes and catalyzes protein synthesis.

21
Q

What are plasmids and where are they found?

A

Plasmids are small, circular DNA molecules found in bacteria and some eukaryotes.

22
Q

What is the primary structure of a nucleic acid?

A

The sequence of nucleotides in the polymer.

23
Q

What are the two strands in DNA described as?

A

They are complementary and antiparallel.

24
Q

What is the significance of the antiparallel arrangement in DNA?

A

It allows the formation of hydrogen bonds between complementary bases.

25
Q

What are the key structural differences between DNA in eukaryotic cells and prokaryotic cells?

A

Eukaryotic DNA is linear and stored in the nucleus; prokaryotic DNA is circular and found in the cytoplasm.

26
Q

What are the main features of the universal dogma?

A

Replication, Transcription, and Translation.

27
Q

What are the major roles of RNA in a cell?

A
  1. Protein synthesis.
  2. Enzymatic functions.
  3. Structural components (e.g., rRNA).
28
Q

How does DNA replication occur?

A

By unwinding the double helix and synthesizing new complementary strands.

29
Q

What enzymes are essential for DNA replication?

A

DNA polymerase, helicase, primase, ligase.

30
Q

What are Okazaki fragments, and where are they found?

A

Short fragments of DNA synthesized on the lagging strand during replication.

31
Q

What produces sticky ends? What about blunt ends?

A

Cleavage sites off the center in the recognition sequence produce sticky ends. Cleavage sites in the center of the recognition sequence produce blunt ends.