Biology Chapter 4 Flashcards

Questions and Answers

What is a nucleic acid and what are its components?

A macromolecule composed of nucleotide monomers used by cells to store or transmit hereditary information, including ribonucleic acid and deoxyribonucleic acid. Components are (1) a phosphate group, (2) a five-carbon sugar, and (3) a nitrogenous base.

Phosphate group and nitrogenous base are bonded to the sugar molecule.

True

Ribonucleotides are monomers of RNA, have ribose as their sugar, and have an -OH group bonded to the 1' carbon.

False

Describe deoxyribonucleotides.

A nucleotide consisting of a deoxyribose sugar, one or more phosphates, and one of four nitrogen-containing bases: adenine, guanine, cytosine, or thymine. Signup and view all the answers

Ribose and deoxyribose have an -OH group bonded to the 3' carbon.

False Signup and view all the answers

Describe the two groups of nitrogenous bases.

Purines (adenine and guanine) and pyrimidines (cytosine, uracil, and thymine). Signup and view all the answers

Nucleic acids polymerize via?

A polymer of nucleotide monomers. Signup and view all the answers

Phosphodiester linkage occurs between a on 5′ carbon of one nucleotide and on the 3′ carbon of another.

unlinked 5′ phosphate, unlinked 3′ hydroxyl Signup and view all the answers

Phosphodiester linkages form a ____________.

sugar-phosphate backbone Signup and view all the answers

Which of the following statements about James Watson and Francis Crick's findings is correct? (Select all that apply)

Two strands are held together by hydrogen bonds between pyrimidines and purines. Signup and view all the answers

Describe the structure of DNA.

DNA consists of linked deoxyribonucleotides, with two strands running in opposite directions wound into a double helix. Signup and view all the answers

What is the significance of Watson and Crick's model?

It revealed that DNA strands run antiparallel, form a double helix, and demonstrate complementary base pairing. Signup and view all the answers

What are the three steps of DNA replication?

<ol> <li>The DNA strands separate by breaking hydrogen bonds. 2. Free deoxyribonucleotides form hydrogen bonds with complementary bases on the template strand. 3. DNA replication produces two identical daughter molecules.</li> </ol> Signup and view all the answers

Explain how DNA's double helix is highly structured.

It is regular, symmetric, and held together by phosphodiester linkages, hydrogen bonding, and hydrophobic interactions. Signup and view all the answers

Describe the primary structure of RNA.

RNA consists of a sequence of linked ribonucleotides with ribose as the sugar and four nitrogenous bases: A, U, G, C. Signup and view all the answers

RNA's secondary structure results from complementary base pairing: A with _; G with .

U, C Signup and view all the answers

Bases of RNA typically form hydrogen bonds with complementary bases on the?

same strand. Signup and view all the answers

RNA strand folds over, forming a ____________.

structure from a single nucleic acid strand. Signup and view all the answers

Two sugar-phosphate strands are ____________.

antiparallel. Signup and view all the answers

Describe RNA's versatility.

RNA molecules perform various functions and fold into complex 3D shapes, making them multifunctional. Signup and view all the answers

A certain DNA molecule is determined to have a guanine content of 40%. What percentage of uracil will be in the RNA synthesized from this DNA?

10% Signup and view all the answers

What determines the primary structure of RNA?

Sequence of ribonucleotides Signup and view all the answers

Provide the complementary strand for: 3' ATTTGGCC 5'.

5' TAAACCGG 3'. Signup and view all the answers

Study Notes

Nucleic Acids

Nucleic acids are macromolecules made from nucleotide monomers, crucial for storing and transmitting hereditary information.
Key types include ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).
Nucleotides consist of three components: a phosphate group, a five-carbon sugar, and a nitrogenous base.

Sugar Molecules

Both phosphate groups and nitrogenous bases are bonded to the sugar molecule.
Ribose in RNA includes an -OH group bonded to the 2' carbon, while deoxyribose, lacking oxygen, includes a sugar that differs at the 2' carbon.

Nitrogenous Bases

Nitrogenous bases are categorized into purines (adenine, guanine) and pyrimidines (cytosine, uracil, thymine).
RNA contains uracil instead of thymine, found in DNA.

Polymerization and Linkages

Nucleic acids polymerize through phosphodiester linkages that connect the 5' phosphate group of one nucleotide to the 3' hydroxyl group of another.
This linkage creates a sugar-phosphate backbone, which has directional properties.

Structure of DNA

DNA has a primary structure of linked deoxyribonucleotides, a secondary structure of an antiparallel double helix formed by hydrogen bonds, and a tertiary structure with supercoiling.
DNA is stable and effectively encodes genetic information through base sequences.

Watson and Crick Model

Watson and Crick identified that DNA is composed of two antiparallel strands forming a double helix with specific base pairing (A-T and C-G).
Their discovery explained the ratios of purines to pyrimidines, noted by Chargaff.

DNA Replication

DNA replication involves the separation of strands, base pairing with free nucleotides, and the formation of complementary strands.
The process ensures the production of two identical daughter molecules.

RNA Structure and Function

RNA has a primary structure of linked ribonucleotides, featuring ribose sugar and nitrogenous bases A, U, G, and C.
RNA can fold into complex shapes, allowing it to perform diverse functions, such as messenger RNA (mRNA) in protein synthesis.

Secondary and Tertiary Structures of RNA

RNA's secondary structure arises from base pairing (A-U, C-G) within the same strand, leading to hairpin loops and additional stabilizations.
RNA strands are also antiparallel, facilitating intricate folding patterns.

RNA Versatility

RNA is versatile, capable of various functions beyond genetic coding, including acting as a messenger, catalyst, and structural component within cells.

Complementary Base Pairing

For a DNA sequence with a guanine content of 40%, the corresponding RNA will contain 10% uracil, following base pairing rules.
The primary structure of RNA is determined by the sequence of ribonucleotides.

Complementary Strands

Given the DNA sequence 3' ATTTGGCC 5', the complementary strand would be 5' TAAACCGG 3'.

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Description

Test your knowledge of nucleic acids with these flashcards based on Chapter 4 of your biology textbook. This quiz covers the definition, components, and functions of nucleic acids, primarily focusing on DNA and RNA. Perfect for exam preparation or review.