Molecular Genetics: DNA Structure & Function
9 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

How many letters are in the alphabet of the genetic code?

four

What is each 3-letter word in the genetic code coding for?

  • Codons
  • RNA
  • Nucleic acids
  • Amino Acids (correct)

    • Translation requires the presence of DNA.

    False

    MicroRNA and small interfering RNA are classified as _________ that regulate gene expression.

    <p>RNAs</p> Signup and view all the answers

    Match the following components required for translation:

    <p>Ribosomes = Protein Synthesizing Machines mRNA = Information source for synthesis tRNA = Adaptor coupling codons and amino acids Amino acids = Building blocks for proteins</p> Signup and view all the answers

    What is the main reason why DNA is considered special?

    <p>DNA can store and copy information</p> Signup and view all the answers

    What are the two types of nitrogenous bases found in nucleic acids?

    <p>Purines and Pyrimidines</p> Signup and view all the answers

    RNA uses uracil (U) in place of thymine (T) as one of its bases.

    <p>True</p> Signup and view all the answers

    Match the types of DNA helix with their descriptions:

    <p>B-form helix = Right-handed helix with 10 base pairs per turn A-form DNA = Right-handed helix with 11 base pairs per turn, common in RNA Z-form DNA = Left-handed helix, GC rich regions, can play a role in gene regulation</p> Signup and view all the answers

    Study Notes

    Introduction to DNA

    • DNA (Deoxyribonucleic acid) is a macromolecule that stores and copies information.
    • DNA is made up of four building blocks: Adenine (A), Guanine (G), Cytosine (C), and Thymine (T).

    Structure of DNA

    • DNA is a double-stranded molecule consisting of two polynucleotide chains running in opposite directions.
    • The bases are on the inside of the molecule, and the two chains are joined together by double hydrogen bonds between A and T and triple hydrogen bonds between C and G.
    • The base pairing is very specific, making the two strands complementary to each other.

    DNA Replication

    • DNA replication is the process of creating a new DNA molecule from an existing one.
    • Each strand of DNA serves as a template for the synthesis of a new complementary strand.
    • DNA replication requires many enzymes that work coordinately, including DNA polymerases.

    Nucleotides and Nucleic Acids

    • Nucleotides are the unit structure of nucleic acids.
    • A nucleotide is composed of three components: nitrogenous base, pentose sugar, and phosphate.
    • Nucleic acids are linear polymers of nucleotides formed by phosphodiester bonds.

    Base Pairing

    • Complementary base pairing is the most important structural feature of nucleic acids.
    • It connects bases of one polynucleotide chain with complementary bases of another chain.
    • Double hydrogen bonds are formed between A and T (or A and U in RNA), and triple hydrogen bonds are formed between G and C.

    Forms of DNA

    • There are three main forms of DNA: B-form, A-form, and Z-form.
    • B-form is the most common form of DNA, with a right-handed helix and 10 base pairs per turn.
    • A-form is less common, with a right-handed helix and 11 base pairs per turn.
    • Z-form is a radical change of B-form, with a left-handed helix and a zig-zag shape.

    Denaturation and Annealing of DNA

    • DNA double strands can be denatured by heat or chemicals.
    • Denaturation is a reversible process, and denatured strands can be re-annealed again.
    • The process of denaturation and annealing can be monitored using the hyperchromicity (melting profile).

    Types of Nucleic Acids

    • There are two types of nucleic acids: DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid).
    • DNA has a deoxyribose sugar and uses the bases A, G, C, and T.
    • RNA has a ribose sugar and uses the bases A, G, C, and U.

    Function of DNA

    • DNA is in action in all cells, and the same genetic information is used in different ways to create different cells.
    • The control of gene expression occurs by regulating the flow of information from DNA to protein.
    • The central dogma of molecular biology is the unidirectional flow of information from DNA to RNA to protein.

    Gene Expression

    • Gene expression is the process whereby the information contained in genes begins to have effects in the cell.
    • Genes are DNA sequences that encode proteins, and gene expression refers to the process of creating a functional product.
    • Transcription is a key step in gene expression, making an RNA copy of DNA.

    Transcription

    • Transcription is the process of creating an RNA copy of DNA.
    • RNA polymerase acts as the enzyme to synthesize the RNA.
    • The decision to transcribe a gene is the most important step in the control of gene expression.

    Genetic Code

    • The genetic code is written in 3-letter words, each of which codes for a particular amino acid.
    • There are 20 different amino acids specified by the genetic code.
    • The genetic code is biology's Rosetta Stone, using 4 letters (A, T, G, and C) to write 3-letter words.

    Translation

    • Translation is the process of reading the information in mRNA to synthesize a polypeptide.
    • Translation requires ribosomes, mRNA, tRNA, and amino acids.
    • The sequence of amino acids determines the structure and function of a protein.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    This quiz covers the basics of DNA structure and function, including its monotony and the four building blocks that make it up.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser