Protein Synthesis and DNA Structure Overview
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Questions and Answers

What are the three main types of RNA?

  • DNA, mRNA, and tRNA
  • DNA, mRNA, and rRNA
  • mRNA, tRNA, and rRNA
  • messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA) (correct)

    • DNA replication occurs in the cytoplasm of a cell.

    False (B)

    What is the process called where the genetic code in DNA is copied into mRNA?

    transcription

    The enzyme responsible for the production of the mRNA molecule is called ______.

    <p>RNA polymerase</p> Signup and view all the answers

    Match the following components of protein synthesis with their corresponding functions:

    <p>mRNA = carries genetic information from DNA to ribosomes tRNA = brings amino acids to the ribosome rRNA = forms part of the ribosome structure</p> Signup and view all the answers

    Which of the following is NOT a characteristic of X-linked recessive inheritance?

    <p>Affected females are more common than affected males. (A)</p> Signup and view all the answers

    In an autosomal dominant inheritance pattern, an affected individual must have at least one affected parent.

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

    What is the term used to describe a pattern of inheritance where a single gene has multiple effects on the phenotype?

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

    A pedigree chart uses ______ to represent males and ______ to represent females.

    <p>squares, circles</p> Signup and view all the answers

    Match the following inheritance patterns with their corresponding characteristics:

    <p>Autosomal recessive = Affected individuals may have unaffected parents, trait can skip generations. Autosomal dominant = Affected individuals always have at least one affected parent. X-linked recessive = Affected males usually have an affected mother, trait is more common in males. Codominant = Both alleles are expressed in the phenotype, no blending occurs.</p> Signup and view all the answers

    Which of the following is an example of a sex-linked recessive disorder?

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

    In sex-influenced traits, the expression of a trait can be affected by the sex hormones of an individual.

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

    Explain the difference between sex-linked traits and sex-limited traits.

    <p>Sex-linked traits are determined by genes located on sex chromosomes (X or Y), while sex-limited traits are expressed only in one sex, even if both sexes carry the gene.</p> Signup and view all the answers

    Flashcards

    Protein Synthesis Pathway

    The process of creating proteins from DNA involves DNA to mRNA to tRNA to protein.

    RNA polymerase

    The enzyme responsible for synthesizing mRNA from a DNA template during transcription.

    Transcription

    The process of copying a segment of DNA into mRNA.

    Three types of RNA

    The main types of RNA are mRNA, tRNA, and rRNA, each serving different roles in protein synthesis.

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    Translation

    The process where ribosomes convert mRNA into a polypeptide chain, forming a protein.

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    Sex Determination

    The process that decides the sex of an individual at conception, typically based on chromosomes.

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    Sex-linked Inheritance

    Inheritance patterns determined by genes located on sex chromosomes, especially the X chromosome.

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    Hemophilia

    A recessive X-linked disorder that impairs blood clotting.

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    Pedigree

    A family tree diagram used to trace genetic traits and their inheritance patterns.

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    Autosomal Dominant Inheritance

    An inheritance pattern where one copy of a dominant allele can cause the trait to be expressed.

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    Autosomal Recessive Inheritance

    An inheritance pattern where two copies of a recessive allele must be present for the trait to be expressed.

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    X-linked Recessive Inheritance

    A type of inheritance where males are more frequently affected by traits associated with genes on the X chromosome.

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    X-linked Dominant Inheritance

    An inheritance pattern where one copy of a dominant allele on the X chromosome can cause the trait to be expressed, affecting more females than males.

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    Study Notes

    Protein Synthesis

    • Protein synthesis is the creation of polypeptide chains (proteins)
    • Two main phases:
      • Transcription
      • Translation
    • mRNA must be processed before leaving the nucleus
    • DNA → RNA → Protein

    DNA and Protein

    • Walter Sutton discovered chromosomes are made of DNA and protein
    • Scientists initially unsure if DNA or protein is the genetic material
    • Frederick Griffith (1928) showed DNA is the genetic material
    • Watson and Crick (1950s) created the first model of DNA

    DNA Structure

    • DNA is made of nucleotides
    • Nucleotides consist of:
      • Phosphate group
      • Deoxyribose sugar
      • Nitrogenous base
    • Four bases: Adenine (A), Thymine (T), Guanine (G), Cytosine (C)
    • Bases pair according to the rules: A with T, and G with C.
    • DNA is a double helix (double-stranded) structure. DNA strands are antiparallel.

    DNA Replication

    • DNA replication produces an exact copy of DNA
    • DNA polymerase is the enzyme involved in this process.
    • Hydrogen bonds between the bases break, and enzymes unzip the molecule.
    • Each old strand acts as a template for a new strand.
    • Complementary nucleotides are added to each template strand.

    Nucleic Acids

    • Include DNA and RNA

    RNA Structure

    • RNA differs from DNA: RNA uses ribose sugar instead of deoxyribose, and uses uracil (U) instead of thymine (T)
    • RNA is typically single-stranded.
    • Three types of RNA:
      • Messenger RNA (mRNA): carries genetic info.
      • Ribosomal RNA (rRNA): component of ribosomes
      • Transfer RNA (tRNA): transports amino acids.

    Protein Synthesis Pathway

    • DNA > mRNA > tRNA (ribosomes) > Protein

    Genetic Code

    • DNA contains a triplet code.
    • Each three bases on DNA (codon) represent one amino acid.
    • Most amino acids have more than one possible codon.
    • The code is nearly universal among living organisms.
    • The sequence of bases (codons) in mRNA determines the sequence of amino acids in a polypeptide chain.

    Transcription

    • DNA sequence is copied into a complementary mRNA strand.
    • Transcription occurs in the nucleus of eukaryotic cells and the cytoplasm of prokaryotic cells.
    • The enzyme RNA polymerase is required for this process.
    • A particular segment of DNA is unzipped to expose the coding region.
    • mRNA moves to the cytoplasm.
    • RNA polymerase synthesizes a complementary RNA strand using one DNA strand as a template. The RNA Polymerase recognizes and binds to the promoter site on the DNA.

    Translation

    • mRNA sequence is translated into an amino acid sequence of a polypeptide chain
    • This takes place in the cytoplasm of the cell, at the ribosomes.
    • Ribosomes assemble the amino acids in the order specified by the mRNA.
    • tRNA brings the specific amino acid to the ribosome based on its anticodon matching the codon on the mRNA.
    • The ribosome forms peptide bonds between successive amino acids to create a polypeptide chain.
    • Initiation: start codon AUG
    • Elongation: amino acids linked from mRNA codon to codon, tRNA brings amino acids
    • Termination: stop codon (UAG, UAA, or UGA).

    RNA Processing

    • Pre-mRNA undergoes processing before leaving the nucleus.
    • Introns (non-coding regions) are removed and exons (coding regions) are joined.
    • Introns are not part of the protein message.
    • The mature mRNA molecule moves to the cytoplasm for translation.

    Ribosomes

    • Ribosomes are the cellular structures where amino acids are joined to form a polypeptide chain.
    • Made up of ribosomal RNA (rRNA) and proteins.
    • Ribosomes have two subunits (large and small).

    Proteins

    • Proteins are chains of amino acids linked together by peptide bonds.
    • Proteins have a primary structure (the unique sequence of amino acids) as dictated by the genetic code.
    • Proteins can have secondary, tertiary and quaternary structures determined by their specific sequences.

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    Related Documents

    Protein Synthesis PDF
    Genetics PDF

    Description

    This quiz covers key concepts of protein synthesis, including the phases of transcription and translation, as well as the structure and replication of DNA. It explores the historical milestones in determining DNA as the genetic material and the composition of nucleotides. Test your knowledge on these fundamental biological processes!

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