Molecular Biology

  1. What is molecular biology? Molecular biology is a field of science that looks at how living things work at a microscopic level. It studies tiny parts of living things called molecules, especially important ones like DNA, RNA, and proteins. The goal is to understand how these molecules interact and make life possible.

  2. What is life? Life, at its most basic, is a system that can do four main things:
    • Grow and develop
    • Make copies of itself (reproduce)
    • React to its surroundings
    • Use energy to stay organized and function

    The smallest unit of life is called a cell. Cells are made up of even smaller parts called molecules, which molecular biologists study to understand how life works.

  3. What are biological molecules? Biological molecules are the building blocks that make up living things. There are four main types:
    • Nucleic acids (DNA and RNA): These store and transmit genetic information.
    • Proteins: These do most of the work in cells.
    • Lipids: These include fats and are important for cell structure.
    • Carbohydrates: These provide energy and structure.

    These molecules are made of even smaller parts called atoms, like carbon, hydrogen, oxygen, nitrogen, and phosphorus.

  4. What is DNA? DNA is like a blueprint for life. It’s made up of four chemical building blocks called nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G). These nucleotides pair up (A with T, C with G) to form a twisted ladder shape called a double helix. The order of these nucleotides forms a code that tells cells how to build and maintain living organisms.

  5. What is RNA? RNA is similar to DNA but has a few key differences. It helps turn the information in DNA into proteins, which do most of the work in cells. RNA is usually single-stranded (not twisted like DNA) and uses a slightly different set of building blocks. There are three main types of RNA:
    • mRNA: Carries genetic instructions from DNA to where proteins are made.
    • rRNA: Forms part of the protein-making factory in cells.
    • tRNA: Helps translate the genetic code into proteins.

  6. What are proteins? Proteins are molecules that do most of the work in cells. They’re made of smaller building blocks called amino acids. There are 20 different amino acids that can be combined in various ways to make proteins. The order of amino acids is determined by the genetic code in DNA. Proteins can act as enzymes (which speed up chemical reactions), provide structure to cells, or carry signals within and between cells.

  7. How does information flow in cells? Information in cells flows from DNA to RNA to proteins. This happens through three main processes:
    • Replication: DNA makes copies of itself when cells divide.
    • Transcription: The information in DNA is copied into RNA.
    • Translation: The information in RNA is used to make proteins.
  8. What is gene regulation? Genes are sections of DNA that contain instructions for making proteins or other molecules. Not all genes need to be “on” all the time. Cells can turn genes on or off as needed. This on/off control is called gene regulation. Gene regulation works in a few ways:
    • Special sections of DNA interact with proteins called transcription factors. These proteins can either help turn genes on or keep them turned off.
    • There are also chemical changes, called epigenetic modifications, that can affect whether a gene is active. These changes don’t alter the DNA sequence itself, but they can make it easier or harder for the gene to be read.

    Why is gene regulation important? It allows cells to:

    • Adapt to changes in their environment
    • Perform different jobs in the body
    • Develop from a single cell into a complex organism with many different types of cells

    For example, a skin cell and a brain cell have the same DNA, but they look and act very differently because different genes are active in each type of cell.

  9. What are mutations? Mutations are changes in the DNA sequence. They can happen in several ways:
    • Mistakes during DNA copying
    • Damage from things like UV light or chemicals
    • Shuffling of DNA during reproduction

    Mutations can have different effects:

    • Some might be helpful, giving organisms new traits that help them survive.
    • Some might not have any noticeable effect.
    • Some might be harmful, potentially causing diseases like cancer.

In summary, molecular biology looks at how living things work at a very tiny scale, studying how small parts called molecules - especially DNA, RNA, and proteins - work together to make life happen.