Podcast
Questions and Answers
What does the central dogma of biology describe?
What does the central dogma of biology describe?
Which of the following is NOT a component of a nucleotide?
Which of the following is NOT a component of a nucleotide?
Which of the following nitrogenous bases is unique to RNA?
Which of the following nitrogenous bases is unique to RNA?
What role do proteins play in metabolic pathways?
What role do proteins play in metabolic pathways?
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What is heredity primarily concerned with?
What is heredity primarily concerned with?
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Which process refers to the breakdown of complex molecules to release energy?
Which process refers to the breakdown of complex molecules to release energy?
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What do metabolic pathways primarily represent?
What do metabolic pathways primarily represent?
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Which of the following best describes a nucleotide?
Which of the following best describes a nucleotide?
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What was Frederick Griffith's significant discovery in 1928?
What was Frederick Griffith's significant discovery in 1928?
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What crucial conclusion did Avery, McCarty, and McLeod reach through their experiments in 1944?
What crucial conclusion did Avery, McCarty, and McLeod reach through their experiments in 1944?
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In the Hershey-Chase experiment, what was the radiolabel used to identify DNA?
In the Hershey-Chase experiment, what was the radiolabel used to identify DNA?
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What role do bacteriophages play in genetic research as shown in the Hershey-Chase experiment?
What role do bacteriophages play in genetic research as shown in the Hershey-Chase experiment?
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Which DNA-related breakthrough did Watson and Crick achieve in 1953?
Which DNA-related breakthrough did Watson and Crick achieve in 1953?
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What component was found to be inside bacteria in the Hershey-Chase experiment after infection?
What component was found to be inside bacteria in the Hershey-Chase experiment after infection?
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What was one of the main concerns during the Avery, McCarty, and McLeod experiment?
What was one of the main concerns during the Avery, McCarty, and McLeod experiment?
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Which strain of Streptococcus pneumoniae was virulent according to Frederick Griffith?
Which strain of Streptococcus pneumoniae was virulent according to Frederick Griffith?
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Study Notes
The Cell
- The cell is composed of a nucleus and cytoplasm
- The cytoplasm includes all other parts of the cell
- The cell is surrounded by a membrane and/or cell wall
Unit 1 – Building Blocks
- Macromolecules are found in the cell
- Macromolecules are important for the cell's transport functions
- Membrane and/or cell wall are also important for transport
Unit 2 – Catabolism + Anabolism
- Respiration is a key process within the cell
- Catabolism breaks down molecules, like glycolysis
- Anabolism builds up molecules, like photosynthesis
Complete Metabolism Map
- Metabolic pathways are a series of chemical reactions occurring within a cell
- Each reaction within these pathways is catalyzed by a unique protein
- This means there are many proteins present within a cell
Exam 3 - Genetic Information Flow
- The central dogma of biology describes how the flow of genetic information works within an organism
- DNA is transcribed into RNA, which is then translated into protein
- This process follows the order: DNA → RNA → Protein
Central Dogma of Biology
- DNA serves as the instruction manual for how cells function
Nucleotides
- Nucleotides are the basic building blocks of DNA and RNA
- Each nucleotide is composed of three parts:
- Nitrogenous Base: Adenine (A), Guanine (G), Cytosine (C), Thymine (T), Uracil (U) (RNA only)
- Pentose Sugar: A five-carbon sugar
- Phosphate: A phosphate group
Nitrogenous Bases
- The five nitrogenous bases are adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U)
- Uracil (U) is only present in RNA, while thymine (T) is only present in DNA
- These bases pair up in a specific way:
- Adenine (A) pairs with Thymine (T) or Uracil (U)
- Guanine (G) pairs with Cytosine (C)
Heredity
- Heredity is the passing of traits from parents to offspring
- Heredity predates the discovery of DNA and the field of genetics
- The question of how traits are determined led to a race to discover genetics
Race to Discover Genetics
- Hundreds of scientists contributed to the discovery of DNA
- Frederick Griffith (1928): Discovered the "transforming principle"
- Avery, MacLeod, McCarty (1944): Identified DNA as the transforming principle
- Hershey-Chase (1952): Confirmed DNA as the genetic material
- Rosalind Franklin (1952): Provided the first detailed structure of DNA
- Watson & Crick (1953): Determined the final double helix structure of DNA
Frederick Griffith (1877-1941)
- Griffith was a bacteriologist who studied pneumonia vaccines
- He worked with two strains of Streptococcus pneumoniae:
- S strain: Smooth colony, virulent, deadly
- R strain: Rough colony, nonvirulent
- Griffith's experiments showed that virulence could be inherited by bacteria
- He discovered the "transforming principle"
Griffith Transformation Experiment (1928)
- Injected mice with different combinations of S and R strains of S. pneumoniae
- Found evidence of transformation: a nonvirulent strain becoming virulent by acquiring genetic information from a virulent strain.
Avery, McCarty, and McLeod Experiment (1944)
- Oswald Avery, Maclyn McCarty, and Colin McLeod repeated Griffith's experiment
- They systematically removed or destroyed different cellular components
- They determined that only DNA caused the transformation of S. pneumoniae
- Their results further solidified the role of DNA as the genetic material
Hershey-Chase Experiment (1952)
- Martha Chase and Alfred Hershey used bacteriophages (viruses that infect bacteria) to confirm DNA as the genetic material
- They radioactively labelled the phage's DNA (32P) and protein (35S)
- Found that only radioactive DNA (32P) entered the bacteria, confirming that DNA is the material that carries genetic information.
Bacteriophage
- Bacteriophage is a type of virus that infects bacteria
- Phages are composed of a protein coat and a DNA core
- Hershey and Chase's experiment demonstrated that DNA, not protein, is the genetic material responsible for bacterial infection.
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