Untitled Quiz

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.