Cell Biology: Cellular Structure and Organelles

Cell Biology

Cellular Structure

• Plasma Membrane:
  • Semi-permeable membrane that separates cell from environment
  • Composed of phospholipid bilayer, proteins, and cholesterol
• Cytoplasm:
  • Jelly-like substance inside cell membrane
  • Contains water, salts, sugars, and various organelles
• Nucleus:
  • Control center of cell, contains genetic material (DNA)
  • Surrounded by double membrane called nuclear envelope

Cellular Organelles

• Mitochondria:
  • Powerhouses of cell, generate energy through cellular respiration
  • Have own DNA and ribosomes
• Endoplasmic Reticulum (ER):
  • Network of membranous tubules and cisternae
  • Involved in protein synthesis, transport, and lipid synthesis
• Golgi Apparatus:
  • Complex of flattened sacs and tubules
  • Modifies and packages proteins and lipids for transport

Cellular Processes

• Cell Division:
  • Mitosis: process of cell duplication
  • Meiosis: process of gamete formation
• Cell Signaling:
  • Communication between cells through signaling molecules
  • Important for development, growth, and response to stimuli
• Cell Death:
  • Apoptosis: programmed cell death, necessary for development and tissue homeostasis
  • Necrosis: unprogrammed cell death, often due to injury or disease

Cellular Structure

• Plasma membrane is a semi-permeable membrane that separates the cell from its environment and composed of phospholipid bilayer, proteins, and cholesterol.
• Cytoplasm is a jelly-like substance inside the cell membrane, containing water, salts, sugars, and various organelles.
• The nucleus is the control center of the cell, containing genetic material (DNA), and is surrounded by a double membrane called the nuclear envelope.

Cellular Organelles

• Mitochondria are the powerhouses of the cell, generating energy through cellular respiration, and have their own DNA and ribosomes.
• Endoplasmic Reticulum (ER) is a network of membranous tubules and cisternae, involved in protein synthesis, transport, and lipid synthesis.
• Golgi Apparatus is a complex of flattened sacs and tubules, modifying and packaging proteins and lipids for transport.

Cellular Processes

• Cell Division involves two types: Mitosis, the process of cell duplication, and Meiosis, the process of gamete formation.
• Cell Signaling is the communication between cells through signaling molecules, essential for development, growth, and response to stimuli.
• Cell Death occurs through two mechanisms: Apoptosis, programmed cell death necessary for development and tissue homeostasis, and Necrosis, unprogrammed cell death often due to injury or disease.

Civics and Citizenship

• Civics is the study of citizenship, government, and civic responsibility.
• Citizenship involves having rights and responsibilities as a member of a country.

Government Structure

• Government refers to the system or group of people that make and enforce laws, policies, and decisions for a country or state.
• The US government is divided into three branches:
  • Legislative: Responsible for making laws, comprising Congress.
  • Executive: Responsible for enforcing laws, comprising the President.
  • Judicial: Responsible for interpreting laws, comprising the Supreme Court.

Types of Government

• Democracy: A system where power is held by the people, either directly or through elected representatives.
• Monarchy: A system where power is held by a king or queen.
• Dictatorship: A system where power is held by a single person or group.

Civic Participation and Engagement

• Voting: The process of choosing leaders or deciding on laws and policies through ballots.
• Volunteering: Giving time and effort to help the community or a cause.
• Protesting: Peacefully expressing dissent or opposition to a policy or issue.

Importance of Civics Education

• Informed Citizens: Civics education enables citizens to make informed decisions and participate in the democratic process.
• Active Citizenship: Civics education encourages citizens to take an active role in their communities and contribute to the common good.
• Preserves Democracy: Civics education helps to protect and maintain democratic values and institutions.