Biology 8 - Unit 2: Life Processes of Living Things

Biology 8 - Unit 2: Life Processes of Living Things - Cells

• The unit covers cell structure and functions.
• The theme for the course is Live 5Cs (Competence, Character, Commitment to Achieve, Collaboration, Creativity).
• The 5Cs will be achieved through academic rigor, growth mindset, and grit.

Characteristics of Organisms

• Organisms are made of cells.
• Organisms require energy (food).
• Organisms reproduce (species).
• Organisms maintain homeostasis.
• Organisms are organized.
• Organisms respond to the environment.
• Organisms grow and develop.
• Organisms exchange materials with their surroundings (water, wastes, gases).

Levels of Organization

• Non-living levels: atom, molecule, organelles, (etc).
• Living levels: cell (makes up all organisms), tissue, organ, organ system, organism.
• Living levels (bigger scale): population, community, ecosystem, biome, biosphere (all living and non-living things on Earth).

Cell Theory

• All living things are made of cells.
• Cells are the basic unit of structure and function in an organism (basic unit of life).
• Cells come from the reproduction of existing cells (cell division).

Number of Cells

• Organisms can be unicellular (composed of one cell) or multicellular (composed of many cells).
• Multicellular cells may organize into tissues, etc.
• Cells in multicellular organisms can specialize (take on different shapes and functions).
• Examples of unicellular organisms include amoeba, bacteria, and paramecium.
• Examples of multicellular organisms include plants and animals.

Cell Specialization

• Cells in multicellular organisms specialize.
• Specialization occurs by turning specific genes on and off.
• This process is called differentiation.
• Examples of specialized animal cells include muscle cells, red blood cells, and cheek cells.
• Examples of specialized plant cells include guard cells and xylem cells, and pollen.

Kinds of Cells

• Prokaryotes (the first cells): lack a nucleus or membrane-bound organelles.
  • Includes bacteria.
  • Simplest type of cell.
  • Single, circular chromosome.
• Eukaryotes: contain 3 basic cell structures: nucleus, cell membrane, and cytoplasm with organelles.

Prokaryotes vs. Eukaryotes

• A comparison chart shows the differences.

Two Types of Eukaryotic Cells

• Plant cells vs animal cells
  • Plant cells have a cell wall, unlike animal cells.

Organelles

• Very small (microscopic).
• Perform various functions for a cell.
• Found in the cytoplasm.
• May or may not be membrane-bound.

Organelles of Animal Cells

• Includes cell membrane, nuclear membrane, nucleus, mitochondrion, lysosome, cytoplasm, ribosomes, centrosome

Organelles of Plant Cells

• Includes cell wall, cell membrane, central vacuole, nucleus, mitochondrion, chloroplasts, plastids (including leucoplast, chromoplast), cytoplasm, ribosomes, Golgi apparatus

Cell Membrane

• Composed of a double layer of phospholipids (phospholipids bilayers) and proteins.
• Surrounds all cells.
• Controls what enters or leaves the cell.

Cell Division

• This is a next topic, but no details are given.

Explore the intricate world of cells and their functions in this quiz for Biology 8. Understand the characteristics of organisms and their levels of organization, alongside the fundamentals of cell theory. Dive into how life processes contribute to the principles of the 5Cs in learning.