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Cells

Organisms are considered open systems. They interact continuously with their environment. Cells in a multicellular organism are also an open system. Homeostasis is the term used to describe how an organism maintains its physiological balance while undergoing innumerable interchanges and exchanges. The body is in dynamic balance.

Cells

Sizes and shapes Cheek cells Yeast Bacteria Plants Prokaryotes and Eukaryotes

Microscope Observation Measurement

Cell parts

Eukaryotic organisms are distinguished from prokaryotes by having a membrane enclosed nucleus where the DNA is. Eukaryotes have additional membrane-enclosed compartments called organelles. Some people consider the ribosome an organelle even though it is not enclosed in a membrane. Many ribosomes are located along the membrane.

• Organelles: All organelles have enzymes, including the cell membrane
  • The cell membrane (Diffusion and Osmosis)
  • The nucleus/nucleoid
  • Cytoplasm (Enzymes), Lysosomes (Enzymes)
  • Ribosomes : Bacteria also have ribosomes
  • Golgi complex
  • Endoplasmic reticulum
  • Chloroplasts photosynthesis generates high energy (nutrients) chemicals from carbon dioxide and water (stores energy from the sun in chemicals, especially sugar)
  • Mitochondria respiration (breathing in common terms exhanges gases in the lungs, picking up oxygen for molecular respiration) PLUS extracting all the energy possible out of molecules (generates energy from the chemical breakdown of sugar)
• Macromolecules
  • DNA
  • RNA
  • Proteins Pro-forms inactive form so the protein does not self-inactivate - Signal peptides, Pre-forms Zip code/address for localizing a protein to a different compartment after (or as) it is being synthesized. Post-translational processing glycosylation, maturation
  • Lipids
  • Carbohydrates
• Metabolites

Cell Shape

• epithelial
  • skin,
• fibroblast
  • skin (wound healing)
  • fat
  • muscle
• ameboid
  • macrophages
  • lymphocytes
  • metastatic cancers

Structure: Function

• Water (peroxide)
• Drugs (morphine/endorphins)
• Oncogenes

Molecules