Year 11 Biology Summaries

Study Notes

Prokaryotic cells are simpler, lack a nucleus, and have no membrane-bound organelles. Examples include bacteria and archaea.
Eukaryotic cells are complex, contain a nucleus, and possess membrane-bound organelles. Examples include plant and animal cells.
Technologies such as microscopy and cell staining help determine cell structure and function.

The fluid mosaic model describes the cell membrane as a dynamic structure composed of phospholipids, proteins, and carbohydrates, allowing for flexibility and movement.
Cell organelles perform specific functions critical for cellular processes, with arrangements varying based on cell type.

Diffusion is the passive movement of molecules from high to low concentration.
Osmosis refers to the diffusion of water across a semipermeable membrane.
Active transport requires energy to move substances against their concentration gradient.
Endocytosis is the process where cells engulf materials from the external environment.
Surface area to volume ratio affects the efficiency of transport processes in cells.
Concentration gradients drive the movement of substances in and out of cells.

Cells require various forms of energy to perform functions, including ATP generated through cellular respiration and photosynthesis.
Removal of waste products is essential for maintaining cellular homeostasis, particularly in eukaryotic cells.
Enzymes facilitate biochemical reactions, and their activity can be influenced by environmental factors like temperature and pH.

Mitochondria:
- Act as the powerhouse, producing ATP through cellular respiration.
- Double membrane with an intermembrane space, enhancing surface area for ATP synthesis.
- Contains cytochrome C for the electron transport chain and has its own DNA.
Nucleus:
- Control center of the cell storing genetic information.
- Comprises a nuclear envelope with pores, nucleoplasm, and nucleolus for ribosome synthesis.
Golgi Complex:
- Responsible for protein transportation and waste export.
- Made of 6-8 stacked cisternae, increasing surface area for efficient transport.
Ribosomes:
- Sites for translating mRNA into amino acid chains for protein synthesis.
- Comprise two subunits that facilitate the binding of mRNA and tRNA.
Rough Endoplasmic Reticulum:
- Assists in the synthesis and export of proteins, highlighted by its ribosome-studded surface.