Week 2 Lecture 1, Principles of Living Organisms:

Energy and Matter-Matter: the physical substance. -Energy: for the purposes of biology, the movement of that matter. -Light-Heat-Chemical

Energy in Living Organisms-Energy can be stored in chemical bonds and can be released when those bonds are broken. -Chemical energy is often transferred through the movement of electrons.

The Aqueous Environment-Consider the states of matter-what would life be like in each of these states? -Solid-Liquid-Gas

Limitations of Diffusion-An analogy-marinating a roast (marinade wouldnt soak inside in too short of time)-Score the outside-increase surface area-Inject the marinade-active transport-Cut into steaks-decrease volume

-Diffusion occurs at a somewhat constant rate. -Life requires that the right substances bump into each other at the right time. -Limit the size-prokaryotic cells. -Increase the surface area-cilia. -Have an active transport mechanism-eukaryotic cells.

-Life: exits in an aqueous environment and must be composed of cells, which must have a way to harness energy and matter.

Week 2 Lecture 2, Introduction to Cells:

Cells-Smallest unit that can perform all the functions of life. -Fundamental principles of life apply to all cells. -Need source of matter and energy. -Need an aqueous environment suitable for diffusion.

All Cells Possess-A plasma membrane-phospholipid bilayer. -Cytosol-contents of the cell. -DNA-each DNA polymer is a chromosome. -Ribosomes-to synthesize proteins.

Prokaryotic Cells: -No membrane-bound organelles. -Small cell size.

-Cell wall (cage)-Provides structure. -Composed of peptidoglycan (protein modified with carbohydrates). -Not the same as a plasma membrane! -No means of regulating cellular transport. -Capsule-Sticky coating. -Composed of polysaccharides and protein. -DNA-Contained in nucleoid region. -Usually one circular chromosome. -Packaged and regulated very differently than eukaryotic DNA. -Flagella-Not all bacteria have them. -Allows for directional movement (taxis). -Structurally different than eukaryotic flagella.

Eukaryotic Cells

-The Nucleus-House chromosomes (Human=23 pairs)-Nuclear envelope is a double membrane (2 bilayers). -Contains pores for transport. -Nucleolus. -Site of ribosome construction. -The Endoplasmic Reticulum-Contiguous with the nuclear envelope. -Within the membrane is the lumen.

Smooth ER-Various functions depending on cell type. -Liquid synthesis. -Detoxifies drugs and toxins. -Storage of

Rough ER-Studded with ribosomes. -Protein synthesis for organelles, secreted proteins, and transmembrane proteins. -Site of phospholipid synthesis.

The Golgi Apparatus-Site of protein modification, storage, and sorting.

The Endomembrane System

The Mitochondria

The Mitochondria-Site of cellular respiration. -Converts food into useful energy. -Sugar ATP. -Requires -Semiautonomous-Contains DNA and ribosomes!

The Real Mitochondria-Vast network, not a sausage.

Peroxisomes-Detoxifies compounds and metabolizes fats, generating hydrogen peroxide as a waste product.

The Cytoskeleton-The cells skeleton. -Used for-Support-Motility-Regulation by mechanical signals

Microtubules-Biggest cytoskeleton filament. -Functions-shape and support-flagellum-molecular highway-cell division-Organized by centrosome.

Actin Filaments-AKA Microfilaments-smallest cytoskeletal filament-functions-support-cell motility and contraction-cell division