Cell Theory

• cell is the most basic unit of life
• cells arise from pre-existing cells
• all living things are composed of cells

• are often much smaller than eukaryotes
• they have structurally different flagella
• DNA is circular
• choloroplasts and mitochondria have their own DNA (which is also circular)

• contain membrane-bound organelles
• the difference between cilia and flagella is lenght/structure

(flagella is typically much longer)

• DNA is linear, it is in the form of chromosomes that have defined ends
• note *plant cells ARE eukaryotic

• proteins

-have numerous fumctions w/in the cell

-are composed of amino acids (structure)

-polypeptides are amino acid chains

• lipids

-varying structure, but typically contain hydrocarbon chains

-also has several dif. functions w/in cell, but less than proteins

• carbohydrates

-building block -> composed of one or more monosaccharide

-function is more limited - typically used/function as/is fuel (energy)

-the whole purpose of glycolysis is to make ATP (energy)

-also good for support/structure function

• nucleic acids

-RNA & DNA

-DNA - information storage

-RNA -many dif. roles in information processing

• ocular, objective, specimen, condenser, light source
• three things are needed: bright light focused on specimen by lenses in condenser; specimen carefully prepared to allow light to pass through it; appropriate set of ocular and objective
• -typical compound light microscope
• phase contrast light microscope

• uses computer to assemble/make layers of images
• good when viewing thick specimen (benefit of layers)
• focused on a single point at a specific depth in specimen

• particular wavelength of light applied to specimen
• specific fluorescent dyes w/ dif. wavelengths used for staining cells
• Two filters:

1) filters light before reaching specimen, passes only wavelengths that excite the particular fluorescent dye

2) blocks out that light and passes only wavelenghts emitted when the dye fluoresces

• allows for much better resolution ability to distinguish between 2 dif. points
• 2 kinds

-Transmission Electron Microscopy

-Scanning Electron Microscopy

SEM

(Scanning Electron Microscopy)

• forms an image composed of reflected e-
• ideal for examining external details
• specimen coated with a very thin film of a heavy metal

TEM

(Transmission Electron Microscopy)

• forms an image based on e- that pass through specimen
• dark spots shown on image are objects large enough to block transmission of e-
• it is typically a (week) long process to prepare solvent in order to form/slice specimen properly for view
• similar to light microscope, but rather than using beam of light it uses a beam of e-
• contrast is usually introduced by staining specimen w/ e--dense heavy-metals that locally absorb or scatter e-, removing them from beam as it passes through specimen

1. nucleus
2. nuclear envelope
3. cytosol
4. ribosome
5. rough endoplasmic reticulum
6. golgi complex
7. mitochondria
8. chloroplast

• contains chromatin

-DNA and proteins

-Histones plus other structural proteins and enzymes

• major processes in nucleus

1)transcription

2)DNA replication

• has 2 separate phospholipid bilayers adjacent to each other
• at certain points the layers meet to form pores
• @ pores -> large complexes plus even larger mRNA that must traverse membrane

-proteins around pores regulate transport

• cytoplasm, organelles, plus molecules suspended in it
• is thick enough that diffusion is relatively slow

• translation begins at free floating ribosomes

1) some proteins may complete translation on free floating ribosomes

2) some require completion in endoplasmic reticulum (ER)

• signal codons on mRNA can direct movement to (ER)

• completes translation
• chaperone proteins inside RER help w/ proper folding of proteins (they ensure that interactions are proper)
• transport -> nuclear proteins sent back to nucleus & other proteins packaged for other destination in the cell
• some amino acid phosphorylation (addition of phosphate)

- complex because it can activate/deactivate on dif. sites of the same protein

• more organization to membrane system than ER
• membranes tend to stack together & form specific cis (enter) & trans (exit) face
• golgi is also involved in directing protein transport
• vesicles constantly leaving trans face for specific location and bring specific proteins

• 2 phospholipid bilayers
• inner layer of bilayer highly convoluted which forms the cristae (realted to how much ATP is produced) -in cells that consumed more ATP there have been more cristae noticed in the mitochondrial bilayer