Cell Biology

smallest functional unit of an organism

• 1) exchange materials with immediate environment
• 2) obtain energy from organic materials
• 3) synthesize complex molecules
• 4) replicate themselves

one that has a true nucleus

contains DNA necessary for protein synthesis and survival. Contains chromatin a genetic material used for replication. Nucleus also contains chromosomes and an envelope that surrounds it that contains pores

3 types of RNA 1) Messenger 2) ribosomal and 3) transfer

it is a colloid solution

ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, perioxisomes, proteasomes, and mitochondria

site for protein synthesis

2 types rough ER and smooth ER

it functions with the endoplasmic reticulum. It packages proteins, enzymes, and hormones.

contain digestive enzymes. Break down cell parts and foreign substances, some "residual bodies" are retained.

quality control mechanism

POWER PLANT of the cell. it transforms organic compounds into energy. it is self-replicating via mitochondrial DNA. It is also a regulator of apoptosis (programmed cell death)

maintains cell shape. Inside contains microtubules that maintain shape and enable transport. Also contains microfilaments that are threadlike structures.

defines the intracellular space. contains a semipermeable membrane.

• 1) controls transport of water and substances
• 2) provides receptors for hormones
• 3) conducts electric currents
• 4) enables cell to cell recognition

• Lipid bilayer: hydrophilic heads and hydrophobic tails
• this allows lipid soluble molecules to diffuse easily.
• Proteins also extend across the bilayer. Glycoproteins: are cell surface markers and recognize and bind with ligands

• cell receptors activated by chemical messengers
• types of cell signaling mechanisms
• autocrine:
• Paracrine:
• Endocrine:

• Go: inactive phase
• G1: start of DNA synthesis
• S phase: DNA replication
• G2: RNA and protein synthesis
• M phase: mitosis

• prophase: appearance of chromosomes
• Metaphase : organization of chromosomes
• anaphase: separation of pairs
• telophase: cells separate

12-14 hours

• all cells undergo mitosis during embryonucu development. Many adult cells lose the ability later on.
• epithelial cells divide continuously

peptides which signal division. specific to cell type for example nerve cells respond to nerve growth factor.

• conversion of nutrients into energy needed for cell function.
• cells use oxygen to transform nutrients into energy for 1) muscle contraction 2) ion transport across membranes 3) synthesis of hormones, enzymes, etc...

carrier for chemical energy in living cells

• adenosine, ribose, and 3 phosphate groups.
• Each molecule contains 2 high energy bonds
• Each bond releases energy when hydrolyzed into ADP

Anaerobic and Aerobic

• glycolytic pathway which occurs in the cytoplasm.
• Energy is liberated from glucose
• one molecule of glucose yields 2 ATP
• Very important during hypoxia
• when O2 is present, pyruvic acid moves into the mitochondria and enters the citric acid cycle

• supplies most of the bodies energy
• pyruvic acid converted to acetyl-CoA
• H+ and carbon molecules combine with O2 to form CO2 and H2O.
• Oxidation of electrons
• Oxidative phosphorylation

• 
• channel proteins
• membrane transport proteins, may use a carrier

• electron potentials across all cell membranes
• determined by differences in ions on inside vs outside
• resting membranes potential maintained by Na+/K+ pump

• depolarization
• Na+ channels
• calcium channels
• repolarization and K+ channels
• absolute refractory period
• relative refractory period