CHAPTER 01- CELL BIOLOGY.txt

1) a lipid bilayer that contains protein channels, enzymes, and receptors

cholesterol

Cells are negative inside compared with outside, based on Na/K ATPase (3Na+ out/2K+ in)

cotransport of glucose, proteins, and other molecules

these are adhesion molecules (cell-cell and cell-extracellular matrix) which anchor cells

these are cell-cell occluding junctions and form an impermeable barrier (i.e. epithelium)

allow communication between cells (connexin subunits)

receptor and response enzyme are a single transmembrane protein

glycolipids on cell membrane

glycoproteins on cell membrane

water will move from an area of low solute concentration to an area of high solute concentration and apporach osmotic equillibrium

• 1)
• G1
• S (protein synthesis, chromosomal duplication)
• G2
• M (mitosis, nucleus divides)
• 2) G1 most variable, determines cell cycle length
• 3) Growth factors affect cell during G1
• 4) Cells can also go into G0 (quiescent) from G1

• 1) Prophase: centromere attachment, spindle formation, nucleus disappears
• 2) Metaphase- chromosome alignment
• 3) Anaphase- chromosomes pulled apart
• 4) Telophase- separate nucleus reforms around each set of chromosomes

• 1) double membrane
• 2) outer membrane continuous with rough endoplasmic reticulum

• 1) inside the nucleus
• 2) no membrane
• 3) ribosomes made here

DNA strand is used as a template by RNA polymerase for synthesis of an mRNA strand

• 1) bind DNA and helps the transcription of genes
• 2) Steroid hormone- binds receptor in cytoplasm, then enters nucleus, and acts as transcription factor
• 3) Thyroid hormone- binds receptor in nucleus, then acts as a transcription factor
• 4) Other transcription factors: AP-1, NF-kB, STAT, NFAT

bind RNA polymerase and initiate transcription

uses oligonucleotides to amplify specific DNA sequences

• Guanine
• Adenine

• 1) Cytosine
• 2) uracil (only in RNA)
• 3) thymidine (only in DNA)

mRNA used as a template by ribosomes for the synthesis of protein

have small and large subunits that read mRNA, then bind appropriate tRNAs that have amino acids and eventually make proteins

As the ribosome moves along the mRNA, incoming aminoacyl-tRNA complexes bind to the A-site on the ribosome, after which a new peptide bond is formed with the nascent polypeptide chain previously attached to the peptide tRNA. The ribosome then moves, ejecting the now-empty tRNA and opening the A-site for the next aminoacyl-tRNA complex

1 glucose molecule generates 2 ATP and 2 pyruvate molecules

• 1) 2 membranes
• 2) krebs cycle on inner matrix
• 3) NADH/FADH2 created

• 1) the 2 pyruvate molecules (from the breakdown of 1 glucose) create NADH and FADH₂.
• 2) NADH and FADH₂ enter the electron transport chain to create ATP
• 3) Overall 1 molecule of glucose produces 36 ATPs.

• 1) mechanism by which lactic acid (cori cycle) and amino acids are converted to glucose
• 2) Fat and lipids are not available for gluconeogenesis because acetyl CoA (breakdown product of fat metabolism) cannot be converted back to pyruvate
• 2) used in times of starvation or stress (basically the glycolysis pathway goes in reverse)
• 3) Cori cycle- an elegant mechanism for the hepatic conversion of muscle lactate into new glucose. pyruvate plays a key role in this process

synthesizes proteins that are exported (increased in pancreatic acinar cells)

• 1) lipid/steroid synthesis
• 2) detoxifies drugs (increased in liver and adrenal cortex)

modifies proteins with carbohydrates; proteins are then transported to the cellular membrane, are secreted, or are targeted to lysosomes

have digestive enzymes that degrade engulfed particles and worn-out organelles

engulfed large particles; these fuse with lysosomes

engulfed small particles; then fuse with lysosomes

• 1) activated by calcium and diacylglyecrol (DAG)
• 2) Phosphorylates other enzymes and proteins

• 1) activated by cAMP
• 2) phosphorylates other enzymes and proteins

thik filaments, uses ATP to slide along actin to cause muscle contraction

1) thin filaments, interact with myosin

• 1) keratin (hair/nails)
• 2) desmin (muscles)
• 3) vimentin (fibroblasts)

form specialized cellular structures such as cilia, neuronal axons, and mitotic spindles; also involved in the transport of organelles in the cell (form a lattice work inside the cell)

a specialized microtubule involved in cell division (forms spindle fibers, which pull chromosome apart)