Chapter 1: Cell Biology. Flashcards
Increases membrane fluidity
Cholesterol
Determinants of cellular charge
Cells are more negative on the inside compared to the outside based on Na/K ATPase (3Na out / 2K in)
Used for co-transport of glucose proteins and other molecules
Sodium gradient
[Na] ECF
140
[K] ECF
4
[Ca] ECF
5
[Mg] ECF
2
[Cl] ECF
103
[HCO3] ECF
24
[SO4] ECF
1
[Protein] ECF
16
[PO4] ECF
2
[Organic anions] ECF
5
Cations in ECF
Sodium, potassium, calcium, magnesium
Anions in ECF
Chloride, bicarb, sulfate, phosphate, proteins, organic anions
[Na] ICF
12
[K] ICF
150
[Ca] ICF
10 x -7
[Mg] ICF
7
[Cl-] ICF
3
[HCO3] ICF
10
[SO4] ICF
-
[HPO4] ICF
116
[Protein] ICF
40
[Organic anions] ICF
-
Adhesion molecules (cell-cell and cell-extracellular matrix, respectively), which anchor cells
Desmosomes / hemidesmosomes
Cell-cell occluding junctions; form an impermeable barrier (e.g., epithelium)
Tight junctions
Allow communication between cells (connexin subunits)
Gap junctions
Intramembrane proteins; transduce signal from receptor to response enzyme
G proteins
Receptor and response enzyme are a single transmembrane protein
Ligand-triggered protein kinase
Glycolipids on cell membrane
ABO blood-type antigens
Glycoproteins (Gp) on cell membrane
HLA-type antigens
What is the osmotic equilibrium?
Water will move from an area of low solute concentration to an area of high solute concentration and approach osmotic equilibrium.
Cell cycle: protein synthesis, chromosomal duplication
G1, S
Cell cycle: mitosis, nucleus divides
G2, M
Most variable portion of cell cycle, determines cell cycle length
G1
Quiescent phase of cell cycle that can follow G1
G0.
Phases of mitosis
Prophase, metaphase, anaphase, telophase
Mitosis: centromere, attachment, spindle formation, nucleus disappears
Prophase
Mitosis: chromosome alignment
Metaphase
Mitosis: chromosomes pulled apart
Anaphase
Mitosis: separate nucleus reforms around each set of chromosomes
Telophase
Double membrane, outer membrane continuous with rough endoplasmic reticulum
Nucleus
Inside the nucleus, no membrane, ribosomes are made here
Nucleolus
DNA strand is used as a template by RNA polymerase for synthesis of an mRNA strand.
Transcription
Bind DNA and help the transcription of genes.
Transcription factors.
Binds receptor in cytoplasm, then enters nucleus and acts as a transcription factor.
Steroid hormone.
Binds receptor in nucleus, then acts as a transcription factor.
Thyroid hormone.
Examples of transcription factors
Steroid hormones, thyroid hormones, AP-1, NF-kB, STAT, NFAT
Bind RNA polymerase and initiate transcription
Initiation factors.
Uses oligonucleotides to amplify specific DNA sequences
DNA polymerase chain reaction
Purines
Guanine, adenine
Pyrimidines
Cytosine, thymidine (only in DNA), uracil (only in RNA)
Forms 3 hydrogen bonds with cytosine
Guanine
Forms 2 hydrogen bonds with either thymidine or uracil
Adenine
mRNA used as a template by ribosomes for the synthesis of protein
Translation
Have small and large subunits that read mRNA, then bind appropriate tRNAs that have amino acids, and eventually make proteins
Ribosomes
1 glucose molecule generates 2 ATP and 2 pyruvate molecules
Glycolysis
2 membranes, Krebs cycle on inner matrix, NADH/FADH2 created
Mitochondria
The 2 pyruvate molecules (from the breakdown of 1 glucose) create NADH and FADH2
Krebs cycle
Enter the electron transport chain to create ATP
NADH and FADH2
How many ATP does 1 molecule of glucose create?
1 glucose = 36 ATP
Mechanism by which lactic acid (Cori cycle) and amino acids are converted to glucose.
Gluconeogenesis.
Used in times of starvation or stress (basically the glycolysis pathway in reverse)
Gluconeogenesis
Why are fat and lipids not available for gluconeogenesis?
Because acetyl CoA (breakdown product of fat metabolism) cannot be converted back to pyruvate.
Mechanism in which the liver converts muscle lactate into new glucose; pyruvate plays a key role in this process.
Cori cycle
Synthesizes proteins that are exported (increased in pancreatic acinar cells)
Rough endoplasmic reticulum.
Lipid / steroid synthesis, detoxifies drugs (increased in liver and adrenal cortex)
Smooth endoplasmic reticulum
Modifies proteins with carbohydrates; proteins are then transported to the cellular membrane, secreted, or targeted to lysosomes
Golgi apparatus
Have digestive enzymes that degrade engulfed particles and worn-out organelles
Lysosomes
Engulf large particles, then fuse with lysosomes
Phagosomes
Engulf small particles, then fuse with lysosomes
Endosomes
Activated by calcium and diacylglycerol (DAG). Phosphorylates other enzymes and proteins.
Protein kinase C
Activated by cAMP. Phosphorylates other enzymes and proteins.
Protein Kinase A.
Thick filaments, uses ATP to slide along actin to cause muscle contraction
Myosin
Thin filaments, interact with myosin above
Actin
Keratin (hair/nails), desmin (muscle), vimentin (fibroblasts).
Intermediate filaments.
Form specialized cellular structures such as cilia, neuronal axons, and mitotic spindles. Also involved in the transport of organelles in the cell (form a latticework inside the cell).
Microtubules.
Specialized microtubule involved in cell division (forms spindle fibers, which pull the chromosome apart)
Centriole.