Cell Biology: Organelles, Cell Cycle, Genetics & Respiration

Prokaryotic cell DNA structure

Single major circular DNA molecule resembling a bracelet

Bacterial cell wall composition

Peptidoglycan

Archaean cell wall composition

Pseudopeptidoglycan

Plant cell wall composition

Cellulose

Fungal cell wall composition

Chitin

Actin microfilaments functions

Muscle cell contraction, amoeboid movement, cytoplasmic streaming, and animal cell division

Microtubules composition and formation

Composed of tubulin, formed by the microtubule-organizing center (MTOC) or centrosome

Flagella cross-section microtubule pattern

9+2 pattern

Intermediate filaments composition and function

Composed of fibrous protein keratin; strictly structural, stabilizes cell shape and fixes organelle positions like a nuclear cage

Rough ER function

Covered by ribosomes; creates proteins for destinations outside the cytoplasm (cell membrane or organelles)

Smooth ER function

Makes phospholipids, steroids, and triglycerides (does not have ribosomes)

Plant central vacuole functions

Turgor pressure, storing hydrophilic pigments (blue/red), storing noxious substances (nicotine, arsenic)

Contractile vacuoles function

Act as a pump to remove water from freshwater protists like paramecia

Lysosomes function

Digestion of phagocytosed material and worn-out organelles (autophagy)

Tight junctions location and function

Between cells in the stomach and bladder; prevents dangerous materials like stomach acid from slipping between cells

Gap junctions function and locations

Allow rapid passage of material between cells; found between cardiac muscle cells in the heart and smooth muscle cells in the uterus

Plasmodesmata function

Join the cytoplasm between two plant cells, functioning like animal gap junctions

Diploid definition

Organisms with two sets of homologous chromosomes (2n)

G0 phase definition

Cells that do not reproduce and stay in G1 (nerve cells in the spinal cord)

S phase of cell cycle

Replication of DNA and the microtubule-organizing center (MTOC)

Prophase I key event: Synapsis

Formation of tetrads (homologous pairs of sister chromatids) and crossing over between non-sister chromatids

Anaphase I key event

Homologous pairs of chromosomes separate from their tetrads (sister chromatids remain attached)

Oogenesis product in animals

One haploid egg and 3 polar bodies

Coenocytic organisms

Organisms whose cells undergo mitosis without cytokinesis, resulting in multiple nuclei within a single cytoplasm

Epistasis definition

A trait that is the result of two or more chemical reactions each controlled by a different gene (Labrador retriever coat color)

Hemizygous definition

Having only one copy of a gene present in an individual (males for X-linked traits in the XX-XY system)

Barr body definition

The visible, inactive X chromosome in female mammalian somatic cells resulting from dosage compensation

Pleiotropy definition

One gene affecting multiple traits (Kartagener syndrome, sickle cell anemia)

Incomplete dominance definition

The phenotype of the heterozygote is intermediate between the phenotypes of the two parents (e.g., red + white = pink)

Codominance definition

Both alleles are fully expressed (e.g., human blood types IA and IB)

Glycolysis location and oxygen requirement

Occurs in the cytoplasm, does not require oxygen

Glycolysis net yield per glucose

Net of 2 ATP and 2 NADH + H+

Krebs (Citric Acid) Cycle location

Mitochondrial matrix

Krebs Cycle starting and ending molecule

Oxaloacetate

Electron transport chain location

Inner mitochondrial membrane

Final electron acceptor in cellular respiration

Oxygen

Cyanide toxicity mechanism

Chokes and cuts off oxygen or Complex IV in the electron transport chain

Total theoretical ATP yield from cellular respiration

38 ATP

Lactic acid fermentation purpose and product

Pyruvate converted to lactic acid; regenerates NAD+ from NADH + H+ without oxygen so glycolysis can continue

Ethanol fermentation products

Pyruvate converted to acetaldehyde, then to ethanol and CO2