BIOLOGY 2D03 Lecture Notes - Lecture 3: Endoreduplication, Microfibril, Glycan
4 Oct 2016
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Plant cell division: divide to produce two daughter cells through mitosis, highly regulated however, can change in response to environment, ex. Storing food, more photosynthesis can occur, etc: required for normal growth in some plants (arabidopsis) Positive correlation between cell growth/expansion and endoreduplication. Synthase: cesa gene family encodes cellulose synthase genes, evidence. Cesa 2,5,6, and 9 perform same function (primary cell wall synthesis) Cesa 4, 7, 8 synthesize the secondary cell wall: more evidence. Rsw1 mutant forms abnormal cellulose microfibrils when temp-sensitive cesa 1 mutant is off . Interactions: cellulose microfibrils are held together by interchain hydrogen bonds between hydroxyl groups, glycans are flexible links between microfibrils, pectins form a network around microfibrils and glycans. Root hairs: microtubules determine direction because they direct how cellulose microfibrils are laid down in cell wall, how do cells expand, taking water into vacuoles turgor pressure, loosening cell wall by reducing microfibril and pectin cross links.
