Organising the Organism Flashcards
What does xylem tissue consist of?
xylem vessels with parenchyma cells and fibres, wall reinforced and waterproofed by lignin which kills cell contents. Cell ends break to made long tubes with wide lumen
What is xylem tissue well suited for?
Transporting water and minerals up the plant, also helps support the plant
What does phloem tissue consist of?
sieve tubes and companion cells, sieve plates form between each cell for movement up/down tubes. Companion cells are metabolically active
What are the 4 main tissue groups in animals?
epithelial tissues, connective tissue, muscle and nervous tissues
What is squamous epithelial tissue?
Flattened cells, lines inside tubes (blood vessels), walls of alveoli in lungs, short diffusion pathway
What are squamous cells held in place by?
basement membrane which is secreted epithelial cells (made of collagen and glycoproteins), attaches epithelial cells to connective tissue
What is ciliated epithelial tissue?
column-shaped cells, inner surface of tubes (trachea, bronchi, uterus), the part exposed to the lumen is covered with cilia - wave to move mucus
How do cilia work in the breathing tract?
Small particles/micro-organisms trapped in mucus, cilia waft to back of the throat to be swallowed and killed by stomach acid
How does smoking affect cilia?
nicotine paralyses cilia, damaged/killed by tar in smoke so there are less and mucus is trapped in lungs
4 requirements for photosynthesis?
light, water supply, CO2 supply, presence of chlorophyll
What are the 5 ways that leaves are adapted for photosynthesis?
transparent upper epidermis, palisade layer: lots of cell with chloroplasts = chlorophyll, spongy mesophyll layer with space for gas circulation, lower epidermis with stomata, leaf vein system of xylem and phloem
How to stomata contribute to photosynthesis?
Allow gas to be exchanged between leaf and surrounding air, 2 guard cells: swell to open, not turgid to close
How are guard cells specialised?
In pairs, contain chloroplasts, cells walls have spiral thickening of cellulose, pore between is a stoma (pl. stomata)
