Unit 1 Topic 2: Multicellular Organisms Flashcards
Properties of stem cells
- unspecialised
- potency
- self-renewal for long periods of time
Potencies
totipotent - can form any cell even the embyronic cells (placenta)
pluripotent - can for any type of body cell
multipotent - forms specialised body cell
hierarchy of organism
- cells
- tissues
- organs
- organ systems
- organisms
differentiation
cell specialisation is determined by gene expression
disadvantages - cells are incapable of independent survival
advantages - increased efficiency due to specificity
structural features of an efficient gas exchange surface
thin
moist
high SA:V
extensive capillary system
capillaries
thin - rapid diffusion
small diameter - slows flow of blood to maximise exchange
high SA:V - more efficient gas exchange
blood flow regulation - tissues recieve appropriate supply of nutrients to meet metabolic requirements.
direction of blood travel
from artery (from heart) to vein (to heart) gets more oxygenated, co2 goes to alveoli.
mechanical digestion
chewing - increases SA:V
peristalis moves food to stomach where stomach muscles churn it
Chemical digestion
mouth (ph 7 ) - amylase, break down starches into sugars
stomach (ph 1) - pepsin and protease, breaks down proteins into amino acids
small intestine (ph 8) - lipase, breaks down lipids into fatty acids and glycerol
Absorption
vili increase the SA, increases efficiency
fat soluble goes through lacteals
water soluble goes through the epithelial wall
large intestine primarily for water reabsorption and waste removal
the nephron
glomerulus - filters out the blood and dumps water and nutrients into the bowman’s capsule, done through high pressure, which forces out the water and nutrients
bowman’s capsule - collects filtrate from blood
proximal convoluted tubule - reabsorb water and nutrients actively
loop of henle - reabsorb water while pumping out salts
distal convoluted tubule - actively reabsorbs salts and water
collecting duct - collects waste, antidiuretic hormone hormone makes it more permeable
ammonia
dilute
toxic
low energy
urea
concentrated
not that toxic
some energy
uric acid
super concentrated
not toxic
lots of energy
stomata and guard cells
gas exchange and transpiration
vacuoles control open or closed
leaf structure
waxy cuticle - stops transpiration
epidermis - transparents allows for light
palisade mesophyll - main site for photosynthesis
spongy meso - allows for efficient gas exchange
xylem - water for photosynthesis
phloem - nutrients for photosynthesis
how does leaft facilitate gas exchange
- waxy cuticle
- spongy mesophyll
- surface area, more stomata, more stomata
Xylem
dead cells, vessel elements and tracheids, unidirectional, transport of water
phloem
companion cells, sieve tubes, sive plates, transport of nutrients, multi-directional
Xylem transport
root pressure, minerals are actively transported into the xylem causing high concentration of solutes causing an influx of water due to osmosis.
the transpiration stream is the continous movement of water up the column, which stays together through the cohesion of water molecules to maintain the column
Phloem translocation
sugars loaded into the phloems actively, high water pressure drives sap to directions to be unloaded and then the osmotic pressure reduces and returms to the xylem.
factors that affect transpiration
wind, humidity, temperature, light, SA, number of leaves
