Openings on plant leaves that allow gas exchange, close at night to reduce water loss
Water and blood in opposite directions which means you should never actually have equilibrium and there will always be a higher concentration of oxygen in the water compared to the blood and that is why we maintain the concentration or the diffusion gradient across the entire gill lamellae
Structures in the leaf
Palisade mesophyll
Spongy mesophyll
Stomata
Palisade mesophyll
Where photosynthesis mainly happens
Spongy mesophyll
Lots of air spaces
Stomata
Where gases diffuse in and out
Oxygen diffuses out of stomata
If not being used in respiration
Carbon dioxide diffuses in through stomata
Because it's needed for photosynthesis
Stomata close at night
To reduce water loss by evaporation
Stomata open in the daytime
When it's bright
This is linked to the light-dependent reaction of photosynthesis
Adaptations of xerophytic plants to minimise water loss
Leaves roll up
Stomata are deep and sunken in
Tiny hairs sticking out
Thicker cuticle
Longer root network
Monomers
Smaller units from which larger molecules are made
Digestion of carbohydrates
1. Amylase in mouth
2. Amylase in duodenum
3. Sucrase and lactase break down disaccharides
Digestion of proteins
1. Endopeptidases hydrolyze peptide bonds in middle of chain
2. Exopeptidases hydrolyze peptide bonds at ends of chain
3. Dipeptidase breaks down dipeptides
Digestion of lipids
1. Lipase hydrolyzes ester bonds in triglycerides
2. Bile salts emulsify lipids to increase surface area for lipase
Micelle
Vesicle formed of fatty acids, glycerol, monoglycerides and bile salts
Absorption of lipids
1. Monoglycerides and fatty acids diffuse across cell membrane
2. Reassembled into triglycerides in ER and Golgi
3. Packaged into vesicles and released into lacteal
Ileum
Covered in villi and microvilli to increase surface area
Thin walls for short diffusion distance
Network of capillaries to maintain concentration gradients
Co-transport
Monosaccharides and amino acids absorbed by active transport due to higher concentration in epithelial cells
Hemoglobin
Quaternary structure protein involved in oxygen transport
Myoglobin
Oxygen-binding protein found in muscle tissue and fetal hemoglobin
Oxyhemoglobin dissociation curve
Shows how hemoglobin binds and releases oxygen at different partial pressures
Cooperative binding of oxygen to hemoglobin
First oxygen binding makes it easier for subsequent oxygens to bind
Bohr effect
High CO2 concentration causes hemoglobin to release oxygen more readily
Different animals have hemoglobin adapted to their needs and environments
Fetal hemoglobin
Has higher affinity for oxygen than adult hemoglobin