Exchange Flashcards
Amylase breaks down …
polysaccharides
Endopeptidase hydrolyzes…
peptide bonds within polypeptides
Exopeptidases hydrolyzes…
peptide bonds at the end of proteins
Features of an efficient exchange surface
large SA
thin (short diffusion)
good blood supply/ventilation
Define digestion
Hydrolysis of large, insoluble molecules into smaller molecules that can be absorbed across cell membranes
Which enzymes are involved in carbohydrate digestion? Where are they found?
Amylase (mouth)
Maltase, sucrase , lactase (small intestine)
What are the substrates and products of the carbohydrate digestive enzymes?
Amylase -> starch into smaller polysaccharides
Maltase -> maltose into x2 glucose
Sucrase-> Sucrose into glucose + fructose
Lactase -> Lactose into glucose and galactose
Lipids are digested in…
the small intestine
What needs to happen before lipids can be digested?
They must be emulsified by bile salts produced by the liver. This breaks down large fat molecules into smaller, soluble molecules called micelles, increasing SA
How are lipids digested?
Lipase hydrolyses the ester bond between the monoglycerides and fatty acids
Dipeptides…
break dipeptides into amino acids
Role of Na+ in co-transport
Na+ is actively transported out of the cell into the lumen, creating a diffusion gradient. Nutrients are then taken up into the cells along with Na+ ions.
how does an organism size relate to their surface area to volume ratio
The larger the organism, the lower the SA:V
How does an organisms SA:V relate to their metabolic rate?
The lower the SA:V, the lower the metabolic rate
How might a large organism adapt to compensate for its small surface area to volume ratio?
Changes that increase SA like:
Foldings
Developing a specialised gas exchange surface
3 features for an efficient gas exchange surface
- Large SA
- Thin/short diffusion pathway
- Steep concentration gradient maintained by blood supply or ventilation
Why cant insects use their bodies as an exchange surface
Have waterproof chitin exoskeletpn and a small SA:V to conserve water
Name + describe the 3 main features of an insects gas transport system
- Spiracles =holes on the body’s surface which may be opened or closed by a valve for gas or water exchange.
- Trachae = Large tubes extending through all body tissues, supported by rings to prevent collapse.
- Tracheoles = smaller branches dividing off the tracheae
Process of gas exchange in insects
- Gases move in and out of the tracheae through the spiracles .
- A diffusion gradient allows O2 to diffuse into the body tissues while waste CO2 diffuses out.
- Contraction of muscles in the tracheae allows mass movement of air in and out
Why can’t fishes use their bodies as an exchange surface?
Have a waterproof, impermeable outer membrane and a small surface area to volume ratio
Process of gas exchange in fish
- Fish opens its mouth to enable water flow in, then closes its mouth to increase pressure.
- Water passes over the lamellae and the O2 diffuses into the bloodstream
- Waste CO2 diffuses into the water and flows back out of the gills
How does countercurrent exchange system maximise O2 absorbed by the fish?
Maintains a steep concentration gradient as water is always near blood with a lower O2 concentration .
3 adaptaions of a leaf that allows for efficient gas exchange
- Thin and flat to procide short diffusion pathway
- Many stomata to allow gases to easily enter
- Air spaces in the spongy mesophyll allow gases to move around the leaf facilitating photosynthesis.
How plant limit their water loss while still allowing gases to be exchanged
Stomata regulated by guard cells which allows them to open and close as needed. Most stay closed to prevent water loss whilst others open to let O2 in.
Pathway by air as it enters the mammalian gaseous exchange system
Nasal cavity - > trachea -> bronchi-> bronchioles -> alveoli
Describe the function of the nasal cavity in the mammalian gaseous exchange system
Good blood supply warms + mositens the air entering the lungs.
Goblet cells in the membrane secrete mucus which traps dust and bacteria
Describe the trachea and its function in the mammalian gaseous exchange system
Wide tube supported by cartilage to keep the air passages open during pressure changes
Lined by ciliated epithelium cells which move mucus towards the throat to be swallowed, preventing lung infections
Carries air to bronchi
Describe the bronchi and its function in the mammalian gaseous exchange system
Supported by rings of cartilage and are lined by ciliated epithelium cells
Narrow and there are two bronchis
Allows passage of air into the bronchioles
Describe the bronchioles and its function in the mammalian gaseous exchange system
Narrower than bronchi
Only has muscle and elastic fibres so that they can contract and relax easily during ventilation
Allows passage of air into the alveoli
Describe the alveoli and its function in the mammalian gaseous exchange system
Mini air sacs, lined with epithelium cells, site of gas exchange
Walls are only one cell thick , covered with a network of capillaries
Process of Inspiration
EIC/C -> R/U/O -> D/C/F - > VT ^ -> APO > API
-> AMI
Process of Expiration
EIC/R -> R/I/D -> D/R/U -> VT/D -> API > APO ->AMO
Tidal volume is…
volume of air we breathe in and out during each breath at rest
Breathing rate is …
number of breaths per minute
A spirometer is …
a device which records volume changes onto a graph as a person breathes (use to calculate pulmonary ventilation rate)
