4 - Exchange and Transport Flashcards
Define metabolic rate
Rate of chemical reactions in an organism over time
Define exchange
Expel a substance and receive another
Define facilitate
To make an action
How to calculate surface area?
Length x length x number of sides cm2
How to calculate volume?
Width x height x length cm3
How to calculate Surface area : Volume
SA/V
How to calculate area of a cirlce
𝜋𝑟^2 cm2
How to calculate SA of a sphere
4𝜋𝑟^2
How to calculate volume of a sphere
(4𝜋𝑟^3)/3
How to calculate SA of a cylinder
𝜋ⅆℎ+2𝜋𝑟^2
How to volume SA of a cylinder
𝜋r^2 ℎ
4 common features of efficient gas exchange
Simple diffusion
Moist surface
Thin and permeable
Big SA
Why does a moist surface lead to efficient gas exchange
Oxygen dissolves in the water
What is Flick’s Law?
Rate of diffusion = surface area x con. difference
——————————————
thickness of membrane
What are the holes in insects called?
Spiracles
What are spiracles controlled by?
Valves
Why can’t the spiracles stay open all the time?
When open, there is water loss
Describe the tracheal system in insects (4)
1 - Air moves into trachea through spiracles
2 - O2 travels down conc. gradient towards cells
3 - Trachea branches off into tracheoles so O2 diffuses directly into body cells
4 - CO2 from cells moves down con. towards spiracles (released into atmosphere
What does the tissue of insects contain?
A fluid that diffuses the hypotonic cytoplasm of resting cells
What happens if lactic acid is produced in the tracheal system in insects?
Reduces osmotic potential so fluid is withdrawn from tracheoles
How is air moved in larger insects?
Abdominal pumping
Fish have a …………… metabolic rate
High
What is the operculum?
Flap that protects the gills
What colour is oxygenated blood in diagrams?
Red
What colour is deoxygenated blood in diagrams?
Blue
What is a gill arch
Tube that connects to the gill fillaments
What are gill filaments?
Attached to gill arch. Increase SA I-------------------------- I\_\_\_\_\_\_\_\_\_\_\_\_\_\_ I I----------------------------- I----------------------------- I------------------------------ I------------------------------ I
What are lamellae?
Lots of capillaries on top of filaments to increase SA
What are the two types of flow?
Parallel and counter-current
Graph for parallel flow
I \ I \ I \ I \\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ I /-------- I / I / I / \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
Click on edit to see graph
Graph for counter-current flow
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\\Describe counter-current flow (5)
Blood and water flow are in opposite directions
Water always has a higher oxygen concentration than blood in gill capillaries
Oxygen diffuses into gill capillaries across entire length of lamellae
Gills absorb ~80% oxygen from water across gills
Equilibrium is never reached
What is the buccal cavity?
The mouth of the fish
What is inspiration in fish? (6)
Mouth opens Operculum valve closes Buccal chamber lowers Volume increases Pressure decreases Water flow into mouth
What is expiration in fish? (6)
Mouth closes Operculum valve opens Buccal chamber raises Volume of cavity decreases Pressure inside increases Water flows over gills
Limitations of tracheal system (2)
Relies on diffusion
Limit insect size
5 ways to increase exchange effectiveness in insects
BIG SA Steep conc. gradient Continual flow Short pathway Abdominal pumping
2 reasons why we need lots of gas to exhcnage
High metabolic rate
High respiratory rate
So we need to maintain out temperature
Do humans have a high or low SA:V
Low
Why are our lungs inside our body? (2)
Body would lose H2O as surfaces are moist
Air isn’t dense enough to support and protect
Name the body parts that are involved in respiration (in order)
Lungs / mouth Trachea Bronchi Bronchioles Alveoli
Where does air enter in people?
Mouth or nose
Why is it preferred for air to enter through our nose? (3)
Warm and lined with capillaries
Moist and secretes mucus
Contains hairs to filter
What shaped are the rings on the trachea? Why?
C- shaped.
Provide strength but still flexible
What is the trachea lined with? Why?
Cilia - beat upwards to secrete mucus. Prevent foreign bacteria from entering lungs
What is the pharynx?
Where trachea and oesophagus meet behind mouth
What are the bronchi and bronchioles?
Each bronchus enters a lung and divides into bronchioles
4 adaptations of alveoli
1 cell thick - short pathway
600 million - high SA:V
Next to capillaries (maintain conc. grad)
Moist - O2 dissolved
What are epithelial cells?
Cells that are in contact with the external environment
What are endothelial cells?
Cells that are NOT in contact with the external environment
What type of cells are in contact with the external environment?
Epithelial
What type of cells are NOT in contact with the external environment?
Endothelial
Where does gas exchange happen in humans?
Alveoli walls
What are the two things are involved in the mechanisms of breathing?
Diaphragm
Intercostals muscles
What does the intercostals muscles do?
Move ribs up and down
Describe the process of inhalation in humans (5)
- Intercostals muscles contract and move up
- Diaphragm contracts and flattens
- Chest cavity increases so volume increases
- Internal pressure of air in lungs reduces
- Outside air flows into lungs
Describe the process of exhalation in humans (5)
- Intercostals muscles relax
- Diaphragm relax and return to arc position
- Volume reduces
- Pressure increases
- Air forces outside of lungs
3 ways insects reduce water loss
Small SA:V
Waterproof coating
Spiracles
2 ways plants reduce water loss
Close stomata
Waterproof cotaing
Why can’t plants have a small SA:V
Needed for photosynthesis
What is a xerophyte?
Plant adapted to having a low water supply
What type of plants are adapted to having a low water supply?
Xerophyte
4 adaptations of plants reducing water loss
Thick cuticle
Roll up leaves
Hairy leaves
Small SA:V on leaves
Why do leaves roll up and how?
Reduce water loss - protects lower epidermis and traps air so no concentration gradient
Why are leaves hairy?
Trap moist air to reduce concentration gradient
Define stomata
Pores mainly found on underside of leaf. Surrounded by guard cells
Where are stomata mainly found?
Underside of leaf
What do the stomata do?
Control rate of gas exchange to minimise water loss
Where does deoxygenated blood go? (4)
Vena cava
Right atrium
Right ventricle
Pulmonary valve then artery
Where does oxygenated blood go? (4)
Enter through pulmonary vein
Left atrium
Left ventricle
Aortic valve then aorta
Atrium associated with deoxygenated blood
Right
Atrium associated with oxygenated blood
Left
Artery associated with deoxygenated blood
Pulmonary
Valve associated with oxygenated blood
Aorta
Describe the process of digesting lipids (5)
- Emulsification of fat droplets
- Micelle formation
- Micelle breakdown when in contact with epithelial cells, releasing FA and monoglycerides
- Triglyceride combines with cholesterol and lipoproteins to form chylomicrons
- Chylomicrons move out of cell by exocytosis and enter lacteals
What are chylomicrons?
Triglyceride combines with cholesterol and lipoproteins
Describe the co-transport of Na, glucose and K (5)
- Sodium moves from epithelial cells into blood by active transport
- Reduce sodium conc. in cell
- Sodium diffuses into the cell by diffusion
- Symporter protein used as AA can also be transported
- Glucose does facilitated diffusion into blood
Define peristalsis
Moves food down the oesophagus
What is the alimentary canal?
Passage from mouth to anus
What are lacteals?
Lymphatic vesicles found in the centre of the villi
What is a lumen?
Hollow part of something
What are micelles?
Emulsified fat droplets
Define exocytosis
Move out of a cell
What is the ileum?
Small intestine
What is the colon?
Large intestine
Define hydrolysis
Chemical breakdown of a compound with water
Define assimilate
Nutrients in food are taken into the cells of the body
Define emulsification
Breakdown of fats into smaller molecules to provide a bigger SA
What happens during the emulsification of lipids
Triglyceride is added to lipase to form a monoglyceride and two FA
Ester bond hydrolyses
What type of digestion happens at each stage of the digestive cycle?
Mouth - mechanical and chemical Oesophagus Stomach - mechanical and chemical S.Intetsine - chemical L.intesine
Where does ingestion happen
Mouth
Where does egestion happen?
Rectum and anus
Two parts of the small intestine
Duodenum and ileum
What is the right spelling: ilium or ileum?
Ileum
What happens in the duodenum?
Pancreatic juices and bile is released
What happens in the ileum?
Main site of absorption
2 examples of physical digestion
Teeth and muscles (churning)
What is chemical digestion?
Hydrolyse large, insoluble molecules by enzymes
Process of digesting carbohydrates (4)
- Amylase hydrolyses glyosidic bond of starch
- Maltose is produced
- Maltase hydrolysis A1-4 glyosidic bond of maltose
- Alpha glucose is produces
Process of digestion (6)
- Salvia mixed with food, which contain salivary enzymes
- Starch goes into maltose
- Food enters stomach and sal. enz. are denatures
- Go to ileum to ix with pancreatic juices
- Peristalsis happens
- Maltase released so maltose goes into glucose
3 ways to digest proteins
Endopeptidases
Exopeptidases
Dipeptidases
What is endopeptidases?
Hydrolysis peptide bond in AA central region
What is exopeptidases?
Hydrolysis bond on terminal AA (end of AA)
What is dipeptidases?
Hydrolyse the bond between the two AA of a dipeptide.
4 adaptations for absorption
Villi contracts so epithelial cells are in contact with food
Microvilli increase SA
Capillary network to maintain conc. grad
Lacteal - fats are absorbed
Define digestion
Break down of large, insoluble food molecules into smaller, soluble ones that can be absorbed into the small intestine
What is the vein rich in?
Nutrients
What is the artery rich in?
Oxygen
