Topic 2 Flashcards
What are examples of gas exchange surfaces
- Alveoli in mammals
- Gills in fish
What are the properties of gas exchange surfaces?
- Large surface are to volume ratio
- Thin for a short diffusion pathway
- Has a maintained steep concentration gradient
Why can’t mammals use diffusion and amiba can?
The rate of diffusion is lower in mammals because they have too high of a volume compared to surface are so diffusion is inefficient
What is Fick’s Law?
How is the mammalian lung’s structure adapted to its function?
Adaptation
- Lots of Alveoli = Large Surface Area
- One cell thick alveoli and capillary walls = thin diffusion distance
- Continuous supply of blood from capillary = maintenance of steep concentration gradient
What is the role of cell membranes?
- Defines cellular boundaries
- Partially permeable
- Regulates flow of information
What is the structure of phospholipids?
- Hydrophilic phosphate head
- Hydrophobic fatty acid tails
- Connected to glycerol by ester bonds
The hydrophilic and the hydrophobic properties of the phospholipid means they are amphipathic
What structures do phospholipids make?
What does the fluid mosaic model explain?
- Made in 1972
- Explains cell to cell communication and interactions (glycolipids and glycoproteins)
- Explains passive and active transport (Channel and carrier proteins)
Label this diagram
A - Glycolipids allow for cell to cell communication
B - Phospholipid bilayer
C - Cholesterol - Increases strength of bilayer and stabilises cell temperature
D - Channel Protein allows for passive transport in and out of cell
E - Glycoprotein used for cell to cell interactions
F - Carrier protein allowing for active transport using ATP
What is Osmosis?
Osmosis is the movement of water molecules from an area of low solute concentration to an area of high solute concentration through a partially permeable membrane
What does hypertonic and hypotonic mean?
In the cell membrane osmosis is in charge of the concentration of cell membrane isotonic.
- Hypertonic ⇒ Too high of a concentration
- Hypotonic ⇒ Too low of a concentration
What types of transport are passive or active transport?
Why do membranes need proteins to aid transport?
The amphipathic nature of the bilayer mean that transportation of dissolved substances needs to be aided with carrier proteins and channel proteins
Why do membranes need proteins to aid transport?
The amphipathic nature of the bilayer mean that transportation of dissolved substances needs to be aided with carrier proteins and channel proteins
What are the different types of diffusion across a cell membrane?
- Facilitated diffusion
- Active Transport
- Exocytsis + Endocytosis
How does Facilitated diffusion work?
Facilitated diffusion
- Uses channel proteins and carrier proteins (Opens and closes depending on hormone signals)
- Passive transport (Down the concentration gradient)
- Large molecule attaches to carrier protein
- Protein changes shape
- Releasing molecule to the other side
How does active transport work?
- Uses ATP (Adenosine Tri-phosphate) and hydrolyses to release energy
- Uses a carrier protein
- Against conc gradient
How does exocytosis and endocytosis works?
Exocytosis and Endocytosis
- Uses vesicles instead of proteins
- Substances packaged in a vesicle
- Travels to and fuses with membrane
- Releasing the contents
What is Cystic Fibrosis?
General Information
- Genetic disease
- Caused by mutation of gene coding for CFTR protein
- Effects opening and closing of ion channels
What does the CFTR channel do?
The CFTR and ENAC channel work together to regulate $Na^{+}$ and $Cl^{-}$ ions between Mucus and Tissue Fluid.
A person with CF would have little/non-functioning/no CFTR proteins meaning the ENAC channel is always open
Drawing water away from Mucus
What is the process of moving $Na^{+}$ and $Cl^{-}$ ions?
- Depending on what channel is open one of the two ions would move across membrane
- Creating an electrical gradient meaning the other ion moves across membrane
- Creating a conc gradient as there is more NaCl on one side of the membrane
- Osmosis would then mean water across the membrane
Pen = ENAC open (Excess water in mucus)
Highlighter = CFTR open (lack of water in mucus)
What happens when there is an excess or lack of water in mucus
Excess water in Mucus
- CFTR channel closed
- $Na^{+}$ moves to tissue fluid through ENAC
- $Cl^{-}$ moves to tissue fluid through basal membrane (electrical gradient)
- Water moves from mucus to tissue fluid through osmosis (conc gradient)
Lack of water in Mucus
- ENAC channel closed
- $Cl^{-}$ moves to mucus through CFTR channel
- $Na^{+}$ moves to to mucus through basal membrane (electrical gradient)
- Water moves from tissue fluid to mucus through osmosis (concentration gradient)
What are the effects of CF on the Resptory system?
- Viscous mucus blocks airways
- Cilia unable to dispose of mucus leading to trapped pathogens causing infection
- Diffusion distance increased reducing diffusion efficiency
What are the effects of CF on the digestive system?
- Pancreatic duct blocked with mucus blocking enzyme release
- Lack of digestive enzymes means less breakdown of food
- Less absorption of carbs lipids and proteins
- Resulting in Malabsorption Syndrome meaning dietary supplements need to be taken with a higher caloric diet
What are the effects of CF on the reproductive system
- Cervix blocked by mucus making fertilisation hard
- Sperm ducts blocked with mucus meaning sperm can’t leave body
What is a mononucleotide?
A single biological molecule made from:
- A pentose sugar (Deoxyribose or Ribose)
- A nitrogenous base (A,T or U,C,G)
- A phosphate group
(Depends on DNA or RNA)
What is a mononucleotide?
A single biological molecule made from:
- A pentose sugar (Deoxyribose or Ribose)
- A nitrogenous base (A,T or U,C,G)
- A phosphate group
(Depends on DNA or RNA)
What is a polynucleotide?
A polynucleotide is a:
- Polymer of nucleotides
- joined by phosphodiester bonds formed by condensation reactions
- DNA has 2 polynucleotide strands
- RNA has 1 polynucleotide strand
What is the structure of DNA?
- 2 antiparallel Polynucleotide strands joined together via hydrogen bonds in a double helix structure
- With the equal amounts of thymine with adenosine and guanine and cytosine (due to complementary base pairings)
- 3 Bonds between C and G
- 2 Bonds between A and T
What is the structure of an amino acid?
A central carbon attached to a amine group, carboxylic group, a hydrogen molecule and a R group
What is the primary stage of protein formation?
A polypeptide chain of amino acids held by peptide bonds
(Formed in condensation reactions)
What is the secondary stage of protein formation
The chain then folds into either a alpha helix or a beta pleated sheet held together by hydrogen bonds
(4 residues down in both structures)
What is the quaternary stage in protein folding?
tertiary structure ⇒ several tertiary polypeptide
Same bonds as tertiary
What are globular proteins?
- 3D Spherical shape - for catalytic processes
- Soluble - Due to hydrophilic side chain meaning easy transport
Amylase and haemoglobin are globular proteins
What are fibrous proteins?
Fibrous proteins
- Long polypeptide chains tightly coiled around
- Lots of bonds (Hydrogen, Disulfide)
- Found in supportive tissue
Collagen is a fibrous protein
What are enzymes?
- Enzymes are 3D globular proteins
- Which are biological catalysts
- which catalyse by lowering activation energies for certain reactions
What is an enzyme substrate complex?
- Where a substrate binds to the active site of the enzymes
- Where the active site changes shape slightly to fit the substrate
This is known as induced fit
What is a pedigree?
