Topic 2: Genes And Health Flashcards
What is CF?
a sticky mucus lining tubes and ducts in the gas exchange, digestive and reproductive organs, causing a cough, chest infection etc.
CF is caused by a faulty transport protein in the membrane of EP cells. membranes acts a barriers controlling what enters and leaves
What are epithelial cells?
They line cavities and tubes in the surface of internal organs.
EP cells work together as a tissue called epithelium.
A basement membrane consists of protein fibres in a protein-carb matrix.
Layers of EP cells sit on a basement membrane which secures the epithelium to connective tissue beneath
what are ciliated epithelial cells?
columned shaped, covering many surfaces.
projections called cilia beat to move mucus up to the throat so it can be swallowed
Describe active transport
uptake of molecules against a conc gradient using energy from respiration.
What is the molecular structure of a globular protein and how does its structure relate to its function?
the polypep chain is folded into a compact sphere.
Soluble due to hydrophllic side chains that protect from the outside of the molecules, therefore they’re important in metabolic reactions.
3D shapes are essential to bind with other substances
What is the molecular structure of a fibrous protein and how does its structures relate to its function?
Several long polypep chains can be cross linked and wind round each other to form a rope like strand held by H bonds between chains.
Structurally important, strong, insoluble proteins
Describe what happens to a cell in hyper, hypo and isotonic solutions.
hyper: cell is surrounded by high osmotic conc, so water leaves the cell.
iso: no net movement
hypo: cell surrounded by more water, water enters the cell in a net movement
What is facilitated diffusion?
charged molecules can’t diffuse easily across the non polar centre of the bilayer, so they use channel proteins that create pores to diffuse. It is passive, and increases diffusion rate
What are carrier proteins?
facilitate diffusion of large polar molecules.
A molecule/ ion combines with the binding site of a carrier protein.
ATP then transfers a phosphate group to the carrier protein on the inside of the membrane.
The carrier has a shape change, carrying and then releasing the molecule in the membrane before reverting back to its original shape.
What direction to Active transport systems move in? What other processes use AT?
Active transport systems only move in one direction!
its involved in impulse transmission, muscle contraction, absorption of mineral salts, excretion
What is the primary structure of a protein?
number and sequence of aa in a polypep chain.
22 aa= huge protein variety.
This determines the properties of the protein which determines function
AA link by peptide bonds in condensation reactions to form a polypeptide
What is the secondary structure of a protein?
The aa sequence twists the polypep chain. It is the way the primary structure arranges itself in space. It has alpha helix and beta pleated sheets that allow H bonds to form.
What is the tertiary structure of a protein?
How secondary structure arranges itself in space. polypeps consist of a helix sections, beta pleated sheets and some unordered regions.
There are more interactions and bonds between R groups. Eg H and disulphide bridges. Hay some hydrophilic and hydrophobic interactions
What is the quaternary structure of a protein?
when more than 1 polypep chain is arranged together. Not all proteins have this.
Haemoglobin has 4 pp chains
Many interactions and bonds between R groups occur to form this structure.
What happens when 2 amino acids join?
they form peptide bonds during condensation reactions to form a dipeptide.
Describe R groups in amino acids
they can form interactions/ bonds between protein molecules.
They form active sites and receptors in membranes.
They affect solubility
Describe cholesterol
organic lipid, essential component of the membrane. It fits between the phospholipids, maintaining membrane strength.
At higher temps it stabilises cell membrane structure, and at lower temps maintains fluidity. The more unsaturated the lipids, the more fluid it will be.
What are conjugated proteins?
have a chemical group associated w/ their polypep chain. Eg haemoglobin has an Iron containing heme group.
What is the importance of H bonds in protein folding?
H bonds cause alpha helix and beta pleated sheets to join.
H bonds are involved in the tertiary structure.
H bonds add strength and stability to the protein structure.
What is the importance of hydrophilic and hydrophobic amino acid side groups in protein folding?
hydrophobic side groups are on the inside tissue. They ensure the protein is rigid and strong.
Hydrophyllic amino acid side groups are on the outside tissue. They allow a soluble protein to be useful in transporting substances.
Give 3 characteristics of gas exchange surfaces
Thin blood vessels
Lots of air spaces.
Covered in capillaries for good blood supply
These factors all decrease diffusion distance, increase diffusion of respiratory gases and maximise SA:V ratio.
Describe how mammals breathe in
Diaphragm relaxes, which contracts the intercostal muscles.
Contraction of external muscles raises ribcage.
Lung volume increases as air moves in.
How is CO2 transported in the blood?
it is dissolved in plasma
it is combined w/ haemoglobin.
Explain what is meant by Fluid Mosaic
There are randomly arranged proteins in the bilayer.
The phospholipids forming the bilayer are free to move
Explain what is meant by partially permeable
allows only certain substances to move through by diffusion
What consists of the FMM?
Proteins, cholesterol, phospholipid bilayer and channel proteins
glycolipd: lipid molecules w/ attached polysaccharides
glycoproteins: protein molecules w/ attached polysaccharides
What occurs in the cell membrane when hay too much water in the mucus?
-Na+ ions are pumped into the tissue fluid. This causes a lack of Na+ ions in the cell, so Na diffuses through a channel protein into the cell.
Buildup of Na+ ions in tissue fluid creates an electrical gradient, attracting Cl- ions to diffuse into the tissue fluid.
NaCl buildup means water moves out of the cell by osmosis. Therefore water moves out of the mucus into the cell and gets less watery
What occurs in the cell membrane when hay too little water in the mucus?
Cl- ions are pumped into the cell across the basal membrane.
Cl- ions leave the cell via a CFTR channel protein via facilitated diffusion.
Buildup of Cl- ions creates an electrical gradient, so Na+ ions diffuse down the gradient into the mucus.
NaCl buildup means that h20 moves out of the cell by osmosis into the mucus. This in turn causes h20 from the tissue fluid to move into the cell to replace lost water.
What occurs in the cell membrane of a patient w/ CF?
The Na+ channel is always open, meaning Na+ ions constantly move into the cell. Cl- ions can’t be transported across the apical membrane bc of faulty CFTR channel protein.
Na+ ions move to the tissue fluid via diffusion. A buildup of + charge creates an electrical gradient, so Cl- ions diffuse down. NaCl buildup causes h20 to move out of the cell by osmosis. Now, lack of h20 in the cell means water from already sticky mucus to leave and enter the cell.
what is a result of excessively sticky mucus?
Cilia cant move the mucus , reducing effective ventilation of the alveoli.
Mucus frequently gets infected. Phagocytosic cell break down and their DNA makes mucus even stickier, causing downward spiral of lung damage and inflammation.
