Genes & Health Flashcards
What are the Symptoms of Cystic fibrosis?
Very salty-tasting skin.
Persistent coughing, at times with phlegm.
Frequent lung infections including pneumonia or bronchitis.
Wheezing or shortness of breath.
Poor growth or weight gain in spite of a good appetite.
Possible treatments of cystic fibrosis?
antibiotics to prevent and treat chest infections.
medicines to make the mucus in the lungs thinner and easier to cough up.
medicines to widen the airways and reduce inflammation.
special techniques and devices to help clear mucus from the lungs.
medicines that help the person absorb food better.
Effects for cystic fibrosis
CF causes thick mucus that clogs certain organs, such as the lungs, pancreas, and intestines. This may cause malnutrition, poor growth, frequent respiratory infections, breathing problems, and chronic lung disease.
What is a gene and what is a gene mutation
Genes are sections of DNA nucleotides located on chromosomes that contain the instructions for production of a specific protein.
A change in the DNA nucleotides in the gene so either no protein or an incorrect protein is made.
Identify the parts of the respiratory that provide the following features:
• Large surface area
• Very thin permeable membrane, for a short diffusion
pathway
• Maintaining diffusion gradients
LSA= alveoli & capillaries
Maintaining diffusion = blood flow & gasses
Short diffusion distance = alveoli epithelial& capillary endothelium .
There are three layers between the blood and the air in the alveoli: the capillary wall, a layer of extracellular matrix and the alveolar wall. This is called the blood-gas barrier.
Explain how the blood-gas barrier of the chicken is adapted to give more efficient gas exchange than the blood-gas barrier of the dog. (3)
• Thinner blood-gas barrier
• Because of thinner alveoli walls/capillary walls
• Therefor a reduced diffusion distance
• Faster rate of diffusion/gas exchange
Emphysema is another lung disease associated with cigarette smoking. One symptom of emphysema is shortness of breath. This is due to the damage to the alveoli and destruction of capillaries surrounding the alveoli. Use your knowledge of the structure of the lung and its adaptations for gas exchange to explain why a person with emphysema has problems with gas exchange.
-reduced diffusion of gases
-due to decrease in surface area of alveoli / gas exchange surface
-and capillaries due to the destruction
-less blood flow and therefore less o2 being carried
-meaning lower concentration gradient.
What is fick’s law ?
Rate of diffusion = (surface area x concentration gradient) / diffusion distance
Fick’s law can be used to calculate the rate of diffusion across gas exchange surfaces. Use fick’s law to explain the adaptations of mammalian gas exchange surfaces
Rate of diffusion is proportional to surface area - alveoli have large surface area so rate of diffusion increases.
Rate of diffusion is proportional to difference in concentration blood flow maintains a difference in gas concentrations.
Rate of diffusion is inversely proportional to diffusion distance. Walls of alveoli and capillaries are one cell thick
Diffusion distance is reduced due to flattened cells forming alveoli and capillary walls.
State 3 things needed for efficient diffusion of gases across the gas exchange surface
- short dif pathway
- large SA
- steep conc gradient
What provides the large SA in the GE system
Alveoli + capillaries
What maintains a steep conc gradient in GE system?
Blood circulation + breathing
What provides short dif pathway in GE system?
Alveoli + capillary walls = 1 cell thick
Define breathing and respiration
Respiration = the process, which occurs in mitochondria , that releases energy stored in organic molecules( food) such as glucose. energy released during respiration is used to synthesise molecules of ATP, which can be used as an immediate source of energy.
Breathing = the process of inhaling oxygen and exhaling carbon dioxide
Draw and Label an amino acid into the 3 groups
Carboxyl group = COOH
amine group = NH2
Variable group = R
+ oxygen
What is the reaction that causes 2 amino acids to join and what to they create. Draw and name the product of the reaction
Use notes to mark drawing .
Condensation reaction
Dipeptide + water
Summarise diffusion
Diffusion is the net movement of particles form a high a lower concentration. Molecules with diffuse both ways but the net movement will be to the area of lower concentration until particles are evenly distributed throughout the liquid or gas.
the concentration gradient is the path from an area of high concentration to an area of lower concentration. Particles diffuse down this.
Diffusion is a passive process- no energy needed for it to happen
How are gas exchange surfaces adapted for efficient diffusion?
Most gas exchange surfaces have to things in common:
- they give gas exchange organs (like the lungs)a large SA:VOL ratio
- they’re thin (often just one layer of epithelial cells). This provides a short diffusion pathway across the gas exchange surface.
The organism also maintains a steep concentration gradient of gases across the exchange surface
Explain surface area to volume ratios & how to calculate them.
-large objects have smaller SA:VOL ratios than small objects
-the smaller the SA:VOL ratio the slower the rate of exchange e.g a substance would diffuse more slowly out of a bigger cube than a smaller cube
SA equation = n x n x 6
Vol equation = n x n x n
Then put both answers into a ratio
How are the lungs adapted for efficient gaseous exchange?
In mammals the gas exchange surface is the alveolar epithelium in the lungs:
- oxygen diffuses out of the alveoli across the alveolar epithelium (layer of thin flat cells) and the capillary endothelium ( a type of epithelium that forms the capillary wall) and into the blood
The mammalian lungs have the following features which all help to + rate of gaseous exchange.
1) Having lots of alveoli means there is a large surface area for diffusion to occur across.
2) The alveolar epithelium and capillary endothelium are each only one cell thick, giving a short diffusion pathway.
3) All the alveoli have a good blood supply from capillaries - they constantly take away oxygen and bring more carbon dioxide, maintaining the concentration gradient.
4) Breathing in and out refreshes the air in the alveoli, keeping the concentration gradients high.
What are the different forms of amino acids?
1) The monomers of proteins are amino acids.
2) A dipeptide is formed when two amino acids join together.
3) A polypeptide is formed when more than two amino acids join together.
4) Proteins are made up of one or more polypeptides.
How are polypeptides formed?(explain and show diagram)
Amino acids are linked together by condensation reactions to form polypeptides.
A molecule of water is released during the reaction. The bonds formed between amino acids are called peptide bonds. The reverse reaction happens during digestion.
Explain the 4 structural levels of proteins
Primary Structure - this is the sequence of amino acids in the polypeptide chain.
Secondary Structure - the polypeptide chain doesn’t remain flat and straight.
Hydrogen bonds form between the amino acids in the chain.
This makes it automatically coil into an alpha (a) helix or fold into a beta (B) pleated sheet - this is the secondary structure.
Tertiary Structure - the coiled or folded chain of amino acids is often coiled and folded further. More bonds form between different parts of the polypeptide chain, including hydrogen bonds and ionic bonds (see next page).
Disulfide bonds can also form (see next page). For proteins made from a single polypeptide chain, the tertiary structure forms their final 3D structure.
Quaternary Structure - some proteins are made of several different polypeptide chains held together by bonds. The quaternary structure is the way these polypeptide chains are assembled together. For proteins made from more than one polypeptide chain (e.g. haemoglobin, insulin, collagen), the quaternary structure is the protein’s final 3D structure.
What are the different bonds that hold the 4 structural levels of proteins together?
1) Primary structure - held together by the peptide bonds between amino acids
2) Secondary structure - held together by hydrogen bonds.
positively-charged hydrogen
3) Tertiary structure - this is affected by a few different kinds of bonds:
• lonic bonds. These are attractions between negative and positive charges on different parts of the molecule.
Disulfide bonds. Whenever two molecules of the amino acid cysteine come close together, the sulfur atom in one cysteine bonds to the sulfur in the other cysteine, forming a disulfide bond.
Hydrophobic and hydrophilic interactions. When hydrophobic (water-repelling) groups are close together in the protein, they tend to clump together. This means that hydrophilic (water-attracting) groups are more likely to be pushed to the outside, which affects how the protein folds up into its final structure.
• Hydrogen bonds.
4)Quaternary structure - this tends to be determined by the tertiary structure of the individual polypeptide chains being bonded together. Because of this, it can be influenced by all the bonds mentioned above.
