Photosynthesis

content/sixth/Biology/Endocrinology/GeneticEngineeringOfInsulin.md

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+---
+title: Genetic Engineering of Insulin
+tags:
+  - endocrinology
+  - biology
+---
+### Procedure
+
+1) Cut out gene for insulin from DNA
+2) Insert into plasmid to make **recombinant DNA**
+3) Insert into bacteria (*E.coli*)
+4) Bacteria produce insulin
+5) Purify insulin
+
+### Stem Cell Treatment
+
+- Undifferentiated cells that can become any cell type
+- Differentiated cells have genes switched on or off in a sequence
+- Stem cells could be made to turn into β-cells which would respond to high levels of blood glucose by secreting insulin
+
+This treatment is difficult because:
+
+- immune system may reject transplanted β-cells
+- large volumes of β-cells required
+
+![[sixth/Biology/Endocrinology/img/Pasted image 20231130154133.png]]

content/sixth/Biology/Photosynthesis/Photosynthesis.md

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+---
+title: Photosynthesis
+tags:
+  - biology
+  - photosynthesis
+---
+### Bond energy
+
+- The same quantity of energy is involved when a particular bond is being broken or formed.
+- The atoms in small inorganic molecules like water and carbon dioxide are joined by strong bonds, meaning that they require a lot of energy to break and release a lot when they form. 
+- Organic molecules like glucose contain many more bonds; these are weaker by comparison.
+- They release less energy when they form and require less energy to be broken.
+
+### Equation
+
+> [!abstract] -> Representation
+>
+> An -> represents light in this equation
+
+6CO₂ + 6H₂O -> C₆H₁₂O₆+6O₂
+
+### Autotrophs and Heterotrophs
+
+- Autotrophs such as plants can synthesise complex organic molecules such as carohydrates, lipids, proteins, nucleic acids and vitamins from simple inorganic molecules like CO₂ and energy sources.
+- Organisms that can photosynthesise are described as photoautotrophs
+
+### Chemoautotrophs
+
+- Nitrifying bacteria -> get energy from reactions such as oxidising nitrite to nitrate
+- Bacteria living in darkness by thermal ocean vents
+
+### Heterotrophs
+
+- Cannot make their own complex organic molecules from inorganic small molecules like CO₂ and H₂O but feed on and digest complex organic molecules into simpler soluble ones.
+
+### Chloroplasts
+
+- 2-10 µm in length
+- Usually disk shaped (sometimes varying)
+- Surrounded by an envelope or double membrane
+- Outer membrane is permeable to many small ions
+- The inner membrane is less permeable and has embedded in it folded into **llamellae** (thin plates) which are stacked vertically. Each stack is called a **granum**.
+- Between grana are **integranal llamellae**
+
+![[sixth/Biology/Photosynthesis/img/Pasted image 20231130155609.png]]
+
+### Photosynthetic Pigments
+
+- Absorb certain wavelengths of light
+- Funnel-shaped structures called photostems push light to a point
+- Proteins embedded in grana hold photostems in place
+- The fluid-filled stroma contains enzymes needed to catalyse reactions of the light-dependent stage of photosynthesis
+- Many grana, consisting of stacks of 100 **thylakoid membranes** provides a large surface area for the photosynthetic protein.
+- Grana surrounded by stroma so products of the light-dependent reaction (needed for light-independent reaction) can readily pass into stroma.
+- LIR - light independent reaction
+- LDR - light dependent reaction
+- Chloroplasts can make some of their proteins they need for photosynthesis using genetic instructions in chloroplast DNA, and the chloroplast ribosomes assemble the proteins.
+
+- Leaves contain a variety of pigments 
+- Each absorbs a different range of light wavelengths
+- Maximises the amount of sunlight that can be absorbed
+
+![[sixth/Biology/Photosynthesis/img/Pasted image 20231130160223.png]]
+