Breadth paper notes Flashcards
Role of epithelial cells
Epithelial cells - specialised for efficient food absorption - group together to form epithelial tissue in the small intestine
Role of goblet cells
Goblet cells - secrets mucus which trap pathogens
Purine bases
Purine bases: Adenine + Guanine
-Double ring structure
Pyrimidine bases
Pyrimidine bases: Thymine + Cytosine
-Single ring structure
Phosphorylation
Phosphorylation involves the addition of phosphate to an organic compound
Why do plants require specialised transport tissue?
Plants require a specialised transport tissue to overcome limitations of diffusion over large distances
When will a compound not be able to form hydrogen bonds?
Compounds with not OH group will not be able to form hydrogen bonds
What does non-overlapping and degenerate refer to for DNA?
-Non-overlapping: each nucleotide is only part of one triplet of bases
-Degenerate: more than one triplet codes for a specific amino acid
Where are endothelial cells found?
Endothelial cells are found in the lining of arteries, veins and capillaries
The role of cholesterol in cell surface membranes
Cholesterol binds to phospholipid fatty-acid tails, increasing the packing of the membrane, therefore reducing the fluidity of the membrane to make it less permeable/selectively permeable
-Cholesterol is temperature dependant = increasing temp decreases phospholipid mobility
Where is cholesterol found in cell surface membranes?
Cholesterol is found in the spaces among the hydrophobic tails of phospholipids in the lipid bilayer
Coenzymes
Coenzymes:
-Vitamin derived
-Organic cofactors
-Faciliates the binding of susbtrate to an enzyme
-Needed to allow the function of the enzyme
Why are plant root tips, eg onions, used to view cells undergoing mitosis?
Root tips are used to observe cells undergoing mitosis because:
-Site of cell division - meristematic tissue
-No chlorophyll or chloroplasts present
Stain used to highlight nuclei of cells
Methylene blue is a stain used to highlight nuclei of cells
Why do mammals store glycogen instead of glucose
Mammals store glycogen instead of glucose because:
–Glycogen is made up of branched alpha glucose molecules with 1,6 glycosidic bonds -> broken down fast for rapid release of glucose
-Insoluble - no effect on water potential
-Metabolically inacitve
-Stores lots of energy
Types of vesicles used by RER, types of vesicles used by Golgi
-RER: packages molecules into transport vesicles
-Golgi: packages molecules into secretory vesicles
How does the fluid mosaic model describe the structure of plasma membranes?
Fluid mosaic model:
-Phospholipids in the bilayer are free to move around eachother
-Hydrophobic tails face inwards, hydrophillic heads face outwards
-Proteins scattered/randomly arranged
Aquaporins
Aquaporins: Aquaporins are the water transporters. The diffusion of water across biological membranes is facilitated by special channel proteins called aquaporins. Aquaporins are designed to have hydrophilic pores which allow water molecules to move through them