Zellbiologie

• What types of chemical bondings are mentioned in the study material?

  Ionic interactions, hydrogen bonds, van der Waals interactions, and covalent bonds
• Why is carbon considered the element of life?

  Because it forms strong covalent bonds and has structural diversity
• What is the maximum number of atoms that silicium can form in a chain?

  1. 3 atoms in a row
• What are the four major roles of carbohydrates in biology?

  Energy reservoirs, part of nucleic acids, structural building blocks, and modifiers of proteins and lipids

  
• What are the types of polysaccharides mentioned in the study material?

  • Glycogen: Animal storage form of glucose
  • Starch: Plant storage form of glucose
  • Cellulose: Structural polysaccharide in plant cell walls
  • Chitin: Structural polysaccharide in fungi and exoskeletons

  
• What type of glycosidic bonds are primarily found in glycogen?

  Mostly α-1,4 glycosidic bonds

  
• How does amylopectin differ from amylose in starch?

  Amylopectin has α-1,6 glycosidic bonds every ~30 α-1,4 glycosidic bonds

  
• What is the most abundant biopolymer on earth?

  Cellulose
• What is the difference between cellulose and chitin?

  Chitin has an N-acetyl group instead of an OH group

  
• What are glycoproteins and glycolipids?

  Proteins and lipids with one or more sugar units covalently attached

  
• What is glycosylation?

  The process of transferring sugar residues to a lipid or protein
• What are the two types of sugars found in nucleotides?

  β-D-ribose for RNA and β-D-2-deoxyribose for DNA
• What are the five major biologically relevant nitrogenous bases?

  Adenine, guanine, cytosine, thymine, and uracil

  
• What type of bond joins nucleotides in nucleic acids?

  Phosphodiester bonds
• What is the directionality of nucleic acids?

  Nucleic acids have 5' phosphate and 3' hydroxyl ends

  
• What is the primary function of DNA?

  To store hereditary information
• How does RNA differ from DNA?

  RNA has ribose and uracil, while DNA has deoxyribose and thymine
• What are the three major forms of RNA and their functions?

  • Messenger RNA (mRNA): Template for protein biosynthesis
  • Ribosomal RNA (rRNA): Component of ribosomes
  • Transfer RNA (tRNA): Adaptor between mRNA and amino acids

  
• How many proteinogenic amino acids are there?

  20 proteinogenic amino acids
• What is the role of methionine in protein synthesis?

  Methionine is the start amino acid of all proteins during translation
• What is the significance of protein phosphorylation?

  It can lead to a change in protein structure and activity

  
• What is the combinatorial diversity of polypeptides?

  • Dipeptide (2 amino acids): 400 possible combinations
  • Tetrapeptide (4 amino acids): 160,000 possible combinations
  • Typical proteins: 50-500 amino acids
  • Example: 300 amino acids = 10^390 possible combinations
• What is the storage form of fatty acids in cells?

  Triacylglycerols
• What is the structure of phospholipids?

  Phospholipids consist of 2 fatty acids, glycerol, and a modified phosphate

  
• What does it mean for a phospholipid to be amphiphilic?

  It has a hydrophilic head and a hydrophobic tail

  
• How do phospholipids arrange themselves in a bilayer?

  They form two layers with hydrophilic heads facing outward and hydrophobic tails inward

  
• What are the key features of biomembranes?

  • Composed of phospholipid bilayers
  • Separate cell interior from the extracellular environment
  • Allow specific chemical reactions in organelles
  • Exhibit asymmetry and fluidity

  
• What is the uid mosaic model?

  A model that explains features of the plasma membrane
• What are biomembranes composed of?

  (Phospho-)lipid bilayers
• What does the term "lipid bilayer" refer to?

  Two layers of laterally arranged lipids
• What is the function of the plasma membrane?

  It separates the cell interior from the extracellular environment
• What do other versions of biomembranes do?

  They seal the interior of organelles from the cytosol
• What are the two types of lipid arrangements in biomembranes?

  Micelles and bilayers

  
• What determines whether micelles or bilayers are formed?

  The shape of the lipid, such as the number of tails
• What are the two types of proteins found in biomembranes?

  Integral and peripheral membrane proteins

  
• What is the composition of the plasma membrane by weight?

  ~45% lipids, ~45% proteins, ~10% carbohydrates

  
• What do glycolipids comprise in the plasma membrane?

  ~5-10% of the lipids
• Where are glycolipids located in the plasma membrane?

  Only on the outer leaflet
• How do glycolipids and glycoproteins relate to blood groups?

  They determine human blood groups
• What is the significance of asymmetric lipid distribution in the plasma membrane?

  It allows for different functions and interactions on each side