biology

• what is the dna in the nucleus tightly wrapped with to make what ?

  the dna is tightly wrapped with the protein histones together forming - chromosomes
• in eukaryotic cells , what is the DNA contained in ?

  in a membrane bounded nucleus
• what is the cell wall of a plant cell and a fungal cell made out of ?


  plant cell - polysaccharide cellouse fungal cell - polysaccharide chitin
• what are the stuctures in a bacteria cell ?

  single loop dna ( nucleoid ) plasmids slime capsule pilli lipid droplets glygocen granules peptidoglycan cell wall ribsomes flagellum cytoplasm
• what is the function of the slime capsule ?


  it protects the bacteria from being engulfed + destoyed by white blood cells ( phagocytis ) - protective slimy layer ( which helps the cell to retain moisture and to adhere ( meaning to hold/stick fast onto) surfaces
• what are the functions of lipid droplets and glycocen granules ?


  they act as nutrient stores for the bacterial cell
• what is the function of pilli ?

  they are fine protein strands on the surface which allows the bacterial cell to attach to surfaces and also to attatch to other bacteria e.g transferring DNA to another
• how is peptidoglycan formed ?

  by peptide and polysaccharide molecules ( peptidoglycan is what the cell wall is made of )
• what are created by bacteria cells when viewing the cell with an electron microscope ?

  infoldings called mesosmes ( they are created when bacterial cells are prepared for electron microscopy )
• what is the function of golgi apparatus ?

  - it procceses and packages proteins and lipids - it also produces lysosme
• what does chromatin consists of ?

  DNA coiled around proteins called histones
• where is ribosomal rna produced ?

  in the nucleolous
• what material does the nucleus contain ?

  nucleoplasm ( contains molecules such as nucleotides and enzymes ) which are needed for dna + rna synthesis
• what is the double membrane surrounding the nucleus called ?

  nuclear envelope
• what does the nuclear envelope consist of ?

  2 phospolipid bilayers ( lipid bilayers )
• what are the function of nuclear pores ?

  they allow molecules to enter and leave the nucleus
• what is the outer layer of the nucleus surrounded with ?

  continous with the rough endoplasmic reticulum
• what does the chromatin consists of ?

  DNA coiled around proteins called histones
• what is it meant that the DNA in a chromoome is a linear molecule ?

  meaning that the ends of the DNA loop are not joined together to form a loop
• when is the chromosomes visible inside the nucleus ?


  only when the cell is undergoing meosis or mitosis
• this is a nucleus ,what is the darker region called ? and what is its function..


  nucleolus ( it is where R RNA is made - ribosomal rna ) and where ribsome subunits are assembled
• what does the rough endoplasmic reticulum consists of ?

  sheets of membranes forming flattened sacs = this is called cisternae ( sisternee )
• what does the cisternae contain ?

  the cisternae contains range of different enzymes
• where are ribsomes made ?

  in the nucleolous
• what are the membranes of cisternae covered with ?

  they are covered with ribsomes
• in the lumen of the rough er what are the chains of amino acid ( polypeptide ) able to do ?

  to folds in its teriatary structure and is then packaged in vesciles to the GOLGI APPARATUS
• what is the job of the smooth endoplasmic reticulum ?

  is to make and to store both lipids and carbohydrates
• what is the main function of the golgi apparatus ?

  proceses + packages proteins and lipids produces lysosomes too
• what are the 2 key features of lysosomes ?

  1. contains hydrolytic enzymes ( digestive enzymes ) it contains powerful digestive enzymes such as ' protease ' digests large molecule into small soluble molecules 2. it has a acidic interior ( in its internal fluid ) since the lysosomal enzymes have a optimual PH of acidic
• how does lysosmes play a key role in phagocytosis ?

  the white blood cells forms a vacoule surrounding the bacteria , the vacoule is called 'phagosome' the lysosme fuses with the phagosome and digests the bacteria
• how does lysosmes play a role in destroying oragnelles which are destroyed and not functioning ?

  cell froms a vacoule around the 'damaged' organelle lysosomes fuses with the vacoule membrane and digest the organelle and realease the digestive product into the cytoplasm where it is absorbed and it can be reused to make new organelles
• how does lysosmes play a role in digesting to remove unwanted proteins and dead cells outside the cell ?

  by excoctysis ( transfers/ secrete their enzymes ) OUTSIDE OF THE CELL
• what is cohesion ?

  its is when water molecules stick together
• what does cohesion allow ?

  - allows long columns of water to travel in the xylem - cohesion causes surface tension ( its allows the surface of the water to act as a habitat )
• give 3 different types of monnosaccharides ( single sugar molecule )

  galactose glucose fructose
• why are monosaccharides soluble in water ?

  because they contain hydroxl groups which can form hydrogen bonds with water molecules so they are soluble in water
• what are the OH groups called ?

  hydroxl group
• what are glucose containing 5 carbon atom

  pentose monosaccharide
• what is exactly a glycosidic bond ?

  when two isomers of glucose ( alpha ) react together to form maltose. a small molecule is lost ( water ) then we are left with 1-4 glycosidic bonds
• how can we break a glycosidic bond ?

  by adding water