Biology Summer examination weaknesses

test for lipids

shake sample with ethanol then water

white emulation is formed

what is the evidence that the cell is undergoing mitosis? how would these chromosomes be arranged if the cell was under going miosis

what is a homogenous pair of chromosomes ?

the individual chromosomes would be visible because they have condensed

Each chromosome is made up of two chromatids because DNA has replicated

the chromosomes are not arranged in homologous pairs, which they would be in meiosis

One chromosome of each homologous pair comes from the mother (called a maternal chromosome) and one comes from the father (paternal chromosome).

state ways in which the arrangement of DNA is different between prokaryotes and eukaryotes

prokaryote DNA is circular

prokaryote is not associated with histones/ proteins

prokaryote DNA is only one molecule

Explain how the binding of the first molecule of oxygen to haemoglobin makes it easier for the second molecule of oxygen to bind

  1. binding of first oxygen changes quaternary structure of haemoglobin
  1. creates second binding site for oxygen - uncovering another heam group to bind to

however the fourth heam group is harder to bind to as the oxygen struggles to find it more

protein synthesis

transcription

translation

  1. mRNA attaches to the ribosome
  1. the enzyme DNA helicase breaks hydrogen bonds therefore separating the DNA strands
  1. this means the bases on the DNA are exposed
  1. a strand of RNA then forms, called messenger RNA this is catalysed by the enzyme RNA polymerase
  1. RNA nucliotides come along and complementary base pair with the bases on the DNA template strand
  1. tRNA in the cytoplasm picks up its specific amino acid. energy is needed for this. the energy is provided by ATP
  1. tRNA carries its amino acid to the mRNA on the ribosome
  1. complementary base pairings occurs between the anticodon on the tRNA and codon on the mRNA
  1. peptide bonds form between amino acids brought by the the tRNA molecules then a peptide chain is formed

formation of tissue fluid

high hydrostatic pressure of blood at the arteriole end causes fluid to leave the capillary wall this fluid is called tissue fluid, overall fluid forced out by ULTRAFILTRATION

low hydrostatic pressure of blood at, venule end of the capillary so tissue fluid is forced back into capillaries lots of water also enters the capillaries by osmosis due to a low water potential in the blood, overall tissue fluid is pushed back in by reabsorption