Challenge Biology 1 Questions expected in the Exam and their solutions. Revised and Verified

Describe one way in which a polypeptide could be modified - AnsCut and combine polypeptide chains explain why cells need to carry out DNA Replication - Ans so that an exact copy of the DNA is passed onto daughter cells After a stem cell differentiates, only certain genes are expressed. Explain how this results in different cell types. - AnsOnly proteins characteristic of that cell type is synthesized apart from being absorbed or reflected what can happen to light that strikes a leaf? - Anstransmitted through leaf pigments that absorb light are found within the leaf cells state the exact location of these pigments - Ansgrana of chloroplast give the sequence of bases that code for an amino acid with anticodon UUA - AnsTTA state the importance of isolating mechanisms in the evolution of new species - Anssplits the gene pool and prevents mixing of gene pool state two ways in which species can be conserved - Ans- Wildlife/Nature reserves - captive breeding explain how a mutation of a gene can cause the production of an altered enzyme (PROTEIN!) - Anschanges order/sequence of bases and nucleotides in a gene leading to a change in order of amino acids which order of amino acids determines the shape, function and overall structure of the protein/enzyme and if this is changed this will result in an altered enzyme. What is the function of NAD in glycolysis - AnsNAD accepts hydrogen which produces NADH and is transferred to electron transport chain State 3 examples of post translation modifications - Ans1. cutting and combining polypeptide chains 2. adding carbohydrates to protein chain 3. adding phosphates to the protein chain in the small compartments of the cell membrane is there a high or low concentration of substrate inside - Anshigh during anabolic reactions is energy taken up or released - Anstaken up at which point in the culture of microorganisms are most enzymes being induced to metabolise available substrates - Anslag phase what are the adaptations of perennial weeds - Ansthey have storage organs and vegetative reproduction what can be sprayed onto a lawn to remove dandelions - Ansselective herbicide describe the effects of altruistic behaviour on the donor and recipient - Ansharms the donor but benefits the recipient why do worker honeybees from the same colony cooperate - Ansthey are closely related describe the function of RNA polymerase in the synthesis of the primary transcript - AnsUnwinds the double helix and adds RNA nucleotides to produce the primary transcript Explain why actinomycin D would not be suitable in the treatment of bacterial infections in humans. - AnsActinomycin D would inhibit transcription and therefore no proteins can be produced State the role of primers in DNA replication during PCR and explain why two different primers are needed. - AnsAllows a starting point for replication and polymerase and each primer targets on a different strand State one advantage of using protein produced by genetically modified micro-organisms to treat human disease. - AnsUnlimited supply produced and no infec