2017 Paper Flashcards
Difference between cellulose and glycogen
Cellulose is made from beta glucose monomer/glycogen is made from alpha glucose
Glycogen is heavily branched/cellulose forms long straight chains that contain microfibrils to provide strength
Why glycogen is a good storage molecule
Helical
Compact
Branched
Insoluble
Large
Glycogen- alpha glucose with 1-4/1-6 so heavily branched
Readily hydrolyse the glycosidic bonds to give off energy and to produce ATP following aerobic respiration
How mRNA is formed in plants
Helicase breaks hydrogen bonds and separated strands
Strands act as templates
Free flowing nucleotides join exposed bases by complementary base pairing
Catalysed by polymerase
Splicing occurs to remove introns and allow Exxon’s to join together
How is an s shaped curve formed
Binding of first oxygen molecule changes shape and makes it easier for other o2 molecules to bind
Advantage of having adult haemoglobin
Lower affinity, so more oxygen unloaded at repairing tissue so greater respiration
Why antibody is specific
Specific base sequence so specific primary structure
Particular hydrogen-ionic bonds so specific tertiary structure
Binding site only complementary to antigen to form antigen-antibody complex
Cohesion tension theory
Water evaporates from mesophyll cells by transpiration
This lowers water potential
Water enters by xylem
Creates tension
Water is cohesive so dorms a continuous column
Water is pulled upwards from roots to the stem
What is non-disjunction
Failure of separation of chromosomes in meiosis meaning one cell has an extra copy and one is missing one-can lead to e.g. downs and turner respectively
What two adaptations does the cell membrane in the uterine lining have that makes it efficient for nutrient transport
Many protein carriers
Thin membrane
Explain the action of the na/k pump
Both bind to desperate areas, ATP hydrolysis used to change protein shape to move na+ against gradient and k+ out
Increased salt results in tissue fluid build up, explain why?
Salt moves out bc there is a lower wp in tissue fluids, so cannot re-enter, lymphatic system cannot completely drain excess fluid
Describe and explain the advantage of secreting extra cellular proteins
Allows faster breakdown of organic matter to release nitrates
Describe the action of membrane bound dipeptidases and explain the advantage.
Hydrolyse the peptide bind between two amino acids in dipeptide, allows for reabsorption of AA
Describe how bacteria divide
Binary fission, organelles, plasmid and genetic material replicated and then grows and splits
Explain how bacterial resistance arises through natural selection and why two antibiotics should be used
Two should be used as likelihood of being resistant to both is low
