Past paper 4 biology

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Created by
alexis

Cards (20)

  • 1 a (I) Loop of Henle (Collecting Duct)
    (II) Antidiuretic Hormone / ADH; Vasopressin
    (iii) 1 - As the RMT increases the concentration of urine increases ( positive correlation )
    2 - Two pairs of comparative figures example: RMT of a beaver is 1.4 and the urine concentration is 0.90 while the kangaroo rat‘s RMT is 8.6 and the urine concentration is 10.50.
    3- There is little water available for the kangaroo rat
    4- so the Loop of Henley is longer
    5 - so more reabsorption of water occurs
    6 - so the urine of the kangaroo rat is more concentrated ( small volume of urine )
  • 1 (b) 1 - Metabolic Water reference
    2 - It obtains water through the ( named ) food it eats
  • Similarities between photoactivation of chlorophyll in cyclic and non-cyclic photosynthesis
    • Photoactivation of chlorophyll occurs in both (excite electrons)
    • Electron transport chain involved in both (ETC)
    • ATP produced in both
  • Differences between cyclic and non-cyclic photosynthesis
    • Only PSI involved in cyclic, both PSI and PSII involved in non-cyclic
    • Reduced NADP and oxygen produced in non-cyclic
    • Photolysis or oxygen-evolving complex involved in non-cyclic
    • Electrons emitted from PSII replaced by water in non-cyclic (water is source of electrons), electrons emitted from PSI returned to PSI in cyclic (PS1 is source of electrons).
  • Characteristics of cyclic photosynthesis
    • No ATP and reduced NADP made
    • No GP/TP made (no Calvin cycle/light-independent reaction)
    • No regeneration of RuBP
  • Genetic engineering using a plasmid | Gene editing
    1. Applies | Applies
    2. Doesn't | Applies
    3. Doesn’t | Applies
    4. Doesn’t | Applies
    5. Applies | Doesn’t
  • Parents Genotype : ( AaBb x AaBb )
    Parents Phenotype : brown brown
    gametes : AB Ab aB x AB Ab aB ab
    | AB | Ab | aB | ab
    AB | AABB | AABb | AaBB | AaBb
    Ab | AABb | AAbb | AaBb | Aabb
    aB | AaBB | AaBb | aaBB | aaBb
    ab | AaBb | Aabb | aaBb |aabb
    offspring phenotypes linked to genotypes
    ratio - 9 brown : 3 black : 4 white
  • Homeostatis in mammals is the process of keeping the internal enviroment of the body an optimum conditions so that cells can function efficiently. Blood water potential, core temperature and blood glucose concentration are all factors that need to be kept at optimum values or set-point.
  • When a condition deviates from its set-point, a corrective mechanism is triggered. An increase in blood glucose concentration triggers processes to decrease it and vice versa. This corrective mechanism is called negative feedback.
  • The pancreas is involved in the control of blood glucose concentration. Glucose binds to receptors on the cell surface membrane of pancreatic cells. These are endocrine (islets of Langerhans/alpha and beta) cells, which secrete hormones such as insulin and glucagon. The two hormones have opposite effects on the blood glucose concentration. For example the action of one hormone stimulates the uptake of glucose by cells for respiration and the action of the other hormone stimulates the breakdown of glycogen to glucose in the liver.
    1. Mating/IVF
    2- removing embryo from mated or artificially inseminated female
    3- selecting the best embryos
    4- may freeze embryos for later storage
    5- implanting embryos in a different females uterus
    6- ref to surrogate mother
    1. add DNA to give a new (named) characteristic/protien
    2. Restriction enzyme endonuclease to obtain a section of DNA
    3. Combine with a vector
    4. Introduce recombinant vector to bacterium
    5. Clone (named) host cell
    1. Evolution
    2. Spontaneous Mutations
    3. Population become morphologically/physiologically different
    4. Less competition in new niche
    5. Adapting some plants to the high altitude allowed them to survive
    6. Change in the gene pool of the populaion
  • Outline how an action potential arriving at this neuromuscular junction can result in depolarization of the sacrolemma :
    1. Ca2+ channels open in the presynaptic membrane
    2. Ca2+ enters the pre synaptic neurons
    3. Vesicle which contain acetyl choline
    4. Continuation of 3: fuse with presynaptic membrane
    5. Acetyl choline (Ach) is released by exocytosis and diffuses across the synaptic cleft
    6. Binds to receptors on the sacrolemma (motor way -muscle cell membrane-)
    7. Na+ channels open and Na+ enters the muscle fiber/sarcoplasm
  • Show the correct order of events:
    S
    V
    Q
    U
    Z
    Y
    W
    R
    X
    T
  • Name region P and Q
    P - Z line ( Z to Z is sacromere and sacromere shortens ) ( also the H zone and I band decrease )
    Q - A band
  • Describe the role of calcium ions (Ca2+ ions) in the shortening of a sacromere:
    1. Ca2+ ions from the Sacroplasmic reticulum bind to troponin.
    2. Troponin changes shape and moves
    3. This exposes the myosin binding site on ACTIN molecules
    4. Myosin head binds to actin
    5. Myosin head tilts and Actin is pulled
  • A motor end plate of a neuromuscular junction is part of a modified cholinergic synapse.
    Explain why mitochondria are present in the motor end plate of a neuromuscular junction:
    • Mitochondria produces ATP
    • And ATP is needed for: synthesis of acetylcholine; exocytosis; transport of Ca2+ ions out of the presynaptic membrane; synthesis of acetylcholinestesase
  • State two factors other than natural selection that could drive changes in populations
    1. Genetic Drift
    2. migration
    3. mutation
  • State two examples of crop features that may be improved by selective breeding to increase yield of crops
    1. Rate of growth
    2. Resistance to disease
    3. resistance to herbicides
    4. mass