Biology paper 1

• Root hair cell - adaption


  Long ejections more surface area for more water

  Meristems for specialised cells
• Reproductive hormones

  Fsh

  Oestrogen

  Lh

  Progesterone
• Roles of reproductive hormones

  Fsh- matures of egg produced in pituitary gland

  Oestrogen - develops thick uterus lining

  Lh- pituitary gland and release of egg

  Progesterone - ovaries and maintain lining of uterus
• Reproductive hormones inhibit and stimulate

  Fsh - stimulates oestrogen

  Oestrogen- stimulates lh but inhibits fsh

  Progesterone - inhibits lh and fsh
• Reflexes


  Stimulus- detects response by receptor

  Receptor- detected change in environment picked up by neurone

  Neurone- sensor carries singal to CNS. Relay send responses the motor neurone - motor is from cns to effector

  Effector - brings about the action

  Response
• Enzymes


  Carbohydrase - carbohydrates to glucose

  Amylase- starch to glucose

  Protease - Proteins to amino acid

  Lipase- fat to glycerol and fatty acids
• Thyroxine negative feedback


  High levels of thyroxine inhibits TSH

  Low levels of tsh inhibts thyroxine
• Diabtets


  Insulin- converts glucose the glycogen

  Glycogen levels fall asleep glucose used

  Glucagon converts glycogen to glucose
• Why is human circulatory system more efficient than lungfish 


  Faster transport if blood more O2 supplied

  Oxygenated and deoxygenated blood in seperate arteries
• Cell differentiation 


  Sten cells becoming specialised
• Describe all stages to test leaves for presence of starch 


  Leaf placed in hot water

  Iodines soltuion- blue / black colour - amalyse to test starch
• Compare glucose and sucrose structures

  Different no of atmos
• Osmosis to explain change in mass against concentration


  Chips get heavier when water moves in

  Water moves out when the water potential inside is greater
• Hypothalamus


  Body temp maintained for optimum work

  Low temp makes reaction slower

  High temp may cause denature of the cell
• how temp affects activity

  potato in hydrogen peroxide solution

  different test tubes in water baths of different temps

  attaxh delivery tube to measuring cyclinder an record how much oxigen has been produced
• how fast a substrate disappears

  amylase breaks starch to maltose

  to test for starch idione should go from brown to bluey

  solutions at different temps

  every 10 seconds drop
• transpiration


  caused bt evaporation and diffusion of water - (at leaves)

  shortage of water so more id drew upwards

  as more water inside the leaf that outside the water escaped through the stomata
• beneftis of transipration

  helps to keep plant cool

  constant supply of water for photosynthesis

  turgor pressure to support the plant and stop it from wilting

  minerals can be brought in with the water
• rate of transpiration

  increase in light intensity they greater the rate - increases rate oh photosynthesis so stomata open more to let co2 in so water can also get out

  increase in temp increase rate as partciles have more kinetic energy so faster diffusion

  increase in air movement- increases rate as water vapour is brushed away fron the outside so less concentrated

  larger surface area ie more leaves increased rate
• hormones

  produced in endocrine glands

  chemical messangers
• thyroxine

  released by thyroid gland

  regulating metabolic rate

  released in response to tsh released by pituitary

  negative feedback keeps the amount right - higher thryoxine inhibits tsh so this then reduces amount of thyroxine