GCSE biology.

• the 2 types of reproduction are asexual and sexual
• which type of reproduction has a genetically identical offspring?

  asexual
• what does genetically identical mean?

  Having the same genetic make-up. They're usually called clones
• How is a dominant allele represented?

  Capital letter
• How is a recessive allele represented?


  Lowercase letter
• What does Homozygous mean?


  Having two identical alleles for a particular gene.
• What does Heterozygous mean?

  Having two different alleles for a particular gene.
• What is the role of the erector muscle?


  This muscle contracts to raise the hair when cold and relaxes to lower the hair when hot.
• what is the role of the blood capillaries?

  The flow of blood through the capillaries can be changed to help heat loss from the skin
• What is the role of the hair?

  Hair can insulate by trapping a layer of warm air
• what is the role of the sweat pore?

  sweat is released onto the skin through the pore, sweat is evaporated by body temperature, cooling the skin and the body.
• what is the role of the sweat gland?

  removes water and salt from blood, producing sweat.
• What is diabetes?


  Diabetes is a condition where the level of glucose in the blood cannot be controlled.
• What is type 1 diabetes?

  Type 1 diabetes is a chronic autoimmune disease in which the immune system mistakenly attacks and destroys the insulin-producing cells in the pancreas, resulting in a lack of insulin production.
• What is type 2 diabetes?


  Type 2 diabetes is a chronic condition characterized by high blood sugar levels resulting from the body's inability to properly use insulin or produce enough insulin.
• what does homeostasis mean?

  keeping the internal environment constant.
• What are 4 examples of conditions inside the body that need to be kept stable?

  • water content
  • waste chemicals
  • body temperature
  • glucose levels
• what Is insulin?


  insulin is a hormone that controls blood glucose levels.
• what does the choroid do?

  A pigmented layer which absorbs light to prevent reflection also contains blood vessels.
• what does the retina do?

  The retina is responsible for detecting and converting light into electrical signals that are sent to the brain for visual processing.
• what does the pupil do?

  The pupil regulates the amount of light entering the eye.
• what does the optic nerve do?

  Transmits visual information from the eye to the brain.
• what does the iris do?

  Controls the size of the pupil and regulates the amount of light entering the eye.
• what is the order of reflex actions?

  1. Stimulus 2. Receptor 3. Sensory neuron 4. Spinal cord 5. Motor neuron 6. Effector
• what is the co ordinator?

  always either the brain or the spinal cord
• what is the effector?


  always either a muscle or gland
• what makes up the central nervous system?

  brain and spinal cord
• what is a stimulus?

  A stimulus is a signal or event that triggers a response in an organism.
• What are reflex actions properties?


  protective, automatic and fast
• how many pairs of chromosomes do humans have?

  23
• Which part of a cell contains genetic information?

  the nucleus
• which chromosome pair contains the sex chromesome?

  Chromosome pair 23.
• what are genes and how are they arraned?

  Each bit of information in a chromosome is a gene, genes are arranges in a row along a chromesome
• what does variation mean?

  variation is the difference between individuals of the same species.
• what is variation the result of?

  genetic information and the environment
• what are the 2 types of variation? and how are they controlled?

  • continuous variation= controlled by more than one set of genes.
  • discontinuous variation= controlled by one set go genes
• what happens when genetically modifying crops?

  transferring genes artificially from one species to another
• what chromosomes does the father carry?

  X and Y
• what chromosomes does the mother carry?

  X and X
• how many sex chromosomes in each sperm/egg?

  One.