biology

• Why is cell division important?

  In order for growth and repair to take place in multi cellular organisms
• What is cell division called

  mitosis
• Why do new cells have the exact same structure as the parent cell from cell division

  This ensures that no genetic information is lost so that the cell can function properly
• Diploid means


  two sets of chromosomes
• Haploid means


  1 set of chromosomes
• Describe the stages of mitosis

  1 Each chromosome makes an identical copy of itself

  2 Chromosomes line up at the equator of the cell

  3 Spindle fibers pull each chromosome to opposite ends of the cells (poles)

  4 Nuclear membranes form around each set of chromosomes

  5 the cytoplasm divides and 2 separate diploid cells are formed
• What is the function of red blood cells and how has it adapted to its function

  Function : to carry oxygen around the body for use in respiration

  
  

  Adaptations; contains haemoglobin which combines with the oxygen, doesn't not have a nucleus and is bioncave in shape to maximise the area available in the cell to carry oxygen.
• What is the function of nerve (neurons) cells and how has it adapted to its function

  Function; to carry messages around the body in the form of electrical impulses

  
  

  Adaptations;they have long extensions to allow them to send information over long distances
• Function and adaptations of egg cells

  Functions; to fuse with sperm during fertilisation and divide into an embryo

  
  

  Adaptations; egg cells contain a large amount of food to provide the energy required to develop in the early stages
• Functions and adaptations of sperm cells

  Functions; to swim through the female reproductive system to fertilise an egg in the oviduct

  
  

  Adaptations; are streamline in shape and have a tail to swim to the egg, they also have lots of mitochondria to priories the energy required to complete this journey
• What is a tissue?

  A group of cells that are specialised to perform a particular function. They can be made up of one type of cell or different types of cells. Muscle cells for, muscle tissue.
• What are organs?


  Organs are groups of tissues that work together to perform the same functions
• What tissues does the heart contain

  Nerve and muscle tissues
• What is a system?

  Different organs work in together such as the digestive system and the respiratory system. They are all in the same organism.
• What are stem cells?


  Unspecialised cells that are used in growth and repair,

  They can reproduce themselves by mitosis without becoming specialised,

  They can also develop into specialised cells to replace those that have been lost or damaged
• Why is the nervous system important?

  To communicate information around the body to ensure that all systems are working effectively
• What is the nervous system made out of

  The brain , spinal cord , nerves
• What is the central nervous system made out of

  brain and spinal cord
• The nerves are part of the peripheral nervous system, what do they connect


  They lead to and from all organs and system
• Medulla


  controls heartbeat and breathing rate
• Cerebrum


  Largest part of the brain; responsible for voluntary muscular activity, vision, speech, taste, hearing, thought, and memory. Controls higher order functions
• Cerebellum


  Controls Balance and coordination
• Describe the spinal cord and information flow

  Sensory nerves carry information from the body's receptors ( sense organs) to the cns and then motor nerves carry information to the bodys effectors ( muscles)
• Nerve cells called neurons make up the ... and a neuron consists of ....

  Make up the nervous system , neurons consist of a cell body attached to nerve fibres
• When does a reflex response occur

  When a stimulus indicates that an organism may be in danger of harm. The brain is not involved in this response and as a result this response is involuntary and fast
• Describe the process of when a sense organ detects a potentially harmful stimulus

  A sense organ detects a potentially harmful stimulus then the sensory neurons passes this information to a relay neurone in the spinal cord , the relay neurone passes this information onto a motor neurone and this causes a response in an effector (usually a muscle)
• What are the gaps between neurones called

  synapses
• What happens when an electrical impulse reaches the end of a neurone

  It stimulates the release of a chemical . This chemical,kcal diffuses across the gap between; the two neurones. When the chemical reaches the second neuron it stimulates a new electrical impulse which then travels along this neuron.
• What are hormones?


  Chemical messages that send information around the body to organs in the bloodstream. Hormones are produced by endocrine glands
• What are target tissues

  Tissues which have cells with specific receptor protiens on their surface. On,y tissues with receptors proteins for a specific hormone will be affected by it
• Why is it important that the levels of glucose are maintained within certain limits

  If there isn't enough glucose in our body then our cells won't be able to respire (respiration ) efficiently. If there is too much glucose in the blood our body may lose water by osmosis
• The hormones that contol glucose blood levels are

  Insulin and glucagon and these are produced by the pancreas
• How much glucose does your liver store and in what form. What is glycogen made up of


  About 100g of glucose in the form of glycogen. Glycogen is made up of chains of glucose and this store can be added to or removed from depending on your body's needs
• What happens when your blood glucose gets too high

  When your blood glucose gets to high ( e.g after a big meal ) cells within the pancreas are stimulated to produce insulin and this is transported in the bloodstream to the liver. This lowers blood glucose levels back within normal levels . The following catalyses reaction happens glucose > glycogen
• What happens when the blood glucose get too low (e.g during the night)

  Different cells within the pancreas are stimulated to produce glucagon , this is transported to the liver where the opposite reaction happens glycogen > glucose this raise blood glucose level back in normal levels
• How do animals reproduce?

  By sexual reproduction, involves the genetic material from two individuals ( parents) combining to produce offspring spring during fertilisation. At this point two haploid sex cells fuse together to form a diploid cell called the zygote. The zygote will divide many times and develop into an embryo
• What is the male sex cell and what organ is it produced in

  Sperm , produced in testes
• Describe the structure of a sperm cell


  Have a small head containing their genetic information and a long gail specialised for their function, swimming to the egg
• What is the female sex cell and what organ is it produced in

  Egg , produced in ovaries
• Describe the structure of an egg cell

  Egg cells are much bigger in size than sperm cells so they are easy to locate. They contain a large yolk to provide energy once an embryo is born