B1 Core revision Session 1 We are going to concentrate on the key knowledge needed for the exam

Answers to Q1 Kingdom Characteristics Animalia multicellular, no cell walls, no chlorophyll, feed heterotrophically Plantae multicellular, have cell walls, have chlorophyll, feed autotrophically Fungi multicellular, have cell walls, no chlorophyll, feed saprophytically Protoctista unicellular, have a nucleus Prokaryota unicellular, have no nucleus I will print this page as a card sort for my starter.

The next 3 questions will take 3min Why are viruses not classified in a kingdom? - Viruses are not living - Viruses do not show the characteristics of life such as growth and feeding What does Chordata mean? - Animal with a supporting rod running the length of its body. What are vertebrates? - Animals with a backbone.

Exam Question (2 marks)

Exam Question (1 mark)

What reasons could cause an animal to become extinct? It says reasons so more than one Predation, disease, competition for resources, environmental change

What reasons could cause an animal to become extinct? Predators killing them Disease Change in environmental conditions e.g snow Loss of food source Increased competition Limited adaptations Unable to reproduce

Exam Question (3 marks)

You get lots of these types of questions Cave Bears have the bimominal name Ursus spelaeus.

You get lots of these types of questions. Taraxacum officinale Russula silivcola. Panthera tigris.

What does geographic isolation mean? When animals are separated from the rest of their group, usually by accident so they can’t all interbreed anymore. E.g an earthquake The two groups will evolve different characteristics to survive

Nervous system What are the three type of neurone? - sensory - relay - motor What is a stimulus? - A change in environment What is an effector? -The organ that carries out the response e.g the muscle that moves

How does information travel along a sensory neurone?

Answers From the receptor To the brain/spinal cord As an electrical impulse

What is the role of the myelin sheath? Insulates (only write insulates – any other word will not get the mark)… The axon and speeds up the impulse

Describe the pathway of a nerve impulse through a reflex arc. Receptor cells detect a stimulus Sensory neurone sends a message to the spinal cord. The message travels from the spinal cord to a relay neurone then to the motor neurone. There is a response in the effector.

Neurons and Synapses Information travels as an electrical impulse along a neuron. The gaps between neurons are called synapses.

Plant growth Hormones What is a seedling? Which way should shoots grow? Which way should roots grow? What is positive gravitropism? What is positive phototropism?

Answers When a shoot emerges from the top of a seed and begins to grow. Upwards towards light Downwards towards gravity Growing towards (positive) gravity Growing towards (positive) light

How shoots grow towards light AUXIN moves to the shaded side Causes cell elongation Shoot bends towards light.

How roots grow towards gravity AUXIN moves to the underside of the root. It Inhibits the elongation of cells on the underside of the root. Cells on the upper side continue to elongate. Root bends downwards. (Inhibits means: to slow down or try to stop)

Exam Question – 3 marks The photograph shows the results of an experiment in which seedlings A, B and C were left to grow for one week. The roots of seedlings A, B and C all began to grow downwards. The seedlings were then rearranged. Seedling A was placed horizontally. Seedling B was placed vertically upwards. Seedling C was left to grow pointing downwards. Explain what happened to the cells in the root of seedling A to cause the change in direction of growth.